Tuzo: The Unlikely Revolutionary of Plate Tectonics 9781487534981

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THE UNLIKELY REVOLUTIONARY OF PLATE TECTONICS

Aevo UTP An imprint of University of Toronto Press Toronto Buffalo London utorontopress.com © Nick Eyles 2022 All rights reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of both the copyright owner and the above publisher of this book.

Library and Archives Canada Cataloguing in Publication Title: Tuzo : the unlikely revolutionary of plate tectonics / Nick Eyles. Names: Eyles, Nick, 1952– author. Description: Includes bibliographical references and index. Identifiers: Canadiana (print) 2022026855X | Canadiana (ebook) 20220268606 | ISBN 9781487563608 (cloth) | ISBN 9781487524579 ­(paper) | ISBN 9781487534998 (EPUB) | ISBN 9781487534981 (PDF) Subjects: LCSH: Wilson, J. Tuzo (John Tuzo), 1908–1993. | LCSH: ­Geologists – Canada – Biography. | LCSH: Plate tectonics – History. | LCGFT: Biographies. Classification: LCC QE22.W55 E95 2022 | DDC 551.092–dc23 ISBN 978-1-4875-6360-8 (cloth) ISBN 978-1-4875-2457-9 (paper)

ISBN 978-1-4875-3499-8 (EPUB) ISBN 978-1-4875-3498-1 (PDF)

Printed in Canada We wish to acknowledge the land on which the University of Toronto Press operates. This land is the traditional territory of the Wendat, the Anishnaabeg, the Haudenosaunee, the Métis, and the Mississaugas of the Credit First Nation. University of Toronto Press acknowledges the financial support of the Government of Canada, the Canada Council for the Arts, and the Ontario Arts Council, an agency of the Government of Ontario, for its publishing activities.

Praise for Tuzo: The Unlikely Revolutionary of Plate Tectonics “Jock ‘Tuzo’ Wilson was a Canadian war veteran and distinguished professor who contributed to the revolution in our understanding of planet Earth. Nick Eyles tells the fascinating story of Tuzo, his family, and the intellectual turmoil among earth science scholars in this meticulously researched and beautifully written and illustrated book. It’s a pity that there are no Nobel prizes in earth science, for, if there were, Tuzo would be a Nobel laureate.” John J. Clague, Emeritus Professor, Department of Earth Sciences, Simon Fraser University “This book is a long-overdue account of the life and achievements of one of the giants of earth sciences, J. Tuzo Wilson. It is a compelling and highly readable chronicle of the remarkable events that dramatically changed our understanding of the earth. Nick Eyles effectively combines insights into the science and the people doing the science to create an inspiring narrative of how scientific ideas develop and evolve.” Claire Currie, Professor of Geophysics and director of the Institute for Geophysical Research, University of Alberta “Tuzo Wilson’s development of plate tectonic theory, explaining the movement of continents and the inner workings of our planet, was one of the greatest scientific achievements of the twentieth century. Tuzo is an epic tale of the messy, unpredictable, and very human side of science, but it is also a coming-of-age story involving war, the development of Canada as a nation, and the exploration of northern Canada.” Stephen T. Johnston, Professor of Earth and Atmospheric Sciences, University of Alberta “Adroitly interweaving narratives of a man, a time, and an idea, Nick Eyles recounts the intellectual odyssey of legendary earth scientist J. Tuzo Wilson. Wilson’s journey from defender of geological convention to leading architect of plate tectonics changed forever our understanding of how the earth works. An instructive lesson in science and a personal story to savour.” Andrew H. Knoll, Fisher Research Professor of Natural History, Harvard University, and author of A Brief History of Earth “This book portrays the most famous Canadian geoscientist in the political and ideological atmosphere of the day. Geological disputes and terms are explained using easily understandable language that’s aided by everyday analogies.” Maya G. Kopylova, Professor of Diamond Exploration, University of British Columbia “When he was director of the Ontario Science Centre, I had the privilege to work under Dr. Wilson. Always jovial and willing to share stories of his many adventures around the world, he was most excited to talk about the latest research in earth sciences rather than his own accomplishments. This book is a remarkable testament to the insatiable curiosity and thirst for new knowledge that drove him to become a world-renowned scientist.” Bob McDonald, OC, host of CBC Radio’s Quirks & Quarks “Nick Eyles offers a fascinating look at how long-entrenched scientific orthodoxy gets overturned in this well-written, illuminating biography of a great pioneering scientist, John Tuzo Wilson. An engrossing account that should be widely read.” Dr. Adam Shoalts, national bestselling author of Beyond the Trees and A History of Canada in 10 Maps

Other books by Nick Eyles

Canada Rocks: A Geologic Journey (with A.D. Miall) Canadian Shield: The Rocks That Made Canada Ontario Rocks: 3 Billion Years of Environmental Change Road Rocks Ontario: More than 250 Geologic Wonders to Discover Georgian Bay: Discovering a Unique North American Ecosystem (Edited) Physical Geology and the Environment (with C. Eyles and others) Environmental Geology of Urban Areas (Edited) Earth’s Glacial Record (Edited) Glacial Geology: An Introduction for Engineers and Earth Scientists (Edited)

To my father, Alfred, who roamed the oceans, and my children, Chris and Claire, for being there

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CONTENTS

Origins and Acknowledgments

ix

Prologue The Day the Earth Moved

1

Chapter 1 In the Beginning

3

Chapter 2 Continents Adrift?

25

Chapter 3 Sources of Friction

53

Chapter 4 Permanentist Foundations

79

Chapter 5 Tuzo’s War

103

Chapter 6 A Geologist in a Strange Land

129

Chapter 7 Seismic Shift

167

Chapter 8 The New World of Plate Tectonics

205

Chapter 9 An Unlikely Revolutionary

235

Appendices Appendix I: Medals and Awards

249

Appendix II: Select Primary Sources

251

Appendix III: The Geological Timescale

257

Glossary

259

Index

269

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origins and acknowledgments

Jock Tuzo Wilson is arguably the most influential geologist of the twentieth century and one of Canada’s most famous scientists. Every geology student around the world becomes familiar with the “plate tectonic revolution” of the late 1960s, which irrevocably changed understanding of Earth history. Tuzo’s profound insights on the workings of the planet and how its surface crust is broken into large moving plates that carry continents like passengers ended the rancorous half-century-long debate between the “permanentists” who rigidly believed in fixed continents and oceans, and the “mobilists” who argued that Earth’s face is always evolving. Tuzo’s impact on the science of geology, and well beyond, is akin to that of Charles Darwin on the biological sciences and the history of life on Earth. As we shall show, plate tectonic theory is a blueprint for simplifying the complexities of the planet’s 4.5-billion-years-long history and is also of immense practical importance in a world evermore hungry for the resources that only rocks can provide. As the world’s population grows, much of it increasingly resident in sprawling megacities, knowledge of plate tectonics is

also the key to managing the threat from earthquakes, volcanoes, and other hazards. Yet, despite his scientific stature and the significance of his discoveries, remarkably little has been written of Tuzo’s own story and especially how he dramatically shed his deeply held permanentist beliefs instilled during his education in Canada, the United States, and Great Britain in the 1930s. Few also know that he served his country during the Second World War with great distinction, leaving the Canadian Army in 1946 with the rank of colonel. As will become very clear, his success in army operational research and training was the key to his later ability to resolve the war of words between the opposing camps of permanentists and mobilists and bring peace to a fractured science at war with itself. The writing of this book arose from a chance encounter one summer on a small island in Lake Huron. Every year I lead a series of “rock walks” with cottagers and boaters exploring the billion-year-old rocks of the Canadian Shield in the 30,000 Islands district of Georgian Bay. Tuzo’s name always comes up. The beautifully banded and highly deformed rocks exposed at surface on the islands formed at depths of many

Origins and Acknowledgments

tens of kilometres graphically illustrate his theory of moving continents, and the life and death of mountains and oceans. On one hot July afternoon on Pine Island, I mentioned that Tuzo’s great discoveries had inspired me as a teenager at school in 1960s London, England, to follow a career in geology. Imagine my surprise when a sprightly, well-tanned lady who had been listening attentively came forward and, much to my amazement, introduced herself as his daughter, Susan. In the ensuing conversation, she mentioned she had been unable to take any geology courses at university and that her father was then very cautious about young ladies entering the profession, given the rigours and hazards of fieldwork. Recounting her childhood memories of living with a famous scientist, she mentioned that he had left a very brief unpublished memoir at the time of his death in 1993, but the part dealing with his sudden conversion to mobilism and momentous discovery of moving tectonic plates was fragmentary. It was a story that needed telling in full to a new generation. My wife, Carolyn, on hearing of the lack of a biography befitting a great geologist who abruptly transformed our view of the world, remarked, “Well, why don’t you do it?” So, after some reflection, that is what I set out to do with Susan’s help, and that of her sister Patty who very kindly granted access to their father’s unpublished papers but sadly passed shortly thereafter. I cannot adequately convey my gratitude to Susan for many hours of conversation shared over mugs of strong coffee, sitting around her dining room table (and later via Zoom), as I learned of the extraordinary life of an amazing soldier and scientist and she, in turn, had a crash course in the history of geology and geophysics, passing with high distinction! She critically read the text as it evolved and grew in successive versions, made

countless perceptive suggestions for its improvement, and generously provided photographs and letters. It has been a hugely enjoyable process, during which I learned a lot, and I am sad to see it come to a close. This book is as much hers as mine, and it would not have been completed without her unfailing encouragement and sound advice. Tuzo was a man of great energy who profoundly influenced those he met and worked with. Many of his former colleagues, students, and associates, such as Tanya Atwater, Oliver Bertin, Andrew Miall, Barrie Clarke, Alan Ruffman, Linda Christiansen-Ruffman, Robert Kay, Suzanne Kay, Eric Grace, Jeff Fawcett, Barrie Clarke, Ron Farquhar, Fred Vine, Vic Tyrer, Geoff Norris, Peter Reynolds, Walfried Schwerdtner, Adrian Scheidegger, and Alan Coode, generously shared anecdotes and other material relating to their experiences with Tuzo as the revolution in geology swirled about them in the late 1960s and 1970s. I am especially indebted to Henry Halls, a long-time colleague and friend of Tuzo’s at the Mississauga Campus of the University of Toronto, for his many insights into the history of geology, and Roger Paulen of the Geological Survey of Canada for reviewing the text. Carolyn Eyles at the School of Earth and Environment at McMaster University, Gail Gallant, and Michael Allder, formerly executive producer of CBC’s The Nature of Things, all very generously provided guidance and suggestions for what worked and what didn’t. I was also very fortunate to be surrounded by excellent colleagues and research students, notably Shane Sookhan, Mike Doughty, and Kirsten Kennedy, and especially Syed Bukhari, who transformed my rough sketches into illustrations, and with whom I enjoyed many fruitful

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Origins and Acknowledgments

discussions in our home (“the lab”) at the University of Toronto. I am very grateful to Stephen Jones, Ian MacKenzie, Christine Robertson, and the production team at the University of Toronto Press, who made this all happen and who expertly shaped the book as it evolved into something shorter and more readable. A wider context is everything in a biography, and this book sets Tuzo’s own story against the broader narrative of how the science of geology evolved over the past century and the many individuals that made it happen. It is written for a public audience and so for continuity, direct citation of sources within the text has been avoided. In a book relating the history of geological science over the past 100 years, and one man’s place in it, I have had to be selective. The reader wanting to know more can easily relate individuals and ideas mentioned in the text with the appropriate books and articles listed at the

end of the book. Quotes from Tuzo and his family are from his unpublished memoirs, his daughters, and an interview made just before his death, with Ron Doel of Florida State University on behalf of the American Institute of Physics. Many required corrections and editing for grammatical or factual reasons, and I was assisted in this process by Susan Wilson. Great care has been taken to identify holders of copyrighted material, and I will be pleased to rectify any omissions. I am indebted to my wife of more than forty years, Carolyn, for her love, for sharing numerous geological adventures, which began when we hitchhiked across the United States in the summer of 1978, for her suggestion of writing this book, and her immense patience and advice while I did it. Nick Eyles

xi

The human understanding when it has once adopted an opinion … draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects and despises, or else by some distinction sets aside and rejects, in order that by this great and pernicious predetermination the authority of its former conclusions may remain inviolate. Francis Bacon, 1620

There is always a strong inclination for a body of professionals to oppose an unorthodox view. Such a group has a considerable investment in orthodoxy: they have learned to interpret a large body of data in terms of the old view, and they have prepared lectures and perhaps written books with the old background. To think the whole subject through again when one is no longer young is not easy and involves admitting a partially misspent youth. Edward Bullard, 1975

PROLOGUE: THE DAY THE EARTH MOVED

In Hawai‘i in August 1961, while gazing out across the smoking crater rim of Mauna Loa towering almost 4,000 m above the Pacific Ocean, a middle-aged professor from Toronto named John “Jock” Tuzo Wilson had an astonishing revelation. Ultimately, it would overturn everything he had been taught, make obsolete most of his previous life’s work and that of many others, and finally result in a true revolution in the geological sciences. Looming out in the distance, the volcanic islands of Maui, Moloka‘i, O’ahu, and Kauai lie precisely astern of one another, much like a convoy of ships some 600 km long. Their volcanoes, however, unlike that of Mauna Loa on Hawai‘i, are now dead, and to look along the island chain shimmering in the blue tropical haze of the Pacific is to travel farther and farther back into the mists of time. Lying at the far end of the convoy, the island of Kauai is 2 million years older than its nearest neighbour, O’ahu, which in turn is about 2 million years older than the island of Moloka‘i, which itself is older than Maui. In the rarefied sulphur-tinged air, Wilson suddenly realized that he was looking at volcanoes being born on the

ocean floor, growing upwards to become islands, and being moved away while dying in the process. This process repeated itself as the Earth’s crust below the floor of the Pacific Ocean moved northwestward over a fixed column of red-hot rock rising from the deep interior of the planet below. Tearing a page from his notebook, he drew the paper slowly over the flame of his cigarette lighter, momentarily pausing to burn a hole before pulling the paper onwards, leaving a track of singed craters. Just as the flame left a permanent scar on the paper, so did the mantle plume of hot rising rock leave behind the long convoy of the Hawai‘ian Islands as the Earth’s crust drifted above it. He later named these “hot spot” volcanoes and wrote in his memoirs that this was “the clue as to how Earth behaved.” Clambering down from the top of the volcano across rough, still-warm lava flows, his mind awhirl with his new ideas, Tuzo embarked on a series of discoveries that showed that not only was the entirety of the Earth’s crust on the move, but it was also broken into a series of large crustal plates that carried continents along like passengers on rafts. Continents were not

Prologue

fixed and anchored in place, as was widely believed, but moved. Oceans were not permanent but opened and closed. We now know that there is no such thing as terra firma, for what is supposedly rock solid is anything but. In fact, the entire Earth’s surface, from the top of Mount Everest to the deepest ocean floor at the bottom of the Marianas Trench, is moving laterally at several centimetres a year and much more in some places. At the same time, the crust under our feet is also either rising or falling. Your home or workplace is not where it was last night, and in turn it will be in a different location tomorrow. It is a very slow process, so even though we think we return to the same place every day, in fact we cannot, as everything is constantly on the move. Living on an active dynamic planet, it is impossible to stand still.

Tuzo’s vision of how the planet had evolved over billions of years and will continue to do so henceforth, closed one of the longest and most hostile debates in science. The war between permanentists, who believed in static, unmoving continents, and the mobilists, who saw evidence of continents that had once been together and then moved apart to create new oceans, was over. Tuzo had created a new language to describe the history of the Earth, galvanized and revolutionized an entire science, and changed forever how humans see their planet and access its mineral wealth. This book relates how geologists came to realize that Earth’s crust, despite its appearance of permanence, is in constant motion. This is the story of the discovery of plate tectonics and how one man knocked an entire science off its once-solid foundations.

2

Chapter 1

In the Beginning

The field of tectonics is no place for a prim individual who likes everything orderly and settled and has a horror of loose ends. Chester Longwell, 1930

From classical times until the mid-1900s, geology was largely a practical science. Geologists spent most of their efforts searching for metals, oil, gas, and coal – strategic resources that won wars and powered empires, raised living standards, and built sophisticated economies. As taught to students in universities, geology was largely an applied “inventory science” emphasizing the collection and classification of rocks, minerals, and fossils, and disparagingly described by other scientists as little more than “stamp collecting.” But with the publication of the Origin of Species in 1859, Charles Darwin posed certain questions that only geologists could answer: How old was the planet and how had it evolved? What was the origin of its continents and oceans? Geology began attracting new attention. There were those such as James Dwight Dana, the first ever professor of geology in any North American

university, who in the early 1870s proposed that continents were evidence of an all-powerful “divine plan” made by a Creator who had established the broad outlines of today’s world fixed in place over hundreds of millions of years. Continents and oceans were immutable, and academic careers and reputations were made by methodically reconstructing snapshots of the geography of ancient continents as shallow seas waxed and waned across their surfaces, and as organisms migrated along land bridges across oceans from one permanently anchored land mass to another. These “palaeogeographic” maps were treated reverentially as icons framing the official history of the planet and dutifully reproduced in textbooks. The guardians of this geological orthodoxy (or “permanentists” as they came to be known) were a tight-knit group: they met frequently at conferences,

Tuzo: The Unlikely Revolutionary of Plate Tectonics

they oversaw who was appointed in their university departments and who was promoted, and they instructed the next generation in the permanent nature of the Earth. They saw off outsiders who had other ideas about how the planet might have evolved by influencing what was published in scientific journals (many of which they had founded and continued to run). They quarantined the impressionable minds of students from dangerous foreign ideas emerging from Europe that proposed the continents were on the move. Detailed calculations by eminent physicists had pronounced that such mobility was impossible: Earth’s interior was far too rigid. In 1915, just as the First World War was claiming the lives of millions, a conflagration within the science of geology was ignited by a German atmospheric physicist and veteran of the trenches in Flanders, Alfred Lothar Wegener. He rejected the dogma of permanentism and embraced “mobilism,” bringing forward evidence of a much more dynamic Earth and of continents now separated, having once been assembled into a supercontinent he called Pangea that eventually broke apart. Continents were still moving, oceans still widening in their wake. Portrayed as heretical and brushed aside as the inconsequential imaginings of a simple “meteorologist,” Wegener’s radical ideas pitted permanentists against mobilists for more than half a century. The battle between these hostile groups gives the lie to many of the myths surrounding how science is done and, more importantly, how old science is undone. Knowledge is never “settled,” and what is perceived as accepted truth today is eventually yesterday’s news. Scientists

are seen as objective and rational beings moving forward step by step, making hypotheses, collecting data, conducting rigorous tests, engaging in argument and debate, while inexorably being drawn toward the light of a greater truth. This picture describes the action of robots, not people made of flesh and blood, passionate about what they do, inspired to make sudden intuitive leaps of imagination or fighting to defend their territory and reputation on which their funding depends. Science is a highly competitive sport and, as this book will relate, the war of words between permanentists and mobilists was often a nasty business with casualties along the way, most often those perceived as outsiders who could safely be ignored, such as young scientists at the beginnings of their careers who failed to receive credit for their ideas or whose results were rejected as being too radical. Nationalism, too, reared its ugly head within the scientific community in the aftermath of the First World War, renewing former hostilities from the battlefields of France; Wegener was, after all, German. The accepted permanentist dogma was viewed as “made in America,” and questioning it was seen as unpatriotic and could end careers. The Second World War and the Cold War that followed accelerated the development of new electronic technology. A new generation of tools that had originally been developed to find enemy aircraft, ships, and submarines could now be used to explore the hidden floors of the oceans and the deeper parts of the planet lying below the Earth’s crust. For the first time, processes operating within

4

In the Beginning

Earth’s interior were linked to dramatic changes on its surface involving continents that migrated, immense supercontinents that formed and broke apart, and oceans that opened and closed. It was a grand rock opera like no other, and rocks, minerals, and fossils now took on a new significance as records of an evolving planet with a 4.5-billion-year history. As former staunch permanentists retired and left the battlefield, the momentum passed to the mobilists to write a new history of the planet. “Plate tectonics,” as it came to be known in 1968, altered forever how we think of our planet and opened new directions for research into the interplay between moving plates, climates, and biological evolution. The theory re-energized university programs and created a new generation of geoscientists armed with a conceptual blueprint for finding the resources that feed advanced economies, and ways to protect communities from natural hazards. The new discoveries brought geology into the public’s living rooms, sparking a fascination with ancient lost worlds and oceans and the strange organisms that inhabited them. The leader of the radicals, who finally turned his back on permanentism on top of Mauna Loa in 1961, was in many ways the least likely person to set the scientific world alight. John “Jock” Tuzo Wilson had been born in upper-middle-class comfort in 1908 in Ottawa, Canada’s capital. He was no firebrand but the privileged and highly educated eldest son of a well-respected federal civil servant and a wealthy mother. Attracted by the outdoors, Tuzo started his career in the mid-1920s when still a teenager, working as a field assistant prospecting for minerals in

northern Canada. He was educated at leading universities in Canada, the United States, and England, and rose to eventually become a prominent member of the geological elite. His career was interrupted by the Second World War when he served in the Canadian Army, where he proved himself a born leader and was rapidly promoted. During his subsequent career at the University of Toronto, he took on the presidency of numerous international geological organizations, becoming well connected with other senior scientific figures, all united in their long-held belief in permanentism. In 1961, when he climbed to the top of Mauna Loa, Tuzo was a well-established family man and father of two daughters, and a senior professor – hardly the stereotypical rebel looking to shake up the establishment. In hindsight, Tuzo’s dramatic break with the accepted theories of geology echoed what was happening at large in Western society. The “Swinging Sixties” saw the emergence of a new postwar generation of young and restless baby boomers and their counterparts in Eastern Bloc countries, many of whom broke with past traditions and asserted their rights to make their own political and cultural choices. It was an era of massive, often violent, student protests, wildcat strikes and sitdowns, the Woodstock festival, John and Yoko, hippies and flower power, JFK and Vietnam. The world would never be the same. Mao’s Cultural Revolution was in full swing and a revolution of a different sort was also beginning to pick up speed in North America – not the civil rights and anti-war movements bursting into flames across the United States, but a global revolution that came to be known as plate tectonics.

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

“Not Much of a Match”

Tuzo’s intuitive leap of imagination in Hawai’i triggered an explosion of studies that quickly converted geology into a much more dynamic planetary science. Once-cherished textbooks became outdated overnight, as did some of geology’s most revered gurus and their disciples, to be replaced by a new generation of professors and students. Abrupt, transformative events such as this are known as “paradigm shifts,” a term used by the American philosopher Thomas Kuhn, who argued that science proceeds not smoothly but erratically in fits and starts, when old data that were anomalous or disputed suddenly take on a new meaning, and long years of consensus, ruling hypotheses, and “facts” are suddenly jettisoned. The world-shaking discoveries of Copernicus and Galileo, Newton, Darwin, and Einstein are examples where the halting progress of “normal science” is suddenly shifted into high gear, takes off in another direction, and is irrevocably changed. Despite the revolutionary nature of his ideas, ­Tuzo’s own story has never been told at length. Much younger contemporary scientists have outlived him and written first-hand accounts of their contributions, but Tuzo wrote surprisingly little of his own personal story and how he arrived at his great discoveries. While he left a thick paper trail of formal scientific publications and books, his personal memoirs are a mere 160 pages long and remained unfinished when he died in 1993; at only four pages in length, that part relating his role in the development of plate tectonics is frustratingly brief and incomplete. This book will flesh out his story and describe Tuzo’s epic journey from his teenage years as a geological assistant in the northern Canadian wilderness to his becoming the venerated father of plate tectonics.

I have been lucky all my life; my initial piece of good fortune was the parents who launched me into the world. A more disparate pair cannot be imagined: my mother affluent and possessed of an awful energy and crusading zeal; my father quiet, self-effacing, and dogged, gently manipulating whatever stood in his way. J. Tuzo Wilson, 1993

The central character of our story was born in Ottawa, Canada’s capital, on 24 October 1908 at the apogee of the British Empire. His parents were John Armitstead (“JA”) and Henrietta Loetitia Wilson, and although he was named after his father he was more commonly known as “Jock.” JA was a mechanical engineer of quite moderate means born near Dundee, Scotland, in 1879. His own father had died intestate in 1898 at the age of fifty-two, leaving the young JA to help support his mother and younger sisters. Dundee was the centre of the British whaling fleet, a busy ship-building port and centre of jute processing, a strong fibre grown in Bengal, India, and used to make rope and burlap; whale oil was needed to soak the fibre and make it pliable. The young JA originally intended to become a sea captain after a trip on a small tramp steamer around the Baltic with an older brother, when ten years of age. Instead, intrigued by the workings of the ship’s engines, he apprenticed as a junior engineer with James Carmichael and Sons of Dundee, who made pumps and steam turbines, before travelling abroad to work on water pumps used in the jute mills of Calcutta, India. There he contracted malaria and

6

In the Beginning

was advised to move immediately to a cooler climate such as Canada’s. Freshly arrived off the transatlantic boat train in Ottawa in November 1905, JA helped an old man struggling with heavy bags on the railway platform. In the ensuing conversation he was offered employment supervising construction of a cement factory along the Bow Valley at Exshaw, Alberta, just down valley from Banff. Now operated by Lafarge Cement, the factory still dominates the floor of the valley on the shore of Lac des Arcs, overlooked by the towering peaks of the Rocky Mountains. In early 1906, virtually without money, living out of a suitcase and sleeping in a cotton tent with nighttime temperatures falling to -40°C, JA would stay now and again in the Banff Springs Hotel to enjoy the comforts of a hot bath and a well-sprung bed. It was there in June of that year that he met a tall and very elegant young woman, Henrietta “Hetty” Tuzo, when she and her widowed mother were en route to visit Hetty’s brother Jack in British Columbia. JA was a man of great optimism and self-belief, much like Charles Dickens’s Mr. Micawber for whom “something will always turn up.” And indeed, so it would, for he and Hetty were engaged in September when mother and daughter were passing back through Banff on their return trip to Britain. Hetty had rejected the marriage proposal of “Mr. Wilson from the cement factory,” claiming that she was too old for him, but he was successful on the second asking, and they were married in England in November 1907. He was then twenty-eight years old and of limited assets, and she was thirty-four, descended from a rich Huguenot family, and comfortably well off.

Tuzo’s mother, Hetty, at age twenty-four on the occasion of her “coming out” in London, England, in May 1897. Dressed in a satin-lined gown complete with ostrich feathers, she was presented at court to Princess Christian, the Duchess of Albany. The ceremony marks the passage of a young upper-class woman (a “debutante”) to a mature and marriageable member of high society. Her desire to follow a career in medicine was thwarted by the death of her father and the need to look after her mother.

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

Learning of the engagement, Hetty’s family was horrified at the apparent mismatch. Her Aunt Caroline took it upon herself to write to JA, declaring, “From the dispassionate family point of view, you must forgive me for saying it is not ‘much of a match’ for her. I mean for a woman of her age and character one would have liked a more assured position but on the other hand you are marrying her and not her family and her family is not marrying you, but she is and as she is very content there is nothing more to be said on that score.” Her mother too wrote, “As I have said every disagreeable thing that I can think of to you both and it has had no effect, you will never hear another one.” Of her daughter she noted, “She thinks she will love life in any part of Canada’s Wild West, but she has only seen it travelling in luxury during the summer. All the year round must be a different matter after our temperate old England.” But it all worked out for the best, and the family’s concerns proved to be entirely misplaced. Both partners brought special qualities to the marriage and passed them on to their son. JA’s great energy and impatience with the mundane, and his positive attitude were to be reflected in Jock’s outlook on science; some ideas work out, others don’t, but the important thing is to keep having them, and there was no shame in having a bad idea and then putting it aside. As we shall see in the late 1960s, when Jock was an already well-known senior academic and a permanentist for most of his career, his new groundbreaking ideas on how the planet worked required him to discard decades of his earlier research suddenly made redundant by new data.

Jock’s interest in the outdoors and travel can be traced to his mother Hetty, whom he worshipped and to whom he would later attribute his natural curiosity about the world at large. Her infectious enthusiasm to be somewhere no one had been before, coupled with a belief that “nothing would go wrong” and that “travel was made possible by a strong digestion, a constitution proof against sea-sickness, a reasonable adherence to the common-sense rules of cuisine and hygiene, the ability to sleep anywhere in any position, patience and above all a firm conviction that all will come out right in the end” was especially influential. Hetty’s maiden name is the source of the famous “Tuzo” (derived from the French name for a variety of wheat), which Jock was given as a middle name and which he would later highlight to distinguish himself from another scientist named J.T. Wilson. Hetty was a westerner born in Nanaimo, British Columbia, in 1873 but had spent most of her younger years in Surrey, England, just south of London, where she had been part of the social elite, before returning to western Canada every other year beginning in 1898 to see her brother. Her father, Henry Atkinson Tuzo, was a Quebecer of French Huguenot descent who eventually became a very wealthy manager of the Bank of British North America in New York. Years earlier in 1853, as a young medical graduate, he had made an arduous seven-month overland journey from Montreal to Fort Vancouver, where he took up the post of physician to the Hudson’s Bay Company. He wrote home to his sister, Anna Maria, of crossing the Prairies “as far as the eye could reach black with buffalo” and being ever “wary of attacks by roving bands of hostile Indians.”

8

In the Beginning

Traversing the Rocky Mountains, he crossed the continental divide separating the Arctic Ocean–draining Athabasca River and the Columbia River that flows to the Pacific. He wrote of having to cross dangerously cold glacial meltwater rivers more than eighty times, with the riverbanks “covered with graves” of people who had drowned. He was thankful for the great skill and courage of his guides in navigating their boats through the “most terrific rapids and tremendous waves.” His daughter Hetty was just as adventurous, equally broad-minded, and highly intelligent. In England she had been constrained by the Victorian social conventions of the day but with her widowed mother had been a regular visitor to Switzerland, where she enjoyed hiking in the Alps. On her return to Western Canada in 1898 she found solace in the Rocky Mountains, and as an outlet for her physical and emotional energy she became an accomplished climber. At this time, professional Swiss mountain guides were employed by the Canadian Pacific Railway working out of the Banff Springs Hotel to drum up interest from wealthy tourists in taking excursions into the surrounding mountains and unexplored icefields. Tourism was seen as a means of recuperating the heavy costs of operating the railway through the mountains. It attracted lots of well-heeled Americans who set about “bagging” unclimbed peaks such that for many years the Rockies were called the “American Alps.” Hetty became an active member of the Alpine Club of Canada, which held its first camp in 1906 at Field, British Columbia. Prospective members of the club had to demonstrate their ability by climbing the

nearby Vice President Mountain (3,066 m above sea level) as a test; forty-four new members completed the climb that year. Club rules stated, “No lady climbing, who wears skirts, will be allowed to take a place on a rope, as they are a distinct source of danger to the entire party. Knickerbockers or bloomers with puttees or gaiters and sweater will be found serviceable and safe.” Out of a sense of patriotism in the face of interlopers from abroad, the Dominion government contributed $500 toward the costs of the camp while the Canadian Pacific Railroad donated the services of their Swiss mountain guides. The secretary of the club, Elizabeth Parker, had written to Hetty earlier that year welcoming her application for membership, declaring, “It is really a great acquisition to our young Club & this for two reasons: first, the number of your Alpine achievements; second, without disparagement to our American Alpine friends, whom we know for their splendid services in the Rockies & for their own selves, we are anxious for an infusion of British blood in our membership. I have been making various efforts to catch the eye of British folk who travel, that they may turn their faces westward with the Star of Empire.” The latter was a reference to the concept of Manifest Destiny and the divinely inspired westward expansion of the United States; at the time, there was widespread distrust of American energy and intentions in western Canada. Henceforth, first ascents of mountains were reserved for Alpine Club of Canada members to forestall claims by outsiders. Hetty is remembered today for the first ascent of Number Seven in 1906 in the Valley of the Ten Peaks (3,248 m above sea level) near Lake Louise. This, the

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

most remote and most striking of the peaks that overlook Moraine Lake, was the only one still unclimbed. After hiding her long skirt behind a boulder, she climbed to the summit in twenty-one hours accompanied by the Swiss mountain guide Christian Kaufman, narrowly avoiding huge blocks of falling rock that ploughed downslope across their tracks. Finally, “at 4:40 in the afternoon we reached the summit. I shook hands with Christian and then was so deadly tired I lay down and went right off to sleep while he built a stone man to commemorate the ascent of this the last unconquered of the Ten Peaks.” The mountain was renamed Mount Tuzo by the Alpine Club of Canada, and its picture formerly graced the back of the Canadian twenty-dollar bill. Later in life, Jock’s wife, Isabel, would express great surprise that her mother-in-law had climbed a mountain in her youth. The old lady is said to have responded, “It wasn’t a real climb; it was just a long walk uphill.” Hetty’s good friend was Mary Vaux, also a climber, who conducted some of the earliest scientific investigations of the glaciers in the Canadian Rockies, measuring their activity and rate of retreat. William Sherzer of the Smithsonian Institute in Washington, DC, in his classic 1907 Glaciers of the Canadian Rockies and Selkirks, paid tribute to the work of Vaux and the “English lady” Tuzo for their explorations. In 1914, Mary married Charles Walcott, an American geologist working at the Smithsonian Institute. In 1909 Walcott had discovered the enigmatic “Ediacaran” fossils preserved in the Burgess Shale in what is now Yoho National Park, British Columbia, which record the rapid emergence of complex forms of marine life during

Canadian Pacific Railway advert from the early 1900s, designed to lure well-heeled travellers to the Canadian Rockies.

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The Valley of the Ten Peaks and Moraine Lake in the Rocky Mountains near Lake Louise, Alberta. Mount Tuzo is the second peak from the right; it was named by the Alpine Club of Canada after Wilson’s mother, who first climbed the mountain in 1906.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

the “Cambrian Explosion” around 540 million years ago. One of the fossils is named “Tuzoia” after Hetty. Susan Wilson, Hetty’s granddaughter and the younger of Jock’s two daughters, remembers the walls of the family home in Ottawa adorned with many photographs of prominent mountains and ascribes Jock’s later interest in their origins, and his subsequent work for his PhD in the Beartooth Mountains of Montana, to his childhood surroundings. Jock later praised his mother as an indefatigable organizer with natural gifts for leadership honed by the long and lonely years she spent caring for her mother and the London poor. Those same years had acquainted her with the Suffragettes, Mrs. Pankhurst among them. Mother was never strident and worked toward her goals by mastering the rules of parliamentary procedure rather than by padlocking herself to railings. She joined the local Council of Women to press for the pasteurization of milk, and the Household League to stop the practice of merchants packaging fifteen ounces of food and labelling it one pound. She was on the first Advisory Board of Parks Canada and was President of the National Council of Women.

These same traits of organization and leadership were to be displayed by her son and were additionally underpinned by the sense of optimism he inherited from his father. The newly married Wilsons moved to Ottawa in late 1907 and JA found temporary employment supervising the building of yet another cement factory on

TOP: Wilson’s parents: his father, JA, and Hetty, his mother. BOTTOM: Jock Wilson at age eighteen months with his mother.

12

In the Beginning

the eastern side of the Ottawa River in Hull, Quebec. Jock was born the following year. JA’s job proved to be short lived, and he experienced a series of false starts, during which the Wilsons put on a “brave front” and lived off Hetty’s annual dress allowance from her father’s estate. At Hetty’s insistence he began to establish connections within the civil service. He would eventually join the government in 1910 working in the newly formed Department of Naval Services. There, he was made responsible for planning and provisioning transatlantic shipping convoys carrying troops and supplies to Europe between 1914 and 1918, and for the construction of new naval air bases at Dartmouth and Sydney, Nova Scotia. In 1918, with the end of the First World War, the need for convoys disappeared, and he turned to the new and rapidly expanding technology of aeronautics and air transport. The airplane was about to change northern exploration for good, and the Wilsons, both father and son, were to lead the way.

imagination of people worldwide, nowhere more so than in Canada. The possibility of transcontinental flight from one coast to another was now real. Jock’s father relentlessly argued the case for airplanes to be employed as workhorses to carry mail, help fight forest fires, conduct topographic surveys, support prospecting and mining, and move people. Journeys to remote areas could be made in hours that previously had taken weeks. He made the case for new regulations to promote the civilian use of aircraft across Canada, and in his capacity as secretary of the Air Board and the senior official in charge of civil aviation in Canada, he helped draft the Air Board Act of 1919 and establish the Royal Canadian Air Force in 1924. However, JA was adamant that the military application of aircraft should be balanced by their use in expanding economic development across the country. That same year, the Laurentide Air Services Company began to transport mail and supplies to the mines at Rouyn-Noranda in Quebec (where Jock was to work as a geologist in 1929), the first such regularly scheduled air service in Canada. In 1924, the newly formed Ontario Provincial Air Service based in Sault Ste. Marie also started to use Curtiss HS-2L flying boats to map forest fires and fly in firefighters. It had now dawned on the powers that be that Canada’s forests were not inexhaustible and that airplanes were the perfect tool to map and manage their extent. During the First World War, Canadians made up a quarter of the strength of the Royal Flying Corps, and in the early postwar years, the air-combat legacy for Canada was the bush pilot. These intrepid individuals would dramatically change how geology and mining were done in the space of a decade. “Punch” Dickins

First World War Comes to an End and Canada Takes to the Skies At the conclusion of the First World War, thousands of airmen were released back into civilian life and cheap surplus airplanes came onto the market. Initially, very few people envisaged any use being made of these machines other than barnstorming around the countryside and putting on air displays. However, the sixteen-hour transatlantic flight in a Vickers Vimy of Captain John Alcock and Lieutenant A.W. Brown from Newfoundland to Ireland in 1919 captured the

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First World War artillery intelligence map made from air photographs of the British front line at Vimy Ridge in January 1917 (later captured by the Canadian Corps in April of that year). Canadian expertise in low-level flying and wartime aerial photography would later be used to map the geology of Canada’s Far North and unlock its mineral wealth. Courtesy of McMaster University’s Lloyd Reeds Map Collection.

In the Beginning

and Wilfrid Reid “Wop” May were veteran pilots who had survived many low-level reconnaissance missions over the Western Front in France and brought their aeronautical skills back home to support geological mapping in the Far North. May is immortalized today in a song by Stompin’ Tom Connors (“Wop May”) and a rock in Endurance Crater on Mars. His name is also given to the belt of highly deformed rocks in the Northwest Territories that record the collision between the crust of the Slave Craton and an adjacent land mass some 1.8 billion years ago (the Wopmay Orogen). The first-ever flight in Canada north of the sixtieth parallel occurred in the winter of 1921, when May flew from New York to Edmonton and on to the oil fields at Norman Wells along the Mackenzie River, using two war-surplus, German-made Junkers airplanes with open cockpits and equipped with skis. The flight showed that aircraft could be successfully operated in sub-zero temperatures. Antifreeze was not then available and to prevent freezing of the engine block, oil would be drained from the crankcase at the end of a flight, heated up in a barrel the next morning, and poured back into the engine. In the late 1920s, Northern Aerials Mineral Exploration was regularly dropping off and supplying geologists in the field around Red Lake in Northern Ontario. This proved very efficient in covering much larger survey areas than hitherto possible by canoe, resulting in several new mineral discoveries. Drilling crews and their equipment could also be flown into remote areas to follow up on discoveries made by the prospectors. In 1919, Imperial Oil had begun to use air photographs for geological surveys, and in 1922, JA was given a report by R.A. Logan, an ex–Royal Flying

Corps pilot who had extensive experience in Canada’s north. Logan spoke of widespread oil and coal deposits and occurrences of other minerals in the Arctic that could be systematically surveyed and mapped from the air. Recommendations were made on the type of plane needed; it needed to be robust enough to work anywhere with interchangeable wheels and skis, and be a float plane. It should also be a “pusher” type with its motor in the rear giving a clear field of view for its pilot and a forward observer with a camera. An early prototype was tested in a wind tunnel at the University of Toronto, the first such test anywhere in Canada, and in July 1923 the Vickers Vedette, the very first such plane specifically made for Canadian conditions, was launched in Montreal. A 200 hp wooden-hulled biplane, it was very successful and in use until 1941, although its wooden hull was prone to leaks. It was literally a flying boat: a canoe with wings and motor. In 1924 the newly formed Royal Canadian Air Force experimented with making topographic maps from air photographs taken at an elevation of 2,000 m. Special optical instruments called “stereoscopes” were invented for seeing the topography in three dimensions from overlapping lines of photographs displayed on huge plotting tables. By 1933 Canada had set up a national index of air photographs, the earliest such system anywhere in the world. It was said that more was learned of Canada’s geography in the decade following 1918 by using planes than had been learned in the preceding 300 years on foot. The director of the National Research Council, Andrew M. McNaughton (who, as we shall see, later had a profound influence on Jock’s career), had just introduced the use of cathode ray tubes to fit inside

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

The Vickers Vedette was a versatile single-engine wooden-hulled floatplane introduced in 1923 to operate in the rough conditions in the north, requiring landing on lakes and (when fitted with wheels or skis) short landing strips. The forward cockpit gave an unobstructed view for air photography. Courtesy of San Diego Air & Space Museum.

a plane’s cockpit to allow pilots to fly along precise predetermined paths using radio waves transmitted from beacons; they were also used in early weather forecasting to predict the approach of thunderstorms by detecting lightning. This system would be developed during the Cold War into the Distant Early Warning

Line (the “DEW Line”) for detecting Russian bombers attempting to traverse the Canadian Arctic to fly into the United States. By 1928, detailed topographic and geologic maps of the Canadian Shield were being routinely produced from air photographs taken with simple Kodak cameras.

16

In the Beginning

heavily involved in development of the Imperial Airship Scheme designed to more closely link the far-flung outposts of the British Empire and to ensure that mail and people could move smoothly and quickly. Rudyard Kipling had just published several popular science fiction stories such as “With the Night Mail,” about a global fleet of massive dirigibles controlled by a supranational body (the Aerial Control Board) that would oversee and control the world’s economy. The optimism was to be short lived. In August 1930, the massive British-made airship the R-100 crossed the Atlantic in seventy-eight hours and became the first passenger-carrying flight from England to Canada. The enormous inflatable craft was 216 m in length and was tethered to a specially constructed mast at Saint-Hubert just outside Montreal, where more than 100,000 people visited every day. Watched by the young Jock, it made a hugely popular flight over Toronto, where it was photographed flying over the tower of the Canadian Imperial Bank of Commerce, which (at least briefly) was the tallest building in the British Empire. It was here that the airship’s elevator got stuck and it almost collided with the top of the tower, only avoiding catastrophe when rising air caught the ship, enabling it to skim over the building with metres to spare. The great airship flew on to Niagara Falls and then successfully returned to Britain. Sir Barnes Wallace designed the air frame of the R-100, the sister ship of the ill-fated R101 which crashed in Paris later that same year after having been rushed into service too quickly. The

Commemorative postal envelope issued for the first air mail flight in 1932 from Rae to Fort Resolution, both remote communities lying on either side of Great Slave Lake in the Northwest Territories. It is addressed to Jock’s father, JA, who had promoted and overseen the great expansion of air travel in his capacity as controller of civil aviation.

It was common practice at this time for bush pilots to have mountains, rivers, or lakes named after them by survey teams; the going rate for this honour according to Grant McConachie, who was to later pilot the first commercial flight across the Rockies in 1935, was a bottle of rum. Ted Nagle and Jordan Zinowich’s The Prospector North of Sixty recounts the adventures and impact of the early ex-military bush pilots in mapping topography, rivers, and lakes, and of course geology. The most notable discovery was that of uranium ore (pitchblende) by Gilbert LaBine in 1930 on the shores of Echo Bay on Great Bear Lake; refined into radium, it greatly lowered the cost of cancer treatments. In the late 1920s, Wilson’s father, in his influential position as secretary of the Air Board, became

17

TOP: The giant British hydrogen-filled dirigible R-100 moored at its mast at Saint-Hubert, Quebec, in June 1930. MIDDLE: Welcoming party of Canadian officials at the arrival of the R-100 at Saint-Hubert, Quebec. Jock’s father, JA, is at the far left standing next to General McNaughton, the chief of the General Staff. BOTTOM: The R-100 flying over the city of Toronto in 1930 framed against the Canadian Imperial Bank of Commerce. Courtesy of the City of Toronto Archives.

In the Beginning

Imperial Airship Scheme was abruptly cancelled, and the R-100 broken up for scrap. In the late summer of 1930, the same year the R-100 visited Canada, the most daring exploration flight of all was made by Walter Gilbert, flying a Fokker Super Universal, on a 6,500 km round trip from Fort McMurray to Victoria Island and the Boothia Peninsula in the Arctic. The purpose of the flight was to learn more of the geographic location of the North Magnetic Pole (essential knowledge for northern navigation) and to complete an aerial survey of the remote, little-known Arctic coast and its icy waters. It was risky flight with no chance of recovery in the event of a forced landing. The first flight from Montreal to Vancouver was that of a Douglas biplane in September 1926, piloted by Albert Godfrey and James McKee; the young Jock Wilson was excited to witness the plane landing and taking off at Ottawa. The flight is still commemorated by the McKee Trophy, which is awarded each year for distinguished service to Canadian civil aviation, and JA received this honour in 1944. The citation from Colin Gibson, the minister of national defence for air, cited JA’s work on the Northwest Staging Route from Edmonton to Whitehorse. This route was crucial when the United States entered the Second World War and the Japanese attacked and briefly occupied part of Alaska right on North America’s doorstep. JA’s vision in using aircraft to open up and map Canada’s north was to be a lasting influence on his son’s career. The study of air photographs was to reveal the broad-scale structure and geological secrets of the Canadian Shield and was to be Jock’s first big

step toward embracing the radical concept that continents move.

School Years and a First Taste of Geology I had begun a lifelong habit of always seeing a little more if it were possible or trying to climb just one more mountain to see the other side. J. Tuzo Wilson, 1993

Jock’s father, JA, was well-connected with many influential people in Ottawa’s diplomatic and military circles, including doctors, architects, diplomats, newspaper proprietors, government ministers, Arctic explorers, and eminent scholars. Many lived close by the family home at Rockcliffe, which sprawled over several acres of land overlooking the Ottawa River. Jock rapidly overcame a natural shyness and learned to talk to people of very different backgrounds and status. JA helped organize the Canadian Arctic Expedition of 1913–18, and Jock met Vilhjalmur Stefansson, the expedition’s Icelandic-American leader (born in Manitoba). Stefansson was a difficult and stubborn person to work with. He famously had abandoned the expedition’s ship Karluk and its crew in early 1914 on the pretence of needing to hunt when the ship became stuck in pack ice off the Alaskan coast, where it was eventually crushed. In the opinion of many, Stefansson lacked the leadership qualities necessary for such a large undertaking, but JA succeeded where many others had failed in developing a good working relationship with him. As a frequent visitor to the family home,

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

Stefansson was to trigger Jock’s life-long interest in the Arctic. The explorer’s insistence on eating nothing but meat (to prove how healthy it was) and “living off the land,” recounted at dinner around the Wilsons’ dining table, stuck in Tuzo’s memory. The 1913–18 expedition had included the geologists John O’Neill and George Malloch, who collected thousands of rock specimens but also wrote scathing reports back to the Geological Survey of Canada on their leader’s lack of attention to detail. Stefansson was a loner, used to living by himself in the Arctic, and his ideas on how to survive were not appropriate to the needs of a large expedition. However, he did establish a stronger Canadian presence in the Arctic, which helped boost the country’s claim of sovereignty over the vast and little-travelled north lands. Jock also met the New Zealand–born Diamond Jenness, the anthropologist attached to the expedition. Jenness was a member of the Geological Survey of Canada and later served after the Second World War as the first director of the Geographic Bureau, whose primary objective was to explore Canada’s north, its peoples and geological resources then still largely unknown. Jenness further inspired Jock’s deep interest in northern Canada, which was to be a recurring theme in his later career. Jock’s visits as a young teenager to England and London, then the “world’s capital,” left him with lasting memories, and he was enthralled by its energy and intoxicating buzz, the dense horse-drawn traffic, bustling train stations with whistling steam engines, with red-coated soldiers on horseback and marching bands. Journeys by train were remembered for the cast-iron vending machines on the railway platform that dispensed chocolate bars. A visit to Crystal Palace,

Jock Wilson’s father, JA, was a senior civil servant in Ottawa, and the Wilsons’ family residence in Rockcliffe received many distinguished visitors. Jock later described it as “a breeding ground for people with an individual cast of mind.” His capacity for showmanship was developed at an early age; here at Christmas 1914, at age six, he is dressed up in beaver skins, a lynx pelt, and a necklace of bear’s claws at a costume party as “Neolithic Man,” when he was introduced to the visiting Arthur, Duke of Connaught, one of Queen Victoria’s sons, and the governor general of Canada.

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Twelve-year-old Wilson’s football team at Ashbury College, Ottawa, in 1921. He is second from the right in the upper row.

LEFT: Jock and his parents on the Gatineau River in 1921. RIGHT: Removing a fishhook while fishing on the Gatineau River with his younger brother Peter on Cartier Lake in 1924. Jock was the eldest of three children.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

built in 1851 for the Great Exhibition, was especially memorable. The streets of the city were not paved with gold, but, as for many new arrivals to “the Big Smoke” before and after, a spark was struck; there was a wider world waiting to be explored. That world naturally was firmly British. At school in Ottawa, Jock was required to learn the geography of the continents (much of it shown in red demarcating the extent of the British Empire) and to memorize the names and dates of the kings and queens of England, which proved to be in later life “an atlas for travel, and a calendar for history. Canadian geography and history were ignored; a vacuum that my education at school did nothing to fill.” Famously, on his arrival at the University of Toronto as a young student in 1926, he admitted to not knowing the name of the large body of water at the foot of Yonge Street (in case you too were wondering, it’s called Lake Ontario). His early schooling at Rockcliffe Preparatory School, where he had started at age seven in 1916, was undistinguished and is little mentioned in his biography, except the actions of the girls who outnumbered boys and “ganged up on us unmercifully.” Three years later he entered Ashbury College, which catered to the unruly sons of wealthy parents who “shipped them up to Ashbury to be caned into shape by its redoubtable headmaster.” By all accounts Jock’s schooldays were lonely and he kept his distance from his classmates, later admitting that it was “an excellent training for his life as a scientist with unorthodox views and a traveller to strange places.” Jock was fit but physically small for his age and disliked team sports but became adept at rowing and skiing. He frequently swam across the cold and fast-flowing Ottawa River,

walking upstream a mile on the other bank to swim back in the strong current to where he had started, having to avoid the large booms of logs being floated downriver to the sawmills on the Quebec shoreline at Hull. These exploits he later remembered “made geological fieldwork seem natural and not a labour.” Jock acknowledged his science teacher Harry Wright at Ashbury as the inspiration for first stirring his interest in physics and chemistry, and he became an avid reader of popular science books. He was also exposed through his father’s many colleagues to the wealth of scientific expertise in government service and to numerous visiting scientists moving through the capital. He participated in Saturday field trips organized by the Ottawa Field Naturalist Society, and it was on one such trip, with Dr. Henri Ami of the Geological Survey of Canada, that he searched for fossils in the gently buckled limestone layers that give rise to Hog’s Back Falls where the Rideau River cascades down over the rocks on its way to the Ottawa River. It was there he first became aware of the vast differences between those rocks and the much older Precambrian rocks of the Canadian Shield found just north of the city. He recalls that “my first interest in geology dates back to these Saturday mornings with Dr. Ami.” On another trip he visited the silver mines near Cobalt on the shores of Lake Timiskaming, still enjoying a postwar boom in silver prices, where he was so fascinated by what he saw underground that he “swallowed geology.” Jock had his first taste of working in the bush and living under canvas in 1924 at the age of fifteen, while being employed for a dollar a day as a forestry assistant counting and measuring pine saplings at

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In the Beginning

Chalk River, a small community on the banks of the Ottawa River just upstream of Ottawa. The Forest Service was becoming concerned at the slowness of natural reforestation in areas that had been logged, and Jock was part of a team working on how tree growth could be encouraged. The experience taught him how to work out of remote camps and above all, how to avoid accidents with canoes, axes, and fires, which he would shortly put to good use while working out of mining camps in subsequent summers. He remembered many conversations with another member of the forestry field crew, a young Paul Martin Sr., who would eventually serve as a cabinet minister under four prime ministers. In 1926, when seventeen years old, Jock worked as junior geological assistant for the mining financier Mackintosh Bell in the Michipicoten area (near Wawa) along the northern shores of Lake Superior in Northern Ontario. He was supervised in the field by the thirty-six-year-old English geologist, war veteran, and mountaineer Captain Noel Ewart Odell, and it proved to be a pivotal moment in young Jock’s life. It was Odell who taught him the rudiments of geological mapping while on long tramps through the bush, and it was in that summer that Jock’s various interests coalesced into a fascination with geology that would later see him take up the subject at university. Odell’s honesty prevented him from writing the overly optimistic reports that some unscrupulous financiers demanded to garner additional investment for what his mapping had shown earlier to be nothing more than worthless “moose pasture.” Odell had to sue the company’s directors to be reimbursed for expenses. His dissatisfaction with prospecting

ultimately lay behind his decision to leave Canada and take up a position at Harvard, from where he would eventually become a professor of geology at Otago in New Zealand. Odell was an experienced mountaineer of no little repute, having started climbing at age thirteen in the English Lake District and north Wales, and just five years later, climbed the notoriously difficult and exposed tooth-like Aiguille du Tour on the Mont Blanc Massif in the French Alps. After the war, he worked as a geologist with the Anglo-Persian Oil Company and famously took part as “oxygen officer” in the 1924 Mount Everest expedition, during which George Mallory and Andrew Irvine perished high on the mountain and about whom many books have been written questioning whether they had reached the summit. Odell had been the last person to see Mallory and Irvine before they finally disappeared in the clouds. Mallory’s body was found in 1999, and its position suggests they were descending when overcome. At times of crises on Everest requiring difficult, potentially life-changing decisions on the disposition of men, oxygen, and supplies on the dangerous mountain, Odell proved to be a calming influence on his compatriots. He would sit on a rock, smoke a pipe, and read well-thumbed, months-old copies of the Times Literary Supplement before issuing directions. His nickname among his colleagues was “Noah,” reflecting their respect for his judgment. Odell set records for living high on the mountain without oxygen and established that Everest’s summit is composed of fossiliferous limestones that once had lain well below sea level. In 1938 he was to return to Everest, getting to within 60 m of the summit.

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

Members of the 1924 Everest expedition photographed by John Noel. Sandy Irvine and George Mallory (back row, far left) would perish on the mountain. The geologist Noel Odell (back row, second from right) had a profound influence on the young Jock and was the inspiration for him taking up geology at university. Jock was to later comment, “His enthusiasm for his subject infected me and introduced me to the study that was to become my life’s preoccupation.” The two corresponded regularly until Odell’s death at age ninety-six in 1987. In 1936, Odell had reached the summit of Nanda Devi, then the highest mountain ever climbed until 1950, when a French expedition climbed Annapurna. Courtesy of the Royal Geographical Society.

Wilson would metaphorically climb his own scientific Everest forty years later in 1961 when he would suddenly throw away most of his earlier work and embrace Wegener’s theory. Without the influence of Noel Odell, the story of twentieth-century geological science would have been very different. Ironically, as we shall discover later, it was Wilson’s work that was to explain Odell’s observation that the summit of Mount Everest is made of fossil-rich limestone from an ancient ocean that had died, its rocks crumpled into high mountains. The world of geology that the young Wilson was about to enter in the 1920s as a young student at the University of Toronto was not a place for the fainthearted. Fieldwork in northern Canada was dangerous,

and many lives were lost in the bush, especially in cold, fast-flowing rivers when heavily laden canoes were upset in rapids. But studying geology in the classroom could be just as dangerous to the unwary. The 1920s were a battleground between the warring tribes of the permanentists and the mobilists, and the stakes were enormous, for the winner would write the narrative of how an entire planet had come to be. Textbooks would be sold, reputations would be made, and also unmade. It was a bloody battle for the very soul of geology. Before we relate the history of the conflict itself, we must look back to see the origins of the two opposing camps and just what they were fighting for. As will become evident, the gathering storm clouds had appeared on the horizon many years earlier.

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Chapter 2

Continents Adrift?

It has often happened during the progress of science that two doctrines immediately opposite have been supported with great powers of reasoning and with almost equal plausibility. Humphry Davy, 1805

Few topics in science have generated so much heated debate as that of the origin of continents and oceans. The accepted wisdom of the ages was that the continents were fixed in place – nobody ever saw them move, so why would anyone think they could? The roots of the novel idea that continents were not created as we see them today but had formerly been clustered together as part of larger land masses can be traced to at least the sixteenth century, when a dramatic increase in world trade, and the new mercantilism that grew in the teeming ports and cities of northern Europe, ushered in a phase of globalization no less profound than that of today. Trade created a demand for surveys and better charts to navigate the safe passage of valuable cargoes across thousands of kilometres of open ocean. The maps also triggered a renewed curiosity in thinking about the face of the planet and how its land masses

and oceans had come to be: many saw that the similar shape of coastlines on either side of the Atlantic Ocean suggested they had once fitted together like a jigsaw puzzle. Abraham Ortelius, a Flemish geographer working in the busy port city of Antwerp, is credited with producing the first world atlas, Theatrum Orbis Terrarum (Theatre of the world) in 1570. He speculated that the Americas had been “torn away from Europe and Africa by earthquakes and floods” and that the Atlantic Ocean was a “vestige of the rupture.” Sir Francis Bacon, in his book Novum Organum written in 1610, and Father Francois Placet (in 1668) are both credited with making first detailed observations that the shapes of the South American and African coastlines, now separated by the South Atlantic, are very similar, as if they were pieces of the same jigsaw puzzle. Bacon suggested that land had once linked them and then sunk

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Antonio Snider-Pellegrini’s 1858 depiction of a single large land mass that broke apart to form the Atlantic Ocean.

below the ocean; Placet instead resorted to a scouring out of the Atlantic by Noah’s flood. In 1801, the German geographer and naturalist Alexander von Humboldt also noted the symmetry of opposing coastlines around the North Atlantic but also saw the ocean as nothing more than a great valley carved out by powerful currents. The first modern scientific proposal to explain the origin of the continents, using geological information, is credited to the French naturalist Antonio Snider-Pellegrini in 1858. His book La Création et ses mystères dévoilés (The creation and its mysteries unveiled) argued that continents had once been clustered together and then moved apart in response to centrifugal forces exerted by Earth’s rotation, stretching the crust and opening wide oceans in the process. He pointed to the same fossil plant types preserved in Carboniferous-aged coal deposits (now known to be about 320 million years old) in Europe, and on the other side of the Atlantic Ocean in North America, as evidence the land masses had once been contiguous. Snider-Pellegrini’s argument for a former land mass that had embraced all the world’s continents was to

gather dust for another forty years until an Austrian geologist marshalled a wealth of geologic data and gave the land mass its name.

Eduard Suess’s Great Southern Continent: Gondwanaland Space would fail, were I to attempt to write the history of this discussion, which is as old as our science itself. Eduard Suess, 1885

Eduard Suess was appointed professor of geology at the University of Vienna in 1861, a position he was to occupy for the next forty years. In his youth he had been imprisoned in the revolutionary ferment that had swept across the Austrian Empire in 1848, only being released at the direct request of the director of the Imperial Geological Survey who recognized his scientific talent. He remained politically active throughout his career, serving for thirty years as a member of 26

Continents Adrift?

the Earth. Like Snider-Pellegrini before him, Suess was struck not just by the shapes of opposing coastlines, but also by the similarities of the ancient fossil flora and fauna preserved in rocks of the same age now scattered across India, South America, Australia, and Africa. In particular, he noted fossilized leaves of Glossopteris (a large tree-fern, now extinct) and fossil fauna such as the early land-dwelling reptile Mesosaurus, which clearly could not have swum across wide oceans. The list was expanded to include Antarctica when Captain R.F. Scott’s ill-fated expedition to the South Pole discovered the same rocks and distinctive Glossopteris fossils, samples of which were recovered from his camp after his death in 1912 on Beardmore Glacier. It was solid evidence of the former continuity of now-separated land masses. Suess also saw, as had others before him, that the coastlines of the southern landmasses can be readily fitted together to form a single large southern land mass, which he named “Gondwanaland” after the ancient indigenous tribe of the Gonds, who inhabited central India where the distinctive rock record shared by all the southern landmasses is best displayed. Suess argued that this primeval continent was separated from the northern continents of North America, Europe, and Asia by a large seaway, which he called “Tethys,” after the Greek goddess and sister of Oceanus, the mother of all the world’s waters. Suess highlighted the presence of very distinctive rocks called glacial “tillites” containing large boulders left by the sliding of ancient glaciers, as evidence of a massive ice sheet much like today’s Antarctic Ice Sheet, that had once covered the near polar parts of Gondwanaland hundreds of millions of years ago. Despite the novelty of his ideas, Suess was a permanentist and saw continents as fixed crustal blocks that had once been interconnected, allowing

The Austrian Eduard Suess is one of the great figures in the history of geological science and the first to take a comprehensive look at global tectonics. To him it confirmed that the present-day continents had formerly been together. But he stopped short of arguing that continents might drift, preferring the sinking of crust to form oceans between fixed land masses. Courtesy of University of Vienna.

the provincial and later national assemblies. He was instrumental in designing the water supply system for Vienna involving construction of an aqueduct that brought in clean water from the Alps, helping to save many lives from waterborne diseases. In 1885 Suess published the first instalment of an innovative and highly influential book, Das Antlitz der Erde, which focused on the nature and origins of the planet’s topographic features, especially its high mountains and the continents and oceans. It was finally published in its entirety in four volumes in English in 1904 as The Face of 27

Eduard Suess’s reconstruction of a southern continent that he called Gondwanaland, composed of parts of South America, Africa, India, and Australia, and separated from northern land masses by the Tethys Ocean. The term “Gondwana” is now used by most geologists, which in Suess’s model was later dismembered into separate continents by subsidence of the floors of the Atlantic and Indian Oceans. Grey areas identify much younger crust now known to have been accreted to the continents after the breakup of Gondwana.

animals and plants to migrate back and forth. In his opinion, the modern-day oceans were formed by the foundering of vast tracts of continental crust below sea level, writing that “great segments of the earth’s crust have sunk hundreds, in some cases thousands of feet.” It was a model that was readily embraced by a wider public fascinated by stories of Noah’s flood and fables of legendary islands lost forever to the sea. If oceans marked sites where large pieces of crust had subsided, then, Suess argued, the world’s high mountains had been pushed up as Earth cooled and contracted. As a young man he had mapped the geology and structure of the Swiss Alps, during long difficult traverses up and over the mountains from one valley to another. In The Origin of the Alps published in 1875, he had proposed that the mountains were much like

wrinkles on the skin of an old, much-shrunken orange left too long in the fruit bowl. He was a paleontologist by training and recognized that the marine fossils in the rocks found on the summits of the high Alps had originated on the floor of the Tethys Ocean. Closure of the former ocean, as the Earth’s surface contracted, had thrown up the mountains. Suess supported his argument by pointing to the results of experiments completed in the 1840s by the French geologist Élie de Beaumont, who stuck patches of fabric on fully inflated balloons to mimic the collision of crustal blocks on a contracting planet as the balloons were slowly deflated. Suess’s work on the Alps provided a powerful demonstration of the value of laboratory experimentation and the extrapolation of the results to the real world. Cooling, in his view, was taking place continually, but was punctuated now and again by “special 28

Continents Adrift?

Taylor’s Crustal Flakes and “Earth’s Plan”

epochs” involving abrupt, short-lived spasms of vastly accelerated worldwide contraction involving massive earthquakes and the rapid uplift of big mountains. He stressed the importance of these violent catastrophic upheavals for life on the planet and coined the term “biosphere,” contrasting it with the planet’s underlying rocky crust or “lithosphere.” Suess is credited with being the first to take a global perspective on how tectonics had shaped the planet’s surface, as if it were being viewed afar from space. He introduced the name “Laurentia” for the ancestral North American continent, “Canadian Shield” for its ancient heartland, and “urban geology” for the deposits left by human activity. Because of Suess, the scope of geology was vastly broadened and began to move away from the strictly practical utilitarian needs of finding resources for industry that had dominated the early years of the science; he showed geologists the value of embracing a more modern and much more expansive view of their science. Upon hearing of Suess’s death in 1914, the leading American permanentist, Charles Schuchert of Yale University, praised The Face of the Earth as “noble” and fondly recounted conversations on the subjects of “paleogeography, seas and barriers” when the two had met in Vienna in 1903 on Suess’s retirement. The two had been intellectual brothers-in-arms sharing a common belief in fixed continents and land bridges on a shrinking, cooling planet. As we shall see later, it was the American who would lead the fight against the much more radical mobilist view that today’s continents had indeed been together in Gondwanaland and then drifted apart to create the oceans. The opening shots in this war of ideas were to be fired from a very unlikely source: Ice Age geologist and expert on the origins of the Great Lakes of North America, Frank Bursley Taylor.

In the opinion of the writer the movements of the continental land masses are not in accord with any form of contraction hypothesis but are in perfect accord with the action of a tidal force. F.B. Taylor, 1923

Frank Taylor was a small-town college dropout with some very big ideas. Born in Fort Wayne, Indiana, in 1860, he had studied geology and astronomy at Harvard but failed to complete his degree because of ill-health and left the university in 1886. Thereafter, his geological investigations were financially supported by his father, a successful lawyer made wealthy by his expertise in writing patents for newly invented electrical and telephone equipment. Frank had a prodigious talent for seeing the forest as well as the trees, and in the early years of the nineteenth century he became an expert on the Ice Age geology of the Great Lakes region and a specialist on the geologic history of Niagara Falls. He published many papers with the US Geological Survey on the rocks and their fossils that underlie the Niagara Escarpment and surrounding areas. He was briefly employed by the Geological Survey of Canada to map Ice Age landforms in Southern Ontario and his 1913 report is still a classic; in it he showed the value of using the first crude air photographs to identify glacial landforms, and his work underpins modern mapping today, using much more sophisticated satellite imagery. He would explore the geology of the Great Lakes region by horse and buggy, with his wife driving while Frank worked on his maps. Taylor was intrigued with the origin of mountain ranges and their crumpled rocks, which he saw as the record of enormous compressional forces acting on the 29

Tuzo: The Unlikely Revolutionary of Plate Tectonics

formerly united and crept away in opposite directions. The mid-Atlantic ridge remained unmoved and marks the original place of that great fracture.” This is a remarkably prescient interpretation of what we shall see was to be proposed as “sea floor spreading” five decades later. Yet Taylor’s hypothesis was largely dismissed or just simply ignored. Geologists were prepared to go so far and accept some lateral movement of continents, say by a few tens of kilometres, as was predicted by the contraction hypothesis that the Earth was getting smaller as it cooled, but movement over the huge distances needed to form wide oceans and throw up big mountains was unacceptable. In particular, Taylor’s explanation of the mechanism underlying continental mobility was considered inadequate; he had proposed that the Moon had become a satellite of the Earth only relatively recently during the Cretaceous some 70 million years ago, and that it had also been much closer in the past. The resulting tidal forces had been sufficiently powerful, he argued, to break up the large polar land mass and move continents toward the equator like enormous landslides gliding across the Earth’s surface across weaker rocks beneath. Taylor acknowledged that he had been profoundly influenced by Suess’s masterful compilation of the geology of the southern continents, especially by his argument for the existence of Gondwanaland. “Crustal flakes” and migrating continents were a step too far for the permanentists, but the animated discussion that followed publication of Taylor’s model did at least help bring about a short-lived truce in the battle between permanentists and mobilists by establishing one area of mutual agreement – tidal forces were insufficiently strong to have any effect on the mobility of the Earth’s crust. It was pointed out by his critics that

Frank Bursley Taylor. A glacial geologist by training, he is credited with the first modern concept of continental mobility. Courtesy of the Geological Society of America.

Earth’s crust. Unlike Suess, who argued that this reflected contraction of the Earth’s circumference as it cooled, Taylor proposed that the mountains were the result of moving and colliding continents. He was the first mobilist and outlined his radical theory, called “Earth’s Plan,” at the 1908 Annual Meeting of the Geological Society of America in Baltimore, Maryland. The principal North American permanentists, Charles Schuchert of Yale University and Arthur P. Coleman of the University of Toronto, were in the audience. Taylor stood up and proposed that continents had previously been clustered together as a large ancestral land mass at the North Pole and had then drifted apart. The process, he argued, was driven by tidal forces exerted by the Sun and the Moon and was still going on. The continents were creeping equatorward, pushing up the western mountains of North America, the Alps in Europe, and the Himalayas in Asia, much like bow waves in front of a large moving ship. A fuller treatment of his intriguing model was published in the Bulletin of the Geological Society of America in 1910. It presented a remarkably modern picture of continents moving like large slabs, which he called “crustal flakes,” and highlighted clear evidence of the “many bonds of union which show that Africa and South America were

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Continents Adrift?

Frank Taylor’s “Earth’s Plan” of 1908. The breakup of the large polar land mass and the migration of North America and Eurasia resulted in intense collisions with the southern continents of South America, Africa, and Australia buckling rocks into high mountain ranges such as the Alps and Himalayas.

if tidal forces had in fact been so large, they would have completely stopped the Earth’s rotation. It was also accepted somewhat grudgingly that in the extremely unlikely event that continents had moved, they were driven not by external forces but by internal processes happening deep within the planet. In this regard, Taylor’s other work on the Ice Age geology of the Great Lakes region gave him a clue to a possible deep-seated mechanism in the mantle lying deep below the crust. Taylor and others had carefully surveyed the heights of ancient shorelines left by the enormous predecessors of the modern Great Lakes, which had been briefly dammed up by a great ice sheet that had been as much as 3 km thick during the last Ice Age, reaching its maximum extent about 20,000 years ago. The great weight of the ice had pushed down the Earth’s crust by as much

as several hundred metres. Taylor’s careful surveying showed that the beaches had been uplifted and raised in elevation as a result of unloading and “rebound” of the Earth’s crust when the ice sheet had finally thinned and melted away. However, he also showed they weren’t horizontal but warped and became higher in elevation when traced toward the former thicker and much heavier centre of the ice sheet over Quebec and Labrador. Here was conclusive evidence that the underlying mantle was not rigid but could be pushed down and moved laterally under the great weight of a large ice sheet, to then recover (much like memory foam) once the ice melted. The implication was that a mantle sufficiently soft and mobile to allow vertical movement of the Earth’s crust might also be weak enough to permit the gliding of rigid “crustal flakes” across its surface.

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A staircase of raised beaches now high and dry along the coast of Nunavut, Arctic Canada. These result from crustal uplift in the last 6,000 years in response to melting of the last great ice sheet to have covered northern North America and unloading of the underlying mantle, which had been pushed down under the great weight of the ice. As each beach is uplifted, a new one forms at sea level only to be raised up in turn. The oldest beaches occur at the top of the staircase. To geologists such as Frank Taylor, this was clear evidence that the mantle was soft enough to deform and permit the drift of continents as giant “crustal flakes.” Courtesy of Mike Beauregard, Government of Nunavut.

Continents Adrift?

At the same time, mapping of the geology of the world’s mountains, especially the Alps and the Rocky Mountains, was revealing more and more evidence of huge lateral displacements of Earth’s crust. Their rocks had been pushed laterally many tens of kilometres and, in the process, folded and refolded again and again like a crumpled carpet. In 1886 the Canadian geologist Richard McConnell reported to his employers at the Geological Survey of Canada that the dominant structure of the Rocky Mountains in Alberta is “a series of gigantic thrust faults, which have carried the older formations forward, and placed them above the highest beds of the series.” Modern estimates suggest blocks of crust as much as 15 km thick have been shoved en masse over a distance of at least 50 km. On the other side of the Atlantic, geologists such as Emile Argand and Albert Heim had mapped similarly deformed rock layers in the Alps of France and Switzerland that had clearly been thrust over long distances. They identified great thicknesses of rocks that had been repeatedly folded and then refolded, to which they gave the name “nappe” in reference to their resemblance to a creased and folded tablecloth. When the Alpine nappes were unfolded (“balanced”) and the rock layers stretched out to their original lengths, it pointed to lateral movements of as much as 500 km. The Scottish geologists Ben Peach and John Horne similarly recognized that the Highlands of Scotland were composed of rocks that had been pushed over much younger rocks by as much as 200 km, far in excess of any possible movement caused by contraction of the planet’s surface as it cooled. The English geophysicist Reverend Osmond Fisher, in his Physics of the Earth’s Crust published in 1881, calculated the change in Earth’s radius resulting from contraction and showed it to

be “totally inadequate” to account for the emerging evidence of great horizontal displacements of Earth’s crust. Nonetheless, despite the steadily accumulating evidence for powerful pushing forces at work, most geologists at the time resolutely clung to the permanentist concept of compressive forces created on the surface of a cooling, contracting planet. In this regard, the influential and highly regarded American geologist Bailey Willis had published The Mechanics of Appalachian Structure in 1893, in which he ascribed the structure of these mountains to compression caused by contraction. The seemingly definitive word on the origin of folded rocks in mountains was written in 1906 by Thomas C. Chamberlin and Rollin D. Salisbury, the eminent heads of the Geology and Geography Departments at the University of Chicago, and founders and editors of the Journal of Geology, considered by many to be the official voice of the discipline in North America. Their impressive and widely adopted three-volume Textbook of Geology published in 1906 stated that “the essence of the movement may be assumed, with some confidence, to have been shrinkage of the Earth.” The possibility that land masses themselves might have moved was ignored. Ironically, Thomas Chamberlin was well known for advocating that scientists should always keep an open mind and needed to consider what he had named “multiple working hypotheses” rather than dogmatically following one single “ruling hypothesis.” But in regard to his views on mobilism, Chamberlin failed to practise what he preached, and his contemporary, Canadian geologist Norman Bowen, noted for his work on volcanic rocks, famously retorted that as practised in the real world of science, it might be better called the “method of multiple prejudices.”

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Structure of the Canadian Rocky Mountains near Banff, Alberta, based on original mapping by R.G. McConnell of the Geological Survey of Canada in 1886. It is typical of many “fold and thrust belts” that record shortening of the crust (by thrusting from left to right), not because of a contracting Earth as advocated by permanentists, but from migrating and colliding continents.

Ridges near Banff, commonly known as “writing table” mountains because of their appearance resulting from the thrusting of great thicknesses of rock (to the right).

In the Swiss Alps, originally flat and undisturbed rock layers have been pushed and bent into overturned folds called “nappes” after their resemblance to a folded tablecloth. From original drawings by Albert Heim.

To most nineteenth-century geologists, these strongly folded rocks were the result of cooling and contraction of the Earth.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

volcanicity … are undoubtedly connected causally on a grand scale.

Frank Taylor’s radical ideas on moving continents and giant collisions between moving crustal flakes expressed as enormous buckles in the rocks of mountain ranges were ignored in the prevailing permanentist world view that dominated North American universities. His ideas did, however, generate keen interest on the other side of the Atlantic, where his basic ideas would re-emerge a few years later as a ground-shaking hypothesis on how the Earth worked. Proposed in 1915 by German atmospheric physicist Alfred Wegener amidst the greatest global conflict the world had ever seen, it was to trigger a scientific war of words that was to last for more than half a century. The battle lines between permanentists and mobilists were now to be drawn up, and a half century of trench warfare between opposing scientists began in earnest.

Alfred Wegener, 1915

If we are to believe Wegener’s hypothesis, we must forget everything which has been learned in the last 70 years and start all over again. Bailey Willis, 1922

The Origin of Continents and Oceans, published in Germany in 1915 by Alfred Lothar Wegener, methodically laid out geological evidence in support of a former supercontinent which he named “Pangea” (Greek for “all the lands”), surrounded by a single ocean “Panthalassa” (“all the sea”) that Suess had named earlier. This enormous land mass occupied almost 25% of the Earth’s surface area and included Eduard Suess’s Gondwanaland (the large southern land mass composed of Australia, India, Antarctica, and Africa), together with a northern land mass that incorporated North America, Europe, and Asia (later to be named “Laurasia” by the South African geologist Alex Du Toit). Then, however, Wegener departed from previous ideas by making the radical argument that Pangea had broken apart and the present-day continents had drifted away, leaving oceans in their wakes. Moreover, they were still moving. The title of his book was very specific, because Wegener considered Pangea to be the urkontinent, the original primeval land mass, from which all the modern continents had sprung. He was very careful to stress that it was a working hypothesis to be amended and altered by new evidence. Wegener was a most unlikely candidate to propose a grand theory on the origin of continents and oceans. He

The “Fairy Tale” of a Mere Meteorologist: Wegener’s Pangea and Continental Drift In the following paper, a first rough attempt will be made to interpret the genesis of the large forms of our Earth’s surface, i.e., the continental plates and the oceanic basins, by one single encompassing principle, namely by the principle of horizontal mobility of the continental plates. Alfred Wegener, 1912, translated from the German by Alan Krill

The forces which displace continents are the same as those that produce great fold-mountain ranges. Continental drift, faults and compressions, earthquakes,

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Continents Adrift?

Alfred Lothar Wegener, soldier, atmospheric physicist, accomplished Arctic explorer, and discoverer of the supercontinent Pangea, smoking a pipe at the “Borg” research station during the Danish expedition to north Greenland in 1912–13. Courtesy of Archive for German Polar Research, Alfred Wegener Institute.

was not a geologist but an accomplished physicist, an expert on atmospheric circulation and the formation of raindrops, an experienced polar researcher and explorer who had crossed the Greenland Ice Cap on foot. He was the first scientist to overwinter there, enduring much physical hardship and danger in ascending the fast-flowing and heavily crevassed outlet glaciers around the ice sheet margin, during which his health suffered, and he developed heart palpitations that would later kill him. He had accurately measured the great thickness of the ice sheet by exploding dynamite on the ice surface and measuring the return times of seismic waves bouncing off bedrock many hundreds of metres below. With his elder brother Kurt, he held the world record for the longest continuous balloon flight of fifty-two hours, which they completed in 1906 to test

Wegener’s 1915 reconstruction of Pangea in the Carboniferous period (approximately 300 million years ago), and its subsequent breakup, which he argued had started in the Eocene some 60–70 million years ago.

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A modern reconstruction of Pangea. To geologists like Eduard Suess, the presence of rocks of the same age with the same fossils of organisms on now widely separated continents such as Africa, Antarctica, and South America, including India and Australia, that could not have swum across open oceans was compelling evidence of a larger land mass he called Gondwanaland. Suess proposed that the ocean floors then subsided, isolating continents that remained fixed in their original position. Alfred Wegener went one step further and argued that the southern continents had drifted apart from Gondwanaland, leaving oceans in their wakes. Wegener’s principal opponent, Charles Schuchert, the most outspoken of the North American permanentists, would disparagingly refer to the German’s reconstructions of Pangea as the “Wegener sliding circus” as if it were of no scientific value, only an amusing sideshow of performing animals travelling around the planet.

Continents Adrift?

meteorological and navigational equipment. Exploring by drifting along in a balloon was one thing; entering the unfamiliar terrain of geology and arguing that the continents could drift was quite another. Wegener had read and been intrigued by Frank Taylor’s 1910 paper on “Earth’s Plan,” with its depiction of continents as drifting “crustal flakes,” and he gave his first public lecture on the topic, to a decidedly mixed reception, on 6 January 1912 at the annual meeting of the newly formed Geology Association in the Senckenberg Museum at Frankfurt, preferring to give it there than at the more traditional German Geological Society, perhaps anticipating some hostility to his ideas. His talk was entitled “Die Heraushebung der Groomsman der Erdrinde (Kontinente und Ozeane) auf geophysikalischer Grundlage” (The formation of large features of Earth’s crust [continents and oceans] explained on a geophysical basis). It was later published in July of that year as an article in Geologische Rundschau, a leading and well-read German publication. In early August 1914, as a reserve officer in the Grenadier Guards, Wegener was mobilized for war service and took part in the German invasion of Belgium, interrupting further scientific progress on drifting continents. There, while involved in attacks on heavily fortified Belgian forts, Lieutenant Wegener witnessed the effects of high explosives in forming huge craters. He suggested that the craters on the Moon’s surface, then widely considered as formed by volcanic explosions, were produced by meteorite impacts. This was shown to be correct in the early 1960s by none other than Robert Dietz, whom we shall meet again later as a pioneer of early plate tectonic theory. Dietz was also the first geologist to identify the impact origin of the 150-km-wide Sudbury Basin in Ontario formed some 1.8 billion years ago. Unfortunately, Wegener also personally experienced the effects

of high explosives on the front line, suffering arm and neck wounds in combat. But he used the time recovering in hospital to expand on his ideas and write his now-famous book. He had formed a very close working relationship and friendship with the eminent geologist Hans Cloos, who, while being skeptical of Wegener’s notion of moving continents, provided much helpful advice on the geology of the continents, especially regarding the close resemblances of their rock records, indicating they had once been part of a larger land mass, Pangea. A modest tome of ninety-four pages, Wegener’s book was published in 1915 and set out the case for migrating continents following the breakup of Pangea some 70 million years ago. Slim it may have been, but it had much wider implications that were to prove highly controversial and ultimately had fatal consequences for its author and his grand hypothesis. Wegener opened his book with words that echo those of Sir Francis Bacon three hundred years earlier: “He who examines the opposite coasts of the South Atlantic Ocean must be struck with the similarity of the coastlines of Brazil and Africa.” He added that “the first notion of the displacement of the continents came to me in 1910 when studying the map of the world. I was impressed by the congruence of both sides of the Atlantic coasts.” Wegener dismissed notions of former land bridges between today’s continents, pointing to the great depths of the oceans. He also marshalled a wealth of geological evidence (as had Eduard Suess before him) clearly establishing that the continents of the present day had formerly been locked together within a single land mass. The succession of rock types and their fossils was the same found on either side of the Atlantic Ocean and across much of India, Antarctica, and Australia. Moreover, he saw that mountain chains often ended abruptly at 39

Ancient climate belts across Pangea ranging from the South Pole to the tropics were reconstructed by Wegener and Köppen in 1924 from the type and distribution of rocks that had been deposited in deserts, the tropics, and high latitude and polar regions. The distribution of ancient fossil organisms similarly made a compelling case for the existence of the former supercontinent.

Glaciers and ice sheets carry bouldery debris at their base that cut deep scratches called “striations” on their beds. When deposited, this debris leaves poorly sorted rocks called tillites (lower left). Ancient striations and tillites that are some 350 million years old can be mapped across today’s southern continents, but the ice flow directions they record indicate that ice would need to have moved across large oceans. On a reassembled Pangea with the continents clustered together, the striations make perfect sense, recording the outward flow of a large ice sheet centred over Antarctica.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

coastlines but are of the same character and structure as those on opposing coastlines now on another side of an ocean. They were clearly ends of the same chain. Unfortunately, because of page restrictions on the original German printing of Wegener’s book in 1915, some of the all-important maps showing how climate belts could be reconstructed from rocks across Pangea based on their distinctive fossils and characteristics had been omitted. These were later published in 1924 in a book co-authored with his father-in-law, the eminent climatologist Wladimir Köppen (who had developed separately the Köppen climate classification still in use today). In Die Klimate der Geologischen Vorzeit (The climates of the geologic past) they laid out the former climate belts on Pangea from the cold high latitudes of the South Pole dominated by cold climate glacial rocks called “tillites,” to rocks that formed along the equator and tropics with their fossils of tropical tree ferns and thick coal deposits. The geological evidence for Pangea was convincing, at least to some. Wegener speculated that Pangea had broken apart quite recently, some 60–70 million years ago, but this is now known to be a considerable underestimate; it began breaking up at least 100 million years earlier, just after 200 million years ago. Accordingly, based on the mean width of today’s Atlantic Ocean (about 3,000 km), he greatly overestimated the annual rate of drift of Europe away from North America. This was a major error for which he would pay dearly in 1930 when attempting to directly measure the rate of movement of Greenland from Europe. He used the transatlantic telegraph cable system to determine the differences in time of the astronomical “fix” of the same star when passing over different

observatories in North America and Europe; the difference reflected the longitudinal separation between the observatories; repeated measurements over some thirty years suggested an increased separation, consistent, so Wegener argued, with ongoing continental movement. The scope of Wegener’s book was expanded in 1922 but was not translated into English until 1924, and the fourth edition published in 1929, in which he clarified many of his ideas, was not translated until as late as 1966. This delay was unfortunate, because the barrage of criticism that arose in the early 1920s was mostly from North American geologists whose comments being published in English received much more attention than the original arguments and data presented in the book itself. Opponents focused on Wegener’s estimate of the rate at which continents moved and his apparent failure to identify a specific mechanism to explain how they might move. In fact, he had been very careful not to identify an underlying mechanism that would allow continental drift, clearly stating in his book that he was reluctant to do so until he had gathered more data. To Wegener, continents were seen as rafts of much lighter rocks (which he collectively referred to as “sial” after their dominant constituent minerals silica and alumina) floating on heavier, more dense rocks below (sima after silica and magnesium), which underlay the oceans. The continents were likened to giant icebergs ploughing their way across a hot plastic sima, buckling the rocks along the leading edges of continents into great mountain belts such as the Cordillera and Andes that lie on the western sides of North and South America, leaving ocean basins trailing behind in their tracks like huge plough marks. Wegener was to later acknowledge the influence of Taylor’s concept of continents migrating

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Continents Adrift?

away from the North Pole, which Wegener named as “polar flight” in response to gravitational attraction of the Earth’s equatorial bulge. Indeed, there is such a force but it is far too weak to move crust around. The first shots at Wegener were fired in anger from the other side of the Atlantic in April 1922. They came from the pages of the Pan-American Geologist, a privately published journal, and were written by Charles Schuchert of Yale University. He entirely rejected the German’s thesis and reaffirmed the scientific ascendancy of North American permanentist views on continents and oceans as being fixed and unmoving. Later that same year, the Geological Society of America was sufficiently intrigued that it held a special session on the subject at its annual meeting in Ann Arbor, but only a single delegate (Reginald A. Daly, whom we shall meet later) spoke in favour of Wegener’s ideas. The next year, the anti-drifter Philip Lake of the Sedgwick Museum in Cambridge, England, wrote highly critical reviews of Wegener’s theory in the Geographical Journal and Nature, where he mistakenly referred to it as “Continental Drift.” Wegener had never used the term, instead referring to it as Verschiebungstheorie (displacement theory), but Lake’s term was much easier to visualize and has stuck. In a simple experiment, Lake attempted to assemble plasticine replicas of the continents into a single land mass on a small globe. He was so unimpressed with the overall fit that he rejected the entire hypothesis, declaring that “it is not even a proof that the pieces belong to the same puzzle, or that all the pieces are present” and that Wegener had “given free play to his imagination.” In his 1924 review of Wegener’s model, published in Science, Edward Berry declared it to be “German pseudo-science.”

In general, the reception to Wegener’s grand idea was more favourable in Britain and its far-flung outposts around the empire, where its geologists had a broader global outlook imparted by the need to find the mineral resources to fuel the imperial engine. Lake had presented his highly critical views of Wegener to the Royal Geographical Society in London in January 1923 but scored an own goal because the following speakers were much more positive and their criticism was directed instead at Lake himself for his rather melodramatic oversimplification of continental drift. Speaker after speaker recognized that though the details might be questioned, and an underlying mechanism only vaguely defined, the German had done their science a great favour by proposing a grand idea that didn’t seem all that outlandish in its broad strokes. The reaction on the other side of the Atlantic was rather different. The American Association of Petroleum Geologists then organized a special conference in November 1926 in New York to review the new theory. It was held at the suggestion of Willem A.J.M. van Waterschoot van der Gracht, who was an experienced Dutch geologist and vice-president of Marathon Oil Company. By the mid-1920s, the first phase of oil exploration – that of drilling into anticlines, where rocks had been folded into broad arch-like folds that trapped oil moving upwards from deeper source rocks – was now over. The search for new resources would require better knowledge of more complex geologic structures and how they had formed. Van der Gracht also grasped that if continents had moved, sediments would have been deposited in vastly different climates and latitudes from where those rocks are now found today, with enormous implications for searching for

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

the all-important organic-rich source rocks such as shales, which yield oil and gas. If correct, Wegener’s grand hypothesis could be of enormous economic potential to the oil industry. As we shall see, recast four decades later as plate tectonics, it has indeed proven to be fundamental to unlocking not just oil and gas reservoirs but also the planet’s mineral wealth. But all that lay in the future, and Wegener’s ideas were now to be examined by a mostly North American audience fixated on unmoving continents and oceans. The attendees in New York included the cream of North American university geologists, and they arrived with their permanentist minds firmly shut. Wegener did not attend the meeting and in absentia was subjected to ill-informed criticism, much of it contemptuous and very personal. His hypothesis was varyingly mocked as “poppycock” and “not scientific,” and he was derided as a scientific outsider, guilty of “meddling” in geology. Charles Schuchert described the results of yet another experiment, like that conducted earlier by Philip Lake, where pieces of plasticine cut in the shapes of the continents were placed on a globe to recreate Pangea. The demonstration was clearly designed to fail from the outset because the reconstruction was so sloppy and poorly done that it resulted (as no doubt intended) in large gaps and mismatches. Schuchert concluded that Wegener had taken “extraordinary liberties” with the Earth’s crust. Much later, in 1965, Edward Bullard, who was to successfully fit the outlines of continents together within a reconstructed Pangea using early computers, would comment that Schuchert’s experiment had been deliberately designed to produce an “extraordinary and quite false result” to weaken the entire edifice of continental

drift. According to Bullard, “The whole story of the fits is an illustration of the sloppy way in which new ideas can be treated by very able men when their only object is to refute them.” But Schuchert’s ruse had worked, and at the conclusion of the New York meeting Lamoraal De Sitter, a well-known structural geologist working in the Netherlands, commented that it had “more or less put an end to the theory.” The first round of the war of words had gone to the permanentists. Wegener had the added burden of having to face widespread anti-German sentiment among the English-speaking scientific establishment after the First World War. The British astronomer W.W. Campbell reflected the sentiments of many, horrified by the human cost of high explosives on the Western Front and by the indiscriminate bombing of cities and civilians. He stated that during the war, Germany, as “the most scientific of all nations, had prostituted science to base ambition.” In presenting a theory about the Earth as a whole, Wegener had also reignited fears of German “supermen-in-­ science,” and the Royal Society in England was urged to exclude Germans from its membership and bar them from future collaborative scientific endeavours. In the United States, German place names were renamed; in Ontario, Canada’s most populous province, the city of Berlin was renamed Kitchener after the British general. German music was banned and university programs in Germanic studies much reduced in size and influence. Wegener was a modest man, by all accounts, who largely ignored and remained above the polarized debate raging between permanentists and mobilists. He never took criticism personally, and to him, whether his theory was “right” or “wrong” didn’t matter; there were so many moving parts to continental drift that

44

Continents Adrift?

it would never be proven right in its entirety. It was above all, he stressed, a work in progress, an idea that ultimately would live or die on its own merits. The important thing was that continents moved, not how. He wrote to a colleague in 1917 that he was unlikely to ever convince some geologists, and acceptance of his ideas might have to await the retirement and death of his opponents. As we shall see, in this he was correct in predicting his own fate and that of his grand idea. The next duel in the ongoing civil war between permanentists and mobilists would be fought over unusual 500-million-year-old fossils found on either side of the Atlantic. It would leave a prominent casualty whose arguments, much like Wegener’s, would be undermined in the eyes of his colleagues by his German background.

Great War could be extremely disadvantageous to one’s career. The most famous casualty of the bitter fighting that broke out after publication of Wegener’s book was Amadeus William Grabau of Columbia University. Born to German Lutheran parents in 1870, Grabau was an excellent and highly productive scholar, an expert on fossil organisms, principally brachiopods. These are a type of marine organism that still live in the oceans and were particularly abundant between 500 and 300 million years ago. In 1909, and again in the following year, Grabau published two massive books, each one close to 1,000 pages long, that set up the foundations for using different species of brachiopods as “index fossils” to fingerprint the different layers of rock in which they are found. This was of great value in matching (correlating) rock strata over long distances (and most significantly from one continent to another). A noted and well-liked professor at Columbia, he mapped the global distributions of fossil brachiopods and, after initially opposing ­Wegener’s arguments for migrating continents, he began to see patterns that could not be explained by a static, unchanging Earth and the views of his colleague, the leading North American permanentist, Charles Schuchert of Yale University. Schuchert was a self-made academic, an amateur who had excelled. He had left school at the age of fourteen to work in his father’s furniture business in Cincinnati, where he developed a prodigious talent for collecting and classifying fossils from the cliffs of shale exposed along the Ohio River. After working as a museum curator, he was appointed as a faculty member at Yale in 1904; being unschooled himself, it was said that when he gave his first lecture, it had been

Charles Schuchert and Amadeus Grabau: The Battle over Land Bridges The writer belongs in the last-named school, holding that both continents and oceanic basins are, in the main, permanent features of the Earth’s surface. Charles Schuchert, 1932

The treatment of the subject matter of Historical Geology employed in the present volume is a somewhat radical departure from that usually followed in textbooks. A.W. Grabau, 1921

Admitting to any interest in mobilism and offering any sympathy for Wegener and German interests after the

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LEFT: Charles Schuchert of Yale University was vigorously opposed to Wegener’s theory of moving continents. He was a paleogeographer whose expertise lay in making maps such as the one on the wall behind him showing ancient seaways that once flooded a fixed and unmoving North America. Courtesy of Yale Peabody Museum. RIGHT: Amadeus Grabau, dismissed from Columbia University in 1919 for being unpatriotic. Thereafter he could only find employment abroad, at Peking University in China. Courtesy of the Geological Society of America.

420-million-year-old Silurian brachiopods, about the size of a quarter. They are commonly named “lamp shells” after their resemblance to Roman oil lamps. They were the subject of intense debate among geologists, and the geographic distribution of various types in ancient rocks was seen as evidence by permanentists such as Charles Schuchert of narrow land bridges connecting fixed continents, dividing large oceans into separate seaways populated by different groups of organisms. Reproduced from Amadeus Grabau’s Textbook of Geology (1921).

Continents Adrift?

his only experience of attending an undergraduate class. He became the internationally acknowledged expert on the evolution of the North American continent as, unmoving and fixed in position, it was successively covered and uncovered by shallow seas that lapped across its surface. In 1910 he published Palaeogeography of North America, which contained 50 maps showing the changing outlines of the continent; updating these maps was to be his life’s work, and their number expanded to 85 by 1913 and to more than 130 by 1922, when he gave his presidential address to the Geological Society of America. His paleogeographic maps were dutifully reproduced in textbooks and when displayed in classrooms across North America became the officially sanctioned snapshots of how the continent had evolved. Schuchert laboured long and hard (day by day for more than thirty years, according to his colleagues) drawing ever more elaborate maps of the changing configuration of the continent over the last 550 million years. His life’s work was the mammoth 1,013 page Stratigraphy of the Eastern and Central United States published posthumously in 1943. In it he recognized three phases of mountain building along the eastern margin of the continent, named the Taconic, Acadian, and Appalachian – all classic terms that are still in use today but now have a very different significance, as we shall later see. The Schuchert Medal for “excellence in research” is still awarded annually by the Paleontological Society. Schuchert and others, such as Charles Doolittle Walcott (who you may remember married Hetty Wilson’s friend Mary Vaux), recognized that ancient Cambrian (500-million-year-old) marine-dwelling brachiopods and trilobites could be divided into two very different

groups. These were named “Pacific” (predominating along the western and southeastern margins of North America) and “Atlantic” (occuring in Europe). But there was a curious feature about their distribution around the Atlantic. North American Pacific-type brachiopods and trilobites also occur locally on the other side of the Atlantic in Scotland in rocks right next door to those containing “Atlantic” fossils. Similarly, rocks with Atlantic-type fossils in Newfoundland and Nova Scotia occur shoulder to shoulder with their Pacific cousins. How could the two groups of organisms have lived within the same Atlantic Ocean but been kept separate such that they couldn’t intermingle? Schuchert thought he had the answer to this conundrum and drew a narrow “land bridge” on his paleogeographic maps, forming a barrier of dry land running right across the Atlantic Ocean through Iceland. In his mind, it had kept the two groups of organisms apart in their own enclosed seaways. In Rhythm of the Ages, published under difficult wartime conditions in 1940, Amadeus Grabau took a very different tack from Schuchert, emphasizing the similarities between the mountain chains either side of the Atlantic. He proposed, like Wegener and Du Toit, that these ranges were formerly conjoined on Pangea. But Grabau went one significant step further than his predecessors and argued that juxtaposing Pacific and Atlantic marine organisms had simply lived on opposing coastlines of the ancestral ocean that had closed as Pangea came together. Rocks containing Atlantic types now in North America, and rocks with Pacific types now in Europe had simply been left behind as the present-day Atlantic Ocean had opened subsequently as Pangea later broke apart. There was

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A puzzling feature of the geology of the margins of the North Atlantic Ocean is the presence of long belts of Cambrianaged rock (500 million years) lying side by side. Whereas the rocks are of the same age, their fossils (such as trilobites and brachiopods) are so strikingly different that they form tribes that clearly did not cohabit the same waters. This paleographic map of the Cambrian was drawn in 1923 by the arch-permanentist Charles Schuchert. It depicts a narrow land bridge running across the Atlantic that had supposedly kept different tribes of organisms quarantined in their own separate seaways.

Continents Adrift?

Reproduction of the 1932 map made by Charles Schuchert and published in the Geological Society of America Bulletin showing continents connected by multiple land bridges in the Permian about 280 million years ago. Bridges would rise up and allow the migration of plants and animals, and then sink. The Bulletin papers of Schuchert and Willis on land bridges mark a watershed in the American debate on continental drift. Intended as a declaration of core permanentist beliefs designed to fend off foreign ideas on moving continents, they effectively halted any informed open debate on the merits of Wegener’s ideas in North America until the mid-1960s.

no need for a land bridge connecting fixed continents to explain the seemingly puzzling distribution of the fossils; the continents themselves had moved! It was an elegant but controversial solution to the puzzle, but his ideas on the existence of an ancient ocean that had predated the Atlantic were simply ignored. Undeterred, Schuchert and Bailey Willis would eventually

publish a succession of articles on the existence of permanently fixed continents linked by ocean-crossing land bridges (isthmian links) in the Geological Society of America Bulletin, the foremost journal of geology in North America. In their minds, land bridges rose up to divide oceans into separate waterways, each with its own distinct marine organisms, and also allowed

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

migrations of land-dwelling organisms and plants from one continent to another. The bridges would then sink, creating oceans between unmoving continents, just as Eduard Suess had originally proposed. But how might land bridges form and how might they have sunk? Wegener had been taken to task for his failure to identify a process that might allow continents to drift, but the permanentists had never specified how land bridges could be raised up from the depths of the oceans and later suddenly founder and disappear. As the evolutionary biologist Stephen Jay Gould has commented, it is strange that while Schuchert and others were perfectly content to build land bridges “flung with daring abandon across 3,000 miles of ocean,” they could not accept the basic premise of continental movement. Like Wegener before him, nationalist sentiments clouded appreciation of Grabau’s scientific contributions. His German parentage and upbringing didn’t help in the immediate aftermath of the First World War, and his professorial position at Columbia University was abruptly terminated in 1919, it is said (the records were later destroyed) on the grounds of his being insufficiently patriotic. During the war he was known to fly a German flag from the window of his study, he spoke German at home, and was also – very unhelpfully, in the eyes of some of his enemies on campus – married to the well-known and best-selling socialist writer Mary Antin. She was a Russian-Jewish immigrant who had escaped the deadly grip of Russian anti-Semitism and whom he had met when she had attended his lectures; she was interested in the seashells found on Boston’s beaches at low tide. Her

lucid account of her difficult upbringing in Russia, immigration to the United States, and her life in the squalid slums of Boston was published as The Promised Land in 1912 and lauded by Theodore “Teddy” Roosevelt as a literary classic. Her lectures on the subject earned enough money for the couple to buy into the upscale neighbourhood of Scarsdale. Ironically, in view of the name of her book, but tragically too, her husband was unable to find any work in the United States after his dismissal from Columbia and left Mary and his daughter in 1920 to accept a position at Peking University in China, only returning to the United States once, in 1933. After a long and successful career working on the geology of China, Grabau wrote Rhythm of the Ages, in which he showed what he considered to be the changing positions of continents through time. Crippled with rheumatism in later life, he died in 1946 after having been captured and mistreated by the invading Japanese Imperial Army and imprisoned in the former British Embassy in Peking. Revered today as the “father of Chinese geology,” he is buried on the campus of Peking University, and the Grabau Gold Medal is the highest honour that can be bestowed by the Geological Society of China. His obituary in the journal Nature noted, “His radical opinions, expressed with a forthrightness not always to the liking of more conservative minds, touched not only American and Asian geology, but also impinged forcibly on the fundamentals of world geology.” Too late to help Wegener, Grabau’s book would gather dust, but his ideas would later greatly influence Jock Wilson who, as a convinced permanentist, met several of Grabau’s

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Continents Adrift?

students on a visit to China in 1958 and became aware of his earlier work. Three years later, Wilson was to abandon his belief in fixed continents and abruptly convert to mobilism, arguing that oceans closed and opened like an accordion. Grabau’s contributions would be fully recognized many years later, but in the interwar years after 1918

there were other powerful reasons why North American permanentists felt confident that continents could not move, as we shall explore next. Continents and oceans had been created much as we see them today as part of a divine plan that could not be questioned. A potent weapon was brought to bear upon ­mobilists – that of religion.

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Chapter 3

Sources of Friction

The great ocean basins are permanent features of the earth’s surface and they have existed where they now are with moderate changes of outline since the waters first gathered. Bailey Willis, 1910

Once a continent always a continent and once an ocean basin always an ocean. Charles Schuchert, 1915

Dana long ago well said: “America is the type continent of the world.” North America is the type continent, because of its simplicity of geologic structure, not only throughout its vast extent but also throughout the geologic ages. Charles Schuchert, 1932

Opposition to mobilism was most intense among senior North American geologists, reflecting the continuing influence of James Dwight Dana (1813–1895) of Yale University. Dana was a committed permanentist and highly accomplished mineralogist (his 1848 textbook Manual of Mineralogy is still in print today in its twenty-third edition); he was well-travelled, especially around the Pacific Ocean, and was an expert on the geology of Hawai’i and California. In 1840,

Dana recognized that the Hawai’ian volcanoes rising steeply from the ocean floor were part of a long chain of islands oriented to the northwest and suggested that they got older with distance away from the Big Island of Hawai’i. Jock Wilson would later return to Dana’s observation and use it as evidence that ocean floors are on the move, carrying volcanoes and continents alike – this was Jock’s “clue as to how Earth behaved.”

Tuzo: The Unlikely Revolutionary of Plate Tectonics

In 1873, Dana proposed that planet Earth had originated as a molten ball of magma that was still cooling and contracting; continents formed as permanently fixed nuclei that then slowly expanded in situ. He made great play of the fact that the oldest rocks occur in the centres of continents (such as the Canadian Shield in North America) and proposed that land masses expanded from these small nuclei by new crust being added to their margins. Here he then borrowed an idea proposed in 1859 by his fellow American James Hall, who had argued that continental growth was accomplished by down-warping of the ocean floor around the margins of the continent, forming deep troughs, much like moats around castles, that he called “geosynclines.” These giant depressions slowly filled with enormous thicknesses of debris and sediment eroded from the surrounding continent and progressively sank, in the process pinching and squeezing its contents much like an enormous squeeze box, resulting in the pushing up of its now buckled and much compressed contents into high mountain ranges. It was argued that the repeated formation and filling of geosynclines recorded phases of accelerated contraction of the Earth’s circumference, defining distinct eras in Earth’s history that coincided with abrupt changes in organisms. In 1923, the Irish geologist and physicist John Joly excitedly wrote of “world revolutions” when “great ranges rose out of troughs of sediment,” which he argued occurred every 150 million years or so. It seemed to be a unified theory of how Earth had evolved: continents were fixed in place and had grown by the filling and contraction of geosynclines around their margins.

Geologists are, above all, practical scientists, and a central tenet taught to all students is that knowledge of present-day geological processes informs the study of ancient conditions preserved in rocks. This is the concept of “uniformitarianism,” or more simply that “the present is the key to the past.” The major question was where has a modern example of a mountain range been built from the destruction of a geosyncline. British geologists working for the Indian Geological Survey established in Calcutta (now Kolkata) in east India in 1859 thought they had the answer. The busy riverside city of Kolkata sprawls across the vast and very fertile Indo-Gangetic Plain built as a huge delta by the Ganges River as it flows into the Bay of Bengal. Over the past 15 million years, the river has dumped enormous volumes of mud and sand washed out from the rising and eroding Himalayan Mountains to the north. The Hooghly River is that branch of the Ganges that flows through the city, but its waters are badly polluted and cloudy with sediment. In sinking deep wells to capture clean groundwater, British geologists noticed at ever greater depths, even thousands of feet below the city streets, that their drills still pushed deeper and deeper through river sediments. It was quickly established that the city and the entire Ganges Delta is slowly sinking, much like a descending elevator under the weight of the accumulating sediment; newly deposited river sediments slowly subside and in turn become buried by new sediment deposited on top. Here, it was reasoned, was a modern geosyncline in the process of subsiding under the great weight of sediment; the giant Himalayan mountains inland to the north were reasoned to result from the destruction

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Dana’s permanentist model of 1873. A static North American continent expands from an old inner nucleus (the Canadian Shield) by repeated formation of deep geosynclines around its margins, their thick fills now preserved as mountain ranges such as the Rocky Mountains and Appalachians. The interior lowlands were created by inland seas that episodically flooded and retreated from the continental interior, leaving great thicknesses of flat-lying sedimentary rocks on the outer margins of the Shield.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

of an earlier geosyncline, supporting the notion that fixed continents expanded in size by the successive filling and contraction of deep geosynclinal moats around their margins. Dana’s 1873 theory quickly became the dominant North American view of how all continents evolved – what scientists call a “ruling hypothesis” – that would dictate how geologists thought well into the 1960s. Fundamentally, the geosynclinal theory invoked a gigantic inversion of relief (from the depths of the geosyncline to high uplifted mountains), and it became widely accepted to view large-scale folds and thrusts (the “nappes” of Alpine geologists) as the product of downhill sliding as the mountains grew in height. Dana’s theory reigned supreme, and there was an important dimension to his argument that Wegener was simply powerless to overcome: Dana and many of the elite North American permanentists were united in their belief that they had God on their side. As a child, Dana was raised in a strict puritan household in Utica, in Upstate New York, where the biblical scriptures were taken literally. The North American continent was the purest example of “God’s plan of creation” built by a “supreme architect,” in contrast to the lands of the Old World on the far side of the Atlantic, which were regarded as decadent, much like the lifestyles and politics of its inhabitants. Religious dissidents had migrated to the shores of North America to avoid persecution. In their world view, natural evolution of species was rejected in favour of creationism, and the history of life on the planet was envisaged as a simple God-driven progression from simple life forms to humankind, illustrating what Dana called “the spiritual element in geological history.” Because of his position

as editor of and frequent contributor to the prestigious American Journal of Science, Dana’s views became widely disseminated and the basis of the American school of permanentism. It has been said that Dana acted as pope in spreading his views, and indeed many of his papers now read like sermons. Charles Schuchert’s review of the theory of continental drift in the American Journal of Science in 1928 declared, in clear deference to the work of his mentor Dana, “The battle over the theory of the permanency of the Earth’s greater features has been fought and won by Americans long ago.” Some went so far as to state that the fit of Africa and South America had been made by the devil himself to vex geologists. The Canadian geologist Arthur Coleman, a former president of the Geological Society of America who would later teach Jock Wilson at the University of Toronto, stated in 1924 that the role of geology, as a science, “was to discover the history of creation and the methods used in building the world through the ages, to reveal the mind of the Master.” As the historian Naomi Oreskes has emphasized, it was in American universities that the “rejection of continental drift was most pronounced and hostile”; opposition to Wegener was viewed as nothing less than a crusade. Dana’s ideas on geosynclines being filled around the margins of fixed continents were to culminate just after the Second World War, in the work of Marshall Kay at Columbia University. In his famous book North American Geosynclines, published by the Geological Society of America, he developed the ideas of the German geologist Hans Stille, an energetic proponent of a contracting Earth and the growth of continents by the filling of geosynclines, to conceive of an entire lexicon of tongue-twisting subtypes of geosynclines

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Sources of Friction

based on their different fills and thickness: zeugogeosynclines, paraliageosynclines, epieugeosynclines, and many others. Decades later, as we shall relate, Kay would recant and embrace plate tectonics, using his encyclopedic knowledge of American rocks to match them across the rest of Pangea. Wegener had proposed that mountain chains were not the product of the filling and uplift of geosynclines along the edges of static continents but were instead the product of buckling along the leading edges of continents as they moved and collided. This concept was anathema to most North American geologists. Suzanne Kay, a recent former president of the Geological Society of America (and well placed to assess the history of American response to Wegener) has written, in language reminiscent of that of the Big Three North American automakers resisting imported Japanese cars in the 1970s, that Dana’s concept of fixed continents that grew by the filling of geosynclines was so widely embraced simply because it was “Made in America.” The subtext here is that anyone adopting the new theory imported from Germany was insufficiently patriotic. And yet detailed calculations had shown the basic geosyncline model was fundamentally flawed because it required their fills, composed of relatively light sediments eroded from continents, to suddenly founder into the much stiffer mantle below. What prevented entire continents from suddenly sinking too? Robert Dietz compared the supposed formation of geosynclines to be “like trying to sink a canoe by filling it with sawdust.” Quick to accuse Wegener of failing to identify a realistic mechanism to allow continents to move, the permanentists conveniently ignored the limitations of their own arguments.

Some scholars of the scientific method seek a purely rational explanation as to why Wegener’s model failed to germinate and take root in North American soil. Because it contradicted known “facts” and relied on intuition (no one can see a continent move!), it could be discounted and ignored as an “immature” hypothesis by those resistant to change. Others opined that Wegener had himself invited rejection of his bold ideas because they required his permanentist opponents to discard their life’s work. There is an element of truth here because, as we shall see in the 1960s, the movement of continents finally became acceptable to many geologists when it was shown that traditional field data collected previously by older generations of permanentists could be repurposed, and, in fact, used in support of the prior existence of Pangea and its later breakup. The main reason for the rejection of the hypothesis of continental drift simply lay in the broader culture of North American geology: a resistance to any outside foreign ideas where there was no room for any divine plan or unique American solution. The 1920s was the key decade in the American struggle against mobilism when successive presidents of the Geological Society of America, united in their belief of Dana’s vision of fixed continents, loudly declared their opposition to the atheistic heresy of continental drift. Their views echoed the broader domestic political consensus on America’s place in the wider world, such as the refusal after the First World War to join the League of Nations, fearing entanglement in foreign conflicts. By extension, radical German ideas about how the entire planet behaved were seen as threats to American exceptionalism. The outside world, in the shape of Wegener, a German geophysicist and polar

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

explorer, had coming knocking on the door of middle America and had been rudely turned away. It is difficult to avoid the conclusion that American geology from the 1870s to the 1930s was held hostage by the belief of its leading practitioners that the study of geology had a deeper purpose in revealing God’s plan. Frank Taylor’s theory on moving continents published in 1910 as “Earth’s Plan” had tried to wrest the science in a completely different direction and was promptly ignored. Wegener is painted, in some circles, as an atheistic non-believer, diametrically opposed to Dana’s view of a divine plan that shaped continents and oceans, but in fact he came from a background more in common with many of his North American opponents. He was the son of a Lutheran preacher in the court of the Prussian king, though his faith had certainly been diminished by his appreciation of Darwin’s work (required reading for officers in the German Army), by his astronomical studies, and by war service. Nonetheless, his conviction that the Earth’s surface is evolving and continents move – driven by unseen processes in the hot, dark, hellish interior of the planet, a very long way from the heavens above – was viewed as anathema to the high priests of North American geology. Much the same conflict was then raging in the biological sciences, where American fundamentalists rejected any notion of evolution and were opposed by modernists who argued evolution had happened, even if it was not yet possible to answer why or how. The Scopes Monkey Trial of 1925 was an attempt to stop the teaching of evolution in Tennessee schools; the lead attorney for the fundamentalists, Williams

Jennings Bryan, remarked, “It is better to trust in the Rock of Ages, than to know the age of the rocks,” in part a dig at the defendant, high school teacher John T. Scopes, a lawyer but also a trained geologist. After the trial, a guilty verdict, and a fine of $100, Scopes enrolled at the University of Chicago for a graduate degree in petroleum geology but was denied financial support, being told, as he put it, “to take your atheistic marbles and play elsewhere!” He went on to have a successful career in the oil industry, hidden out of sight and out of mind deep in the jungles of Venezuela. The fundamentalists were successful in banning the teaching of evolution in Tennessee until 1967, virtually the same year that plate tectonics became part of the geological mainstream in American universities, displacing the old beliefs in the God-given permanency of continents and oceans. The permanentists didn’t need a public show trial to stop the teaching of mobilism because they enjoyed a massive advantage over their rivals; they controlled what was taught in universities and acted as gatekeepers able to regulate the content of the scientific journals where geologists publish their research findings. Charles Schuchert and his Yale colleagues Carl Dunbar, Chester Longwell, and Richard Flint co-authored highly influential textbooks such as Textbook of Geology, Historical Geology, and Physical Geology, which went through many reprints and added additional co-authors from 1915 to 1969. All but the very last editions of the “Yale textbooks” completely ignored Wegener. To paraphrase Winston Churchill, Earth history perfectly reflected their permanentist beliefs simply because they themselves had written it.

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Sources of Friction

In the meantime, on the other side of the Atlantic in Britain, there were other scientific heavyweights outside geology lined up to pour cold water on the idea that the Earth’s surface evolves and that continents move.

The eminent British physicist Lord Kelvin had proposed that Earth had cooled and contracted from a molten sphere in the last 20–40 million years and that its interior was rigid. It was a number widely accepted and seized upon by opponents of Darwin’s theory of natural selection, which clearly required a vastly increased timeframe to work. Kelvin was an authoritative figure, having been knighted by Queen Victoria in 1866 for his work on the first transatlantic cable, where he greatly increased its “data speed” (and thus profitability). He died in 1907 and is buried in Westminster Abbey, flanked by the graves of Isaac Newton and Charles Darwin, and is immortalized by the unit of temperature in the International System of Units, which was posthumously named in his honour. There were those who disagreed with Kelvin’s estimate of the Earth’s age, but they were largely ignored. The Irish engineer and mathematician John Perry, a former assistant of Kelvin’s, argued that his one-time employer and teacher had it all wrong and the Earth’s interior could deform (he used the analogy of warm wax). He pointed to the slow squeezing shut of old mine tunnels as evidence of stress in the Earth’s crust, but it was only as the new century dawned that the discovery of radioactive decay in rocks was seen as a fatal blow to Kelvin’s model as an additional but previously unrecognized heat source within the Earth that slows its cooling and could just possibly allow its interior to deform. In his influential book The Earth, Its Origin, History and Physical Constitution, written in 1924, the English physicist Sir Harold Jeffreys of Cambridge declared that Wegener’s concept of Pangea that broke apart to allow

Continental Drift Is Stalled by Sir Harold Jeffreys and the Physicists My main complaint against the theory is that the physical causes that Wegener offers for the migrations of continents are ridiculously inadequate. Harold Jeffreys, 1924

Physicists’ generalizations have tended to be too sweeping and geologists’ too detailed. J. Tuzo Wilson, 1963

On university campuses in the first half of the twentieth century, geology was a bit player in the wider scientific establishment and geologists were its underdogs. Science was dominated by the powerful disciplines of physics and chemistry, whose stature had been greatly elevated by the growing technological needs of an emerging industrial and urban world in the late nineteenth century. In universities, the disciplines were led by a professorial faculty whose heavyweight opinions – right or wrong – had to be listened to. The physicists were mostly sedentary scientists surrounded by laboratory instruments and were quick to show their intellectual disdain for grubby field geologists who enjoyed going off and exploring the more remote corners of the planet.

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

icebergs through stiff rocks, where was evidence of the enormous wakes and troughs that would surely be left in their trail? In the discussion that followed Philip Lake’s critical lecture on Wegener’s theory at the Royal Geographical Society in London in 1923, and reported in the Geographical Journal of that year, Jeffreys remarked that moving continents required forces of extraordinary strength to be at work in the Earth’s mantle, none of which had ever been detected. In Jeffreys’s world, physicists laid down the laws for geologists to meekly follow; mathematical theory and numbers provided the foundation for understanding the Earth, and geologists merely filled in the details through their “stamp collecting” activities out in the field. His book outlined the physics of a contracting Earth and even took a swipe at the stamp collectors by remarking that “if the geologist cannot follow a part of the book, he will omit it and go on to the next non-mathematical passage.” Jeffreys had set down the rules of the game that permanentists felt Wegener had purposely ignored. Rollin T. Chamberlin of the University of Chicago (son of Thomas C. Chamberlin) assumed the role of umpire and in 1928 declared, “Wegener’s hypothesis in general is of the footloose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories. Its appeal seems to lie in the fact that it plays a game in which there are few restrictive rules and no sharply drawn code of conduct.” In other words, Wegener wasn’t the type of gentleman who would ever be admitted to their club. The ascendancy of the physicists in framing the debate on how the Earth worked was clear to all, and the views

Sir Harold Jeffreys gazing at land masses and oceans that he regarded as fixed and immutable. Courtesy of the estate of Zsuzsi Roboz represented by David Messum Fine Art Ltd.

continents to drift free was “physically impossible.” He was the foremost British adherent of permanentism and contractionism, believing that continents had remained fixed in position ever since their formation. A mathematician, statistician, and astronomer, Jeffreys was a highly quantitative scientist who simplified complex natural processes using mathematical models, often based on assumed values of important variables. Jeffrey’s calculations indicated that the mantle was too rigid to allow the drift of continents, and furthermore, that no known force was powerful enough to push them around the planet. Like all such models, the advanced mathematics created an illusory perception of precision seemingly beyond criticism. Nonetheless, they pointed to a serious problem with Wegener’s model. If the continents drifted like giant

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of Jeffreys were widely adopted in the interwar years, even though many geologists felt very uneasy. Arthur P. Coleman of the University of Toronto had worked throughout the Southern Hemisphere on the geology of the southern continents. His initial reaction on reading Jeffreys’s book in 1925 was typical of many: “All the subjects are handled in a highly mathematical form and some of its conclusions are questionable because of unfamiliarity with the geological premises involved.” In reality, that was to prove the fatal flaw in Jeffreys’s work, and would later completely undermine the apparently rock-solid foundations of permanentism. Jock Wilson put his finger on it when he wrote that Jeffreys “was a mathematician really” and “didn’t know any geology.” In fact, the eminent physicist knew very little of the geological evidence in support of continental mobility and was guilty of ignoring information that indicated the strength of the mantle was in fact much weaker than he had thought and could deform and move. Late in life, Jock Wilson looked back on his early career and recalled, “The difficulty all along is that the people trained as physicists think in terms of mathematical terms – and everything has to be precise. If Jeffreys had the physics and the mathematics right about the mantle of the Earth, then that was the answer. There was no possibility that other people might be right, too, if you looked at it a different way.” Unerringly and probably without being aware of it, Jock had highlighted his own philosophical underpinnings: the importance of intuition and “gut feelings” gained by long experience of travelling the globe and looking at rocks. “Geologists’ work,” he argued, “was all descriptive and not mathematical. They didn’t mind reversing their opinion between breakfast and lunch.

They had a totally different way of looking at things.” Standing up and challenging the dogmatic views of physicists was quite another matter, but there were some geologists prepared to try.

Geologists Push Back: The Earth’s Mantle Can Move It must be admitted that the widespread proofs of great crumpling of the rocks of the crust present a difficulty, for they indicate a capability of yielding to strain such as has been supposed impossible in a globe possessing the rigidity of steel or glass. Sir Archibald Geikie, 1893

Wegener’s presentation has provoked much discussion and many objections and there is a danger of a too speedy rejection of the main idea. Reginald Daly, 1923

As the 1920s unfolded, some mobilists began to find their voice again, aided by emerging ideas about the real nature of the Earth’s interior. The dominance of Sir Harold Jeffreys’s views on the rigidity of the mantle in the debate on continental drift was unfortunate because there was innovative work being completed at McGill University in Montreal that clearly showed that mantle rocks were not “like steel” but are much softer. Professor Frank Dawson Adams gained his PhD at Heidelberg, Germany, in 1892, but his thesis topic was on the origin of the rocks of the Canadian Shield exposed around the small community of Haliburton in central Ontario. These rocks make up the Grenville

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Province, which underlies much of eastern North America extending from Mexico to Labrador. Using specialized high-magnification petrographic microscopes newly developed in Germany, Adams showed that the rocks had been highly deformed deep underground by intense heat and pressure (metamorphism) and had moved like hot wax, just as John Perry had earlier proposed. He recreated the temperatures and pressures that could make rocks deform in his laboratory at McGill using a “hot press” and showed how under certain conditions under very high temperatures and pressures, what are now hard brittle rocks exposed at the Earth’s surface would begin to creep and deform, and thus move. Adams’s work was published as a famous Geological Survey of Canada memoir in 1908 and was potentially hugely significant to the debate about continental drift, and yet it had escaped the attention of Jeffreys. The last edition of Jeffreys’s book published in 1970 (years after the basic tenets of plate tectonics and mantle convection currents had been firmly established) remained unyielding in its opposition to drift.* There was also very good field evidence – the last place Jeffreys would look! – that rocks could flow when subjected to great heat and pressure. By coincidence in the late 1920s, the young Jock Wilson worked as a geological assistant with W.H. Collins, the director of the Geological Survey of Canada and a former student of Coleman at the University of Toronto. Collins was

an expert on the “Grenville” Precambrian rocks, the same rocks studied by Frank Adams, widely exposed on the many islands of eastern Georgian Bay in Lake Huron, an area known as the Thirty Thousand Islands. By studying the complex folding and banding of the highly metamorphosed and often beautiful gneisses exposed on the ice-scoured islands, Collins recognized that rocks had been deformed under heat and pressure and in turn surmised what that implied for crustal mobility. On the basis of the results of their mapping across the Thirty Thousand Islands area, Collins and his colleague T.T. Quirke published a classic study in 1930 entitled “The Disappearance of the Huronian.” The evidence pointed to a major collisional event (now called the Grenville Orogeny) along a former continental margin and wholesale deformation and metamorphism (and thus “disappearance”) of older Huronian rocks under intense heat and pressure. Forty years later, it would be shown that the collisional event marked the assembly of the supercontinent Rodinia. By 1930 it had already been well established that the rocks that underlay continents are much less dense than those that make up the ocean floors. As early as 1802, the British East India Company employed geologists for the Great Trigonometrical Survey (later under the leadership of George Everest) to accurately measure the height of the Himalayas. Early results were regarded as inaccurate because the plumb bobs used to level the survey instruments were pulled away from the vertical

* Jeffreys’s book went through six editions and remained in print until 1976, its author dying in 1983 as an unrepentant permanentist. Fred Vine, a central contributor to the development of what would be known in the late 1960s as plate tectonics (and who we will meet later in these pages) remembers a lunch with Jeffreys at St. John’s College, Cambridge, in the early 1970s when the great man questioned Vine’s mental capacity for believing that Earth’s surface was mobile and continents migrate.

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by the gravitational attraction of the great mass of the mountains. But it was also found, quite the opposite of what had been expected, that the gravitational pull on the plumb bob increased away from the mountains toward the coast (where there are no mountains). The paradox was explained in 1855 by George Biddell Airy, Britain’s astronomer royal (who also established the prime meridian at Greenwich) in his theory of isostasy. He argued that continents, even with their high mountainous relief, are made of less dense rocks than those that underlie the oceans. The denser the crust, the lower it floats on the mantle, and vice versa. This simple difference explains why there are ocean basins; their floors are underlain by mostly iron-rich oceanic crust (Wegener’s sima) and form giant depressions on the Earth’s surface pulled down by the weight of their heavier rocks into the mantle below. The continents, on the other hand, are composed of lighter, more buoyant crust dominated by silica-rich granitic rocks (Wegener’s sial) that float higher on the mantle like rafts and create dry land. The plumb bobs on the survey instruments near the coast were being attracted by the denser, heavier crust underlying the Indian Ocean. The fundamental differences between the composition (and thus density) of continental and oceanic crust were confirmed when the Dutch geophysicist Vening Meinesz perfected a mobile “gravimeter” (a sensitive device for measuring changes in the value of gravity around the Earth’s surface) that could be mounted onboard ships and was unaffected by the ship’s motion in waves. Systematic surveys fully confirmed that the Earth’s continental crust was relatively light and floated on denser mantle material below. Meinesz had another trick up his sleeve. Taking his gravimeter deep

underwater in a submarine, he was able to show that the long trenches that run along the margins of some continents, especially those around the margins of the Pacific Ocean that in places are as much as 9 km deep, are marked by distinct gravity anomalies that suggested the heavier crust below the ocean floor was being bent and pushed downwards to form the deep trench. As we shall see, the importance of his work was only to be realized much later by studies of how Earth’s crust had deformed during the Great Alaskan earthquake of 1964. Meinesz had in fact discovered what later would be called “subduction zones,” where heavy oceanic crust is pushed down and overridden by much lighter continents. As we have already seen, geologists were also aware that continental crust was mobile and moved up and down, suggesting land masses were supported by a mantle that might be much softer than considered by the physicists. Upward movement of the Earth’s surface was unambiguously recorded by the sudden raising of coastlines and beaches above sea level after major earthquakes. This phenomenon had greatly impressed a young naturalist named Charles Darwin during the 1835 Concepción earthquake in Chile when beaches still encrusted with living marine organisms were uplifted by as much as 3 m in a split second. Darwin also witnessed evidence that ocean floors were also sinking, and in 1848 he hypothesized that old, now-inactive volcanoes in the Pacific Ocean, with their summits that had once been above sea level, had slowly sunk, their craters now rimmed, much like haloes, by coral reefs known as atolls. The significance of these long-dead volcanoes for understanding the movement of the crust of ocean floors would be rediscovered in the 1960s.

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Ancient sea floor sediments along the Chilean coast record episodic earthquakes and related uplift of Earth’s crust.

Maupiti atoll in the southwestern Pacific Ocean near Tahiti; a circular coral reef growing upwards from the rim of an old, long-dead volcano slowly being eroded and drowned in response to sinking of the ocean floor. Courtesy of Dr. Andy Bruckner, National Oceanic and Atmospheric Administration.

Sources of Friction

The columns of the Roman Temple of Serapis at Pozzuoli in Italy were bored by marine bivalves when the coastline sank after its construction. It was later elevated several metres above sea level in response to volcanic activity and crustal uplift in the Campi Flegrei caldera, close to Vesuvius. The bored columns and their story of a crust that could move up and down were noticed by Charles Lyell in 1828. This triggered interest in geological processes at work on a dynamic Earth rather than catastrophic changes brought about by a divine creator. It was the beginning of “uniformitarianism” – “the present is the key to the past” – a concept that underpins the whole of geologic science.

The frontispiece to Sir Charles Lyell’s famous 1830 textbook Principles of Geology consists of an engraving of the Temple of Serapis at Pozzuoli near Naples, Italy, whose columns showed evidence of slow sinking of the crust below sea level and later uplift. It was graphic evidence that the crust lay on something that was soft and moved. Despite all the evidence available to geologists pointing to a much more mobile crust than envisaged by the physicists, any rational discussion of the merits of Wegener’s grand hypothesis of continental drift continued to be prevented by disagreement on the structure of the deep interior of the planet. Most believed Earth’s interior to be solid simply because there was no evidence for deformation of the planet’s shape resulting from tidal forces created by the Sun and

Moon pulling on a fluid interior that might stretch and deform. Surely, it was argued, the interior of the planet had to be stronger than solid steel to resist such forces. Lord Kelvin’s 1864 model had proposed that Earth could be compared to a molten ball of iron that was slowly cooling with a still-hot molten core surrounded by a cooled, rigid mantle. The German Emil Wiechert, on the other hand, argued in 1896 that the core was solid and that Earth was essentially cooling from the centre outwards. It all posed the question of what was really going on down there. Answers were beginning to emerge from an unlikely source: earthquakes. By the early 1900s it was appreciated that energy released by powerful earthquakes in the form of seismic waves passed right through Earth’s interior

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The Nobi earthquake in Motuso City in central Japan in late 1891 killed more than 10,000 people. Part of the fault, which ruptured and moved during the earthquake, has been excavated and is exposed in the nearby Earthquake Observation Museum. The rocks on the left of the fault dropped 6 m against those on the right. It was the first time geologists made the link between earthquakes and faulting of the Earth’s crust.

from one side of the planet to the other. The newly invented telegraph system was the basis of a new global network of stations that recorded the time of arrival of seismic waves from distant earthquakes, whose location could now be precisely fixed. This system allowed precise measurement of the time it took for the waves to traverse the planet’s interior. One such event is now famous: the Nobi earthquake in Japan on 28 October 1891, which occurred a few decades after the nation had embarked on an ambitious program of modernization. The Nobi earthquake destroyed newly built Western-designed buildings and railway bridges made of steel, brick, and concrete, as

they had been too rigid. The official inquiry produced an innovative report written by John Milne and W.K. Burton (“The Great Earthquake of Japan, 1891”), which concluded that earthquakes were caused by slip on faults separating blocks of crust. They later wrote Earthquakes and Other Earth Movements, which established the science of seismology. Their colleague Fusakichi Omori was the first professional Japanese seismologist and plotted earthquake epicentres around the world; his map of Pacific earthquakes identified what was later to be called the “Pacific Rim of Fire” and was later to be a key piece of evidence in the discovery of tectonic plates in the 1960s.

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Omori is best remembered today for his “seismic gap theory,” which assumes that by mapping the location and timing of past events, the frequency of major earthquakes is revealed for that area, giving potentially life-saving clues to the likelihood of the next event. Large earthquakes in the Tokyo area had occurred in 1633, 1703, 1772, and 1853, and Omori proposed that a succession of earthquakes in 1922 had released pent-up energy, closing the seismic gap for the region. He was wrong, and the Great Kanto earthquake of 1 September 1923 killed some 140,000 people, many trapped in the collapsed buildings and fires that followed. Omori died weeks later, his reputation shattered, but his concept of seismic gaps is still used to identify areas overdue for a large earthquake, such as the Pacific Northwest near the cities of Vancouver and Seattle. Seismic waves are much like ripples created by throwing a rock into a pond, radiating outwards from the “focus” of an earthquake (the place where it is triggered at depth, as against the “epicentre” being the point on the Earth’s surface directly above the focus). But not all seismic waves are equal; some travel relatively slowly around the Earth’s surface (surface waves), whereas others pass right through the planet (body waves) at high velocities. The first type of body waves to arrive are called primary waves (P waves for short) and they travel very quickly at velocities as high as 8 km/second. P waves can pass through both solids and liquids. Later arrivals are the secondary (S) waves travelling more slowly at 5 km/ second; these can only move through solids. Here then was a means of identifying whether the Earth’s interior was solid or liquid, based on the ability of body waves to travel from one side of the planet to another. As early as 1913, German-American

seismologist Beno Gutenberg had proposed that Earth’s core was solid and lay at a depth of 2,900 km below the surface marked by an abrupt boundary, now known as the Gutenberg Discontinuity. In the 1920s the young Danish seismologist Inge Lehmann went a step further and saw that some P waves had unusually taken much longer to travel through the planet. She had an intuition that they had been delayed by bouncing off a hitherto undiscovered liquid layer wrapped around the core. This was confirmed in 1936, when she identified an S-wave “shadow zone” on the far side of the planet farthest away from the origin of earthquakes. She reasoned, in the face of strong criticism from her male colleagues, that the shadow zone resulted from S waves being prevented from passing through a very hot molten outer core wrapped around a solid inner core. Her ideas, once seeming far-fetched, were confirmed using computers in 1970, and the boundary between the inner and outer core is named the Lehmann Discontinuity in her honour. Geophysicists then began to measure the amount of heat leaking from Earth’s interior and quickly established large outflows of heat from the oceans, pointing to the existence of mantle rocks that were hot and soft, not far below the ocean floor. There was now a growing realization that the mantle might not be as rigid as proposed by the mathematical models of Jeffreys and other physicists. Moreover, the mantle might in fact be on the move, being stirred by enormous convection currents like those seen in a lava lamp, rising from the hot, molten outer core identified by Lehmann. If this was the case, then perhaps continents might be shuffled around like rafts, by convection currents in the hot mantle. Others would take this idea and run with it.

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The energy released by large earthquakes provides a tool for mapping the Earth’s interior. “Shadow zones” are created on the other side of the planet by the changes in the pathways of high-velocity P (primary) and lower-velocity S (secondary) seismic waves as they pass through the planet’s interior. The P wave shadow zone (left) is the result of those waves passing through and being reflected off the outermost liquid core; that for the S waves (right) is due to their inability to penetrate the liquid outer core.

Sources of Friction

Holmes and Daly Try to Stir Things Up Our solid Earth apparently so stable, inert and finished is changing, mobile and still evolving. R.A. Daly, 1926

We may therefore conclude that the dominant forces involved in crustal movements must arise within the Earth itself. A. Holmes, 1931

By the late 1920s, just as Jock Wilson was completing his apprenticeship as a young geological assistant in Northern Ontario, a new idea that the Earth contained a hot mantle that slowly deformed and allowed the crust to move was beginning to make headlines. This radical proposal was made by the young geologist Arthur Holmes, based initially at Durham University on the banks of the River Wear in northeast England, and later professor of geology at the University of Edinburgh, in Scotland’s capital. He was to profoundly influence Jock and the two would develop a firm friendship and rapport. Holmes’s book The Age of the Earth, published in 1912, is a classic of geological science, in which he determined the great age of the planet (he estimated it at more than 2 billion years) and the timing and duration of the many events in its subsequent history. At that time, as we have noted, geologists based the age of the Earth on estimated cooling rates of an originally molten planet or the amount of sediment washed off the continents, which had accumulated in the oceans – methods that gave very young and clearly unlikely ages. Holmes’s work was radically different and founded on Ernest Rutherford and Frederick Soddy’s “disintegration

Arthur Holmes’s use of radioactive decay to date rocks was a breakthrough in geology and established the great age of the planet, but his ideas on mantle convection and how they might move continents were rejected in the prevailing permanentist climate of the 1920s; he was fully vindicated in the 1960s. Courtesy of the Geological Society of London.

theory” of 1902, where unstable radioactive elements, such as uranium, break up and produce stable daughter products such as lead that are very different from the parent. The rate of decay is constant, and measurement of the quantity of lead in uranium-bearing minerals was the basis of radiometric age-dating of rocks. Holmes refined his methods, revising Earth’s age to 3 billion in 1927 and eventually to 4.5 billion years old in the 1940s, which is little different from the currently accepted age of 4.56 billion years.

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Holmes’s model of drifting continents created by the breaking apart of a larger land mass in response to stresses imposed by rising convection currents within a hot plastic mantle. The outward displacement of the continents created mountain belts along their leading edges, where crust was recycled back to the mantle.

Glasgow where few North American geologists would ever see it. A fuller paper finally appeared in 1933 in the Journal of the Washington Academy of Sciences, but physicists such as Jeffreys and their many followers remained unconvinced. Holmes expanded on his ideas of mantle convection and how it might drive the drift of continents on Earth’s surface in his textbook Physical Geology of 1944. He wrote that “the currents drag the two halves of the original continent apart,” with mountain building taking place along their leading edges, and an ocean develops and widens in the “gap” created where mantle currents rise to the surface. In most respects he had identified the basic process now known to be at work in moving crust around, but it was not until just before his death in 1965 that these ideas would re-emerge to influence a new generation of geologists. There had been another voice that also went largely unheard in the mobilist wilderness – that of

Holmes also saw that the decay of unstable radioactive isotopes produces heat, lots and lots of it, concluding that there had to be massive heat loss from the interior of the planet. He argued that this was accomplished by convection currents rising slowly in the mantle, much like giant thunderclouds rising in the sky on a hot afternoon. After their upward journey and cooling, these massive columns would slowly sink back deep into the mantle, triggering in turn the upward movement of new plumes. In 1927 he wrote a short article outlining how convection currents might engineer the drift of continents and the opening of new oceans. He submitted his report to the prestigious American Journal of Science, but Carl Schuchert, the most vociferous of Wegener’s many permanentist opponents, was the editor and in that lofty capacity curtly rejected Holmes’s submission because it supported continental drift. His paper was eventually published in Britain in 1931 in the Transactions of the Geological Society of

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Sources of Friction Reginald Daly at Harvard University was an expert on how rising magma is intruded into overlying rocks. He recognized that crustal spreading must occur to accommodate igneous intrusions. Here was a mechanism that potentially could explain the lateral displacement of crust on the Earth’s surface. His ideas were largely ignored until the 1960s.

Canadian-born Reginald Aldworth Daly working at Harvard. He had graduated in mathematics at the University of Toronto and was lured into the study of geology in 1891 by none other than A.P. Coleman, a leading permanentist who would also unduly influence the young Jock Wilson in the 1920s. Daly was to remain one of the very few North American geologists of that era who believed in mobile continents and, not surprisingly, faced stiff criticism from his colleagues. He alone was brave enough to publicly express support for Wegener at the 1922 meeting of the Geological Society of America in Ann Arbor and was admonished by his colleagues and specifically by his mentor Coleman for doing so. One speaker accused Daly of advocating on Wegener’s behalf, more like a trial lawyer acting for the defence than a professional scientist. Unperturbed, the next year Daly presented a very supportive critique of the Taylor–Wegener hypothesis to the Washington Academy of Sciences, declaring that despite the theory’s problems, “geologists have good reason to retain the root idea.” The following speaker, W.D. Lambert, was quick to pour cold water on the hypothesis, emphasizing once again the doubts of physicists and mathematicians. Daly’s book Our Mobile Earth, published in 1926, was based on a series of public lectures he had given at the Lowell Institute in Boston in January 1925. In the introduction he declared that many geologists found the ideas of Wegener and Taylor “bizarre, shocking; yet an increasing number of specialists are convinced that it must be seriously entertained.” He stressed that they had not yet discovered the “force

Courtesy of Harvard University.

which did the gigantic work” of moving continents and went on to take a “bold step” and present the “inescapable conclusion that the continents are not securely anchored.” He identified two possible forces (later named “sea floor spreading” and “slab pull”) that might be strong enough to shove continents around the Earth’s surface and was sufficiently convinced of his ideas that he prefaced his book with the immortal phrase attributed to Galileo E pur si muove (And yet it moves), guaranteed to upset his permanentist critics. Daly had earlier undertaken a wide-reaching exploration of the geology along the US–Canada border, noting the distances that rocks had been shoved eastward and what that implied for continental mobility. Daly had the breadth of vision to synthesize these observations of crustal mobility and proposed that continents slid laterally over a relatively soft substrate of hot mantle rock, able to deform and creep. It wasn’t that far removed from the mechanism proposed earlier by

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Taylor and Wegener, but in the process, he took a giant step further and identified a long-sought-after driving mechanism. Daly’s research focused on how magma ascends to Earth’s surface through older rocks, and he realized that much of the geology of volcanic islands consists of cooled lava that had accumulated flow by flow, layer by layer, one on top of another during successive eruptions, much like piled newspapers. He also noted many thousands of closely packed vertical intrusions of volcanic magma that had risen through the horizontal layers, and then cooled to form “dikes,” in reference to their wall-like appearance. These intrusions stand shoulder to shoulder, much like soldiers on parade, and he showed they were the result of magma forcing its way to the surface along cracks and fissures; this process clearly necessitated the spreading of pre-existing rocks in order to accommodate thousands of later dikes. Here potentially was an outward pushing force that might be strong enough to drive crust around Earth’s surface. His idea of repeated fissuring and filling of cracks with magma as a means of forming new crust is essentially “sea floor spreading,” as was later proposed by Harold Hess and Robert Dietz in the early 1960s (but without any reference to Daly). He had also proposed the slipping of crust down below geosynclines into the hot mantle as “giant landslides,” suggesting that the process could be strong enough to pull continents over the mantle. In hindsight, Daly saw what Taylor and Wegener had missed, and, if his pushing and pulling forces hadn’t been ignored in the prevailing permanentist climate of the time, continental drift might have been taken more seriously sooner than it was. Unfortunately, the leading mobilists were squabbling among themselves

in public. Arthur Holmes reviewed Daly’s book in 1927 for Geographical Journal, and while the overall tone of his comments was quite complimentary, declaring it to be a “stimulating” attempt to solve the “obdurate riddle” of continental drift, he also listed “fatal objections.” He took issue with Daly’s concept of continents as slabs of lighter granite resting on and in places sinking into a mantle composed of glassy basalt and disparagingly described Daly’s ideas as “guesses and speculations.” In doing so, Holmes found himself in strange company. Charles Schuchert, the arch–North American permanentist, had earlier published a review of Daly’s Our Mobile Earth in the journal Science on Christmas Eve in 1926. While refraining from direct criticism, he limited the wider appeal of the book (and thus its dangerous mobilist ideas) by noting that it was “heavy reading and highly speculative.” As a result, it never sold widely, was not reprinted, and most importantly, was never adopted as a textbook where it might corrupt the minds of young geologists such as Jock Wilson. Daly would return to the theme of mobile continents gliding across the face of the Earth in his Strength and Structure of the Earth published in the dark days of 1940 when unfortunately there was another war being fought and geologists and geophysicists were preoccupied with events elsewhere. In retrospect, Holmes and Daly had together developed a credible model for how continents could be moved by convection currents stirring deep in the Earth’s mantle. Again, however, their ideas were subsumed under the dead weight of permanentist opinion that continents were cemented in place on top of a rigid mantle. Holmes’s and Daly’s remarkably modern ideas were to lie dormant and gather dust

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Daly identified a “pushing force” capable of moving continents created by the repeated intrusion of magma into preexisting rocks to form vertical igneous dikes (top). In the same fashion, insert a book (such as Holmes’s great textbook Physical Geology) into a closely packed bookshelf, and the bookends (continents) are pushed outwards.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

By the late 1920s, the hypothesis of continental drift was essentially dead and buried in the opinion of most North American permanentists, and its principal author was soon to suffer the same fate. Wegener badly needed hard data to prove that continents were on the move. He argued that they were drifting by several metres a year, and he had convinced himself that the fastest rate of drift was occurring between Europe and Greenland; earlier Danish surveys had suggested more than 10 m a year, which, if correct, meant that the two land masses had separated only some 10,000 years ago. Additional data suggested that Europe was pulling away from North America at a rate of as much as 4 m every year. The definitive proof of continental drift, Wegener declared, would be found by careful surveying in Greenland, and there he went in the spring of 1930 with other scientists to set up survey stations on the western and eastern margins of the Greenland Ice Sheet and at its centre. The decision was to cost him his life. The cool summer of 1930 left thick winter sea ice lingering along the coast of western Greenland, delaying the landing of supplies at Kamarujuk Fjord, threatening the survival of a survey party left behind the previous year to overwinter in the centre of the ice sheet at “Eismitte” (Mid-ice). Only in September was Wegener finally able to set out inland from the coast with a relief party of Greenlanders travelling on dog sleds and skis, along with the meteorologist Fritz Loewe and a young Inuit Rasmus Villumsen, to resupply his stranded colleagues 400 km distant. To save weight, they made the decision to leave their radio on the coast. The exhausted group finally reached the remote camp high on the ice sheet in late October, after a gruelling forty-day trek battling

Daly proposed that sinking of continental crust into the mantle below geosynclines created a “pulling force” that might pull land masses together, compressing the fill of deep geosynclines to create mountain ranges. Geologists pointed out the impossibility of having light continental crust sink into the much denser mantle below, but Daly’s ideas would re-emerge in greatly modified form in the 1960s as “sea floor spreading” and “slab pull” when heavy oceanic crust slides back down into the mantle (“subduction”).

for another thirty years before being resurrected and reconfigured as “sea floor spreading” and “subduction” as the engines of continental movement. Sadly, neither Wegener in his role as the chief architect of mobilism, nor Holmes and Daly would live to enjoy it.

Death on the Ice You consider my primordial continent to be a figment of my imagination, but it is only a question of the interpretation of observations. Alfred Wegener, 1923

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extreme cold with temperatures plunging to -54°C, constant high winds, and poor visibility in blizzards. They found their stranded companions in good health. On 1 November they celebrated Wegener’s fiftieth birthday with chocolate and raisins, and the relief party, its mission now accomplished, set out over the ice sheet to return to the coast. Loewe remained at Eismitte with badly frostbitten toes, which required amputation with a pocket knife. On the return journey, Wegener, who was a heavy pipe-smoker and suffered from arthritis and heart palpitations, died in his sleep, most likely of a heart attack brought on by exhaustion. With no radio to alert his colleagues at the coast, Rasmus Villumsen marked the grave with skis pushed into the snow and disappeared, never to be seen again. Unaware of the mishap, a party of Wegener’s colleagues led by his brother Kurt would set out inland from the coast in May the following year, only to discover Wegener’s body halfway to Eismitte wrapped in a sleeping bag and partially buried in the snow. Germany’s President von Hindenburg sent his condolences to Wegener’s widow, Else, who turned down a request to return his body to Germany on a battleship and bury him with full military honours. She requested instead that Wegener’s body be left entombed in the ice where he had died, the gravesite marked only by a 6 m cross. Long since buried by accumulating snow and ice, his body now lies at a depth of about 100 m and is being slowly carried westward by movement of the ice sheet and by the steady drift of the North American plate, now known to be at a rate of about 3 cm a year. Wegener’s death was announced on the front page of the New York Times on 14 May 1931, marking the passing of a great Arctic explorer and the end of the heroic age of polar exploration where henceforth

airplanes, motor transport, and radios would replace dog teams, skis, and sailing vessels. The following years also saw a great reduction in international scientific cooperation in the face of emerging nationalism in Europe, culminating in full-blown world war in 1939 when the Germans used Wegener’s theory as a symbol of national superiority. The Nazis’ propaganda magazine Signal highlighted their countryman’s hypothesis throughout the occupied territories (Wegener’s wife responded that her husband “had been a good German but not a nationalist”). The French geologist Pierre Termier, riding on the back of chauvinistic anti-German sentiment, retorted that Wegener’s work was nothing more than a “beautiful dream that vanishes like smoke, when you try to capture it.” Not to be outdone, Bailey Willis, an otherwise very gifted American geologist and expert on earthquake hazards, would refer to continental drift as a “German fairy tale.” As we have already seen, Wegener never attended the fateful New York meeting of the American Association of Petroleum Geologists in 1928 where, in his absence, the principal North American permanentists were free to pour scorn on continental drift. By then he had essentially given up the fight, not out of any sense of failure, but simply because in his opinion, the evidence in support of his theory was unambiguous and made it impossible for anyone to reject it as a mere fantasy. His work had been done; continental drift was real. Significantly, Wegener’s last revisions and additions to his great book were also made in 1928 when he took the opportunity to add the latest determinations of the longitudes of New York and Paris that pointed to a widening separation between the two cities because of continental movement (but at an annual rate later shown

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attribute evidence for severe crustal shortening evident in the highly deformed rocks of the Alps and other mountains, to contraction of a cooling planet where continents always stood still.

Continental Drift Goes South and Du Toit Takes Up the Baton A world without some form of crustal drifting would appear as unreal as one lacking in biological evolution.

The 6 m cross marking Wegener’s gravesite on the Greenland Ice Sheet flanked by propeller-driven snowmobiles. Courtesy of Archive for German Polar Research,

Alexander Du Toit, 1927

Alfred Wegener Institute.

After Wegener’s death in 1930, there was sharp divide in cultural and scientific practices between mostly inward-looking and conservative North American geologists and their more globally oriented colleagues in Britain and South America, Africa, and Australia, where the science of geology was of great strategic and economic importance in the running of overseas colonies and empires. The work of newly established government geological survey departments across the British Empire in the nineteenth century was fundamental to continued trade and prosperity. The making of maps and the completion of geological inventories were important elements in discovering and controlling a colony’s mineral resources, especially coal, oil, and iron ore, and thus its entire economy. The empire and its vast trade routes were held together by the Royal Navy, and until the early twentieth century its ships required prodigious amounts of coal. Geological information from around the world was widely disseminated among the profession in what was known as “imperial science.”

to be much exaggerated). He confided to his brother Kurt, just before his death on the Greenland Ice Sheet in 1930, that it was his wish that any future editions of his book should remain unaltered; in his view, the accumulated evidence in support of continental drift was by then so overwhelming that it was impossible for any single scientist to assimilate and summarize. True to Wegener’s wishes, his book remained unchanged, except for a brief biographical account of its author’s life added by Kurt to the final edition of 1961. Hearing of Wegener’s passing, Frank Taylor unsuccessfully insisted on joint ownership of the hypothesis of continental drift, proposing that it should henceforth be known as the “Taylor–Wegener theory.” With the untimely and premature death of its leading protagonist, the concept of continental drift was in full-blown retreat. With a few notable exceptions such as the Swiss geologists Emile Argand and Eugene Wegmann, most continental Europeans continued to

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Following Wegener’s untimely death, the mantle of mobilist-in-chief was taken up by Alexander Logie Du Toit, a South African mining engineer. He was an exceptional scientist, well-travelled and intimately familiar with the geology of the southern land masses that Suess had earlier assembled into a single large continent, Gondwana. The similarities from one country to another were so striking they could not be coincidental, prompting Du Toit to comment during a field trip to South America in 1924 that “to a visitor from South Africa the resemblances to that country are simply astounding. I had great difficulty in realizing that this was another continent and not some portion of one of the southern districts of the Cape.” It required no great stretch of the imagination to see that South America and South Africa had once been conjoined, as argued by Wegener and Taylor. In 1937, Du Toit published the now-classic Our Wandering Continents: An Hypothesis of Continental Drifting dedicated to the memory of Alfred Wegener. In it he was especially critical of how conservative many geologists had become in dismissing continental mobilism as “speculative” and how the science of geology risked becoming “stereotyped through too close an adherence to accepted beliefs.” He proceeded to lay out substantive evidence confirming the existence of Wegener’s northern land mass, which he named Laurasia, and Suess’s Gondwanaland to the south, which he argued had collided several hundred million years ago to create Pangea before subsequently breaking apart again. He urged geologists to expand their horizons and collect data on a global scale from all continents, proposing a new branch of the science he called “comparative geology,” which would showcase the similarities from one land mass to another to reveal

Du Toit’s reconstruction of Laurasia and Gondwana within Pangea.

their common origins. He wrote to Wegener in 1928, inviting him to visit South Africa “so that everyone will be able to meet the man who has revolutionized our understanding of the structure and history of the Earth.” Wegener did not accept the invitation, being immersed in planning his ill-fated expedition to Greenland. A blind and slowly dying Frank Taylor had written to Du Toit in 1938 just after the publication of Our Wandering Continents and graciously commented, “You certainly gave me a full measure of recognition as the first man to put the idea of continental drift on a firm scientific basis.” The geological evidence was compelling, but once again the whole idea foundered in the face of fierce resistance from mainstream permanentists and the physicists who continued to point to the lack of a comprehensive explanation for how precisely continents might be able to move. Du Toit not only possessed an encyclopedic knowledge of the geology of the continents of the Southern

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Hemisphere but also a detailed understanding of the fossil record of ancient organisms preserved in their rocks. In 1944 he famously locked horns with George Gaylord Simpson, the doyen of American biologists opposed to continental drift. Simpson had a classical permanentist education, having been taught by the arch-permanentist Charles Schuchert at Yale in the mid-1920s. He later became the most influential American paleontologist of his generation and in that lofty capacity published a sharply written critique of Wegener in the American Journal of Science in 1943, then the house journal of North American permanentists, intending to strike a mortal blow against the entire hypothesis of continental drift. In a long rejoinder, Du Toit turned the tables on his opponent and showed that, in fact, Simpson’s own fossil data strongly supported continental mobility. He also pointed out that many of Simpson’s own colleagues had accepted the basic premise of drift and were already busy working on the evolution of long-distance migration of

animals, and the many animals and plants that today, being widely separated, have very different traits but that can be shown to have had common ancestors on a reunited Pangea. It was not enough to sway Simpson from his belief in isolated communities linked by land bridges that went up and down like elevators between fixed continents. Lingering bitter arguments between physicists, geologists, and biologists about the most basic of questions of how planet Earth worked and functioned was the scientific background in which the young Jock Wilson found himself as he enrolled as an undergraduate at the University of Toronto in the late 1920s. Four decades later the Canadian would turn Wegener’s theory into a comprehensive model of how an entire planet worked. However, it wasn’t all smooth sailing, as we shall see, and Wilson’s journey from first-year university student to internationally known geologist almost never got off the ground.

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Permanentist Foundations

I was energetic and inquisitive by nature, but also lazy and untidy. I took my first course and lecture in geology, and I thought, “My God, this is science!” J. Tuzo Wilson, 1993

In 1926 there was no university in Ottawa that offered a degree in science, so, at his father’s suggestion, Jock enrolled at Trinity College at the University of Toronto. His aim was to study physics and mathematics, which were then taught in the Faculty of Arts and thus required proficiency in Latin. Getting up to speed in the classical language took three months of intense cramming under the guidance of a private tutor, Miss Cowan, who distinguished herself by giving Jock the very same English translations of the original works of Horace and Virgil on which he was to be later examined for his ability to translate them into English. Regardless of its dubious legality, her scheme was highly successful, and Jock passed the entrance exam at the first attempt. He later wrote of his tutor that “she, like Benjamin Franklin, was obviously of the opinion that her ability to swim was no reason

to refuse the use of a bridge.” Geology owes much to Miss Cowan’s artfulness. As it turned out, Jock needed no further help and proved to be a gifted, precocious student who deliberately projected an air of laziness to his classmates, passing exams without seeming to work. He had a prodigious memory and found that if he devoted a couple of weeks to revising lecture notes he could make excellent marks in exams. Unfortunately, and predictably, much of his time as an undergraduate at Toronto proved rather uninteresting. While he regarded the faculty in the Department of Physics as competent and conscientious, they were also in his opinion “uninspired.” The undergraduate program, though well taught, focused exclusively on classical aspects because several of the faculty had not yet fully embraced the work of Einstein. The dominant character in physics

Tuzo: The Unlikely Revolutionary of Plate Tectonics

at that time in Toronto was Professor John Cunningham McLennan, whom Jock regarded as being better suited as a “business tycoon.” McLennan had raised the funds for the construction of Convocation Hall and the Sandford Fleming Building, then occupied by the Department of Physics, and had been awarded the first doctorate in physics at the University of Toronto in 1900. Jock’s lasting impression of him was that of a white-coated martinet with a military bearing “terrifying faculty and students alike and who ruled a scientific empire in the palace that he had built.” Life at Trinity College was rather monastic; students wore gowns, usually attended evensong in chapel, were expected to be in by ten o’clock every night (women had to be in by nine), and attendance was taken both morning and evening. Lectures, fifty minutes in length, lasted from nine o’clock in the morning to one o’clock in the afternoon, six days a week, followed by homework and the writing up of laboratory reports. The worst instructors, Jock found, were in the Department of Mathematics. They successfully managed “to stifle any urge I might have had to study,” and the lack of proficiency in advanced mathematics was later to prove a serious handicap to him as a postgraduate student at Cambridge in England. The tedium in the classroom was relieved by summer fieldwork with the Geological Survey of Canada, during which he made the fateful decision to switch his undergraduate major from physics to geology, attracted by the opportunity to travel. He recalled, “Much as I admired the elegance of physical theories, which at that time geology wholly lacked, I preferred a life in the woods to one in the laboratory.” Being able to “follow Odell and his hammer across the Canadian Shield made toiling

over equations within the claustrophobic walls of a physics laboratory unappealing indeed.” Jock’s wish to switch academic programs was strongly resisted by his physics professors, who still regarded the discipline of geology as a very lowbrow science, much inferior to that of their own, and greatly reduced in stature from the heady days of the mid-nineteenth century when geology’s star was in the ascendant. Darwin was proud to be identified as a geologist, and geologists had formerly been among the leading scientists and explorers in Canada. Sir William Logan, the first director of the Geological Survey of Canada, had been well known to the public, as was Sir George Dawson at McGill University, who had discovered in Ontario the oldest fossil then known anywhere in the world. Prominent geologists across North America had been trailblazing leaders of the academy, and founded academic journals, learned societies, and even entire universities. But by the 1930s the status of geology as a subject for study was derided as a result of the constant need for fieldwork to collect and classify rocks, fossils, and minerals from distant places, and the reticence of many geologists to engage in the seemingly definitive quantitative theorizing undertaken by the physicists. With its emphasis on models and equations, physics appeared elegant and precise with immutable laws – everything that geology wasn’t. “The sad result,” Jock later recalled, was that “if anyone enquired of the whereabouts of the Geology Department on any campus, he was inevitably directed to the oldest and shabbiest building. When I asked to take geology, everybody was very upset. The physicist, McLennan, said you’re a good student – why go into something like geology? Why would you leave physics just when

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Jock Wilson (second from right, front row) in the undergraduate Science Club at Trinity College, University of Toronto; his role was to organize a program of invited lectures. Jock was an active college member involved in dramatics, running (he was president of the Harriers Club), and debating. Annual tuition at the University of Toronto was then $40.

it’s getting very exciting?” Jock’s response was that he “didn’t know it was getting exciting because I’d had nothing but classical physics in my first year.” The move across the road into the Geology Department was also fraught with difficulties, because the geologists were “reluctant to have a physicist come in for fear they might be found out that they didn’t know any mathematics or didn’t know any calculus and didn’t understand geophysics.” He was potentially stuck in an academic no-man’s-land between two warring factions. Others were very pleased with Jock’s decision. Noel Odell, who had supervised his work in Northern Ontario as a teenager, wrote in 1926 that he was “very glad to learn that you have already decided on geology with specialization in physics. I somehow felt, or at least hoped, that you would eventually tend toward geology.”

The physicists and mathematicians at Toronto may have looked down their noses at geology, but the study of rocks had one major advantage that those sciences lacked – it was of immense practical use. Geologists were held in high regard by industry in the search for lucrative mineral deposits. Jock’s transfer was ultimately successful, thanks largely to Professor Lachlan Gilchrist, a physicist and mathematician by training and a very popular professor who was then exploring the use of physics and newly developed electronic survey instruments to map minerals, especially iron and nickel, hidden deep underground on the Canadian Shield. These techniques were eventually to blossom into the scientific field called “exploration geophysics.” For Jock, it was the perfect blend of geology and physics; making instruments, taking them out into the

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bush to conduct field surveys, and potentially identifying new lucrative mineral prospects. Gilchrist’s skills were in very high demand, and he earned substantial sums in consulting fees, which he turned over to the university to support scholarships and equipment; he was especially good at what Jock portrayed as “wheedling large sums of money from his rich friends to support research.” As a result, a strong tradition developed at Toronto of directing the teaching of physics to helping the mining industry, and Jock became hooked on the emerging new discipline. The solution was for him to complete a double degree in physics and geology and thus keep everyone happy, even his mathematics and physics professors. He wrote to his friend Lionel Curtis that he found “physics and geology an interesting if unusual combination,” and for the next three years until his graduation, he settled down “to be a docile and cooperative student accepting the rivalries and jealousies of the two faculties.” It was at the University of Toronto that Jock was unduly influenced by the views of one geologist in particular, Professor Arthur Philemon Coleman, a determined critic of Wegener’s ideas. Coleman was an authoritative, well-connected, and very public figure, and formerly president of the Geological Society of America in 1915, the fateful year when Wegener’s book had been published. Coleman wrote weekly opeds in the widely read Toronto Star Weekly on a wide range of topics, such as the discovery of diamonds in Canada, the origins of the Great Lakes, fossil trilobites in the rocks around Toronto, Niagara Falls, climate change, and past Ice Ages on which Coleman was a recognized expert. Coleman’s belief that the study of geology revealed the mind of a Creator, a commonly held view among North American permanentists, has already been noted.

Arthur Philemon Coleman (right), professor of geology at the University of Toronto, at the annual camp of the Alpine Club of Canada at Maligne Lake in 1930 with Captain C. Crawford, newly returned from Mount Everest. Courtesy of Victoria University Library (Toronto).

Coleman had mapped the strategically important nickel deposits of the Sudbury District in Ontario, and this had resulted in a mining boom just before the outbreak of the First World War because of the need for armour plating. He also explored the rich iron deposits of Labrador and mapped large parts of the eastern Rocky Mountains (where he has a mountain named after him that overlooks the Icefield Parkway near Lake Louise). Using convict labour from the Don Jail in Toronto to 82

Permanentist Foundations

clear away debris, Coleman revealed the climatic significance of the sand and mud layers exposed in the walls of the north slope of the Don Valley Brickyard, which in turn furnished the bricks for the University of Toronto’s Convocation Hall spearheaded by John McLennan. His work identified more than one Ice Age and intervening warm-climate intervals (interglacials) in the recent geologic past. Public interest was sparked by the finding of the teeth of the extinct giant beaver in the Don Brickyard, and the British Association for the Advancement of Science was sufficiently excited to contribute funds to Coleman to aid further excavation and study. Jock was taken to the pit on field excursions by Coleman, and he gained an interest in glacial geology that he was to develop further while later working for the Geological Survey of Canada mapping the birthplace of the last great ice sheet on the Canadian Shield. Coleman had also uncovered evidence of the then oldest-known Ice Age anywhere on Earth at Gowganda in Northern Ontario, now known to be 2.4 billion years old, which revealed that the planet had experienced cold phases early in its history at a time when it was widely regarded as having been much hotter. Coleman produced the first geological map of the City of Toronto in 1912 and established that much of the city and its suburbs had been built on the floor of a former Ice Age lake – glacial Lake Iroquois that existed about 12,000 years ago. He carefully mapped the elevation of its shoreline as it was traced eastward toward Quebec and showed that it was warped upwards. This was evidence, as Frank Taylor had already demonstrated, of the much greater depression of Earth’s crust and upper mantle under the heavier load near the thickest part of the ice sheet located over Quebec. The warped shorelines pointed to a plastic,

mobile mantle that, when pushed down during an Ice Age, rebounded when the ice load was removed. This aspect was downplayed by Coleman, as it strayed dangerously close to accepting a mantle that could deform and continents that might drift. As a student, Jock used Coleman and W.A. Parks’s textbook Elementary Geology published in 1922. In it, the Earth’s mantle is depicted as being “solid as steel,” incapable of allowing overlying crust to move, and there is no reference to Wegener’s continental drift or Taylor’s “Earth’s Plan.” It is difficult to escape the conclusion that students were being sheltered from these radical ideas. No such inhibitions prevented Coleman from playing to the audience when he wrote in the American Journal of Science in 1924 that “nothing is sacred to Wegener,” declaring that continental drift was “merely an interesting speculation” by a “German oceanographer.” Coleman was the recognized expert on 300-millionyear-old Ice Age deposits now widely spread across parts of South America, South Africa, India, Australia, and even Antarctica. In his 1926 book Ice Ages Recent and Ancient he argued that these rocks were evidence of a “world-wide refrigeration” that had plunged the tropics into a deep freeze. He wrote of his experiences of examining ancient glacial deposits in Brazil containing striated, glacier-scratched boulders while working in torrid heat and being surrounded by tropical vegetation and coffee plantations where the “contrast of the past with the present was astounding.” But, as we have already seen, Wegener and Suess had showed years earlier that these cold-climate deposits could be brought together on a reassembled Pangea to demarcate a large ice sheet that had formed over the polar regions of the supercontinent. Not once in his many articles written 83

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for a popular audience did Coleman mention the topic of continental drift, despite the debate raging among geologists in North America. Yet Coleman had been in the audience when Taylor had given his presentation on ”Earth’s Plan” and continental mobilism at the Baltimore meeting of the Geological Society of America and had read his full paper on the topic published by the society in 1910. Coleman was, in addition, fluent in German, after having completed his doctoral degree in Germany, and would have been very familiar with Wegener’s grand idea, and the attendant discussions, when it appeared in 1915. At the 1922 annual meeting of the Geological Society of America, Reginald Daly, who, we have already noted, was far ahead of his time in recognizing field evidence for crustal displacement, stood up and commented favourably on Wegener’s ideas, only to be publicly chastised by Coleman, who referred sarcastically to his colleague’s “poetic imagination.” Two years after his death in 1941, in the last edition of Elementary Geology published posthumously, Coleman briefly acknowledged serious problems with the idea of vanished land bridges, given the great depths of the oceans, but still concluded, however, that “no other satisfactory theory has yet been proposed” to explain similarities in the geology of widely separated continents. This then was the rather blinkered environment in which Jock completed his first degree at the University of Toronto. Unduly influenced by Coleman’s dogmatic permanentism at Toronto, and later during completion of his master’s degree under the British permanentist Sir Harold Jeffreys at Cambridge, Jock would later complete his doctorate at Princeton University at the very nerve centre of American permanentism. With this apprenticeship, Jock would remain hostile to any

notion of mobilism for the next three and a half decades before shaking off the past and abruptly embracing continental mobility in 1961.

Summers in the Field At the end of the university year after sitting exams in May, Jock would escape the boredom of the classroom to spend his summers working as a field assistant in Northern Ontario. He became the epitome of a field geologist: energetic, physically fit, a good swimmer, at home in the bush, and able to complete arduous geological traverses and portages through poorly known, trackless country on foot and by canoe. He was adept at living off the land, catching ducks and trout, and, on one occasion killing an injured moose that had been mauled by a wolf, by lashing a knife to the handle of a paddle and driving the animal out into deep water where they finished it off. He and his companions dined on its meat for a week until it rotted. During the summer of 1927, Jock was paid the princely sum of $4.50 a day to work underground with the Pioneer Mining Corporation in Wawa, Ontario, along the northern shoreline of Lake Superior, where he learned to use hand drills. He was summarily promoted to the important position of camp “cookie” to provide provisions for fourteen men after the incumbent suddenly quit. The kitchen was rudimentary: “a ring of stones set on a pleasant beach with two forked stakes driven into the ground with a pole stretched between them on which to hang pots.” He learned to add raisins to rice to disguise evidence that mice had invaded the supplies, and to produce prodigious quantities of porridge, ham

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LEFT: Nineteen-year-old Jock Wilson in 1928 at Kirkland Lake, Northern Ontario, while working as a field assistant with Noel Odell, mountaineer and geologist, who introduced Jock to geology. RIGHT: Axe in hand at Noranda, Quebec, while working for the Geological Survey of Canada in the summer of 1929. A year later he would graduate from the University of Toronto with the first-ever degree combining geology and physics awarded at a Canadian university.

and eggs, pancakes, coffee, and toast. Making bread was a problem, his first attempts resulting in “bricks that even the squirrels would not eat,” but the men had huge appetites and were not used to anything better. Annie, his parents’ housekeeper back in Ottawa, mailed recipes and offered other sundry tips to help the new apprentice, but he was also learning his geology and was tested on his knowledge of rocks each evening around the campfire. By summer’s end he had cleared the sum of $250, but the experiences were priceless. On one occasion that summer, after not having seen any signs of other humans for six weeks, Jock’s field party

was visited by a group of upper-crust Englishmen on an arduous canoe trip across Canada. Worn out by unaccustomed hard travel, they had set up their camp on the far side of the lake and were invited to come across for dinner. Jock’s responsibility was to “cook up the best meal our dwindling resources could provide.” Unfortunately, en route to dinner, the visitors’ canoe was upset by waves, and the visitors arrived onshore wearing their only dry clothes consisting simply of shirts and long underpants. A few years later, while at a formal dinner at Cambridge, Jock would remind the Honourable William Astor, son of Lady Nancy, that

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on the previous occasion they had dined, he had been without his trousers. Astor was apparently unimpressed. The following year, in 1928, Jock worked once again with Noel Odell in a gold mine at Kirkland Lake in Northern Ontario, drilling and blasting at the mine face, and as a “mucker” pulling cars filled with rock off the mine hoist and pushing them to the mill. He learned to work with dynamite, which he came to regard as “nice safe stuff” and which would prove to be a useful skill in wartime as a member of the Canadian Army. In 1929 he obtained a position with the Geological Survey of Canada as an assistant to Dr. H.C. Cooke at Noranda in the Abitibi-Témiscamingue region of Quebec, which was experiencing a mining boom fuelled by the recent discovery of gold and copper. Jock later recalled that “a great plume of grey sulphurous smoke poured ceaselessly from the stack of the town’s copper smelter like a gigantic wind pennant stretching to the horizon.” He climbed to the top of the stack to enjoy the view of molten slag being poured much like red-hot volcanic lava onto the waste heap. His boss, Dr. Cooke, was an eccentric “dressed in a nondescript garment that appeared to be tied on with string,” who spent all his leisure hours playing bridge, but he was an excellent geologist, and Jock learned much from Cooke of the practical side of finding minerals and of the geology of the Canadian Shield. Near Noranda, the Shield is composed of huge expanses of rock called “greenstone belts” many tens of kilometres in length and width, composed of beds of lava erupted underwater where magma was squeezed out onto the sea floor, much like red-hot toothpaste that cooled very quickly into rounded “pillows.” These have a distinctive tear-drop shape with a rounded top and a pointed projection at their base where balls of still-soft

Pillow basalt typical of the many “greenstone belts” found across the Canadian Shield; they record volcanism on the floors of ancient Archean oceans older than 2.5 billion years, that were trapped when crustal blocks collided to form the Shield.

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magma had sagged down into the gaps between the pillows below. Their origin was not then fully known, but their shape afforded geologists a means of determining whether ancient rocks were in their original upright position or had been overturned, as was commonly the case in highly deformed folded rocks of the Shield. Jock was given a pot of white paint and a brush and told by Cooke to paint the outlines of pillows to highlight their appearance on black-and-white photographs to be included in their report of the region’s geology. Today, greenstone belts are recognized as the remains of the floors of long-dead oceans destroyed between colliding land masses as the Shield was built piece by piece. Jock’s most memorable experience of working in the far north was when a float plane carrying a trader and his family southward from a remote community in the Arctic landed nearby. The pilot “asked to tie up at our mooring until daylight. While the grown-ups went up to our tent to get a cup of tea, a small child stayed with me by the shore. I tried to entertain him, but he remained completely absorbed in examining a small spruce, feeling it and patting it and walking around it. He had lived his entire life in the Arctic and had never seen a tree.” Returning to Toronto and the classroom for one last year, Jock sat his final exams and finished his degree in the early summer of 1930. Professor Lachlan Gilchrist had been far ahead of his time in combining the disciplines of geology and physics into a single degree, and Jock was the first and only graduate of the first such program anywhere in Canada. He had briefly considered moving to Finland for postgraduate studies to examine the ancient Precambrian rocks of the Fennoscandian Shield, which are like those he had worked on across the Canadian Shield, but the

Jock Wilson on his graduation from the University of Toronto in 1930. He described his university record as a “hodgepodge,” but “the five summers I had spent in the bush left me competent in camping, canoeing, mining and swinging an axe.” From his college courses and summers spent in the north, he “was beginning to get a grasp on geology.”

requirement to master either the Finnish or Swedish language as a condition for graduation was a barrier to further progress – where was Miss Cowan when he needed her? There was also the issue of funding. In the spring he had sat the exam for a prestigious Rhodes Scholarship, which would provide money to continue his postgraduate studies, but to his great dismay, Jock discovered that the topics on which he was to be tested were “stacked against any candidates

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from the sciences for they all dealt with philosophy, literature, politics or economics.” His disappointment didn’t last long, however, and after a personal interview with Vincent Massey and his wife, who were major donors to the University of Toronto, he was awarded a prestigious Massey Scholarship, which allowed him “to do anything I liked.”

As a new graduate student, Jock was among distinguished company, meeting the Nobel laureate J.J. Thompson, who had discovered the electron, and Sir Gerald Lenox-Conyngham, former director-general of the Geological Survey of India who had identified marked differences in density of continental crust and oceanic crust by systematic gravity surveys. St. John’s College at that time, however, was firmly in the permanentist camp. Lenox-Conyngham was no supporter of Wegener, having questioned the German’s scientific credentials at the same public meeting in London in 1923 that Philip Lake of the Sedgwick Museum, just a few streets away in Cambridge, had also taken him to task. Jock spent most of his time with the principal British opponent of Wegener’s ideas of drifting continents, the physicist Sir Harold Jeffreys, who had used tens of thousands of earthquake records to build the first coherent picture of the structure of the Earth’s mantle, which he regarded as being too rigid to allow any movement of the overlying crust. Jock remembered him as being “very pleasant and shy,” often wearing a flat working man’s cap and amusing his students by speaking “Geordie,” a Northumbrian dialect spoken in the northeast of England and akin to old Norse. An imagined conversation might have gone thus:

Wilson Goes to Cambridge It seemed to bother no one that there was nothing clearly arranged for me to do. J. Tuzo Wilson, 1993

Funded by his postgraduate Massey Scholarship and the proud possessor of the Coleman Gold Medal for excellence in geology from the University of Toronto, Jock went to England in the fall of 1930 to complete a master’s degree at St. John’s College, Cambridge, founded in 1514, where geology had been taught on campus for “two or three hundred years.” He was excited at the prospect of enrolling in a new graduate program combining geology with physics, but it failed to materialize because its intended instructor, Teddy Bullard (later to become Sir Edward Bullard, and whom we shall encounter again), was away in East Africa completing surveys of the Great Rift Valley. Despite the lack of direction for his program of study at Cambridge, Jock’s experiences there were to play a major role in his career. Later, in 1965, Bullard was to invite Jock back for a “most stimulating and fruitful six months,” during which time he established the essential foundations of plate tectonics.

JOCK: “And what is your considered view of mantle convection Sir Harold?” JEFFREYS: “Girraweh mon! Noo then, meks nae matter, niver talk tae me aboot cunninentool drift, mantle canna gaw. An ivverybuddy knaw ta’t Wegener doant knaw wat ’e’s talking abooot an’ a’. Now’t. It doant woork an’ divvn’t ask me agin, awreet.” JOCK: “Yes, quite so Professor.”

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Jock found himself ill-prepared for Jeffreys’s classes on the physics of the Earth because of his unfamiliarity with advanced mathematics, a problem inherited from his lack of interest in the subject at Toronto. He attended eight of Jeffreys’s lectures and admitted that most of the material “sailed right over my head because I was not equipped to deal with his lectures, and he was also a very bad lecturer though he was brilliant and his book [The Earth] was very lucid.” Jock remembered that Jeffreys “worked alone, hardly ever said anything and had no idea of teaching.” The geophysicist Gordon MacDonald left a vivid portrait of Jeffreys’s lecturing style: “Scribbling a series of detailed equations on the board, wandering to an open window and while gazing out away from the class, discussing at length the peculiarities and complexities of fluid dynamics as if addressing the numerous pigeons roosting outside.” Jock was to later admit that he had been “brainwashed” by Jeffreys into accepting that continents were fixed and rested on a solid mantle that could not move. It was in Jock’s second year at Cambridge that news came of Wegener’s death. The theory of continental drift had already been rejected by Jeffreys, and the calamitous event on the Greenland Ice Sheet and the loss of a fine scientist went unmarked at Cambridge. Quickly realizing that there was no specific plan of study for him at Cambridge, Jock concluded that the only “academic problem was entrance and once safely inside those venerable walls one had to behave very foolishly to fail to get a degree.” By his own admission, Jock was not a good student, being easily distracted unless closely supervised.

Jock’s tutor and nominal supervisor was James M. Wordie, who had been the geologist on Sir Ernest Shackleton’s famous Imperial Trans-Antarctic Expedition of 1914, when the expedition’s ship the Endurance was caught in the ice of the Weddell Sea and crushed a year later. Wordie was satisfied that under the influence of Harold Jeffreys, Jock “was getting a sufficiently satisfactory education for a colonial” and left him alone. As a quick mark who could excel seemingly without putting in too much elbow grease, Jock successfully evaded his tutor’s watchful eye and spent his holidays travelling in the best tradition of the wandering scholar across Britain and Europe. In Germany, armed with bread, wine, sausage and cheese, he hiked from Cologne to Munich (where he had to ask the meaning of swastikas scrawled on walls) and climbed the Zugspitze, the highest mountain in the country right on the border with Austria, all while notionally being “in residence” at Cambridge. He bought an old motorcycle to explore the length and breadth of Britain, developing a fascination for castles and ancient British stone works, especially Stonehenge. In north Wales he hid his motorbike under bushes, slept out on Pen-y-Pass, and climbed Mount Snowdon, the highest mountain in Wales (some 1,000 m above sea level), enjoying fabulous early morning views before the clouds rolled in. It was at Cambridge that he finally overcame his dislike of team sports, but not for any obvious athletic or social reasons. Just like today’s junior ice hockey players in Canada, graduate students were billeted out with families in the surrounding community. There they had to endure that quintessential British

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experience of using an outside “privy” (toilet) located in the backyard of homes, a common phenomenon even until the 1970s and an especial delight in winter. Taking a bath was even more problematic as it required Jock walking two blocks wearing only a dressing gown, usually in the rain, to queue for a tin tub that took thirty minutes to fill with lukewarm water. The simple solution for an impatient Canadian used to swimming in cold northern rivers and lakes was to take up sport, “for all the major ones had their own changing houses with cold showers.” Jock rowed for the college third team and took part competing in the “Bumps” held on the River Cam. The river is too narrow to race boats abreast of one another, so they follow behind each other in a line. Spaced equidistant at the beginning of a race, each boat tries to catch up with the boat in front and make contact (“bump”). The referees would race up and down the tow path on horseback monitoring the race; the boat with the most bumps would win. Training for each race was rather straightforward, consisting of the time-honoured practice of “consuming vast quantities of food and beer” in which Wilson’s team excelled; they “won their oars,” and he would later carry his back to Canada, sawn in half for ease of transport. Jock’s team celebrated the win by climbing high up on the college’s chapel tower and clothing its protruding gargoyles in scarves and academic dress. Jock also signed up with the RAF Cambridge University Air Squadron, learning to fly Avro trainers out of nearby Duxbury airbase before graduating at Old Sarum Airbase near Salisbury on a Bristol biplane. This had been the principal British reconnaissance

aircraft of the First World War with a top speed of about 250 km/h. On one occasion, he was forced down by a dense fog bank and had to land “in a strange field.” Jock returned home to Canada in 1932 with a graduate degree (an MA), a substantial collection of German beer mats, and a pilot’s licence, but with no clear plan of what he would do next. Vincent Massey tried to convince him to enter politics and work for the Liberal Party, but he was disinterested. Completely unsure of his next move, Jock returned to familiar surroundings and began to work once again with the Geological Survey of Canada, this time prospecting for gold in the Annapolis Valley of Nova Scotia. He and his assistants used a magnetometer for identifying anomalies in the local magnetic field created by buried metallic ores, but it was unrewarding and nothing significant came of their surveys. His most vivid memory of that summer is of being exposed for the first time to Nelson’s blood, a heavy West Indian rum, which local farmers proffered him and his two assistants in large measures and which he described as deadly, endowing him with a life-long aversion to the liquor. Returning to Ottawa with nothing to show for the season’s work, a permanent position with the Geological Survey was out of the question. These were the years of the Great Depression, there was no money to hire anyone, and government salaries had just been cut by 10% across the board. The Survey’s director, W.H. Collins, gave Jock a job in the laboratory working on rock samples from Sudbury, but it was only a temporary position, and he advised Jock to leave and pursue his studies elsewhere.

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A Royal Air Force Bristol fighter flying over Stonehenge. Jock had qualified on two-seater Air Trainers with open cockpits at Cambridge University, flying with the RAF Cambridge University Air Squadron based at Duxford Aerodrome, where he learned the two essentials of maintaining sufficient speed to avoid stalling and always looking to see where one could land in the case of engine failure. He moved on to the versatile two-seater Bristol biplane in 1931. This photo was taken by Jock himself.

The Princeton Years

writing Our Mobile Earth in 1926, in which he identified forces in the Earth’s crust that might be powerful enough to move continents. However, the lukewarm reception given to the book, combined with the outright hostility of his permanentist colleagues at Harvard to any ideas that might support Wegener’s drift theory, was so intense that Daly gave up any intention of “teaching anything as outlandish as geophysics.” Rebuffed, Jock considered working on a geophysical problem with the young Maurice Ewing at Lehigh

Go off and get a Ph.D in geology. W.H. Collins to Jock Wilson, 1932

With little hope of finding a permanent job in Canada, Jock approached the Canadian-born geophysicist Reginald Daly at Harvard with a proposal to begin a doctoral research project in geophysics. As we have already noted, Daly had made waves among the geological community by

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University, who was using explosives as an energy source to map the structure of the New Jersey coast by recording the echoes made by seismic waves pinging off harder rocks at depth. Ewing, however, “was addicted to his research and quite unable to take the time to give us any lectures or to instruct us,” and after some initial meetings, Jock could “discern no Ph.D at the end” and gave up the venture. Finally, at the suggestion of his old employer at the Geological Survey of Canada, W.H. Collins, Jock decided to enrol for a PhD at Princeton University, partly because his father was friendly with Lester Cooke, a faculty member at Princeton who shared a common interest in developing specialized cameras for taking photographs from planes. The emerging aerial technology was to be of vital importance later in Jock’s career and reflects the considerable influence of his father, who had championed the value of air surveys in his capacity as secretary of the Air Board. Working with “airplane photographs” was to be a central theme of his son’s geological work and later allowed him to see the “big picture” when mapping the highly complex rocks of the immense Canadian Shield while everyone else was lost in the details. In June 1933, Jock was awarded a part-time teaching assistant position at Princeton with an annual salary of $300, but his experience there started badly. He later remarked that “the graduate school was a loss, a sterile place, as far as I was concerned.” On his arrival, the faculty discounted his considerable experience with the geology of Canada and “said that I hadn’t done any geology that mattered and I should do my Ph.D on American geology.” It was another example of the rather closed-minded exceptionalism typical

of many North American geology departments at the time that had led to the rejection of Wegener’s innovative ideas on continental drift. Jock’s lack of enthusiasm about his time spent at Princeton was also due to a sense of isolation and detachment, and he felt that he was simply part of “an academic assembly line that would produce a Ph.D thesis at the end of three years.” Part of this was no doubt due to his being strapped for funds and having to live in cheap digs in town for $2 a week and having to heat “messes of one sort or another warmed over a Bunsen burner in the lab for lunch and dinner.” Life there did have its small diversions, such as when making frequent visits to the Physics Library he “would walk around Einstein, who was sitting in the same easy chair everyday thinking about life and writing things on a piece of paper.” He attended lectures by the great man but understood little because of his thick accent. At the suggestion of Professor William Thom at Princeton, Jock began fieldwork in the summer of 1933 on the geology of the Beartooth Mountains in Montana. He was disappointed to give up geophysics and embark on a standard geology thesis, but his field area lay close to Yellowstone National Park and had been chosen because of its varied geology. Jock was given money “to buy a car, drive west, spend the summer, drive back to Princeton and I did it!” The long drives across the Midwest in 1933 and again the following year allowed Jock to see the site of the World’s Fair at Chicago, but also exposed him to the darker sights of the Depression with hungry and desperate men riding the rails, looking for work. Violent bank robberies were commonplace, with robbers often taking travellers as hostages to prevent

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being shot at by police when escaping in high-powered cars, but Jock felt safe driving the old beaten-up 1926 Dodge and rather enjoyed being entertained at gas stations by stories of the “latest episodes of the drama unfolding around us.” He arrived in Butte, Montana, where copper mining was the lynchpin of the state’s economy and the skyline was dominated by giant smoke-belching chimney stacks of the copper smelters, only to find the city in the midst of a bitterly contested strike with armed guards patrolling the town. It was a hardscrabble city and lynching of labour leaders and bombings were not unknown. The rugged Beartooth Mountains lie in the remote Rocky Mountains of Montana and northern Wyoming and are very different in shape from the Canadian Rockies familiar to Jock. The mountains in Montana record the eastward thrusting of large thick slabs of hard Precambrian granites and gneisses (part of the deeply buried Canadian Shield). This has left flattopped mountains, very unlike those of the Canadian Rockies where much younger and softer sedimentary rocks had been pushed over the Shield below. These had been folded and creased like a tablecloth, which today are expressed as the knife-sharp, parallel-crested mountain ridges typified by the breathtakingly famous vistas around Banff, Alberta. At the time of Jock’s mapping, the Beartooth Mountains were classically regarded, following traditional permanentist thinking, as the product of a deep geosyncline along the outer margin of a fixed unmoving continent. Blocks of rigid basement had supposedly been raised up during the contraction of the geosyncline, and great thicknesses of overlying younger sedimentary rocks supposedly slid downslope producing large folds. Today, thanks

In 1933, Jock bought a 1926 Dodge sedan Series 126 for $50 in Montana, which lasted him for two field seasons and completed three journeys across the continent between Montana and Princeton. It had a 3.5-litre engine that produced a meagre thirty-five horsepower with a simple three-speed transmission. It proved to be a faithful servant, and Jock remarked that “it placed no demands on my limited means beyond gasoline and an occasional jolt of oil.” He was to later sell it on his return to Canada for $25.

to Jock’s groundbreaking work completed thirty years after his graduate studies, these mountains and their deformed rocks are seen as pieces of the Canadian Shield and overlying younger sedimentary rocks that were pushed eastward beginning about 70 million years ago by powerful compressional forces created as North America pushed westward to override the crust of the Pacific Ocean’s floor. The same process was at work to the north in what is now Canada, but in Montana the telescoping has reached far deeper to break off and uplift slabs of the hard Shield basement. Overlying sedimentary rocks have been stripped off, exposing the ancient surface of the Shield as gently sloping flat-topped mountains that have been deeply cut and dissected by Ice Age glaciers. It was strenuous working in such rugged terrain, involving constant climbing to reach bare rock exposed above the tree

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line, and Jock’s ability to navigate safely in remote country at high elevations was severely tested. His PhD thesis on the geology of the Beartooth Mountains was duly written up and successfully submitted at Princeton in the spring of 1936, but the results never saw the light of day. It was all traditional stuff and amounted to the classic “stamp collecting” so derided by geophysicists, and, as Jock well knew at the time, the results were of low impact and virtually unpublishable. Intending to write up a series of shorter papers, he would carry his bulky thesis in a backpack everywhere he went during his wartime service in Europe after 1939 before finally bringing it back home to Canada in 1943. The passage of time slowly weakened his resolve to publish and “the weight on my conscience lost the power to disturb my sleep.” The papers were never written – a condition with which many academics eventually become familiar. Reading the thesis today, there is no inkling of the genius to come. Jock could not know it at the time, but the seeds of a new scientific discipline within the broader science of geology were germinating at Princeton that would be a major influence on his later career and help usher in the global revolution in Earth sciences in the 1960s. It was at Princeton that he met Richard Field and Harry Hess, the founders of “marine geology.” Field was an inspiring, highly energetic individual, who argued to anyone who would listen that the science of geology was incapable of generating any “big ideas” of how the planet worked when it continued to restrict itself to the study of dry land, which amounted to just 30% of the planet’s surface. In his opinion, geologists needed to consider the entire Earth, which included the oceans too. Hess would later propose innovative ideas on the origin of oceans that

Jock Wilson in 1933, aged twenty-four, while working in the Beartooth Mountains of Montana for his PhD at Princeton University. “I was given a strip a hundred miles long and they said go map it. My thesis area ran from four thousand four hundred feet at Livingston, upwards to eleven thousand eight hundred feet. In the upper parts you were required to get acclimatized a bit.”

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Jock (right) taking a break from fieldwork in the Beartooth Mountains. The far peak is Mount Hague with an elevation of 3,756 m. “The highest point of my area was rather inaccessible, but I reached it by walking, climbing and running for the best part of three days and sleeping at night by a fire.”

would inspire Jock to move away from permanentism in 1961. Were the ocean floors as flat as widely believed? Did they simply consist of foundered continental rocks of former land bridges as argued by permanentists, or were they different and uniquely oceanic? These were fundamental questions that needed to be answered before any realistic consideration of Wegener’s theory of continental drift could be made. Eventually in 1948 Maurice Ewing was to persuade the wealthy Lamont

family to donate their palatial summer residence, high above the Palisades overlooking the Hudson River some 25 km north of Manhattan, to Columbia University. As a new marine geological observatory, it was to pioneer Cold War research in the 1950s on the geology of the ocean floors. It was to prove to be the impetus for the recognition of crustal plates and a radical new understanding of the planet, which Field had predicted and which Jock would lead. But that was all in the future.

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Jock Returns to Canada and Becomes Tuzo

on their summits and, when lit up at night, resembled ships at sea, “as if the ocean had come in.” He was, as we shall see, to take up the study of drumlins in 1958 when he mapped their distribution across Canada. Overall, 1937 was a very disappointing year, as Tuzo had originally been promised work in northern British Columbia and in the Yukon but instead found himself in the mosquito-infested swamps of northern Quebec, just south of James Bay. He supervised a crew of twenty ill-prepared assistants who had been given a government job because of “overdue political debts to party faithful but had never been further than five miles from the city.” Many could not paddle a canoe and had never done any physical work at all. Camp life was enlivened only by a cook who was the life of the party and who hid his drinking habit by consuming bottles of vanilla flavouring laced with alcohol. The following summer saw Tuzo employed once more as an assistant geologist, but this time working out of Yellowknife in the Northwest Territories on the broad expanse of the Canadian Shield between Great Slave Lake and Great Bear Lake. This time it was to prove a pivotal experience. His field area lay in remote country, traversed by the explorer Samuel Hearne in 1771–2, where the difficulties of mapping trackless terrain reinforced the importance of using air photographs. The usual working practice at the time was to simply mark an X on a map, then set off with a party of as many as twenty men and their supplies, navigating across the bush with heavily laden canoes, mapping the rocks seen en route to the allotted target. Getting lost was an ever-present hazard. The “most important problem was knowing where one was not so much with the thought of making a map but to be

Jock returned to Canada in the spring of 1936 with not only a PhD from Princeton but also a new identity. It was at this time that he started using “Tuzo” to avoid confusion with the American James Tinley Wilson (1914–1978), who was also a geophysicist. Tuzo starting using his middle name, which had been his mother’s maiden name, and made it his own, and that is how we shall address him from now on. Tuzo was once again hired on by the Geological Survey of Canada as an assistant geologist, and he completed a series of summer field seasons between 1936 and 1938 in Nova Scotia, northern Quebec, and the Barren Lands of the Northwest Territories. In Nova Scotia he gained valuable experience in mapping broad expanses of Precambrian rocks that had been deposited as sediments deep underwater but had subsequently been crumpled and folded. He would later use this information to argue in 1966 that these rocks had been deposited in an ancient ocean, older than the current Atlantic Ocean, that had closed when surrounding continents had converged to form Pangea. However, Tuzo was a confirmed permanentist in 1936 and viewed the deformed rocks of Nova Scotia as a product of a contracting, cooling Earth. His work there also brought him into contact, once again, with landscapes left by the last great ice sheet to have covered Canada, and he became intrigued with the origin of drumlins, which are the classic archetypical landform left by ice sheets. They are elongate hills resembling upside-down rowboats, as much as 30 m in height and more than a kilometre long separated by low-lying swales. He noted that farmhouses were built

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Tuzo (seated at centre) surrounded by his staff at the Geological Survey of Canada while working on a mapping project in Nova Scotia in 1936. “The life of a geologist was in one respect the reverse of the normal rhythm of the working year of the average wage earner; into the four months of summer was crammed a year’s activity and the other eight months were occupied by the tedious, unhurried business of getting the results down on paper.” Much time was spent, inevitably, on justifying and accounting for expenses.

sure of getting back.” Navigating through dense bush, Tuzo kept track of his location by “pace and compass,” keeping closely to a predetermined direction and noting the location and types of rocks along the way. Each day, a survey geologist was required to map an area of approximately 30 km2, requiring constant hard labour. The bigger regional picture was often difficult to grasp, and much time was wasted on simply surviving and navigating. It was slow and tedious work, a grossly inefficient way of mapping large areas of remote country, but it was the cornerstone of how geology had been done by the Geological Survey for almost a century. The resulting maps were disparagingly referred to by the survey geologists as “Christmas tree maps” in reference to the convention of the time of depicting granites in red, lavas in green, and other rocks, such as gneisses, by polka dots in a variety of colours.

In completing the survey of the Fort Smith map area (some 12,000 km2), Tuzo and his party completed 245 portages involving manhandling of heavy canoes and their loads from one watercourse to another. It was dangerous work, and he later remarked that he was “frightened by rapids and exhausted by portages.” Tuzo was almost killed on two occasions: on the fast-flowing Abitibi River in Ontario, and on the Taltson River near Great Slave Lake, where the current nearly swept him and his assistant over a 30 m waterfall. Drownings of otherwise excellent swimmers in icy cold water were common and the effects of hypothermia had not yet been recognized. These dangers informed his later opinion that field geology was inherently unsafe and not a fitting profession for young women, hence his objection to his daughters studying geology.

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TOP: Field mapping of remote areas of the Canadian Shield required numerous portages from one waterway to another and the carrying of heavy canoes and supplies. It was dangerous and inefficient, with many drownings in cold, fastflowing rivers. This was to soon change as aircraft began to be used for reconnaissance of remote, difficult country. BOTTOM: Geological Survey of Canada field party on the Harricana River on the Canadian Shield in northern Quebec, May 1937; float planes dropped off food and mail every three weeks. Tuzo began to employ aerial photographs to map large tracts of the Canadian Shield, but it was not popular with the “boots on the ground” attitude prevalent among many field geologists.

Permanentist Foundations

Airplanes alleviated the drudgery and dangers of working in the remote bush, and Tuzo quickly discovered that geological features barely visible on the ground stood out clearly from the air. The most striking features were faults, where rocks had been torn apart along enormous fractures and the blocks on either side shoved in opposing directions. Their presence is marked in the landscape by deep, narrow valleys (“gashes”) or by high escarpments many tens of kilometres in length. With his pilot’s licence gained at Cambridge, he convinced the pilots ferrying supplies and personnel to the Geological Survey camps to let him borrow the plane and fly along the faults. “The view from above, far broader and illuminating, reinforced the growing opinion that air photographs were a powerful tool in reconnaissance geology. Prospectors, fanning out from Yellowknife, had followed these three or four almost parallel gashes. Here they stood out, bold and clear, like airway markers for planes.” He soon realized that regionally, the long faults divided the Shield into immense blocks of crust many hundreds of square kilometres in size, which together formed a gigantic mosaic. The significance of the faults and the need for further study were underscored by the clustering of rich mineral deposits along their length (called “breaks” by miners). With the aid of air photographs, he greatly expanded his mapping area “without the necessity of laboriously walking all over the country” and the attendant risks of getting lost or drowning. Throughout his life, Tuzo had a keen eye for colour and design, and the views from low-flying planes produced a new canvas to be filled with patterns simplifying the complexity of the details on the

ground. To his everlasting dismay, however, the new aerial survey methods met stiff criticism from the Geological Survey of Canada, who argued that “one had to stand on the ground first” and viewed the use of air photographs as “reprehensible and dishonest, akin to cheating.” Tuzo persisted, however, and laid the groundwork for a new appreciation of how the Canadian Shield had formed, which he would later revisit and refine in the 1950s as an academic at the University of Toronto. The rocks of the Shield are dominated by gneisses – old metamorphic rocks with beautiful banding often complexly rucked and folded because of having been heated and partially melted at great depths underground. Some at the Geological Survey in the 1930s still considered them as volcanic in origin, formed by the cooling of the surface of an originally molten planet, vestiges of Earth’s original igneous crust. The monotony of the pink and grey gneisses that cover enormous areas of the Shield is relieved by enormously long walls of dark green and often black volcanic rock, sometimes many metres in width, which extend many tens, sometimes hundreds, of kilometres in length. These are Reginald Daly’s “dikes,” produced by upwelling of magma along narrow fissures that in some cases result in giant radiating “dike swarms.” Tuzo immediately grasped that these did not fit with the model of a cooling planet, because the dikes had intruded into the gneisses much later. His ideas fell on deaf ears in Ottawa, and most of the detailed geology he had mapped from the air was wasted, never to be used by the Geological Survey of Canada, who, according to the “accepted geological dogma of the day, believed that all gneisses had once been molten. The great faults and dikes … could not be explained by the current gospel

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Outcrops of banded gneiss typical of huge expanses of the Canadian Shield and formerly viewed as igneous rocks formed by cooling of a “magma ocean” early in the planet’s history. These are now recognized as metamorphic rocks that were deformed by heat and pressure at depths as much as 25 km below high mountains uplifted along the boundaries of colliding land masses.

of a rigid earth and so were ignored.” Tuzo complained that “the tyranny of one closed mind destroyed much of the product of a whole summer’s work,” and it finally convinced him that the Geological Survey of Canada was, not then at least, the place to develop new ideas on the evolution of the Shield. The long faults within the Shield that Tuzo had observed from the air near Yellowknife are indeed now recognized as marking the boundaries of immense crustal blocks many thousands of square kilometres in size. These

blocks are variously named “provinces,” “cratons,” or “terranes,” such as the Slave Craton, brought together when small land masses collided, closing an ancient ocean in the process, to form a much larger land mass. Conversely, the many dikes he had marvelled at are now seen as a record of crustal stretching and upward intrusion of magma from the mantle when the primeval land mass was stretched and almost broke apart. And there was yet another innovative application of Tuzo’s work using airplanes and aerial photographs

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An igneous dike, like the many mapped by Tuzo, resulting from magma intruding upwards into the crust along fissures. Being composed of rocks much harder than those into which it intrudes, it now stands proud like a giant wall running across the landscape as a result of erosion of softer surrounding rocks. In 1936, Reginald Daly recognized that intrusion of hundreds of dikes requires extension of the crust, which might exert a spreading force that could move crust laterally. The idea was ignored until rediscovered and reborn in the early 1960s as “sea floor spreading.” Courtesy of Mike Beauregard, Government of Nunavut.

in the Northwest Territories. His observations from the air reinforced his interest in Ice Age glacial landscapes and landforms that he had developed working in Nova Scotia. These had been left by the melt of the last great ice sheet to have covered Canada, which had been named the Laurentide Ice Sheet by G.M. Dawson in 1887. During his years as an undergraduate at Toronto, Tuzo had been inspired by A.P. Coleman, the noted Ice

Age expert, to read about ancient ice sheets and their effects on landscapes. In his time with the Geological Survey of Canada, Tuzo amassed a wealth of data on glacial landforms across a large swath of northern and eastern Canada, being especially interested in eskers, an Irish word for long sinuous ridges of sand and gravel deposited in subway-sized tunnels melted under the ice, and elongated drumlin ridges found side by side

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LEFT: Tuzo’s map of faults and dikes and other structures on the western part of the Canadian Shield made from air photographs in 1938. RIGHT: Modern map made by Wouter Bleeker of the Geological Survey of Canada showing the structure of the same area. Tuzo had unknowingly identified a large crustal block called the Slave Craton, bounded by the Great Slave Lake Shear Zone, the Wopmay Fault Zone, and the Bathurst Fault.

in their thousands in “swarms.” The Survey, however, argued that these were of no economic significance and so “struck them off the map.” In October 1938, upon his arrival back in Ottawa from fieldwork in the Northwest Territories, Tuzo married Isabel Jean Dickson, whom he had known as a school friend since the age of eleven. He had briefly overlapped with her while they were students at the University of Toronto but had lost contact when he had moved to Cambridge and Princeton. Subsequently, while working with the Geological Survey of Canada and in the position of being “firmly established on the government payroll,” he was able to “mount a

serious campaign,” and he and Isabel became engaged. In time-honoured fashion among geologists, Isabel was quickly coerced into helping Tuzo complete his geological maps and reports in Ottawa over the winter. The following summer of 1939 he left for the Territories, mindful of events unfolding in central Europe. His field party lacked a radio, but letters and newspapers delivered to their camp by air brought increasingly ominous news of German aggression and likely hostilities. While he looked forward to getting home at the end of that summer to settle down into a peaceful domestic routine with Isabel, this was to prove impossible. There was now a war to fight.

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Chapter 5

Tuzo’s War

The long hours I had spent studying air photographs of the Canadian Shield had persuaded me that anyone who could recognize a drumlin could doubtless identify an enemy pill box. J. Tuzo Wilson, 1993

The Second World War broke out on 3 September 1939, when Britain, shocked into action by the German invasion of Poland, declared war on the Third Reich. Canada announced her support of the Motherland seven days later, and by the end of the month almost 60,000 Canadian men and women had enlisted, many more than had joined up in the first five months after the outbreak of the First World War. Out of a population of 11 million, one in ten Canadians would ultimately serve their king and country. Tuzo was resolved to enlist, but given the desperate need for metals for the war effort, geologists were exempt from military service. He remembered, “They told me I couldn’t join the army because finding minerals was more important, and we were considered to be of greater use looking for new ore bodies than learning to be soldiers.” Deeply disappointed but undaunted,

he used the military connections of his father, JA, in Ottawa to enlist. JA had earlier been commissioned into the Governor General’s Foot Guards, the most senior militia infantry regiment in Canada, and knew General Andrew McNaughton through their work on employing veterans to build airfields in the 1930s. This relationship would turn out to be very valuable for Tuzo, not just for helping him enlist, but also for his later career as a geophysicist after hostilities ended. McNaughton was a formidable individual: a highly successful civilian-soldier, a former lecturer in engineering and physics at McGill University, and an expert on high-voltage transmission lines at a time when Canada’s hydroelectric potential was just being realized. He had served with distinction with the Canadian Field Artillery in France in the First World

Tuzo: The Unlikely Revolutionary of Plate Tectonics

War, where he developed an international reputation as a “scientific gunner.” Wounded several times in action, he achieved the rank of brigadier-general by the age of thirty-one and was the leading expert on counter-battery operations using an early form of radar to identify the location of enemy artillery, which he later patented in 1924. It had been at the battle of Vimy Ridge in April 1917 that McNaughton, with his pet lion cub Tony in tow, developed the use of rolling artillery barrages that lobbed shells fused to explode on contact with the ground over the heads of advancing Canadian troops to destroy German machine gun emplacements and rip open their tangled rows of barbed wire. Up-to-date intelligence on the placing of the enemy’s defences was fundamental, and McNaughton was a pioneer in the use of airplanes and cameras to make accurate daily maps of trenches and the disposition of opposing enemy artillery batteries, ammunition dumps, and troop staging areas. In doing so, he faced the same resistance from conventional gunners and the same accusations of cheating that were later to be levelled at Tuzo by the Geological Survey of Canada when using air photographs to map the geology of the Canadian Shield. However, the success of McNaughton’s innovative geophysical methods could not be ignored, and there were political repercussions back home. The Canadian military success at Vimy had created a sense of national identity, and for the first time shortly thereafter, a Canadian commander (General Currie) was placed in charge of dominion troops on the Western Front,

creating a national fighting force independent of British control. By August 1917, McNaughton’s techniques had been made so precise that the location of an opposing artillery battery could be mapped to within 25 m of its location, while detecting the calibre of the weapons and their fields of fire. That same month, McNaughton displayed his skill at what he called “killing by artillery” when Canadian shock troops seized Hill 70 – a strategic highpoint overlooking the important coal-mining city of Lens. By eliminating enemy artillery, repeated German counterattacks were driven off. McNaughton had shown that direct frontal attacks by massed soldiers, which had proved so horrendously costly in lives earlier in the war, were no longer needed. The Second World War was a time of vastly accelerated investment in applied science, and many of the new innovations were to be used later in peacetime for geological and geophysical surveys on land, from the air, and at sea. On the Western Front, the American John C. Karcher used microphones embedded in the ground to locate enemy artillery batteries. One day he recorded a surprise event, possibly from an earthquake, and would later use sound waves generated by explosives to locate oil-bearing geologic structures kilometres underground, helping to trigger the postwar boom in oil exploration in the Middle East and North America. In 1929 McNaughton was appointed chief of the General Staff, head of Canada’s military, and later in 1935 head of the National Research Council (the federal science research body) to promote the application of applied science to the

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country’s industrial development. He was known for his dynamic personality and his belief that the application of science and technology to waging war could shorten the fighting and thus save lives; this made him very popular with the men under his command. It was also a very useful political position in Canada in 1939, when the population was being reminded of the great losses suffered by its citizens abroad in the First World War, and there was growing opposition, especially in Quebec, to any form of national conscription. In the end, Tuzo would enlist in the Royal Canadian Engineers, and it was his geological expertise, specifically with drilling, that eventually got him in. McNaughton suggested that Tuzo put his years of experience in geophysics and geological field craft to good effect and join the Third Field Company of the Royal Canadian Engineers as a “sapper.” General McNaughton’s instincts about Tuzo’s potential were proved correct, and the technical developments that Tuzo was to develop for field commanders and combat engineers in Europe were not only invaluable to the war effort but also a key preparation for his later university work as a geophysicist in the decades after 1945. McNaughton had been approached by R.A. Bryce of the Ontario Mining Association, who recognized that drilling techniques widely used in mineral exploration in Canada could be put to good use in Europe. The basic idea was to drill under German-held fortifications, fill the drill holes with explosives, and blow them up, or use the holes to pump in poison gas to disable defenders.

McNaughton had visited France in December 1939 to assess the technique and was impressed. Colin Campbell was placed in charge of the 12th Field Company, and Tuzo was enlisted to supervise drillers recruited from Northern Ontario and Quebec. It was a case of history repeating itself: an earlier generation of Canadian miners in the Great War had used their tunnelling skills in France, most famously at Vimy Ridge in 1917 where the Canadian Corps had excavated 6 km of electrically lit “subways.” These were used to move troops to the front undetected and detonate explosives right under the German positions, tearing great gaps in the front line and enormous craters. Mining technology and drilling techniques had greatly advanced in the interwar years, and McNaughton was interested in drilling as a means of offensive action against fixed German defences. Canadian mining companies donated equipment, which was sent overseas as private baggage, as it was not government issued. Before Tuzo could contribute to the war effort, more mundane matters had to be seen to; he had to reimburse his former employer, the Geological Survey of Canada, who paid for a special messenger to track him down to demand payment of $4.50 owing for two rolls of toilet paper, one canned tin of ham, and a hotel dinner, for which he had submitted no receipts at the end of his last mapping project. In the end it would take no less than fourteen months and four letters to resolve the issue, long after he had departed for England. There might have been a world war on, but some things never change.

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LEFT: Newly enlisted Lieutenant Tuzo Wilson of the Royal Canadian Engineers photographed in Ottawa by Yousuf Karsh in the fall of 1939. Tuzo had signed up as a “one pip wonder,” a reference to the single shoulder “pip” worn by second lieutenants. Since Tuzo was promoted to first lieutenant immediately afterwards, the photographer simply added a second pip in the darkroom to the final print. RIGHT: First Lieutenant Wilson in Vancouver.

Tuzo’s War

First Lieutenant Wilson Arrives in Europe

in England. The drillers were all volunteers from the mining districts of northern Ontario and Quebec who had simply donned military uniforms and as such claimed they were not subject to Army discipline and the king’s regulations. The Official History of the Corps of Royal Canadian Engineers drily notes that Tuzo’s crews were high-spirited, untrained as soldiers, lacked any knowledge of military administration, and suffered from a lack of discipline. Drawing on his experiences with the cadets at school in Ottawa, Tuzo would quickly learn the ropes, and his highlight of the war was to “take the battalion” on morning parade, where the ability to “bawl out an order to see an entire parade ground obey gave one a sense of power that I have never felt before.” Life as an officer highlighted the peculiarities of regimental life and the Army’s rigid class system. After dinner was completed in the officers’ mess surrounded by “the full panoply of regimental plate including solid silver representations of palm trees and onrushing savages brandishing spears commemorating old campaigns in Zululand, Afghanistan, Burma and Ceylon,” the port was circulated around the table (to the left, clockwise until it was finished), the furniture would be cleared away, the senior officers would retire to smoke and play bridge, and the younger officers would play soccer while lying on their backs on the floor “kicking a waste paper bin while propelling ourselves on our heels and knuckles. It was unreal, like something lifted from the pages of Rudyard Kipling’s Plain Tales from the Hills.” On the other hand, Tuzo’s crews were hard-living working men who “drilled their way through some of the loveliest countryside in England.” Unhampered by military police or army regulations and adopted

The first convoy of Canadian troops of First Division arrived in Britain in December 1939; the first soldier ashore was the Battalion Sergeant Major – an Aberdeen terrier named Corky, the regiment’s mascot, who was promptly quarantined by the British only to be rescued on a ruse when quick-witted Canadian soldiers freed it from captivity by swapping it with a local British-born terrier. Tuzo crossed the Atlantic in January 1940 as part of the third convoy of Canadian troops. En route, he served as duty officer on board the Empress of Australia – a German-built cruise ship previously owned by Kaiser Wilhelm and now ironically used as a troop transport – which was accompanied across the Atlantic by the Royal Navy battleships HMS Valiant and Royal Sovereign. The Empress had only just been commissioned by the Canadian Army and not yet modified for use by large numbers of soldiers; it still afforded the luxuries of a bar with beer at ten cents a bottle and delicacies for dinner. Tuzo arrived in England with the rank of first lieutenant to join the 1st Canadian Tunnelling Company at Aldershot, the primary British Army base in southern England. Canadian tunnellers had just finished excavating huge underground openings under the Rock of Gibraltar to accommodate hospitals, and the resulting waste rock was used to extend airstrips. The Australian war correspondent Alan Moorehead saw the work being completed and wrote that it was “staggering to see this underground fortress that could close up like a clam and live its life underground beyond the reach of any bomb or shell.” Neither Tuzo nor his drilling crews received any formal military training

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by welcoming locals who had never met a Canadian soldier in the flesh, they would disappear on benders, requiring them to be found and ordered out of pubs or be bailed out of the local police station after having been arrested for being drunk and disorderly. Their habit back home was to get drunk on a Friday night and they would stick to it. Tuzo was required to pay the resulting fines of ten British pounds and for years afterwards kept a battered leather wallet stuffed with unpaid IOUs of chastened but unrepentant drillers. Typically, by the time he had paid the fines and had filled in the forms to pacify the authorities, his men were off on yet another pub crawl. The biggest problems with discipline tended to occur in winter when daylight hours were short and the blackout made the men miserable and depressed. But they were hard workers, and many were recommended for good conduct medals, which they refused to wear, arguing they would worry about decorations when the war had been won. The “business of being a good soldier was one thing, advertising the fact to the world and therefore destroying a perfectly good reputation as a rough and ready character was another,” notes the Official History. On one occasion, Tuzo had to court martial the company’s cook, who had profited by “regularly flogging our rations to a nearby pub, the Prancing Horses” in which General McNaughton had set up his mess, claiming it served the best food he had ever eaten in wartime until he found out its source. In the spring of 1940, Tuzo was given command of a company of 100 men and ordered to begin work in northern France drilling under the heavily fortified Siegfried Line, known in Germany as the Westwall

and constructed right opposite the French Maginot Line. Tuzo’s orders were to blow up the Westwall in the event of a German invasion, but the work was abruptly abandoned on 10 May, just a day before Tuzo and his men were to embark for France. German tank divisions rolled into France and the Low Countries in an awe-inspiring demonstration of blitzkrieg, circumventing the Maginot Line and occupying Paris in June. This, and the German attack on Norway and Denmark in April, ended the “Phoney War” and its eight months of “sitzkrieg” waiting for the enemy to make its move, which now would clearly be across the English Channel to invade Britain. After Dunkirk and the successful evacuation of more than 300,000 men of the British Expeditionary Force from the French coast in May 1940, Tuzo and his men were put to work strengthening coastal defences in southern England, principally in the county of Kent, which overlooks the English Channel. Based at Gravesend on the south shore of the River Thames just downriver from London, he was ordered to repel all invaders armed with a single Lewis gun and very little ammunition. His evenings were spent with fellow officers riding motorcycles along country lanes to join the local citizenry for a pint and sing Vera Lynn songs in the White Hart pub in the village of Chalk. McNaughton was disappointed to see that huge trenches being dug across airfields to prevent German airborne landings also denied their use by the British. In response, the Canadian Pipe Mine (nicknamed ­“McNaughton tube”) was developed: three-inch ­diameter steel pipes were pushed by hydraulic jacks horizontally at shallow depths underground and filled with nitroglycerine. The fuses were handed to the local

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Home Guard detachment and, being undetectable from the air or by an approaching enemy, could be quickly detonated when needed to create deep trenches and destroy airfields. Deep tank traps could be dug instantly, pathways safely made through minefields, and signal cable laid quickly in trenches without need for large crews of men, which would attract the attention of the enemy. Comfortable in using nitroglycerine (a skill learned in his days in Northern Ontario working as a geological assistant), Tuzo became an expert in demolition and the handling of explosives, but the nitroglycerine was unstable, gave off dangerous fumes that made the men sick with excruciating headaches, and would deteriorate in the buried pipes, requiring careful excavation and replacement. Tuzo’s drillers were to eventually install some 12 km of pipe containing 100 tonnes of explosives. Most were never used and were left in the ground; as late as 2006, unexploded Canadian-made Second World War pipe mines were still being unearthed and defused at British military bases across southern England. At the outbreak of the Second World War, British airfields were too exposed to enemy attack to be safely used for training air crews, and the British Commonwealth Air Training Program was initiated, whereby servicemen and women could be instructed in the much safer wide-open skies of Canada for flight service in Europe. Still fearful of the political cost of the large numbers of casualties that might result if the army were to be fully employed in European combat, the Canadian government was keen to see the air training program as the nation’s major contribution to the war effort, and Tuzo’s father, JA, was appointed director of Air Services to supervise the mammoth task of

TOP: First Lieutenant Tuzo Wilson conversing with General McNaughton (left), early 1940. Both shared a passion for using geophysics to advance the war effort. BOTTOM: General McNaughton, holding aloft a section of pipe, with Tuzo in a trench newly excavated by detonation of a McNaughton tube bomb in southern England, 1940.

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constructing more than 200 airfields to serve the new initiative. Precisely at the time his father was overseeing this massive expansion of airfields in Canada, Tuzo was devising effective means of destroying them on the other side of the Atlantic. Airfields at the time had to be close to each other, because the single-engine planes in use were of dubious reliability and navigational aids were non-existent. By war’s end, more than 130,000 airmen and women had passed through the scheme, which proved crucial on many battle fronts, especially in the Battle of Britain of late 1940 when lost planes were easier to replace than lost pilots. Canada was portrayed as the “Aerodrome of Democracy,” and the country would eventually provide half the trainees that passed through the program. JA was awarded the Commander of the Order of the British Empire in 1945 for his wartime contributions to the Air Training Program. The senior Wilson’s wartime work required a firm resolve and a diplomatic touch. Canada itself was seen by many Americans as woefully defended, and if Britain fell to the Germans, it might provide an open door for an attack on the United States. The arrival of Americans in large numbers in Canada after the entry of the United States into the war in December 1941 triggered age-old concerns that had festered since the War of 1812 about Canadian sovereignty and a possible American takeover by stealth. JA got caught up in the intrigue as head of aviation in Canada, and Tuzo recalled several incidents of overzealous Americans assuming it was now their war and who would act accordingly with their northern neighbours. “Some fellows flew up from the States and landed in Winnipeg to take charge of the airport. They were told they were not running the

airport, and this upset them to no end. The Canadians knew there was a war and had been in it for some time and running things fine, thanks. They would be glad to have American help, but they weren’t going to have the Americans tell them what to do.” On another occasion, “the Americans told my father, chief of civil aviation and in charge of airfields in Canada, that they were going to build an airport at Goose Bay in Labrador. Dad said, ‘That’s very nice and we’re glad to have you help but it’s almost finished.’” The Americans also decided they would build the Crimson Route from Winnipeg, The Pas, Churchill, Coral Harbour, Baffin Island, Greenland, Iceland, and to Europe for flying fighter planes to Europe and bringing the wounded back. They couldn’t believe that the Canadians had already built the fields. Back in Britain, the massive Allied troop concentrations and large military camps then being assembled in southern England, and the destruction of pre-existing water supplies by German bombing, required finding new underground sources of water and the development of the hydro-geological expertise necessary to locate and develop them. Tuzo worked closely with the director of the British Geological Survey, the decorated First World War veteran Sir Edward B. Bailey, who had lost one arm and the use of an eye at the Battle of the Somme in 1916, in drilling for water and strategic minerals such as tungsten, iron, and zinc. Bailey’s experiences with highly deformed rocks of ancient mountain belts in Scotland and elsewhere in Europe and eastern North America had led him to be an early advocate of continental drift. He and Tuzo were to meet up again after the war in the mountains of Scotland, much to Tuzo’s later embarrassment, as we shall see.

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Tuzo giving instructions to members of a Canadian drilling crew at Aldershot, the principal British Army base in southern England in early 1940. The truck was donated by the Anglo-Iranian Oil Company, which was assisting Tuzo in how to place explosives in drill holes.

Tuzo’s work soon became popular with visiting dignitaries in England. A large crowd gathered to witness the results of a successful demonstration of the use of “McNaughton tubes” in excavating a tank trap in June 1940. General McNaughton is third from left. The Canadian minister of national defence, James Ralston, witnessed Tuzo’s “pipe pushers” in action and declared he was “proud of the men.” Other reactions were not so positive, one disgruntled brigadier complaining that Tuzo “had ruined the best picnic spot near Aldershot.” Courtesy of the Canadian Army.

Much of the drilling involved “proving up” mineral deposits and demarcating their dimensions deep underground so that they could be mined more effectively. Old abandoned tin mines in Cornwall were investigated and reopened, and a tunnel was bored to divert water to a hydroelectric plant to increase the output of aluminium from the bauxite plant at Laggan, near Prince William in Scotland. There the Canadian crews set new records for driving lengths of 3 m wide tunnels during a twelve-hour shift, after which they were rewarded by “a banquet from the

contractors, at which a most satisfactory portion of the food was liquid.” By late 1940, the Germans had installed massive fifteen-inch naval and railway guns at Cap Gris Nez on the French coast overlooking the Straits of Dover and proceeded to lay down harassing shellfire on slow-moving shipping convoys winding through the Channel and on towns spread across southern England. The enormous shells weighing 900 kg could reach as far as Gillingham on the River Medway some 50 km southeast of London. The British retaliated at first by

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bombing from the air but it proved ineffective, and Churchill demanded the installation of large naval guns on the British coast, if only for psychological reasons (one was appropriately nicknamed “The Piecemaker”). This required deep excavation of the massive gun emplacements in the hard white chalk rock of Kent and detailed geological knowledge in their siting. Ironically, it was ultimately troops of the 9th Canadian Infantry Brigade who finally captured the guns at Cap Gris Nez in September 1944. While working on gun emplacements along the coastal cliffs of the English Channel, Tuzo had a grandstand view of the German offensive of Operation Sea Lion, the planned cross-Channel invasion of Britain, that began with air attacks to destroy the Royal Air Force in June 1940. “I watched the Battle of Britain from Dover Castle where I was stationed amid all the barrage balloons up in the air. I saw fifty-four German airplanes coming over in the afternoon to bomb London. They got the hell kicked out of them. Tremendous dog fights ensued, and we could see planes falling from the sky, crewmen jumping clear and drifting down in parachutes.” His letters home described Stuka dive bombers attacking ships in Dover Harbour but spoke to the optimism among people he met that any German invasion would be repulsed. The failure of the Luftwaffe to destroy the Royal Air Force during the long hot summer of 1940 resulted in the German bombing of cities and civilians by night. Saturday, 7 September 1940, and the following “Black Sunday” marked the beginning of the Blitz, when Londoners endured fifty-six nights of continuous heavy bombing. Tunnelling companies were hastily reorganized and Tuzo was seconded to supervise

bomb disposal duties in southeast London. Nighttime German bombers used the meandering moonlit River Thames as a pathway to guide their approach into inner London to bomb the busy riverside docks in Rotherhithe and the Isle of Dogs, but to gain speed and height on their return to avoid British fighters they would randomly scatter strings of unused bombs across the densely packed suburbs and towns of north Kent. The area quickly became known as “Bomb Alley,” and there was the additional danger later in the war of being under the flight path of V1 rocket-propelled flying bombs (“doodlebugs”); by war’s end in May 1945, more than 2,400 had fallen over Kent, 200 more than in London. German bombs that penetrated deep underground before exploding created large, dangerous subterranean cavities that would swallow vehicles and people but were marked only on the surface by “camouflets” – a round hole about 30 cm in diameter, made when the bomb had bored into the ground. Many failed to explode, and Tuzo supervised experiments using magnets to find buried bombs and then to carefully excavate them using jets of high-pressure water. He wrote that he “got little pleasure standing on the edge of a crater supervising a bunch of sappers wielding shovels, digging out one of these objects and hoisting it to the surface,” and many were booby-trapped. When recovered and their fuses disarmed, bombs were hauled by red-painted trucks with sirens wailing to a “bomb cemetery” deep in the marshes along the banks of the River Thames, near Erith, and detonated, creating a “most satisfactory bang.” It was “nervous work” and Tuzo greatly admired the casual attitude of the bomb-disposal engineers, especially their habit

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of standing around a bomb casing from which the detonator and all wiring had been removed, tossing a lighted rag into the dynamite to “warm their stiff, cold fingers in the resulting blaze.”* Canadian soldiers stationed in Britain were relatively well paid, compared to their British comrades. Given their reputation as revellers, they were seen as quite a catch for local girls, though fraternization between females and soldiers was, of course, strictly forbidden and subject to severe military punishment. During the Blitz, the author’s mother, then a teenager working in an aircraft assembly factory, would cycle down from south London with her older sister to visit the same riverside marshes at Erith where Tuzo’s bomb disposal engineers worked. There, they would have lunch with the young Canadian gunners manning anti-aircraft defences guarding the Thames and the approaches to London’s docks. Rations taken surreptitiously from their mother’s food pantry were shared with the Canadians to relieve the monotony of their Army rations. Being out on the low-lying marshes, the approach of officers could be seen from afar when the girls would be quickly hidden among piles of ammunition and a large aggressive Alsatian guard dog placed nearby to deter the inquisitive. My

mother’s sister would eventually marry a Canadian soldier and as a “war bride” emigrate to Montreal in 1944, one of an estimated 50,000 to make the move to Canada. Tuzo lived just outside London in Esher, Surrey, with other officers, including Charles P. Stacey, a fellow graduate student at Princeton from the early 1930s who would later write the official history of the Canadian Army in the Second World War. Tuzo’s leaves were spent exploring bookstores along Tottenham Court Road, picking up inexpensive first edition books on the exploration of Arctic Canada such as those by Samuel Hearne, who had explored that part of the Shield near Great Slave Lake where Tuzo had worked before the war. The value of books had plummeted in the Blitz because they were difficult to store and were easily damaged and could, as a result, be bought cheaply. He noted that the Canadian Army might be insensitive to one’s personal wishes but was remarkably efficient at shipping one’s possessions around the world, and his books were duly transported home to Canada in “sturdy pine boxes with rope handles, my name and rank boldly stencilled on the lid.” While Tuzo was in Europe, Isabel found work back home in Ottawa driving Tuzo’s father, JA, to and

* The threat of German bombing didn’t prevent 60,000 fans showing up to see Arsenal lose 2–1 to Preston in the final of the League War Cup in May 1941 at Wembley, and it was precisely at this time that the author’s father, Alfred, a teenager in the Home Guard (the civilian militia) was charged along with his father, Albert, a veteran rifleman of the Middlesex Regiment wounded by a grenade in the trenches of the First World War, with the responsibility of disarming German incendiary bombs landing on the roof of St. Paul’s Cathedral armed only with buckets of water, a stirrup pump, and sandbags. My father resolved to join the Royal Navy after the family was bombed out of their apartment on Southampton Row in Holborn during the devastating raid of 10 May when the House of Commons and Big Ben were badly damaged. A black slate clock that stood on their mantelpiece, hands fixed in position ever since by the blast, is still in our possession. Just 6 km away from St. Paul’s, Arthur Holmes wrote his great book, Principles of Geology, scribbling night after night sitting on the roof of the Geological Museum on Exhibition Road in South Kensington while waiting to smother German firebombs.

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from the newly built airfields to monitor progress in construction and the training of new pilots. While in London, Tuzo would lunch at the Beaver Club located near Trafalgar Square, which had been opened by the Queen Mother in 1940 for Canadian servicemen to get news of home and use the canteen. It was there that he attended a lecture that alerted him to the need for women drivers in Britain by the Mechanised Transport Corps. The MTC was widely regarded as a mix of the “ludicrous and admirable,” consisting of a small group of wealthy women “with a high sense of duty and patriotism and a Bentley or its equivalent,” but it provided the opportunity to bring Isabel to London at a time when Canadian wives were banned from entering the country (their presence in Britain in the First World War had proved problematic for soldiers’ discipline). Isabel finally managed to join her husband in London in September 1941, having been recruited as an MTC driver for which the “only requirements were an independent income (of $100 a month), passage money across the Atlantic and the ability to back a five-ton truck through Lady Pope’s gateposts.” Her duties were varied, one day driving a load of nuts and bolts to an aircraft workshop just up the street from the factory in London, another delivering the chassis of a new but unfinished truck lacking both protective bodywork and a windscreen, several hundred kilometres to Northumberland in northeast England, all the while being exposed to the wintry elements for eight hours. Since German bombing raids were noted to precipitate early labour in expectant women, all members of the Transport Corps were trained as midwives and expert at delivering babies in underground air raid shelters.

Tuzo and his wife, Isabel, newly arrived from Canada, outside their residence at Portland Place in London, September 1941. They lived in the former library, which was unheated, and there were 118 steps up to the bathroom. Note the blackout curtains on the window; all the glass had been blown out by a bomb during the Blitz. Accommodation was in short supply, and their next residence in Chelsea was a “shoebox that would rattle and shudder every time the anti-aircraft battery protecting Battersea Power Station came in action.” For a short time, they lived in an apartment block at Highpoint atop Hampstead Heath in north London. Surrounding properties had been razed by bombs, but Tuzo noticed that German bombers used the tall tower block as a landmark and took great care to leave it standing, rendering it “the safest spot in London.” It survived the war.

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Tuzo wrote many reports on the success of training exercises for regular troops, which he duly sent back to Ottawa stamped “Secret and Most Confidential.” Initially he found these difficult to write, “every sentence achieved only with laboured thought and much chewing of my pencil,” but over the course of the following twelve months he submitted more than 500 reports and developed an easy writing style that would be useful after the war in writing up the results of his geological research for scientific journals. One of his earliest reports noted that the first Canadian troops to arrive in Britain were “soft, with not enough practical training and too many lectures.” The typical recruits were Depression-era kids for whom military service provided an escape from poverty, offering a steady income and regular meals, but they were physically unfit, poorly equipped and trained, and their officers mostly lacking in leadership skills. Most enlistees favoured the Royal Canadian Navy or the Air Force, where they might be posted to an exotic location overseas and pick up a skilled trade that would be useful if they survived the war. The Army, in contrast, was seen as unattractive, offering no real change from the deadly meat grinder that their fathers had endured in the bloody trench warfare of northern France a generation before; the recruiters’ promise of “four square, a clothing allowance and a short stroll through Europe” convinced few to sign up. Tuzo’s reports paint a picture of the massive task needed to get raw, unwilling, and undisciplined soldiers ready for combat and to ensure that they would receive the best possible equipment and training. The logistics of supplying a transatlantic army were enormous and required detailed knowledge of how

the American and British armies operated, their command structures, equipment, and weapons systems. Much of Tuzo’s time and that of his crews was spent calculating the most efficient loads for the standard Canadian Military Pattern (CMP) three-ton truck, produced in large numbers by GM and Ford, ensuring that spare parts, no matter how small, accompanied weapons and other equipment into the field, to be available when needed. Canadian sailors and airmen saw immediate action with British units after September 1939, most famously and heroically on convoy duties in the North Atlantic and in the Battle of Britain. General McNaughton, ever mindful of the political cost of combat casualties back home, resisted calls to employ the Canadian Army piecemeal in the field, preferring to keep its troops in Britain as a garrison force to guard against a possible German invasion. McNaughton maintained that “the acid test of sovereignty is control of the armed forces,” and although Winston Churchill had wanted Canadians to take part in an invasion of northern Norway in April 1940 under British command, McNaughton, much to his credit, resisted. The invasion proved to be a costly failure. Later, poorly equipped and poorly led Canadian soldiers had been killed and captured, somewhat cheaply, by the Japanese during the humiliating fall of Hong Kong in December 1941. Hard lessons were to be relearned once again in August 1942 when Canadians suffered severe losses in a direct frontal attack on the heavily fortified enemy-held port of Dieppe in northern France. Eventually, however, the battle honours and medals won by British, New Zealand, Australian, South African, Indian, American, and other Allied troops pressured Canada to employ its own army before the war

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finished; national prestige in the impending postwar world and a seat at the table of the soon-to-be victorious world powers were at stake. The Canadian Army was stuck immobile and untested in Britain while history was being made elsewhere, and it was said, only half in jest, that it was the only army in the entire world whose birth rate was higher than its death rate. It was not until the summer of 1943 that Canadian troops of 1st Division would take part in the invasion of Sicily (Operation Husky) as an effectively trained, well-equipped fighting force led by Major-General Guy Simonds. Italy was initially perceived as the soft underbelly of the Axis powers, and the Italian campaign with the potential for limited casualties should have played well back home; however, with its long, bloody slog up the Italian mainland to Rome while fighting well-entrenched Germans in mountainous country, the reality was to prove costly in Canadian lives. General McNaughton was not to see his troops in action in Italy; regarded by some as prickly to deal with and a poor tactician, he was viewed by his superiors as being more concerned with technical issues than the practical leadership of his men in the field and was “happiest looking under a truck to fix the transmission or checking the hydraulics out on guns” according to the military historian J.L. Granatstein. He had no time for diplomatic niceties and military “spit and polish” so loved by the British and could often be very blunt. He had famously fallen out with Major A.F. Brooke at Vimy Ridge in 1917 when McNaughton had relocated field guns previously sited by Brooke to new locations where they could much more effectively drop their shells on German troops massed on the other side of the ridge. Brooke was furious and, when eventually promoted to general and chief of the Imperial General

Staff, never forgave the Canadian gunner for what he viewed as insubordination. Operation Spartan, a major training exercise in southern Britain in March 1943 and the dress rehearsal for an invasion of the Continent, saw a particularly poor performance by Canadian troops under McNaughton’s command and proved to be the last straw. McNaughton was consequently barred by General Bernard Montgomery from visiting his troops in Sicily in 1943 and he was retired for “health reasons” back home to Canada, eventually to become minister of defence in 1944. Tuzo was later to write that McNaughton had been “thrown to the wolves.” Meanwhile, McNaughton’s protégé Tuzo thrived. The First World War had largely been static, fighting from fixed entrenched positions, but the Second was one of mobility. Mastering the logistics needed to fight a mobile war in widely different terrains and climates, often with combat engineers leading the way, required detailed knowledge of local conditions well in advance. After-action damage assessments revealed there had been a critical lack of forward intelligence about beach conditions and German defences at Dieppe (tanks had difficulty with the steep gravel beaches and there was a lack of up-to-date information on German defensive positions), underscoring the importance of air reconnaissance and analysis of ground conditions from air photographs. Tuzo’s experience and skill in their use came to the fore, and much effort was spent on working with various camera systems and lenses and determining the types of aircraft (and time) needed to deploy each one. He noted that “the RAF had amassed thousands of photographs of enemy defences but had trained very few people to interpret them.” The techniques of air photograph analysis introduced under Tuzo’s leadership were quickly adopted as a valuable 116

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Tuzo’s duties as an Army sapper included reporting on the performance of enemy equipment such as this German Tiger Mark I heavy tank wrecked by Allied ground fire in Sicily in 1943; his assessment concluded that they were over-engineered, required constant maintenance, and had a limited range because of excessive fuel consumption. In short, they were an ideal enemy weapon.

tool in operational planning. He pioneered the identification and mapping of “engineering terrains” from air photographs now made even more important by the need to move heavily motorized equipment and troops across country, avoiding areas of soft ground, roads clogged by refugees, or mined. Topography and geology were assessed for their ability to hinder or aid the movement of men and vehicles and to provide cover from enemy fire. Tuzo trained troops to identify fixed defences on air photographs, such as mortar pits and pillboxes, to assess potential targets for bombing and the effects of air raids and artillery bombardments in after-action reports. “Plotting tables” where photographs could be laid out became a fixture of company command posts in the field. New techniques were developed for the rapid production of topographic maps using air survey methods developed in Canada before the war, and regular “speed tests” were conducted to assess how rapidly maps could be produced from

photographs; the record was twenty-nine hours for a 150 km2 map sheet. These efforts would come to the fore after D-Day in June 1944, when the aerial surveyors would use mobile printers mounted in trucks travelling just behind the Allied front lines to produce maps of those areas more than 100 km ahead of troops rapidly advancing across northern France. Large, plastic 3-D topographic maps were also made and distributed to front line troops in pieces (lessening the risk if captured), to be assembled when needed. They were illuminated at night by special lamps that could not be observed from the air.  At the outbreak of war, the British Army had a single bridge engineer (Don Bailey), and, as an officer in operational research, Tuzo supervised and reported on the design and testing of Bailey’s portable prefabricated bridges. These could be easily moved around in sections by a few men and bolted together to replace bridges demolished by the enemy. Bailey’s designs were typically drawn up “on the back of an 117

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As an Army engineer, Tuzo worked closely with Donald Bailey, who was responsible for designing and assessing the performance of portable bridges. Bailey Bridges were prefabricated, easily moved in sections and installed at night under the cover of darkness to replace those destroyed by the Germans. The bridges had to be able to carry a loaded tank transporter weighing more than eighty tonnes.

envelope,” and initial attempts to have Canadian steel companies make the sections in large numbers back home were unsuccessful, given their demand for precise plans and their experience of building bridges on fixed foundations “designed to last a century.” But they eventually began to mass produce the required sections, and Tuzo travelled to the Mediterranean theatre with the deputy engineer-in-chief of the British Army, Joe Hallam, to assess how successful the bridges and landing assault craft had performed under fire during the Allied invasion of Sicily. Like many others in operational research, Tuzo had to overcome the professional soldier’s distrust of outsiders such as scientists, especially when their after-action reports had identified failures of equipment and the inaccuracy of much Allied bombing and

artillery fire. When General Montgomery was asked if scientists could observe his battles, he is said to have replied that he was perfectly capable of observing them himself. In Sicily it was Tuzo’s job to write reports and recommendations on behalf of his commanding officer “while Hallam played cards,” and it required initiative in dealing with battle-hardened engineering officers and soldiers who had no time for “boffins.” He quickly found that “the best idea of finding out what was going on was to get the officers drunk. I had to provide the whiskey, a bottle a day and I found ships’ pursers were the best source if I could bribe them.” Suitably lubricated, the hitherto silent engineering officers and their men would gradually open up, and Tuzo would “keep quiet, listen hard and make mental notes for the report I would write.” He was also overseeing the 118

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design and testing of inflatable boats and tanks (popularly called “crabs”) equipped with heavy rotating steel drums to which were attached lengths of stout chains that acted as flails striking the ground in front of the advancing tank, blowing up mines and blasting corridors through minefields. Booby traps, camouflage nets, special rations, and “shaped” explosive charges for demolishing concrete and penetrating armour plate were all investigated and tested. The work involved a great deal of travel from one camp to another, affording Tuzo the freedom to explore the byways of England and visit many out-of-the-way places, providing him some moments of tranquility from the hectic pace of “journeying to test sites and writing reports” and where the war seemed a long way away. In the new war, combat engineers worked under fire in advance of the front line and took heavy casualties; reports made to Tuzo from Sicily after its invasion in 1943 spoke of numerous fatalities among the troops he had trained in Britain but also identify a Canadian 1st Division that was now well honed, had the full confidence of Allied high command, and had the Germans on the run. Tuzo wrote in July 1943, when assessing the work of his engineers under deadly mortar fire in Sicily, that “no praise is too high for them” and that their training and expertise in using motorized transport and equipment was far superior to that of the Germans, who still relied heavily on horse-drawn transport. By late 1943 “all the training, waiting and frustrations of the past four years were beginning to come to a slow boil.” Tuzo, now with the rank of lieutenant colonel, was ordered to take over the planning of new airstrips for the Royal Canadian Air Force in northern France needed when the Allies eventually returned to

the Continent after a cross-Channel invasion. But events intervened, and with General McNaughton being sent home to Canada in December 1943 after having lost the confidence of Allied commanders, Tuzo, as a trusted colleague, followed soon after to take up the position of director of Army Operational Research in Ottawa. Both he and Isabel were very disappointed with the order to return home and “felt cheated.” After enduring the cold and dark of wartime London, she had wanted to stay and celebrate when the lights finally went on at war’s end. He, in turn, had lost the opportunity to do “some real soldiering” and finally take the battle to the enemy across the English Channel. After scouring London for “bottles that might provide drinks for all the people we had shared our meat rations with over these past years,” Tuzo and Isabel embarked on the Queen Elizabeth for New York and travelled west across the Atlantic aboard the zigzagging and unescorted former cruise liner, now heavily camouflaged and converted to carry as many as 14,000 troops at a top speed of thirty knots to outrun chasing German submarines. Its living quarters were poorly ventilated and infested with cockroaches, but at least it was warm and safe, though Isabel suffered from sea sickness. The much slower transatlantic convoys of transport ships moving at seven to ten knots, on the other hand, were savaged by submarines when out of range of land-based anti-submarine aircraft, and there was much activity on both sides of the Atlantic aimed at protecting Allied vessels as they crossed “the Gap” or the “Black Pit” as it was also known. To this end, Tuzo had worked with Geoffrey Pyke, who had developed “pykcrete,” a special mix of ice and sawdust, which would float but was very strong and could absorb the shock of explosives. 119

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Given the wartime shortage of steel in Britain, pycrete seemed an ideal material with which to build aircraft carriers that would be positioned in the Mid-Atlantic to allow anti-submarine aircraft to operate over areas previously out of range from land. The plan (called Project Habakkuk) was to build the carriers in Corner Brook, Newfoundland, where the winters were sufficiently cold and long enough to allow the complex assembly process to be completed. Early experiments had taken place in secret at Patricia Lake near Jasper, Alberta, and in the meat freezers at Smithfield Market hard by St. Paul’s in London and came to a successful conclusion when Lord Mountbatten placed a block of pykcrete in Churchill’s warm bath to demonstrate its resilience to the prime minister. However, ships made of pykcrete were never deployed, and that is rather fortunate, since modern experiments have shown the material is easily bent when stressed. The deadly Gap was to be closed in 1943 when long-range B-24 Liberator bombers became operational out of Newfoundland. Upon his arrival back in Canada, Tuzo discovered that Army Operational Research in Ottawa during the closing years of the war was highly disorganized and largely ineffective. Its work was viewed with deep suspicion by his commanding officer, General McMurchie, who gave Tuzo an office and staff but no outline of what his duties were. In characteristic fashion, he used the time to travel. “When I eventually found somebody to report to, they said, ‘We don’t know; you’ve been in England, and they have operational research over there so do what they’re doing.’ The first thing I did was I thought I better look and see what was going on.

I got them to send me from the Aleutians to Mexico and see a lot of places in between. I found out what sort of training they did, what the camps looked like and what their problems were.” In Ottawa, Tuzo supervised psychological experiments and aptitude tests for assigning new troops to specialist tasks (such as crewing tanks) and worked on eliminating the bizarre but very real threat posed by Japanese hydrogen-filled “balloon bombs” that carried incendiary devices across the Pacific from Japan into Canada and the United States with the intent of creating forest fires. They were to prove little more than a nuisance, though some reached as far east as Manitoba. Much more significant was the Japanese invasion of Alaska’s Aleutian Islands in June 1942 (although they quietly withdrew a year later). This highlighted the lack of any defence of the northern back-door route into North America, and as a result, much effort was directed in Ottawa to planning for Arctic warfare. Tuzo led an ambitious program of cold-weather testing of vehicles and men in the winter of 1943–4, and in quick succession, several exercises were put into effect. Operation Eskimo with 2,000 men advanced 250 km in sub-zero temperatures from Prince Albert in Saskatchewan to Lac la Ronge, and Exercise Polar Bear involved 1,154 men and their machines moving across 750 km of deep snow in the Coast Ranges of British Columbia near Williams Lake. Both exercises identified the crucial importance of air support and were an excellent preparation for the much more ambitious Operation Musk Ox, which Tuzo would lead as the Second World War came to an end and the Russians became the new enemy-in-waiting of the Western Allies.

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The Cold War Comes to Canada’s Arctic: Operation Musk Ox

in the final search for any remaining undiscovered islands using radar. The Cold War in Canada would be fought in the Arctic between 1944 and 1946. As head of Operations Research for the Canadian Army, Tuzo threw all his energies into planning and leading Operation Musk Ox, an ambitious project designed to test men and machines while traversing Canada’s north. The key was having suitable vehicles, and he enlisted the help of Joseph-Armand Bombardier, who was then a garage mechanic in Valcourt, Quebec, developing tracked vehicles that would “float on snow” – the first snowmobiles. Bombardier had lost a son to appendicitis because of the inability to get him to the local doctor in a blizzard, which had prompted him to develop his new vehicle. Tuzo later remembered Bombardier as a “brilliant mechanic.” Equipped with a powerful 125-horsepower Cadillac V8 engine with automatic transmission, the “Snowmobile, Armoured Canadian Mk 1” was based on the Chaffe light tank. Nicknamed “Penguins,” they soon gained a reputation for their ability to traverse deep mud, sand, and snow, having been proved successful as a lightly armoured reconnaissance vehicle in the North African and Italian campaigns. Tuzo realized that testing a vehicle in the winter was one thing, but serious problems would only arise when multiple vehicles and men were organized into a large mobile force. Operation Musk Ox involved forty-eight men, eleven of Bombardier’s Penguins, and several much lighter American-made Weasels. The vehicles left Churchill, Manitoba, and Baker Lake in the Northwest Territories, where temperatures plummeted to -45°C and where the practice of using “wind chill” to describe the combined

As one of those responsible for the exercise, I feel strongly that the Russians have done far more to develop the North than we have and I hope that the demonstration provided, and the publicity, may do something to further Canadian interest in their north country. J. Tuzo Wilson, 1946

The hot war finally came to an end with the Allied victory over Japan in August 1945. The Cold War was officially declared in March 1946 when Winston Churchill gave his speech in Fulton, Missouri, on the “Iron Curtain” that Stalin had now dropped on Europe separating the Allied and Russian spheres of influences from the Baltic to the Adriatic. This tension was to culminate in the Soviet blockade of the Allies’ road, rail, and canal routes into Berlin, which necessitated a massive airlift of supplies and equipment beginning in 1948. A potential Russian invasion of North America through the back door of the Canadian Arctic was a common topic of conversation, however unlikely it was in practice. The severe problems of fighting in Arctic conditions had been laid bare in the Second World War by the British experience in ­northern Norway in 1940, and that of the Nazis in Russia after 1941 when they were defeated by “General Winter.” Nonetheless, Canada needed to show the flag in its own northern backyard, even if much of it was covered in snow and devoid of roads. The last of the Arctic islands had only been charted in 1941 (the Tweedsmuir Islands west of Baffin Island), and Tuzo had flown as an observer over the North Pole

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The route taken by Operation Musk Ox in early 1946.

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effect of wind and temperature was first adopted. Then the force struck north to Victoria Island, turning south to Port Radium and on to Great Bear Lake. From there, men and vehicles travelled to Norman Wells on the Mackenzie River and thence south to Grande Prairie, where the vehicles were taken by train to Edmonton. Operation Musk Ox was completed without incident after eighty-one days of travel across some 5,000 km of frozen ground. Apart from minor mechanical problems with Bombardier’s snowmobiles in the cold weather, the biggest concerns had been the lack of space and the risk of carbon monoxide poisoning in the cramped vehicles, and the effects of dust on their engines. The international media fed off widespread anti-Russian sentiment and turned the exercise into a major military incursion, with specialized tanks, into the Arctic; no less than ten foreign military attachés visited the operation in Churchill. The Canadian government, on the other hand, played down its importance, emphasizing it was not a tactical exercise but was designed simply to test the performance of soldiers and motorized transport in cold conditions. The Canadian ambassador in the United States, Lester B. Pearson, affirmed in a speech in New York that Canada was not about to build its own Maginot Line in the far north against a possible Russian invasion. In a letter to his old mentor Vilhjalmur Stefansson, Tuzo wrote, “If you can do anything to counter-act the unfortunate notion that this exercise is planned by those with anti-Russian feelings, I wish you would do so. As one of those responsible for the exercise, I feel strongly that the Russians have done far more to develop the North than we have and I hope that the demonstration provided, and the publicity, may do

something to further Canadian interest in their north country.” He was quick to emphasize that Operation Musk Ox “wasn’t a military operation. My desire, and I think the desire of the Canadian government, was that we should know how to operate in our own country. We were not really planning to go anywhere else and we certainly had no notion of going across the North Pole to the Russians, which the Americans might imagine one would do, because it was a very bad way to get to Russia!” He also commented “that the southern end of the exercise at Edmonton is almost as close to Mexico as the northern part of our route is to Russia, but so far no one has accused us of trying to defend Canada from attacks by Mexicans.” Shortly thereafter, the principal threat to Canada’s north was not from Russians travelling overland but from airborne bombers and, later, intercontinental ballistic missiles aimed across Canadian territory into America’s heartland. Beginning in 1957, the Distant Early Warning (DEW) line of radar stations was built across Canada’s Arctic to warn of impending attacks. Operation Musk Ox showed that any winter military operations in the far north were highly vulnerable to air attack and could be sustained only by massive air drops from cargo planes and gliders; by the end of the operation, some ten tons of air cargo had been delivered for every soldier. Fears of a Soviet invasion greatly diminished once it became obvious that long distance motorized transport in winter was impractical and became impossible in summer when winter roads across frozen lakes and tundra disappeared and the vast tracts of muskeg thawed and turned into deep muck. Canadians learned important lessons in the winter use of motorized vehicles in their own northern

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TOP LEFT: The expedition rolling out of Churchill, Manitoba, on 15 February 1946 in sub-zero temperatures and biting winds: “Our eyes streamed with tears in the bitter wind and then were frozen shut.” TOP RIGHT: Colonel Tuzo Wilson, Colonel Edward, the senior American observer, and Lt. Colonel P.D. Baird, a geologist who had spent much time exploring Baffin Island before the war and who later trained parachutists in Arctic warfare. BOTTOM: Large crowds gathered in Edmonton on 6 May 1946 at the conclusion of Operation Musk Ox, which had covered nearly 5,000 km in eighty-one days without incident and arrived only one day late. The arrival of the expedition in Edmonton coincided with the end of wartime beer rationing in Alberta. Courtesy of the Arctic Institute of North America.

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The Inuit women were astonished to see men carrying out menial tasks such as cooking and carrying; their men were equally surprised to see that the soldiers had brought no women along to perform such work. It was there that Tuzo tried to explain the workings of a combustion engine, “but it failed to answer the question that had been behind the eyes of every Inuit we had met along the way. ‘Why use a gigantic flying machine to drop fuel by parachute to allow other machines to do what a dog team and some frozen fish could do equally well?’” He worked off his unease with the future impact of development on local Inuit communities by driving one of the Penguins to the uranium mine at Great Bear Lake over ground he had last explored on foot in the 1930s. Tuzo kept his reservations about developing the north to himself but publicly he supported it. The demands of the Cold War had shown the need for international cooperation in conducting scientific research in the north, and in 1947, as chairman of the Board of Governors of the newly formed Arctic Institute of North America, which he had helped found, Tuzo declared, “Today, it is appropriate to look back a century and realize that these same inhospitable regions are the scene of activity such as they have not known in the intervening years.” But he also warned that “the Canadian Arctic is a scientific vacuum which other countries have shown a willingness to fill.” At the conclusion of Musk Ox, Tuzo had dinner with the old Arctic explorer and family friend Vilhjalmur Stefansson, who berated Tuzo for not living off the land, hunting seals and caribou, and travelling by dog teams. “In vain, did I try to explain that the object of the exercise was to demonstrate that forty men could

On one occasion, Tuzo was presented with a length of muffler pipe fitted with various prisms and lenses and named an “Intuit” – a comical reference to his responsibility as leader of Operation Musk Ox to “look into things” when problems arose.

backyard, which were of tremendous importance to the resource industry in the ensuing postwar years. While Tuzo was very pleased with what Operation Musk Ox had achieved, he felt “pangs of regret” for the potential impacts of the opening of the Arctic on local Inuit, whom he described as stoic and cheerful. The operation had required Inuit guides over several parts of the route where proximity to the North Magnetic Pole rendered magnetic compasses useless. On one occasion, Tuzo drove 50 km out onto the sea ice north of Coppermine to join a seal hunt, arriving “in a noisy confusion of the barks and howls of sled dogs pegged outside the igloos and the excited chatter of the inhabitants who came tumbling out to shake hands.”

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travel three thousand miles by mechanized vehicles supplied by aircraft.” Operation Musk Ox showed that aircraft could carry heavy payloads into remote areas and were much more effective than land vehicles. Operation Musk Ox was a personal success for Tuzo. His leadership skills had been tested under very trying circumstances while under the spotlight of widespread media attention. He was widely known and respected among the ranks for helping privates with the washing up, and was held in very high regard by his superiors back in Ottawa. General Charles Foulkes, chief of the General Staff, asked him to stay on in the Army, but it was an unappealing prospect, given that the opportunities for further advancement in peacetime were bleak and he had never regarded himself as a professional soldier. Unlike the British and Americans with their ability to draw on large numbers of men and women from a population accustomed to regular wars, and where many families had a long military tradition, Tuzo was the epitome of the “civilian-turned-soldier” that Canada was able to successfully produce in large numbers for the war effort, and now he was ready to return to civilian life.

the rank of colonel in August 1946. His substantial contributions to the war effort were recognized by the British, who awarded him the Order of the British Empire, and by the Americans from whom he received the Legion of Merit. The citation for the OBE noted that under Tuzo’s direction, “operational research teams at the Armoured Corps and Signal Training Centres so improved the methods and techniques of instruction by the introduction of more scientific methods that a greater number of trained servicemen were made available to the Canadian Army at a critical time.” For Tuzo at least, it had been a successful war and he had served with distinction. His war service, moreover, helped shape the style and direction of his later career. Schooled in the wartime need for rapid assessment of the performance of men and equipment, he was well prepared for the mantle of international scientific leadership that was to shortly follow. As we have already noted, Tuzo had written hundreds of lengthy dispatches for his superiors in Ottawa, detailing the many complexities of preparing Canadian soldiers and equipment for combat. In later life, he stressed the value of learning to write up investigations tersely and quickly. “One lesson of the Libyan Campaign in early 1941,” he reported, was the “weakness of written reports, which were often slipshod and incomplete.” Henceforth he ordered his subordinates to “keep reports short and clear.” This skill was the essential foundation for his later success in geophysical research in the critical decade of the 1960s when discoveries were being made in quickfire succession. Often involving multiple researchers coming to the same conclusions, only the first to publish an article in a reputable peer-reviewed scientific journal could claim ownership. Tuzo would prove a master of

Colonel Wilson Leaves the Army I was tired of playing war games in the snow with half the Army melting away. J. Tuzo Wilson, 1993

In early 1945, the Canadian Army was 250,000 strong; a year later that number had dwindled to 25,000. Tuzo was demobilized from the Canadian Army with

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the academic blood sport of “publish or perish,” having served his apprenticeship with the Canadian Army. Tuzo also put to good use another skill acquired in wartime. While in Europe, he had been a great ambassador for Canada and learned the art of communicating to the public the importance of geology and developing the country’s mineral resources for the war effort. This theme would be a feature of his later career, in the role of director of the Ontario Science Centre, which he would use as a platform to inform the public, and the wider scientific community at large, of the importance of the new understanding of the planet arising from the theory of plate tectonics. In London during the war, Tuzo had made radio broadcasts from a studio buried deep below Oxford Street, as part of a weekly on-air “Senior Geography” course offered by the BBC Home Service for school children whose education was interrupted by wartime bombing. Tuzo spoke of the history of mining on the Canadian Shield and contrasted the wealth at surface in southern Canada (in the form of good soils and farmland) with the mineral wealth hidden deep underground in the rocks of the Shield. He spent much time conveying the great size and remoteness of much of the country to a young, mostly urban British audience growing up in confined spaces. He spoke enthusiastically of his first experiences as a fifteen-year-old geological assistant working deep in the bush just south of Hudson Bay and left no doubt in the minds of his listeners that the minerals and mines of Canada, and the armaments made from their metals, would ultimately help win the war against fascism. When the war was over, those resources could be put to peaceful purposes, and new mineral deposits would need to be found to help fuel

the postwar economy using newly developed electronic technologies tested against enemy submarines, boats, and planes. In April 1940, Tuzo had reported at length to the Royal Society of Canada on the emerging technology of using air photographs to map faults on the Canadian Shield, emphasizing their value to mineral prospectors. By 1948 the technique was routine, and the Royal Canadian Air Force was photographing as much as 1 million km2 of the Canadian north each summer, the largest such survey operation of its kind anywhere in the world. Tuzo was fond of playfully remarking that it had only been under stressful wartime conditions in Europe that he developed another useful skill: the ability to sleep anywhere, at any time, which had been one of his mother’s recommended skills for the accomplished traveller. However, this could also prove to be a source of occasional embarrassment when unexpectedly deployed while giving after-dinner speeches, presiding over university graduation ceremonies, at work in his office, and even sitting around the family dining table. Barrie Clarke, a former student of Tuzo’s (and now emeritus professor at Dalhousie University) relates how in Baffin Island in 1964, Tuzo was able to continue sleeping peacefully under a tent that collapsed on him during a violent snowstorm. Tuzo’s experiences in operational research in the Canadian Army, supervising the painstaking organization of men and their equipment needed to take the battle to the enemy on foreign shores, save lives and win, while diplomatically balancing the needs of other Allies, was an excellent preparation for taking on the organizational demands required in his capacity as the president of the International Union of Geodesy and

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Geophysics (1957–60). In this role, he visited many university departments and government agencies around the globe, including those in Russia and China, to glean what he could about new developments in geology and geophysics. In hindsight, the technical and organizational skills acquired by Tuzo under General McNaughton in wartime and during Operation Musk

Ox were ultimately those needed in the new electronic age to interpret masses of geological and geophysical data on a global scale and glean the big picture. With the end of Tuzo’s war service, a new chapter was about to open for him, but in familiar surroundings involving the warring factions of geologists and physicists at the University of Toronto.

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Chapter 6

A Geologist in a Strange Land

Always at the back of my mind, whenever there had been a momentary lull in the crowded days of the past six years, was the puzzle of the Canadian Shield. I knew my early tentative efforts to change geology had been too conservative. I knew in research one must be imaginative and far-sighted, but I had no idea who or what would give me the opportunity to try to implement this approach. J. Tuzo Wilson, 1993

In February 1939, University of Toronto Professor Lachlan Gilchrist, the innovative pioneer of the first geophysics program in Canada, wrote to Tuzo declaring, “I look forward to the day when they will give you money and instruments to develop geophysics. I am convinced it is certain to come if you have a little patience.” Although Gilchrist was eventually proved right, Tuzo needed more than a little patience, as the opportunity to move to Toronto and begin academic research on the Canadian Shield did not happen until after the war. In May 1946 at the conclusion of Operation Musk Ox, Tuzo left the Canadian Army to look for a job but was unsure what to do. Nominally still on leave from the Geological Survey of Canada, he was offered

the carrot of eventually being appointed its director, but he had developed strong feelings about what he saw happening around him in Ottawa. Formerly well-directed and singularly focused wartime research groups were slowly being strangled by an emerging postwar bureaucracy. His views in the early postwar years of the Geological Survey, with which he had spent so much time in the 1930s, were harshly critical but accurate. “I thought the Survey was then a hell of a dull place. All government departments inevitably in time become poor places to do research because the type of people that remain there want a secure job and long pension. They can’t get out once they’ve locked themselves in and politics will always intervene if not at the beginning sooner or later.”

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Isabel, his wife, also made her views known, stating that the choice of career was up to Tuzo, providing he did not return to the Army or rejoin the Geological Survey, and this wish was to prove instrumental in his eventual move to academia and a position at the University of Toronto. Leery of locking horns with bureaucrats, he resigned from the Survey and cashed in his pension, which amounted to the grand sum of $43 and several cents. He wasn’t to remain unemployed for very long and, as he later remembered, “with my usual good fortune, it turned out that the job found me.” At the invitation of Professor Burton, head of physics at the University of Toronto, Tuzo was appointed Lachlan Gilchrist’s successor as professor of geophysics with tenure in the Department of Physics. However, Tuzo was still primarily a geologist and, as such, was mistrusted not only by his colleagues in physics but also viewed with suspicion on the other side of campus in geology. He was very surprised that successful geophysicists such as Norm Keevil (later head of the mining conglomerate Teck Corporation) and Arthur Brant (who discovered the Steep Rock iron ore deposit near Atikokan in Northern Ontario) hadn’t been considered, but there was still then a marked resistance in university circles to appointing anyone who had done well in the private sector and made money. Before he accepted the proffered position at Toronto, Tuzo had sought advice from colleagues; their suggestion was “go back to the university but accept no administrative positions.” Tuzo found that little had changed at the University of Toronto since his student days, and he noted wryly

that the “old wrangle between physics and geology was as noisy as ever, their fiefdoms just as clearly defined, and their boundaries just as vigorously defended.” He was surprised at the level of distrust shown by his erstwhile colleagues in physics, commenting, They were jealous that I was appointed a full professor even though I had no Ph.D. in physics. My Ph.D. was in geology and what the hell was I doing in their department? Physics had been converted in the 1920s into an analytical subject that you could handle mathematically whereas geology was still into the descriptive thing. The trouble with a lot of geophysicists is that they don’t really understand Earth at all.

Faculty salaries at the University of Toronto were then very low, but this deficiency had been accepted by professors after 1939 as their contribution to the war effort. Hostilities were now over and university maintenance staff, especially boiler men, earned more. Tuzo was paid $5,500 a year, representing a 50% cut from his wartime Army pay as a colonel, and it was not until 1948, after a noisy and rancorous meeting of the University’s Board of Governors where Tuzo successfully “pulled rank” as a former senior Army officer, that professorial salaries were doubled at a stroke. Despite gripes over remuneration, it was a very good time to be in geophysics, as the discipline was buoyed by the ever-expanding needs of the mining industry. Virtually all of Canada’s mineral wealth lies deep underground or is hidden by glacial sediments of one type or another, and geophysical surveys are needed to

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find them. In the early years after the war this required a concerted national effort in prospecting for the mineral deposits that would be needed to power the expected postwar economic boom. In 1944, the Canadian Legion Educational Services had foreseen the emerging trends in the resource industry and started to publish a series of their own instructional booklets on geology, mineralogy, and prospecting in Canada for active service personnel still serving abroad and beginning to wonder about their employment prospects on their return home to civvy street. On their back page the paperback, pocket-sized books carried in bold typeface the stern admonishment that only a military wordsmith could come up with: “DO NOT THROW THIS BOOK AWAY” – a warning aimed presumably at Canadian combat soldiers faced by an enemy who might stumble across discarded copies of the book, find a brief review of the geology and rocks of Canada to their advantage, and go on to defeat the Allies as a result. It was emphasized in the books that “prospecting affords an individual great opportunity to act on their own initiative and appeals to one who quickly tires of routine. The good prospector must be physically fit, mentally alert and of considerable physical endurance.” These are enduring qualities for those on active duty, and not surprisingly, veterans rushed to enrol and improve their skills in Canadian universities. The returning soldiers were very familiar with and highly respectful of the lifesaving applications of the new wartime technologies previously directed against the enemy and that now could be used back home in the search for resources. The discovery of the massive Leduc oil field in Alberta in 1947 resulted

Educational booklet of 1944 issued to Canadian servicemen on active duty abroad describing the skills and knowledge needed to work in mineral exploration and mining back home at the end of hostilities. By 1946, the University of Toronto would accommodate one quarter of all returning student veterans in Canada, and a temporary campus was set up in Ajax on the site of a former munitions plant. Geology and geophysics programs at U of T experienced a boom. Courtesy of Michael Allder.

from the application of new seismic reflection methods (using sound waves to locate oil-bearing structures at depth). It was a powerful demonstration of the value of geophysics to the country and elevated the reputations of geology and geophysics among the public. It was also a very good recruitment tool and cast a “new light on the struggling, ill-regarded

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Tuzo Denounces Continental Drift

hybrid of geophysics.” Newly “demobbed” servicemen, attracted by the freewheeling life of the geologist and by the financial rewards on offer in the mining and oil industries, eagerly enrolled. Between 1949 and 1980 some eighty doctorates were awarded in geophysics just at Toronto, and these were the foundation for the teaching of the discipline in universities across Canada and its broader application in the resource industry. The postwar renaissance in geophysics at the University of Toronto started in the inauspicious surroundings of a shabby, rundown house on campus at 49 St. George Street. Beginning in 1946, this was the new home of the Department of Geophysics, where students shovelled coal into the basement boilers in winter and the lecture room was in a first-floor front room. A toilet had to be removed to make space for laboratory equipment in the washroom. A colleague of Tuzo’s at the time and now emeritus professor, Gordon West recalls that Tuzo’s “office was in the second-floor front room, the undergraduate teaching laboratory in the third-floor front room. The basement housed seismology and rock magnetism, equipment storage, and a workshop. Isotope labs were in the former kitchen and bedrooms. The secretary’s office was in the stair well” and the intercom system was simply “a shout up the stairs whenever a call came in.” It seemed the very last place to begin a career that would ultimately change geology forever, and Tuzo’s first steps in his new academic position, and his continuing embrace of permanentism in which he had been firmly schooled earlier in his career, seemed to underline that.

The two continental masses, with great slowness, drifted asunder. Edward Bailey, 1928

All fancy and physically impossible. J. Tuzo Wilson, 1947

In the early years of his academic career at Toronto, Tuzo found that filling the shoes of his predecessor Lachlan Gilchrist was a considerable challenge. Geophysics was then considered “an outer bastion of the fiefdom of physics,” and never having taught a course of lectures before, he found it to be “tough sledding” and slanted his teaching toward geology and its practical application to mining. This choice would prove to be a source of friction with the more traditional and classically trained physics faculty, but the lectures proved very popular because graduates were in great demand and got well-paying jobs. Not surprisingly, Tuzo showed no interest in the work of Alfred Wegener and continental drift, having been deterred by his undergraduate experiences with Arthur P. Coleman and later as a graduate student with Sir Harold Jeffreys, the arch anti-drifter at Cambridge. One of his first acts on being appointed to the university was to return to the fold and formally declare himself a committed permanentist. The Swiss geologist Rudolph Trumpy has related how Tuzo met up again with Sir Edward B. Bailey, former director of the British Geological Survey, with whom Tuzo had worked as an army engineer in Britain

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in 1940. They linked up in Scotland in 1948 to explore the geology of the Highlands, and Tuzo remembered the one-armed and one-eyed First World War veteran “beginning each day at seven in the morning striding down in the cold drizzle to the beach for a swim” after shedding his clothes and “providing titillating entertainment for all the maids lined up at the hotel windows.” Bailey had been an ardent proponent of continental mobilism from the outset, arguing in 1925 “that some sort of continental drift becomes a matter not of interpretation but of observation.” The object of the 1948 field trip to the Highlands was to examine the intensely deformed rocks exposed on the valley sides near Glencoe, just south of Fort William (the site of the famous massacre of the members of the Clan MacDonald in 1692). It lies close to the Great Glen Fault, which runs as a straight, knife-sharp valley between Fort William and Inverness, dividing Scotland in two and filled in part by the long narrow lake called Loch Ness. Tuzo had travelled from Canada to Scotland by air (his first transatlantic flight) in a war surplus B-52 bomber converted to civilian use with a bar in the former bomb bay where as many as eighteen passengers could gather to enjoy a drink. One of the engines failed on the flight, noticed only by Tuzo among the passengers. He was asked by the pilot to keep it to himself lest the plane be grounded on its arrival in Ireland and forced to abandon its onward journey, preventing the pilot from spending his leave in London’s pubs. In northwest Scotland, Tuzo was aware that, as a permanentist, he was venturing alone into hostile territory. The Scottish Highlands had been the focus of

“the Highland Controversy,” one of nineteenth-century geology’s most well-known debates that had anticipated much of the later arguments between permanentists and mobilists. The great Scottish geologist Sir Roderick Impey Murchison (1792–1871), who had been lured away from the British Army to take up the young science of geology by Sir Humphrey Davy (inventor of the Davy safety lamp, which saved countless lives of coal miners), defined the Silurian Period in 1839 on the basis of its distinctive fossils found in sedimentary rocks, which are widespread in Wales. Turning north to Scotland, he saw so-called primitive formations (highly metamorphosed banded gneisses typical of very old Precambrian basement rocks) lying on top of fossiliferous Silurian rocks and argued controversially that the gneisses were much younger and had simply been altered in situ by heat and pressure. Other geologists such as Charles Lapworth strongly disagreed, finding that there were significant breaks in the rocks, suggesting that the uppermost rocks were very old and had been pushed across the younger ones. Lapworth is said to have suffered a mental breakdown in the ensuing debate. In 1883, the Scottish geologists Ben Peach and John Horne were dispatched north into the Highlands by the Scottish branch of the Geological Survey of Great Britain to re-examine Murchison’s and Lapworth’s competing ideas and clear the matter up. They did this by meticulous mapping on foot in remote wild country, which Tuzo surely would have appreciated, even if he would later disagree with their findings. Peach and Horne published a famous report in 1884, later expanded into The Geological Structure of the Northwest

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Highlands of Scotland in 1907. There they set out the case for an enormous “thrust,” which they named the Moine Thrust, which had moved the Lewisian Gneiss (a slice of much older shield rocks) for more than 200 km to the northwest, emplacing the basement rocks on top of much younger Silurian fossiliferous rocks. It was a hugely influential finding and became the framework for mapping and interpreting the structure of other mountains, including the Rockies and the Alps. The take-home message was simply that the Earth’s crust has been compressed and shortened by thrusting and compression far beyond anything that could be expected by contraction of a cooling planet. The extent of deformation required large horizontal movements of the Earth’s crust, which, in the later opinion of Edward Bailey and many other British geologists at the time of Tuzo’s visit to Scotland, had happened during the assembly of Wegener’s Pangea, when the ancestral North American continent was shoved up against parts of northern Europe. This was completely unacceptable to Tuzo, a devout permanentist at the time. On long hikes across the Scottish moors in search of outcrops that poked through the heather, he admitted to being “spoilt by the enormous expanse of gneisses across the Canadian Shield” and remained skeptical of Bailey’s conclusions. He made his contrary views public. At the end of a long climb, standing on a high peak overlooking the broad sweeping valley of Glencoe, Tuzo loudly declared to the gathered participants that Bailey’s ideas on continental mobilism were completely wrong. He was ultimately to regret his hastily delivered sermon from the mount, and in 1966 it was to be none other than Tuzo who was to prove the essential

In 1888, Ben Peach and John Horne’s classic work on the Moine Thrust in Scotland inspired Henry M. Cadell, their assistant, to create thrust structures in the laboratory using layers of damp sand and plaster of Paris using a large vice to duplicate compressional forces. Observing the resulting folds, Cadell wrote, “Here was a mountain in embryo, newly upheaved.” Courtesy of the British Geological Survey.

correctness of Bailey’s ideas about Pangea and mobilism in general. The Scottish rocks near Glencoe had been deformed at a time long before there was an Atlantic Ocean, when Europe had indeed collided with North America, closing an older ancestral ocean now called Iapetus, and its predecessor the Rheic Ocean, to form Wegener’s Pangea. The current Atlantic Ocean had only opened as Pangea broke up and North America and Europe went their separate ways, leaving the Appalachian Mountains in North America and the

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Grampian Mountains in Scotland as evidence of their former union within the supercontinent. In 1948 Tuzo’s appreciation of the close similarities between the geology of Scotland and eastern North America, arising from shifting continents and oceans that opened, then closed, then reopened, much like an accordion, lay well in the future. At the time, he resolutely clung to the permanentist view that the former nuclei of the continents had remained fixed in position and that deformed rocks such as those of Glencoe and the Northwest Highlands had been added around their periphery by contraction of a cooling planet. But Tuzo also had very valid reasons for questioning Bailey’s ideas and continental drift in general because it didn’t provide a credible explanation of how continents might move, nor did it provide a guide to the much longer part of the planet’s history long before Pangea, especially the formation of the very old Precambrian rocks that Tuzo had laboured over long and hard when mapping the Canadian Shield.

of Canada under the leadership of Duncan Derry published a new map of the structure of the Canadian Shield (the Tectonic Map of Canada). This revealed it to be composed of large geological “provinces” that extended over many thousands of square kilometres, surrounded by belts of highly deformed rocks that had been crumpled by some form of mountain-building event (“orogeny”). It was just as Tuzo had foretold in the 1930s when mapping the long faults that bound each of the blocks from the air in the Northwest Territories, but his ideas had fallen on deaf ears. The area involved was huge; virtually half a continent had been mapped in one go, just as the postwar mineral boom was underway. The new tectonic map was in part the result of painstaking work on the ground and the fitting together of numerous map sheets completed over many decades. However, much of it had been quickly compiled from air photographs, which were Tuzo’s major contribution to the project and brought out his talent for generalization and seeing the “big picture.” What the 1950 Tectonic Map of Canada brought home to Tuzo was that the Shield had a long history and had been built piece by piece by the coming together of huge blocks of crust. But when had that happened and what processes had been involved? These questions could be answered only by using the new techniques of radiometric dating, which had been pioneered in Britain by Arthur Holmes, who had proposed in the late 1920s a mechanism that would allow the drift of continents, involving giant convection currents in the Earth’s mantle. As we related earlier, these ideas had been rebuffed and ignored at the time. Tuzo, the permanentist, and Holmes, the mobilist, first met in

The “49 Club” Unlocks the Mystery of the Canadian Shield It is possible that geology is much less complicated than had always been imagined, and that beneath all the chaotic wealth of detail in a geological map is an elegant, orderly simplicity. J. Tuzo Wilson, 1993

The year 1950 turned out to be a milestone in Canadian geology. It was then that the Geological Survey

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London in 1948 and, despite their very different views, got on very well together. A vigorous correspondence ensued, remembered in a recent interview with Henry Halls, a former long-time professorial colleague of Tuzo.

geological clock. The chemical analyses were done in time-honoured fashion at Toronto by young graduate students and early-career colleagues such as George Cumming, Ron Farquhar, and Norm Keevil, who were all members of what became known as the “49 Club,” a reference to the address of the geophysics laboratory in the old run-down house at 49 St. George Street. They were instructed by Tuzo on how to use the spectrometer, which had been installed in the former washroom where the bathtub used to be, and then they were left largely to their own devices. The results were startling, because they revealed that rocks became older and older toward the centre of the Canadian Shield, pointing to successive addition of younger and younger rocks around an original nucleus. This nucleus was identified as a 172,000 km2 piece of ancient crust called the Slave Craton in the Northwest Territories around Great Slave Like and Great Bear Lake. This was the same area where Tuzo had worked in 1938 using air photographs to map the long faults that bound the outer margins of the craton. The rocks in the innermost parts of the Canadian Shield are as old as 4 billion years, while those of its outer margins were still very old but much younger, at 1 billion years. The conclusion was that the Shield had evolved over enormous lengths of time during which it had grown, a very different model from long-established American views of how the Shield had formed. American geologists such as T.C. Chamberlin and R.T. Salisbury, authors of the influential textbook Geology: Earth History first published in 1906, argued that the Shield, and its ancient gneisses, had formed in its entirety in a single event by rapid cooling of

The University of Toronto archives contain a series of letters exchanged between Tuzo and Holmes during this scientifically critical time. The series begins very formally with a letter from Tuzo with an opening “Dear Professor Holmes” which was met with a reply of “Dear Professor Wilson” from Holmes. The next letter from Holmes was a breakthrough: “Dear Wilson” which immediately elicited the response of “Dear Holmes.” The ice was now truly broken, the following letter being “My Dear Wilson” which was met immediately by a “My Dear Holmes.” They were now acknowledging that they were scientifically on an equal footing, holding each other in the highest respect.

Tuzo listened to Holmes’s advice, and once back in Canada, with the vigour and directness in marshalling resources and getting results that had distinguished his wartime service, he commandeered an ancient, long-disused mass spectrometer from McMaster University. This instrument could measure minute quantities of lead and other elements preserved in the crystals of ancient rocks. Holmes had shown that lead was a “daughter product” produced by the decay of unstable uranium isotopes present at the time of the rock’s formation; the older the rock, the more lead would be present in any one crystal, and if it could be measured sufficiently accurately, it could be used as a

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a large primordial magma ocean. Chamberlin had founded the prestigious Journal of Geology, described as a “semi-quarterly magazine of geology and related sciences,” and used it to aggressively promote his views. Tuzo, on the other hand, had now shown that the Shield was a mosaic composed of pieces of crust, which was much more complex and much older than the relatively small, outermost part of the Shield studied by American geologists in Minnesota and Wisconsin. In Tuzo’s opinion, they had failed to appreciate the complexity of the Shield across Canada and its newly revealed history spanning billions of years. As Tuzo was to remark, it was “quite natural that those schools taught what was correct for the United States without realizing that their views were not sufficiently general to apply to the whole Canadian Shield.” It was the same frustration that he had felt when working with rather inward-looking American geologists at Princeton in the early 1930s. Tuzo also admonished his Canadian colleagues for not being sufficiently critical or bold enough to embrace the model where fixed continents grew around a very old primordial nucleus. But he still believed, contrary to the views of his now good friend Arthur Holmes, that it had occurred as result of a contracting planet and that continents had remained fixed in position throughout their history. To provide a firmer physical underpinning to his idea, he began a long collaboration with Adrian Scheidegger, a young Swiss-Austrian applied mathematician who had previously worked on relativity. He was an expert on the stresses existing in the Earth’s crust and how they were expressed in landscapes, especially in mountain ranges such as the

Alps. He would shortly thereafter write an influential textbook on the subject, Principles of Geodynamics. Tuzo and Scheidegger argued, very much in keeping with traditional permanentist views, that ancient mountain belts were built by compressive stresses within the Earth’s crust as the planet contracted and its circumference progressively shortened. Then they went a step further and pointed to the distribution of modern volcanoes and deep earthquakes along distinctly curved arcs in oceans (“island arcs”) and along the margins of continents (“magmatic arcs”). These, they suggested, were the surface expression of steeply inclined faults produced by contraction of the Earth’s cold, brittle crust over a still-hot mantle. The deep faults functioned as conduits for magma moving up from the mantle to feed volcanoes on the Earth’s surface. The French geologist Emile Argand had suggested much the same thing in 1924, but his writings on volcanic arcs were little known in North America. Tuzo and Scheidegger proposed that the successive formation of arcs along the outer margins of continents gave rise to mountains and great thicknesses of volcanic rocks and sediments in belts, resembling growth rings in trees. They pointed to the great age of the Shield and the much younger surrounding mountain chains of the Appalachians and Cordillera as confirmation of growth of the North American continent. The Wilson–Scheidegger model, in fact, was very similar to the “geosynclinal theory” proposed in 1873 by James Dwight Dana, who, as we have seen, also invoked a cooling, contracting planet where stationary continents grew by the repeated filling of

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Wilson and Scheidegger’s permanentist model of 1950 proposed an unmoving North American continent growing outward from an original nucleus (the Canadian Shield) on a contracting planet. Concentric belts of mountain ranges, such as the Cordillera in the west and the Appalachians in the east, were argued to form around the outer margins of the rigid Shield as a result of shortening and compression of the Earth’s crust. Deep faults created by contraction allowed magma to rise to the Earth’s surface to form distinct curved arcs of volcanoes. Extensive flatlying rocks of Paleozoic age such as limestones below the prairies and plains recorded shallow seas waxing and waning across the interior of the unmoving continent.

A Geologist in a Strange Land

deep basins (geosynclines) around their margins. Tuzo and Scheidegger’s model was based on a modern knowledge of stresses existing in the Earth’s crust and also invoked volcanic activity along arcs, but it was more notable, in retrospect, for what it had left out. Their argument for large-scale contraction of the Earth ignored compelling geological evidence that large parts of the crust have been stretched and fractured to form “normal faults” produced when rocks are pulled apart (“extended”) and which are very common in the Earth’s crust. Stretching of the Earth’s crust to produce such faults is incompatible with a contracting planet, where rocks would be subject to ever-increasing compression as its circumference slowly shrank. Tuzo later acknowledged that in his enthusiasm for a contracting Earth with fixed continents that grew in situ, he had completely forgotten about the many wall-like igneous “dikes” he had mapped in their many thousands across the Canadian Shield in the 1930s. The widespread intrusion of magma implied expansion of the Earth’s crust, not contraction, just as Reginald Daly had argued in 1926. Tuzo admitted that he and Scheidegger had failed to appreciate the work of the Scottish geologist Ernest M. Anderson, who had authored a paper entitled “The Dynamics of Faulting” in 1905 (later expanded into a textbook), where the role of extension was highlighted as an important process across large areas of Earth’s surface. Anderson and Daly had expressly pointed out that the intrusion of igneous rocks into older strata necessitated extension of the Earth’s crust to accommodate the large volume of magma welling up from the mantle. In fairness, it is clear from cartoons scribbled by Tuzo in notes

made in 1951 that he was then toying with the ideas of mantle convection and mobile continents first proposed in the late 1920s by Arthur Holmes and then again by G.S.F. Hills in 1947. Both had suggested that continents were large moving islands of lighter crust (like the “crustal flakes” of Frank Taylor) that drifted across the surface of the denser mantle below. While radical mobilist ideas may have been in the back of his mind and confided in his notes in private, they were to be disregarded and unexplored in public by Tuzo for another ten years.

Ice Age Legacy: Tuzo’s Glacial Map of Canada Hurrah for eskers and drumlins. It delights my heart to see a good Precambrian geologist bring out such excellent by-products. Keep it up! Professor Paul MacClintock at Princeton University to Tuzo, 1938

Looking down at the Canadian Shield from airplanes in the 1920s had brought into view another underappreciated chapter in Canada’s long geologic history, the youngest, which is dominated by Ice Ages. Canada is a big northern country prone to being smothered by large, long-lived and kilometres-thick ice sheets every hundred thousand years or so during Ice Ages. The imprint of these massive ice masses is found across all of Canada and well into the United States, and the study of the thick covers of sediments left behind when ice sheets melt is known as glacial geology. Frank B. Taylor was primarily a glacial geologist when

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he proposed “Earth’s Plan” as an early version of plate tectonics in 1910. Tuzo Wilson was also a keen student of ancient ice sheets, having been greatly influenced as an undergraduate by A.P. Coleman and, subsequently, by Richard F. Flint’s classic textbook, Glacial Geology and the Pleistocene Epoch published in 1947. Tuzo and Flint were close colleagues, not only sharing an interest in Ice Age glacial geology but also like-minded in their determined opposition to Wegener and continental drift. Like Tuzo, Flint had a very similar wartime experience in operations research, the American having been head of the Arctic Section of the Arctic, Desert, and Tropic Information Centre of the United States Army Air Force, shortly thereafter becoming a faculty member at Yale, the epicentre of North American permanentism. In his textbook Glacial Geology he had dismissed the evidence for continental migration as “dubious” and “purely fantastic.” As a diversion from looking at the rocks of the Canadian Shield, Tuzo spent much of the mid-1950s using air photographs to map the footprint of the last great Canadian ice sheet (the Laurentide Ice Sheet), which had finally melted away from southern Canada only a scarce 10,000 years ago. He used the same techniques of examining air photographs that he had brought to bear on the Shield rocks to create the first Tectonic Map of Canada in 1950. Tuzo had an aviator’s eye for landscapes, and he noted thousands of drumlins, the streamlined landforms formed under ice as it flowed across the landscape. Eskers, on the other hand, are long ridges of gravel, much like raised causeways, deposited in subway tunnels cut

into the base of the ice sheet through which water and sediment had flowed under high pressure. The tunnels became choked with sediment, ice melted away, leaving snake-like ridges resembling the letter S from which their original Celtic name is derived. Some eskers are more than 100 km long and often form dense networks resembling arteries recording the drainage system under the enormous ice sheet. The significance of mapping glacial landforms had first been appreciated by the Americans just before the outbreak of the Second World War when they established a US National Committee chaired by Richard Flint to create a comprehensive glacial map of North America. It would reveal the size of the last ice sheet, its outflow centres, the directions in which ice had flowed from Canada into the United States, and the many varied types of landforms and sediments left by its melt and eventual decay. Tuzo was invited to join the US National Committee to help produce the map (eventually published in 1945), but his involvement was prevented by war service in Europe. Later, Tuzo supervised compilation of the first detailed Glacial Map of Canada published by the Geological Association of Canada in 1958. Much of the interpretive work was done by George Falconer, and the map highlighted the rich heritage of landscapes left by the Laurentide Ice Sheet, which had reached its maximum size and thickness some 20,000 years ago. Tuzo’s old colleague from Operation Musk Ox, P.D. Baird, described the map as “lavish” and praised the “flying cameras” of the Royal Canadian Air Force, which had flown the aerial surveys over enormous

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Hundreds of bullet-shaped drumlins near Peterborough, Ontario, the “Trent Hills.” These record the direction of flow of the last ice sheet, in this case from top right to bottom left. Tuzo described drumlins “in reality a mile long but on the map and painted light brown they looked like nothing so much as a nest of ant eggs.” Tuzo wrote that compiling the glacial map of Canada “was an enormous job and never would have got done if it hadn’t been for air photographs. You could see glacial features so plainly.” Courtesy of Dr. S. Sookhan.

areas. In Tuzo’s opinion it “would grace any wall,” but it wasn’t just a pretty picture. It was of immense practical and economic importance because far-­ travelled, glacially transported sediments blanket the mineral-bearing rocks of the Canadian Shield, hiding their riches from view. The valuable rocks can be located only by looking at the chemistry of the covering

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glacial sediments as evidence of the rocks over which ice had passed, and by careful backtracking along the route sediments had been carried by ice, to identify source areas of valuable mineral deposits. Systematic mapping of the orientation of thousands of drumlins is the key to determining which way ice had flowed. The Glacial Map of Canada first made by Tuzo, and

Tuzo’s leadership in creating the first comprehensive glacial map of Canada in 1958 using air photographs showed the importance of understanding the country’s great Ice Age heritage: every city and every town sits on glacial sediments, which also obscure much of the mineral wealth of the Shield and create the country’s rich soils and farmlands. Tuzo’s map has been updated since, notably by Art Dyke and others of the Geological Survey of Canada. The latest version (2020), reproduced courtesy of Chris Brackley and Canadian Geographic, shows the outlines of the Laurentide and Cordilleran Ice Sheets at their greatest extent about 20,000 years ago when they reached thicknesses of as great as 3 km. The principal moraines, esker ridges, and huge lakes ponded as the great ice sheets waned and melted back (such as the enormous glacial Lake Agassiz, which was many times larger than the Great Lakes today) are also depicted. Today’s ice covers over Greenland, Canada’s Arctic, and along the western mountains are a reminder of what once was.

A Geologist in a Strange Land

successively updated since by the Geological Survey of Canada, was a massive achievement because it confirmed the presence of several distinct outflow centres within the Laurentide Ice Sheet, which had consisted of several high-standing domes, both west and east of Hudson Bay. There, ice had been as much as 3 km thick, feeding ice that flowed radially outwards from each centre to cover most of Canada and the northern parts of the United States. Here was a key to unlocking Canada’s mineral resources hidden by glacial sediments on the Shield. Tuzo also realized that the study of ancient Ice Age ice sheets in Canada had to be based on a detailed understanding of the country’s modern glaciers and ice caps, but hitherto they had been largely ignored by geologists, and their distribution and behaviour was only poorly understood. In the late 1950s, Tuzo was instrumental in getting the Canadian government to begin systematically mapping glaciers and ice caps in the western mountains and the Arctic. It was a significant step, because Canada’s glaciers are significant sources of water to many western communities, especially the cities of Calgary and Edmonton, and for farming across the dry Prairies. Glaciers are also the canaries in the climate coal mine, growing or shrinking as global temperatures fluctuate. Once again, the use of airplanes proved crucial; the US Army had been instrumental in collecting the first such aerial photographs of Canada’s glaciers during the Second World War, and it was the American glaciologist Mark Meier who completed the first detailed study of a Canadian glacier, Saskatchewan Glacier in the Rockies, in 1960. It was time to show the flag at home, and the Glaciology Division was set up in Ottawa in 1960 to make

J.A. Jacobs, Tuzo Wilson, and R.M. Farquhar examining geophysical equipment in 1958 at the University of Toronto to be shipped out to Salmon Glacier in northwestern British Columbia, the first Canadian glacier to be systematically studied using modern geophysical techniques.

a Canada-wide inventory of its glaciers and to begin systematic surveys of their changing size. Today the national inventory of glaciers started by Tuzo remains the basis of assessing the state of health of Canada’s ice masses in a warming world. Glaciers and glacial geology were a long-lasting fascination of Tuzo’s, and he would later regret not making more of his work on the glacial map of Canada, “failing to publish the interpretation that it deserved.” New discoveries were being made elsewhere in geophysics that were to take him away from the study of modern and ancient ice sheets back to his permanentist roots.

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Map of Thompson Glacier on Axel Heiberg Island, Nunavut, made from air photographs in 1962. The glacier is about 3 km wide.

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The 1950s: Tuzo’s Wasted Decade

anyone travelling so far to see what they were doing and were especially eager to show Tuzo their rocks in the field. “Few people can ever have seen so much of the Earth’s geology so rapidly under such superb circumstances,” he later remarked. Armed with a new Leica SLR camera bought for him by his father, Tuzo first visited Egypt, travelling southwards up the River Nile from Alexandria in a flying boat operated by the British Overseas Aircraft Corporation en route to Johannesburg and Cape Town. In travelling through Egypt, Tuzo was paying his respects to predecessors who had laid the foundations of geology thousands of years earlier. Ancient Egypt has fittingly been described as the “State of Stone” and the Nile as “the river of mining.” It is where geology first began as an organized discipline more than 5,000 years ago. Tuzo’s flight along the Nile took four days, with time for overnight stops on the river, a journey impossible today. There was an onboard bar selling cold beer in the plane’s tail and it would land on the river each day for lunch with the remainder of the day reserved for sightseeing. The only risk was of the plane landing on groups of hippopotami that would suddenly surface, requiring the pilot to abruptly change his approach. Seldom flying above a height of 1,000 m, the slow-moving aircraft afforded spectacular views of the Nile and the many pyramids and temples along its banks and into the desert beyond. One evening Tuzo “found a guide and, in the dusk, wandered among the vast but primitive pillars which the ancient Egyptians had raised so many thousands of years before.” Ancient Egypt can lay claim to be the world’s most durable civilization, which lasted, with a few short breaks, over three millennia from the Predynastic

Continental drift is without a cause or a physical theory. It has never been applied to any but the last part of the geological time. J. Tuzo Wilson, 1959

Tuzo’s 1950 paper with Adrian Scheidegger, arguing for a contracting planet on which fixed continents grew, was well received internationally, and, as a result, he was invited to Australia to give a series of lectures. That year he spent three months travelling across the country visiting state universities and the newly founded Australian National University in Canberra, a largely graduate institution designed to keep domestic students in their home country rather than being sent abroad for training, mostly never to return. While ANU was under construction, outside experts were invited in to travel the country and lecture, and Tuzo was appointed as a visiting professor. Tuzo’s grand design on the long journey down to Australia and back was to simply “see as many Precambrian shields as possible,” and this was the justification for getting a grant from the Carnegie Foundation to undertake a five-month world tour in which he travelled more than 130,000 km (the Earth’s circumference, as he was fond of pointing out, is only 40,000 km) and moved ninety-three times by boat, road, and plane. Long distance air travel routes were being opened for the first time after the war, and the modern mass tourism industry was still in its infancy. He saw glimpses of a former world slowly emerging from the British Empire and in rapid transition. Moreover, many of the geologists he met were unused to

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LEFT: British Overseas Airways Corporation flying boat stopped for lunch on the Zambezi River at Victoria Falls in 1950 while en route from London to South Africa. Tuzo flew from Alexandria at the mouth of the River Nile to its source at Lake Victoria in the East African Rift, stopping en route at ancient Egyptian temples. “Bumping along a few thousand feet above the earth one could see it all spread out below like a relief map with all the major features clear and stark.” RIGHT: Tuzo gazing out over the East African Rift.

period to the early Christian era. Large-scale working of rock, on an industrial scale, was the key to social cohesion and the extraordinary continuity of Egyptian civilization. It required massive organizational skills that Tuzo greatly admired following his wartime experiences in army operational research. The geology of Egypt varies greatly, with the southern part of the country underlain by old Precambrian rocks of the Arabian Shield, and its northern part by much younger limestones. Four

and a half thousand years ago, the pharaohs of the Old Kingdom, based at Memphis in the north, built limestone pyramids; a thousand years later the New Kingdom rulers built huge temple complexes made of sandstone and granite in the south, near Aswan. This required an intimate knowledge of the rocks of Egypt and, for the first time, the emergence of trained geologists. In visiting the Nile, Tuzo was reminded of his teenaged years spent with prospectors searching the Canadian

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Shield for metals. It had been essentially no different in Egypt thousands of years earlier, apart from the size of their operations. Prospecting teams, of up to 10,000 people, explored large areas of the Arabian Shield, their exploits recorded by inscriptions cut into the walls of Wadi Hammamat (Valley of Many Baths) connecting the Nile Valley with the Red Sea. The pharaoh Ramses IV (1156–50 BCE) was a royal geologist who guided large expeditions through remote country; inscriptions speak of the great pride in returning with enough material for an intact sarcophagus lid (approximately 2 m wide, 3 m long, and 1 m thick) without the loss of men or animals. The prospecting parties included infantrymen, miners, stonecutters, prospectors, and scribes who were highly regarded and well looked after and rewarded with prodigious quantities of beer, “at least five litres every day.” According to one carved inscription “wine, was like a flood and beer overflowed in this place.” Some geological traditions last through the ages. Ramses IV was assisted by his supremely talented scribe Ammenakhte, who completed the oldest-known geology map that survives anywhere in the world – the “Turin mining map” completed over 3,000 years ago. The map accurately depicts the geology, topography, gold mines, springs, and tracks of Wadi Hammamat and is a remarkable technological achievement, a milestone in our relationship with the planet. The observational techniques and concepts used in making the map were later adopted by the Greeks and Romans and by miners in central Europe, such as Georgius Agricola, who wrote the earliest known book on mining engineering in 1548.

Ammenakhte’s great geological map, now 3,000 years old, in the Museum of Egyptology in Turin, Italy.

Amazingly, thanks to the Emperor Napoleon, we also know where Ammenakhte lived. A scientist attached to the French army that invaded Egypt in 1798 found the now famous map buried in a tomb close to Luxor at Deir el-Medina, and Ammenakhte’s house was identified from inscriptions carved in its doorway. It is the birthplace of geological mapping. Leaving Egypt and its massive monuments to the world’s first professional geologists, Tuzo flew south along the East African Rift to Johannesburg, South Africa, where he spent time with the paleontologist Edna Plumstead. She was in the process of identifying and matching ancient plant fossils now spread across the southern continents, which showed they had lived on a single large land mass, Gondwana, just as Wegener, Suess, Du Toit, and others had argued years prior. The close linkages between the now separated continents was not limited to the fossil record either. Many modern birds (notably penguins), flowering plants, ferns, trees,

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Tuzo Arrives Down Under Most of Earth’s bigger scars, sutures and dimples etc., were more visible on her bottom and the people down under were quicker to see them. H.E. Le Grand, 1968

On his arrival in Australia, Tuzo would have been quite familiar with the country’s geology, since its overall structure is very similar to what he had compiled on the Tectonic Map of Canada. Australia has Precambrian Shield rocks older than 2.5 billion years, like those of the Northwest Territories, surrounded by younger belts of highly deformed rocks. These are in turn covered to varying extents by younger fossil-bearing sedimentary rocks that, in the Tasman Fold Belt in eastern Australia, are highly deformed, like the Appalachians or Rockies in North America. On his visit to Adelaide University in South Australia he was shown around by the head of the Geology Department, the legendary Antarctic explorer and geologist Sir Douglas Mawson. In 1912, Mawson had almost starved to death in Antarctica after a dogsled bearing most of his provisions and his companion, Lt. Belgrave Ninnis, was lost down a crevasse. His heroic 500 km journey back to Cape Denison on the coast, on foot with his surviving companion Xavier Mertz, who died en route, is recounted in his book Home of the Blizzard. Mawson took Tuzo to see the famous exposures of ancient Ice Age rocks in the cliffs of Hallett Cove, now a suburb of Adelaide, where the rock surfaces show deep scratches (called striations) made by the movement of a 280-million-year-old ice sheet dragging debris at its base. However, the direction of ice flow recorded by

Tuzo examining banded rocks of the Bushveld Complex on his trip through South Africa in 1950. The layering results from the gravitational settling of minerals of different density within fluid magma 2 billion years ago. These rocks host much of the world’s chrome, vanadium, and platinum.

and many insects found today across the southern continents share a common ancient heritage, having co-evolved on the southern continent Gondwana, which then dispersed as separate land masses as Pangea broke up. This shared legacy between “living fossils” would be impossible to achieve with a few narrow land bridges separating permanently fixed continents. Joseph Hooker, the botanist colleague of Charles Darwin, had proposed as early as 1851 a great “Southern Continent” to explain the clear affinities between the flora and fauna of South America, India, Antarctica, New Zealand, Australia, and Southern Africa. Tuzo was greatly impressed but remained unconvinced, recollecting in 1985 that “it all seems so sensible now but at the time I did not believe a word of it.”

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the ancient striations is puzzling, as if the ice sheet had flowed inland onto Australia from a source now far out in the deep ocean. Their orientation makes sense only if Australia is pushed back southwards into its former position beside Antarctica (along with India, South America, and Africa) to form the southernmost land mass (Gondwana) of Pangea. The centre (and thickest part) of the ice sheet lay over Antarctica near the South Pole and had flowed radially outwards across the surrounding land masses as Wegener had proposed in 1915. The Australians, much like their counterparts in South Africa, South America, and India, were keenly aware of the essential continuity of the rocks and structures seen in their countries, which were demonstrably all crustal pieces of the same Pangean pie that had broken apart. At every stop on his journey in Australia, geologists had “spent every free moment trying to convert me to their belief in continental drift but to my lasting regret I remained deaf.” Tuzo later reminisced that despite “having the most intensive course in Australian geology and geophysics that one can imagine,” he remained unconvinced of the evidence and his mind “remained closed.” While in Australia, Tuzo took the opportunity to explore the heavily forested volcanic mountains of New Guinea. He hitched a ride on a small two-seater Dragon Rapide biplane carrying mail and supplies to remote communities on what was then called the “Bible Run,” because each small settlement had a missionary. The biplane was preferred by local pilots because it had a very low stalling speed (55 km/h) and was capable of successfully crash landing on top of the thick forest canopy, giving its occupants a good chance of surviving the impact. At the time of his visit,

Tuzo and his father, JA, with koala bears in Adelaide, Australia, in October 1950. After meeting Sir Douglas Mawson, the head of the Geology Department at the University of Adelaide, JA would write home to his wife that “I have just driven in from the airport from meeting Jock! He looks in great shape, very burnt from his tropical trip and in great form. He evidently has enjoyed his Australian tour tremendously and has made friends everywhere. Sir Douglas Mawson and his staff speak in the highest terms of his work and personality.” Mawson was so impressed he wanted Tuzo to replace him as head of the department.

the airstrips were steep and very rudimentary; planes would land uphill and roll to a stop, turn around, and gather sufficient speed rolling downhill to take off. Tuzo flew around active volcanoes en route to the island of New Britain and the port community of Rabaul and its nearby volcano, which had killed 7,000 villagers in an eruption nine years earlier. Built inside the confines of an old volcanic caldera, the sheltered port community suffered more devastation from its intermittently active neighbour in 1994, when 50,000 people were evacuated.

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TOP LEFT AND RIGHT: Tuzo at Rabaul Caldera, a volcano on the island of New Britain in Papua New Guinea in October 1950 when he travelled though the western Pacific after having spent many months in Australia as a visiting professor. BOTTOM: Tuzo’s airplane just after it had landed in the Highlands region of Papua New Guinea in October 1950. At that time, grassed airstrips were mowed by the wives of the ground crew using scissors while being “dressed in magnificent head dresses bright with beadwork and heavy jewellery.”

A Geologist in a Strange Land

Tuzo’s continued obstinacy against accepting continental drift throughout the 1950s in the face of a wealth of evidence supporting mobilism did not sit well with him in later life, and he regarded his time spent still flirting with permanentism after his visits to South Africa and Australia as “wasted years.” He admitted that “to my lasting regret I remained deaf to these arguments for the next nine years. Years when my energy was at its height and my wits clear, years wasted on trying to explain phenomena produced by a mobile earth with arguments based on the concepts of a static one.” By his own reckoning, he had “remained inflexibly stupid” during the 1950s, convinced that continents were fixed in place and the Earth was contracting. Stupid or not, by the end of that decade Tuzo was internationally well known, and he would use his status to spread the permanentist gospel as far as Russia and China.

was unrivalled among his peers. In 1985 he declared that he “had circled the world by ten different routes and could boast that I had done it all at no expense to myself.” The IUGG had been formed in the immediate aftermath of the First World War, when science was seen as potentially playing a crucial role in bringing nations together and advancing the material progress of their peoples. The ill-fated League of Nations was to prove entirely ineffective in the face of American disinterest and Italian, Japanese, and German aggression in the 1930s, but it established the International Council of Scientific Unions; the IUGG was one of the first member bodies. As its president from 1957 to 1960, Tuzo hurriedly organized a conference in Toronto in 1957, when the original meeting, planned to be held in Buenos Aires in Argentina, was cancelled following the abrupt collapse of the Peron government two years earlier. Ever the showman, Tuzo brought in marching bands to open the proceedings. It was unheard of in academic circles, and Tuzo rightly referred to the meeting as a “circus,” but it was a very useful one where close working relationships were built among geophysicists from many countries. For the first time in Cold War North America, there was a sizeable delegation of visiting scientists from the USSR accompanied by numerous KGB minders “who with their counterparts from the CIA, endured hours of boredom as one highly technical seminar followed another.” Tuzo used the Toronto meeting to further develop his permanentist credentials, arguing, as he had with Adrian Scheidegger in 1950, that continents were “zoned,” having grown outwards from old nuclei (shields) while being fixed in position.

Tuzo Takes the Permanentist Message on the Road After 1957 Tuzo embarked on a series of lectures and visits to other countries as part of his responsibility as president of the International Union of Geodesy and Geophysics (IUGG). When offered the position as professor of geophysics at Toronto in 1946 he had been told not to take any administrative posts, but he overcame his reluctance and took on the heavy bureaucratic responsibility with IUGG largely because the organization paid for his travels. These excursions were invaluable to his research and would ultimately give him a global view of the planet’s geology, which

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In 1957, Tuzo wrote the introduction to a new book on the rocks of the Canadian Shield, published by the Royal Society of Canada, in which he argued that “continents have not been permanent features. They have grown from nothing.” Conspicuous by its absence was any reference to any possibility that continents might move. That same year, Tuzo proposed that early in its history the planet had been literally “turned inside out,” speculating that the original nuclei of continents had formed by upwelling of magma from deep in the underlying mantle. The study of powerful seismic waves released by earthquakes passing through the body of the planet had revealed a major boundary (the Mohorovičić Discontinuity, or “Moho” for short), defining the base of the Earth’s crust. Known to be at shallow depths (~ 6 km) along the middle of oceans, it is as deep as 100 km below continents, and Tuzo argued that the entire thickness of overlying crust was simply magma that had welled up from the mantle along fractures. In Tuzo’s mind the now deeply buried “Moho” represented Earth’s ancient primeval surface. He pointed to the many thousands of dikes of cooled magma that had invaded fractures he had mapped on the Canadian Shield. He also emphasized, in a definite nod to his old mentor Sir Harold Jeffreys, that the loss of huge volumes of magma from deep within the mantle would result in further cooling and contraction of the planet. As a result of contacts made at the Toronto conference, Tuzo gave a series of lectures in late 1957 in Bucharest, Romania, which was at that time firmly ensconced behind the Iron Curtain. He scored points on his hosts by showing photographs that he had taken himself of mountains all around the world. His purpose was to

As the newly elected president of the International Union of Geodesy and Geophysics, Tuzo visited the Peruvian Andes in 1952, where he drove through Ticlio Pass, one of the highest in the Cordillera Central. For the next decade Tuzo travelled widely and amassed an unrivalled knowledge of the world’s geology. While he later regarded these years as wasted because of his continued adherence to permanentism, he was able to think on a global scale after his sudden conversion to mobilism in late 1961. “This panoramic view of the Earth was of inestimable value in my attempt to find the fundamental principles I was convinced must lie hidden under the confused, extravagant details of the geology I had tramped over on foot.”

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emphasize that as a Westerner he “was a free agent to travel and make whatever point I wanted to make! I have never seen such crowds. You could hardly get into the building or get onto the campus! I said, ’What’s all this’ and they said, ’They’ve come to hear you.’ I wondered why they wanted to hear me on mountain building. They said, ’You represent the West, and we have little opportunity to show our solidarity. ’” The communist authorities in Bucharest provided Tuzo with an attractive female interpreter, intending to lure him into a “honey pot,” the well-worn Soviet-era trick of installing the girl in an adjacent hotel room separated by an unlocked door. If successful, the blackmail attempt would force Tuzo to praise the political achievements of his hosts and Russian science, especially Sputnik, the first Earth-orbiting satellite that had been launched in October of that year. Having been forewarned by the British ambassador, Tuzo jammed his suitcase against the door and enjoyed a peaceful night’s sleep alone. Tuzo later met the young woman’s mother, who was the widow of the former astronomer royal of Romania. She showed him the visitor’s book of the state astronomical observatory, pointing out the signatures of one after another distinguished visitor, at the end of which “she invited me to add my name, a compliment I accepted as a tribute to the respect I had shown for her daughter’s virtue rather than to my knowledge of astronomy.” Tuzo’s visits to the communist Eastern bloc in the late 1950s, and especially China in 1958, involved travel to areas that were strictly off-limits to Americans because of the ongoing Cold War. The Americans took a keen interest in Tuzo’s itinerary, and he frequently briefed them on his return to Canada about the people

he had met and what he had observed. He admitted that the Americans trusted him because he had been a colonel in the Canadian Army and was clearly not a communist himself. To Tuzo, both at home in Canada and internationally, politics interfered with common sense, and he was able to travel and discuss science frankly and freely without regard for the political backgrounds of the many scientists he met. His daughter Susan noted that “Dad was a scientist and a teacher, first and foremost. He knew how politics worked but ignored it and avoided being involved in it as much as was possible.” Tuzo attributed this to his home life as a young man in Ottawa, declaring that “I am not the least interested in politics. Mother and Dad; one was a good conservative and the other a good liberal, so they decided never to discuss politics and they never did.” During his visit to Russia in 1958 he worked closely with Urey Goudin, a young Soviet geophysicist who had just been awarded the Stalin Prize for finding deeply buried oil-bearing rocks using seismic methods. Tuzo flew across the vast prairie-like steppes east of the Ural Mountains in a small Yak-12 plane to meet Goudin at a remote field camp, but it wasn’t a successful first meeting. The Russian had never met anyone from the West and was initially hostile, regarding his Canadian visitor as an “effete and dangerous exploiter of the downtrodden.” However, the two quickly established a close rapport after Tuzo pointed out that as a capitalist, he had started summer work when he was only fifteen years old – two years before Goudin. On his many trips, Tuzo always made a point of dressing down like an ordinary tourist, carrying battered suitcases to avoid drawing attention to their owner. However, his unkempt appearance did not go

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In August 1958, Tuzo flew in a small three-seater Yak-12 aircraft to visit Russian geologists, led by Urey Goudin, who were using geophysics to find oil deep below the Russian steppes east of the Ural Mountains.

over well in Moscow, with his well-dressed host, the geologist Vladimir Vladimirovich Beloussov, upbraiding his Canadian guest for his shabby appearance and his habit of throwing his cigarette butts out of the car window. Beloussov and Tuzo did not trust one another, and their awkward relationship can be traced back to the 1957 meeting of the IUGG in Toronto. At that time, Norm Keevil’s laboratory, with its newly developed mass spectrometer, was turning out large numbers of precise age determinations on ancient rocks of the Canadian Shield. Suitably impressed, Beloussov asked for a tour of the laboratory and when shown the primitive conditions at 49 St. George Street he became suspicious that the real operation was elsewhere and was being deliberately hidden from him. Tuzo travelled onward to China on the Trans-Siberian Express where, in his capacity as president of the IUGG,

he had to grapple with the delicate issue of whether to admit communist China or capitalist Taiwan as the sole Chinese representative in the union – what then was referred to as the “two-China problem.” It was a difficult task requiring considerable diplomacy, and he would eventually decide quite rightly that there should be two representatives. Tuzo was received very warmly in mainland China, largely out of respect for his countryman Dr. Norman Bethune, originally from Gravenhurst, Ontario, who had introduced blood transfusions to the Chinese medical community during the Sino-Japanese War but later died of a blood infection picked up in his own battlefield surgery. Bethune had been memorialized for his humanitarian work by none other than Chairman Mao, and on his second trip Tuzo would hand out postcards of Gravenhurst. On the back of each card was an inscription made by his daughter Patty, who could read and write Chinese.

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Nanjing in China, but on entering graduate school in the United States four years later he was informed that it had been “proven wrong and was no longer talked about.” It was during Tuzo’s visit to China where he became aware of Grabau’s work, planting the first seeds of doubt about his strongly held permanentist convictions. He recounted his experiences behind the Bamboo Curtain in a well-received book, One Chinese Moon (1959), which revealed his broader humanist side and was eagerly sought after as a guide for first time visitors. General Bernard Montgomery (by now Viscount Montgomery of Alamein) wrote to Tuzo in 1960, saying he was going to Peking to have talks with Mao Tse Tung, and that he had been reading his book “with enormous interest; it is a first-class story.” On returning to Canada, Tuzo visited the Canadian Arctic, where, with future sovereignty issues on his mind, he noted the relative inactivity of Canadian researchers in the region compared to those from the United States. As a guest of the US Army, he then flew off to tour the Antarctic bases of the United States and New Zealand, where he reviewed how their major scientific institutions operated and how effective they were. His results were dutifully reported back to Canada and would eventually help shape the nature of government funding of science in an expanding postwar university system. It was a time when technology was very much in the public’s mind as the Space Race took off. In 1961, at the end of his self-declared “wasted decade,” Tuzo published a book, IGY: The Year of the New Moons, in which he summarized the results of the International Geophysical Year and his travels around the world meeting colleagues and visiting

Tuzo preparing to board the Trans-Siberian Express in Moscow in 1958 en route to Peking. The Russians had solved the problem of different time zones along the route by simply running the entire system on Moscow time, with the result that the restaurant car “produced whatever meal Moscow clocks deemed suitable for the hour”; breakfast was served at 2 a.m.

These gestures especially impressed his hosts, and he was granted permission to visit research institutes and laboratories hitherto off-limits to Westerners. His meetings with Chinese geologists were especially influential for him because he met two of Amadeus Grabau’s former students. Banished to China in 1920 after his dismissal from Columbia University, the German-American paleontologist had written Rhythm of the Ages in 1940, where he reconstructed the positions of the continents prior to Pangea. Ken Hsu, a marine geologist and expert in deep sea drilling, whom we will meet again later, recollects that he was taught about continental drift in 1944 at the University of

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Tuzo with Chinese colleagues on his first visit in 1958. The purpose was to assess whether the People’s Republic of China or the Republic of China based on Taiwan should be admitted as the sole Chinese representative on the International Union of Geodesy and Geophysics. Tuzo in 1958 with a Tucker Sno-Cat tractor at McMurdo Station, the US Antarctic base during the US Navy’s Operation Deep Freeze.

their institutions. Essentially, it was a report card on the health of the discipline worldwide, as practised in some sixty-seven countries. The purpose of IGY had been to collect data between 1957 and 1958 on geophysical phenomena, which could be expected to show significant changes that could be seen from orbiting satellites. These included the Earth’s magnetic field, storms, earthquake activity, solar activity, ocean circulation, fallout from nuclear testing, and changing sea ice cover in the Arctic, to name a few. Today, it would be called “real time monitoring,” and the launching of satellites in the late 1950s made it possible

for the first time. For Tuzo, IGY was the excuse that allowed him the opportunity to “go and see as many mountains as possible.” One of the most notable achievements of IGY was the planet-wide mapping of earthquake epicentres. Under the leadership of Maurice Ewing of Columbia University, IGY was able to show that earthquakes occur along two principal belts. One is restricted to the midlines of the oceans, typified by small events at shallow depths associated with high submarine

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mountain ranges that form a continuous underwater chain around the globe, while a second belt marks the location of deep, very powerful earthquakes along continental margins marked by deep submarine trenches. It was speculated that the first belt marked the location of rising convection currents in the mantle, and the other was where crust was being shoved back down below the continents. The Dutch geophysicist Vening Meinesz had said as much in the 1930s, and Arthur Holmes had expanded on the same theme in his great textbook of 1944, but these were far from comprehensive explanations for the global distribution of earthquakes. Tuzo did not then know it, but the game changer was already on the horizon in the form of new oceanographic survey data then being collected by the Allied navies. These huge databases were initially classified because of their military value but when later released gave geologists a radical new understanding of more than 70% of the surface area of the planet. In turn, this would lead to profound insights into the origins of the continents themselves.

divinely inspired “Made in America” plan that saw the repeated formation of geosynclines around its margins. But as the United States re-engaged with the wider world, that long-standing belief in geological exceptionalism underwent fundamental change. After 1945 the demands of a new global cold war saw the emergence of a new generation of scientists who now began their own geological explorations unfettered by past tradition and beliefs. Guided by newly developed geophysical tools, their focus was very different from anything prior: the huge expanses of the oceans and what lay deep on their floors. The immediate post–Second World War world order belonged to the victorious Allies, especially the Americans, but for how much longer? The arms race was in full swing, and the Space Race was just commencing. In the face of a perceived Soviet threat, the United States needed much better information, not only on the topography of the continents themselves but also the floors of the oceans, where Russian submarines prowled in the darkness. The first officially designated US Navy oceanographer was Dr. Mary Sears, a marine biologist seconded to the Office of Naval Intelligence in 1943. She began to systematically collect oceanographic data on water depths, tidal ranges, waves, and currents to be used in the planning of Allied combat operations involving beach landings on enemy-held coasts. Once the value of the information was appreciated by commanders and combat engineers in the field, the scope of oceanographic investigations expanded rapidly, to be further enlarged during the early postwar years in the face of an expanding Russian naval threat. In 1945, the ocean floors were still mostly unknown and dismissed by many as flat, uninteresting, and

The Cold War Heats Up and the US Navy Hunts for Russian Submarines The principal proponent of permanentism, Charles Schuchert of Yale University, died in 1942, just twelve months after the entry of the United States into the Second World War, marking the end of American isolation from international affairs that had begun in 1918. The geological evolution of the North American continent was still regarded as the product of a

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largely devoid of life. Nevertheless, in 1947, the US Office of Naval Research began funding a massive “dual use” research program to map the floors of the oceans both for military contingencies (such as anti-­ submarine warfare, acoustic communications, and deep sea rescue and salvage) and civilian academic research in oceanography, biology, and geology. Manned and autonomous submersible equipment was designed to allow direct observations at great depths and to install probes in the ocean floor to listen for submarines. At the same time, “seismic” techniques were developed to map sea floor sediments using sound waves. New oceanographic survey ships that could spend weeks at sea were built, and oceanographic institutes on the west and east coasts such as at Scripps in California, Woods Hole in Massachusetts, and the Lamont-Doherty Geological Observatory at Columbia University were expanded. It was these institutions that would lead the way in training the large numbers of students and faculty needed to conduct the new science of marine geology. The tragic loss of the US fast-attack submarine USS Thresher in 1963 with its entire crew of 129 men in deep water off Cape Cod, and the ensuing search, was the catalyst for the development and application of sophisticated geophysical tools to measure magnetic, gravity, sonar, and seismic properties of the sea floor and to identify anomalies that might be submarines. These and other rapidly evolving electronic techniques, especially in computing, to handle vast amounts of data, were quickly adopted and today are the standard tools of marine geoscientists. The deep-sea submersible vessel Alvin, built in 1964, participated in the recovery of a hydrogen bomb lost in deep water off the Spanish coast in 1966; its first geological mission

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was to survey the deeply carved submarine canyons off the east coast of the United States, laying to rest more than thirty years of debate on how they had formed. By 1966 almost sixty US-built submersibles were working worldwide, and Britain and other nations were heavily involved in oceanographic surveys and marine geology. It was the new scientific frontier, and a trailblazing American geologist was to take the lead in its exploration.

Mapping the Ocean Floors Oceanographers mapped the ocean floors and discovered that their geology is relatively simple quite unlike that of the continents. J. Tuzo Wilson, 1993

In the late 1950s the scientific work being conducted at sea was unlike anything done previously on dry land. Vast amounts of geological data could be collected remotely and quickly synthesized from enormous areas using new shipborne geophysical techniques. It was just like the colossal impact the airplane had made fifty years earlier on mapping geology on land, but the scale on which it could now be carried out at sea was even more remarkable. Entire oceans could be mapped by a handful of scientists. The first inkling of the true nature of the ocean floors came about in 1952 from an unusual source for that time: a young female geologist with a master’s degree in petroleum geology named Marie Tharp. While working as a geologist in Oklahoma, she had been prevented from working in the oil fields and

A Geologist in a Strange Land

confined to the office to make maps, a separation of duties typical of a time when women were viewed as a possible distraction to men isolated in remote camps, when fieldwork was physically demanding and dangerous, and women were prevented from going underground in mines, as their presence was seen as inviting bad luck. This attitude quickly changed after the Japanese attack on Pearl Harbor in 1941 as young men of military age went off to serve in uniform, requiring women to take up jobs hitherto reserved for their male colleagues. The Geology Department at the University of Michigan opened its doors to women in 1942 and Marie was among the first intake. Her father had been a soil surveyor constantly on the move making maps across different parts of the United States, and by the time she entered university she had attended more than two dozen schools and developed a keen eye for changing topography and landscapes. With map-making in her blood, she was employed during the war to use air photographs as a tool to locate and plot the location of the many hundreds of lost American aircraft brought down in enemy territory in the European and Pacific theatres. Beginning in 1948, Marie was employed as a cartographer by Maurice Ewing (Tuzo’s old friend from the 1930s) at the Lamont Geological Observatory at Columbia University and assigned to work with Bruce Heezen, who was collecting data on the depths of the oceans derived from numerous research cruises. Women were not allowed to work onboard the university’s research ships, and her task was simply to stay behind in the office, or “on the beach” as it is still called, and compile thousands of depth-sounding profiles. It was

not until 1968 that she was finally cleared to work at sea as a shipboard geologist. Early editions of her maps were classified as “top secret” out of fear they might fall into the hands of the Soviet military. They revealed a high mountainous ridge running uninterruptedly along the middle of the Atlantic Ocean from north to south with a steep-sided valley right along its centre. She proposed in 1952 that the valley might function like the East African Rift, where magma came to the surface and flowed out to create new crust. It was an early suggestion of what was later to be called “sea floor spreading,” but her idea was dismissed by her supervisor Heezen, a committed permanentist and expansionist, as inconsequential “girls talk.” Eventually, as the evidence mounted, Heezen became a convert. In 1956 Tharp and Heezen presented their initial findings at the meeting of the American Geophysical Union and proposed that midocean ridges formed a continuous network on the floors of the world’s oceans. The wider scientific significance of the new information could no longer be ignored since it revealed that ocean floors were far from flat and monotonous. Tharp’s Mid-Atlantic Ridge, which she had first identified in 1952, was now seen to be part of a spine of mountains that ran along the central axes of the oceans with wide rift valleys and active volcanoes, just as she had earlier suggested. It supported Arthur Holmes’s concept made three decades prior, that midocean ridges lay directly above rising columns (plumes) of hot mantle rocks that fed large volcanoes along the ridges. The ocean floor map also revealed the presence of huge knife-sharp fractures that cut the midocean mountain ranges into segments, the wide continental shelves rimming the continents around the Atlantic Ocean, and the very

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LEFT: Marie Tharp and Bruce Heezen with their classic map of the newly discovered topography of the floor of the Atlantic Ocean. RIGHT: Tharp and Heezen’s map showing numerous long fractures that offset midocean ridges, in addition to shallow water “continental shelves” that rimmed the continents. The map not only accelerated understanding of global tectonics but also triggered exploration of oil and gas resources in the thick accumulations of sediment below the shelves. Courtesy of Lamont-Doherty Earth Observatory and the estate of Marie Tharp.

A Geologist in a Strange Land

deep submarine trenches around the margins of the Pacific Ocean. None of these discoveries, however, were linked in any systematic way into a coherent global theory of how the Earth might work. Not yet anyway.

Magnetic Pole at the time the parent magma formed millions of years prior. Some data indicated that remnant magnetic records in ancient rocks no longer pointed toward the present-day North Magnetic Pole but to another location entirely. At first this was attributed to either instabilities in Earth’s magnetic field or to wandering of the magnetic poles themselves (which they do, but only to a relatively small extent each year, requiring small annual adjustments of magnetic compasses). However, it slowly became clear that the rocks themselves had moved large distances after they had cooled and rotated from their original orientation along the way. As early as 1952, a young postgraduate student, Ted Irving, and his supervisor, Stanley “Keith” Runcorn, determined that India had moved north by some 6,000 km in 65 million years while drifting through fifty-five degrees of latitude. It was an astonishing discovery and a remarkable confirmation of migrating land masses but unfortunately was promptly disregarded by most geologists. Irving had his PhD thesis at Cambridge rejected in 1954, largely, it is said, because his results, supporting mobilism by showing the dramatic drift of India, were deemed too radical by his examining committee. He was finally given his doctoral degree in 1965. Undeterred, by 1955 Irving and others such as Ken Creer were publishing detailed “wander paths” for other continents that fully supported Wegener’s model of Pangea that had then broken apart. In 1956, while Irving was in Australia just after publishing his controversial paleomagnetic findings, he was surprised to receive a letter from Tuzo, who stated that he had always “tried to persuade geologists to take physical measurements, and now look what you have

“Far Too Radical”: Ancient Magnetism and Wandering Continents What geology … needs today, is a frank recognition that imaginative thought is not dangerous to science but is the life blood of science. R. Daly, 1914

Tuzo had been a champion of the International Geophysical Year from 1957 to 1958 and in his 1961 book he had praised its achievements in amassing data on Earth’s ever-changing surface, now measurable for the first time from space using the newly launched Russian Sputnik 1 and American Explorer 1 satellites. But he was far less enthusiastic about new geophysical data emerging from other laboratories that clearly pointed to long-term movement of continents. Compelling evidence was now being published by “paleomagnetists,” who study the magnetic characteristics of rocks and determine how and when they acquire them. Iron-rich igneous rocks, formed by the cooling of fluid magma, retain a relict or “remnant” record of the position of the Earth’s magnetic poles at the time these rocks cooled. Small iron particles floating in the liquid magma act as bar magnets much like compass needles that are “locked” in position when the magma solidifies as a rock. It is a straightforward exercise in the laboratory to identify the location of the North

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turned up.” While Irving was deeply impressed that the most senior and well-known advocate for permanentism had taken the time to communicate with him, a twenty-nine-year-old junior scientist, the overall tone of Tuzo’s letter was that of indignation and disbelief. The two met the next year in Toronto, where Irving was relieved to find that the new paleomagnetic data were troubling Tuzo to the point where he was beginning to question his own long-held beliefs in fixed continents. It was, Irving noted favourably, a sign of Tuzo’s ability to keep an open mind despite firmly held and closely argued opinions – the hallmark of a good scientist. The profound implications of the paleomagnetic data for the permanentist camp could no longer be ignored. Today the innovative paleomagnetic work of the mid1950s by Irving and others is widely recognized as the first quantitative test of Wegener’s thesis, and it had passed with flying colours. In 1956 Runcorn demonstrated that 270-million-year-old rocks now on land in North America and Europe retain ancient magnetic poles that point in very different directions; if the North Atlantic Ocean is closed and the land on either side moved together, then the poles align perfectly. This confirmed that the continents had been locked together within Pangea before diverging and drifting apart along separate pathways as a new ocean (the Atlantic) slowly opened. Keith Runcorn was professor of physics at the University of Newcastle upon Tyne, where his long absences working with colleagues abroad earned him the nickname of “the theoretical visiting professor of physics in Newcastle.” In 1962 he edited Continental Drift, which showed how paleomagnetic characteristics of ancient rocks unambiguously recorded the movement of continents over thousands of kilometres. Yet

another amazing discovery was made by Ted Irving, who now demonstrated that the Earth’s magnetic field had reversed on many occasions (when the North Magnetic Pole flips to become the South and vice versa). Their findings were ultimately to be the key to unlocking the origin and age of the ocean floors and demonstrate that they are on the move. The long battle between permanentists and mobilists should have been over and done with by 1964, had geologists fully accepted the paleomagnetic evidence. That year, Ted Irving summarized a wealth of data supporting continental drift in his book Palaeomagnetism and Its Application to Geological and Geophysical Problems, yet opposition lingered. Many participants in the development of plate tectonics of the late 1960s have since queried why the geological community at large had been so slow to understand the significance of the paleomagnetic data acquired more than a decade earlier. The simple answer is that the study of paleomagnetism wasn’t then considered part of mainstream geology, more a part of physics, and the new data and their profound implications were seen by many as being not credible. Geologists were cautious; after all, they had been sidetracked before by physicists such as Sir Harold Jeffreys with his dogmatic rejection of any notion that the mantle was soft enough to deform. At the time, few geology departments had a palaeomagnetic laboratory or a paleomagnetist on staff, and the data were generated by just a handful of specialists around the world; their story wasn’t yet sufficiently part of the mainstream to undermine permanentist attitudes. Even the paleomagnetists were divided among themselves about the significance of their data. In 1960 Alan Cox and Richard Doell, addressing a largely

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LEFT: “Apparent polar wander” (APW) pathways for North America and Europe. These are created by plotting the successive positions of the North Magnetic Pole recorded by magnetic particles trapped in progressively younger igneous rocks over the last 600 million years. In fact, the position of the North Magnetic Pole has not noticeably changed over geologic time, but instead the continents (and their rocks and magnetic records) have drifted and rotated like rafts. RIGHT: Closing the Atlantic Ocean to reassemble Pangea results in a single pathway for North America and Europe.

skeptical permanentist audience, wrote that they were lukewarm about the notion of drifting continents. The view was commonly expressed that Earth’s magnetic field was highly variable (“a bit like the weather”) and couldn’t have remained sufficiently stable in rocks hundreds of millions of years old to faithfully track the migration of continents. Possibly, too, the rock record had been overwritten and irrevocably changed by younger magnetic fields. Ironically, the work of

Cox and Doell would later contribute significantly to demonstrating how paleomagnetism and the episodic reversals of Earth’s magnetic field could be used to interpret the age of ocean floor crust and its evolution following the breakup of Pangea. There were also new geological data supporting drift. In 1960 the American geologist Gordon Gastil compiled all the available ages yet determined for the rocks of Precambrian shields worldwide, not just

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

in Canada, but in Australia, South America, Europe, Africa, and India. His data supported Tuzo’s model of continents that grew by crustal accretion around very old cores, but in some cases, there were notable exceptions. He pointed to very old rocks along coasts, such as parts of California and Labrador, and concluded that this might be the result of the fragmentation of continents that had exposed their inner and oldest parts. It was a prescient idea with which to usher in the first year of a new decade of discovery, one where Tuzo would sweep away the foundations of permanentism and confirm not only that Wegener’s supercontinent Pangea had indeed broken apart, but also how it came to be in the first place.

Hess saw oceanic crust as a conveyor belt moving outwards from the midocean ridges newly identified by Marie Tharp, to eventually plunge back into the mantle on the far side of the ocean down deep trenches. Previously active, high-standing volcanic islands were carried away from midocean ridges, to be slowly worn down by waves en route to form flat-topped stumps. These eventually sank underwater as underlying crust cooled and subsided, creating guyots. As we have already noted, Charles Darwin on the five-year journey of the Beagle (1831–6) recognized that coral reefs grow like a halo around the crater rims of dead volcanoes, forming the circular coral reefs called atolls typical of the Pacific Ocean. Hess later found that many of his guyots had long-dead coral atolls on their rims that had formerly grown at sea level and been killed when submerged too deeply under water. Harry Hess’s theory emerged simultaneously with a similar idea by Robert Dietz, who coined the now more widely accepted term “sea floor spreading” in 1961. The two would later argue with each other over who had come up with the concept first, but in truth their ideas of sea floor spreading were heavily influenced by the earlier work of Arthur Holmes, who had argued that crustal movement away from the centre lines of oceans was driven by upwelling mantle convection currents. R.A. Daly had also identified (but not named) virtually the same mechanism in the late 1920s, and Wegener himself had come close to identifying the role of midocean ridges in 1912 (although his paper had been written in German, and we have already seen how great a hurdle the language barrier had proven to be). Anecdotal evidence suggests that Tuzo was very upset with Hess’s lack of recognition

Sea Floor Spreading Harry Hess had been a fellow graduate student of Tuzo’s at Princeton in the early 1930s, later serving with distinction with the US Navy in the Second World War as the commanding officer of the US troopship M/S Cape Johnson, ferrying young marines to bloody landings on Japanese-held islands such as Iwo Jima and the Marianas. Using sonar to record ocean water depths on different routes taken by the ship back and forth across the Pacific Ocean, the resulting maps of the sea floor revealed large numbers of hitherto unknown flat-topped stumps rising from the deep ocean floor. Hess reasoned that these “seamounts” were long-dead volcanoes, which he named “guyots” in honour of Arnold Guyot, who had been the inaugural professor of geology at Princeton.

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of the earlier work of his good friend Holmes. It is a common enough occurrence in science, and Hess and Dietz’s ideas are a good example of “independent rediscovery.” Though both scientists either ignored or just simply forgot the source of their inspiration, the concept of sea floor spreading now fell on fertile ground and encouraged others to take a fresh look at long-ignored evidence in support of continental

mobilism. In deference to the permanentist establishment in North America, Hess referred to his own work as “geopoetry,” some say to soften its impact and minimize criticism, but poetry or not, it was influential in nudging geologists toward mobilism. It prompted Tuzo to eventually take a wholly unexpected U-turn away from his earlier work, ultimately culminating in the theory of plate tectonics we know and love today.

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Chapter 7

Seismic Shift

The scientific revolution, like others before it, was long in the making. J. Tuzo Wilson, 1993

I was slow to realize that the pieces of the jigsaw that could in time produce the answer to the puzzle of the Earth’s behaviour lay scattered in the panorama that had been unfolding around me for so many exciting years. It took a long time to change my focus from the details of geological mapping to the search for broader features, and even longer to consider what caused them. J. Tuzo Wilson, 1985

For most of his career as a firmly committed permanentist, staunchly and very publicly opposed to Wegener’s ideas, Tuzo was on the wrong side of history. His geological apprenticeship had been served in Canada, the United States, and Britain under leading permanentists. According to his daughter Susan, “he didn’t stand a chance” of thinking independently. His conversion to mobilism in middle age was a seismic shift in his own beliefs of how the Earth works, and one that had profound effects not only for him personally but also for the entire discipline of geology. In a letter written to Allan Cox in 1972, he admitted that “a firm

grounding by the geophysicist Harold Jeffreys, and by North American geologists at Toronto and Princeton, coupled with my own work on the extremely stable Canadian Shield, convinced me that continental drift was not the answer.” He later spoke of having been in awe of, and unduly influenced by, the ideas of Sir Harold Jeffreys, admitting that any criticism of the eminent physicist’s opposition to continental drift was tantamount to “sinning against the Holy Ghost.” Tuzo’s final divorce from permanentism was a long time coming, and there is the impression of a slow burn of accumulated

Tuzo: The Unlikely Revolutionary of Plate Tectonics

knowledge and growing dissatisfaction prior to his abrupt conversion to mobilism on Mauna Loa. The vast knowledge accumulated during his global travels left him uncomfortable with permanentist explanations, and his unpublished memoir briefly and obliquely attributes his epiphany to a series of “square pegs that could no longer be fitted into round holes.” Neither did he keep a regular diary – “never getting past January” according to Susan – in which his accumulating doubts about permanentism might have been recorded for posterity. Notably, when he visited China in 1958, Tuzo had become aware of Amadeus Grabau’s book The Rhythm of the Ages, with its reconstructions of the likely positions of the continents both before and after Pangea. Wegener had limited his theory to events after the breakup of the supercontinent, which had always seemed a major flaw to Tuzo, and seeing Grabau’s maps may have helped Tuzo overcome his lingering doubts about the relevance of drift theory to earlier, much older phases of Earth history. But it still wasn’t enough to nudge him away from his long-held belief in fixed continents. As late as the summer of 1960, Tuzo had referred to continental drift as an “entirely discredited theory,” even going so far as to refuse to help organize and fund a conference in Newcastle upon Tyne in northern England that brought together geologists interested in examining how changes in rock types and fossils through geological time might, like text on the pages of a book, tell a story of continents migrating through different latitudes and climates. In the absence of any precise timeline in Tuzo’s memoirs, it appears that his conversion to mobilism came to a head following discussions after Robert Dietz’s talk on the likelihood of sea floor spreading

delivered at the Pacific Science Congress in Hawai’i in August 1961. Dietz fully embraced Arthur Holmes’s ideas of giant mantle convection currents rising under midocean ridges; he reasoned that oceanic crust moving away from the ridges was at times “coupled” with continents, resulting in their being pushed around the Earth’s surface like a surfboard pushed in front of a swimmer. At other times, ocean floor crust was “uncoupled” and pushed down below continents. This latter process, Dietz argued, created severe compressional forces along the margins of the continent sufficient to buckle thick accumulations of deep-sea sediment into high mountains. As he recognized, his idea was a modern take on Dana’s classic concept of geosynclines, so dearly beloved of North American geologists since 1873. It was given a new lease on life, now married to the new concept of sea floor spreading. Not long after the meeting, Tuzo climbed to the top of Mauna Loa volcano, where he was struck by the significance of James Dana’s observation of the Hawai’ian Islands becoming older and older with distance away from the Big Island. There he realized, lying right in front of his eyes, was actual geological confirmation of Dietz’s theoretical picture of sea floor spreading and movement of the ocean floor. It was the straw that finally broke the camel’s back, forcing Tuzo to finally abandon permanentism and his earlier work on a contracting planet with expanding but fixed continents. The conversion was swift, and by early October 1961 he was already writing in Nature that a mantle convection current “rising under the mid-Atlantic ridge provides an explanation for the earlier views of Wegener and Du Toit that the opposite coasts of the ocean have moved apart.” The conversion from permanentist to mobilist was now complete. His next 168

Seismic Shift

step would be to search for tangible geological evidence that might cast light on whether continental drift was simply a process restricted to the last few hundreds of millions of years after the breakup of Pangea, or if it had also occurred throughout Earth history and might possibly explain the origin of billion-year-old rocks, notably those of the Canadian Shield. Ironically, he would find the evidence in the very place where he had very publicly stated his rejection of continental drift earlier in his career. Revisiting the scene of the crime in Scotland, he would now find new clues that revealed an altogether different picture that underscored the importance of the new mobilism far beyond that ever envisioned by Wegener.

Tuzo Links Old and New Scotland to Make Pangea Wegener had proposed that Pangea was the original land mass (his urkontinent), which had then broken apart, but geologists had questions about its earlier history and how the original land mass itself had been put together. Tuzo was an expert on the geology of Nova Scotia, where he had worked with the Geological Survey in 1936. Compiling the Tectonic Map of Canada of 1950 had also given him an unsurpassed view of the entirety of Canadian geology, and in 1962 he saw the wider significance of a very prominent feature of the geology of Canada’s “New Scotland.” Tuzo was struck by the presence of a large fault (which he named the Cabot Fault) that cuts eastern Canada almost in two. Movement along the fault has offset the rocks on either side by as much as 100 km and is an example of what is called a “strike-slip fault,” like 169

today’s San Andreas Fault where the western margin of the United States, extending from San Francisco to the southernmost tip of the Baja Peninsula, is sliding northwards against rocks inland. While studying maps of the rocks of Glencoe, Scotland, where, in the company of Sir Edward Bailey in 1948 he had loudly declared the premature death of mobilism and continental drift, Tuzo now grasped the significance of the Great Glen Fault. This slices northern Scotland in two, displacing rocks on either side with the same direction and amount of slippage recorded by the Cabot Fault in Canada. Ice Age glaciers have scoured its length, cutting deep lake basins such as the famous Loch Ness. If the Atlantic is closed and eastern North America brought into contact with northern Europe, as they were in Wegener’s 1915 reconstruction of Pangea, Tuzo saw that the two faults joined up as if “they were simply two ends of the same fault.” It was undeniable evidence that eastern Canada and Scotland had previously been locked together within the former supercontinent before being moved apart to their current locations by the opening of the Atlantic Ocean. Geologists now recognize many other faults in eastern Canada, and the Cabot Fault has been renamed (as the Long Range Fault) and its position more accurately determined, but Tuzo’s fundamental story of being able to trace geological structures that were part of a former land mass that broke apart still holds water. In some respects, Tuzo’s connection of the two faults on either side of the Atlantic Ocean was essentially his catching up with what was already widely appreciated by other geologists working principally in the Southern Hemisphere. They had long pointed to geological evidence indicating that the continents

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Hawai’ian Hot Spots and the New Mobilism In 1963, inspired by what he had learned in Hawai’i on top of Mauna Loa, Tuzo formally proposed a new global theory of how the Earth might work in Scientific American. Freed of the constraints of more rigorous scientific publications where hard quantitative data are obligatory, Tuzo started with Hess and Dietz’s model, where mantle convection currents rising toward Earth’s surface are the driving force behind sea floor spreading and the outward movement of ocean floor crust toward deep ocean trenches, pushing continents in the process. He plotted the directions of what he called the “convection flow” of ocean floors between spreading centres and distant trenches. It was a grand hypothesis, but where was tangible geological evidence for the movement of the ocean floors and continents? Lacking the generous contracts from the US Navy enjoyed by some geologists in the United States and Britain, Canadian postwar university research on ocean geology was comparatively limited in scope. The Royal Canadian Navy had been the fourth largest navy in the world during the Second World War with 400 warships but had shrunk sharply to 50 ships by 1960. In 1962 the Bedford Institute of Oceanography was established in Halifax, Nova Scotia, as the largest federal oceanographic research centre in Canada, but it then lacked the necessary global reach for any meaningful contribution to resolving the debate over continental drift. If Tuzo couldn’t go to sea and map the geology of the ocean floors by ship, as the Americans and British were doing, he could at least map the geology and determine the age of the many islands where ocean floor rocks appeared above water. And this is what he did, financed, not surprisingly, by a

Tuzo’s 1962 sketch map where he closed the Atlantic Ocean, bringing together what he named the Cabot Fault of Nova Scotia with the Great Glen Fault of Scotland. The once-continuous fault had been broken when the Atlantic Ocean later opened during the breakup of Pangea and North America and Europe separated.

had been clustered together within Gondwana and Pangea, but Tuzo had not been persuaded. By 1962, however, he was now buying into what Wegener, Suess and Du Toit, and others had proposed decades earlier to now explain the geology of eastern Canada. Reconnecting Old and New Scotland was a personal milestone, where Tuzo ditched his long-held belief in immobile continents and fully embraced mobilism. His focus would now shift away from the geology found on land on either side of the Atlantic, to the remote islands of the Pacific Ocean. 170

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Tuzo’s reconstruction of a mobile Earth’s surface published in Scientific American in 1963. It depicts continents being moved by convection currents in the mantle that rise to the surface under midocean spreading centres (in white) and descend along deep trenches marked by heavy blue lines. It wasn’t so very different from the model proposed by Holmes in 1931. This map was made two years prior to his discovery of transform faults and the recognition that Earth’s crust is broken up into moving plates.

large contract from the US Air Force, who saw remote oceanic islands as future air bases. Tuzo’s investigations rapidly established that ocean floor rocks get older the farther they are away from midocean ridges and are oldest at the outermost margins of oceans, supporting the model of sea floor spreading. However, he also discovered anomalies that appeared to contradict the model, such as the Hawai’ian Islands, which lie remote from any spreading centre but are made of very young rocks surrounded by very old ocean floor crust. To explain 171

this odd juxtaposition Tuzo published the concept of mantle “hot spots,” which he saw as giant columns of red-hot rock slowly rising from the mantle, melting en route and forcing magma through the Earth’s crust to build volcanic islands much younger than the rocks of the surrounding ocean floor. Movement of the underlying oceanic crust would then move the volcano away, resulting in the growth of a new volcano in its place, and so on, leaving a “hot spot track” of dead volcanoes now reduced to submerged stumps – the guyots discovered by Harold Hess.

TOP: Global “hot spot” volcanoes fed by magma columns rising from the mantle. The plumes are fixed in position, whereas the crust through which they penetrate is always moving. BOTTOM: “Hot spot” volcanoes on the ocean floor are fed by columns of magma called “plumes,” whose position is fixed. Volcanoes are carried away from the hot spot by movement of oceanic crust and die. Lowered by erosion, their graves often marked by coral atolls, they slowly sink below sea level to be preserved as flat-topped submarine seamounts (also known as guyots). The repeated birth and death of volcanic islands gives rise to a “hot spot track” of dead volcanoes.

The most famous example of a “hot spot track” of living and dead volcanoes is that of Hawai’i and the seamounts to the north that extend to the Emperor Seamount chain in the North Pacific Ocean. The age of the islands (in millions of years) increases down the chain away from the hot spot and provides a 75-million-year-long record of movement of the Pacific Plate over the mantle. Note the sharp bend in the hot spot track between the Hawai’ian and Emperor chains, indicating an abrupt change in the direction of motion of the Pacific Plate some 40 million years ago. Volcanic activity on the Big Island of Hawai’i will end as it moves away from the hot spot; the building of the next hot spot volcano (Loˉ’ihi) is already occurring unseen on the ocean floor and will eventually grow into a large island.

Tuzo would have the experience (unusual for him) of not having his ideas accepted by a heavyweight journal such as Nature, and his landmark paper on Hawai’ian hot spots finally appeared in the Canadian Journal of Physics. Today, some fifty active hot spots are recognized on the planet, both on the ocean floor and on land. Oceanic hot spot volcanoes such as in Hawai’i and the Canary Islands are among the tallest features on the planet, very close to Mount Everest in height and bulk, since their bases are below sea level in

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water as much as 4 km deep, with their tops reaching as much as 4 km above sea level. The abrupt collapse of their steep side slopes once they become extinct and inactive is known to produce catastrophic tsunamis. By now Tuzo was in full flow. In early June 1963 Tuzo published another short article in Nature entitled “Hypothesis of Earth’s Behaviour.” In it he proposed that the Earth’s outermost layer, known as the “lithosphere,” some 100 km thick, slid across hot, weakened mantle rocks he called the “asthenosphere.” Tuzo’s

Tuzo: The Unlikely Revolutionary of Plate Tectonics

article dutifully acknowledged the earlier ideas of Arthur Holmes, who had linked the movement of continents and oceans to underlying mantle processes in the 1930s. Other geologists quickly followed Tuzo’s lead. Just one week after his breakthrough article on Hawai’i appeared, Nature published a two-page note by Ron W. Girdler with the title “Rift Valleys, Continental Drift and Convection in the Earth’s Mantle.” It took Tuzo’s basic framework a big step forward by recognizing midocean ridges as parts of a single globally encircling “world rift system” (as Tharp and Heezen had advocated in 1957), linked to rising plumes in a churning mantle. However, there was still no indication of how the midocean ridges functioned. That was to come later the same year, when a young graduate student at Cambridge, Fred Vine, and his supervisor, Drummond Matthews, published their findings on magnetic stripes on the ocean floors either side of midocean ridges, one of the most profound geological discoveries of the twentieth century.

The wartime habit of towing magnetometers behind ships to detect steel-hulled enemy submarines after 1942 was routinely continued after the war as ships tracked back and forth across the oceans. When the magnetic data were plotted on maps, they revealed strikingly odd patterns in the magnetic properties of the ocean floor rocks in the form of zebra-like stripes of “normal” and “reversed” polarity either side of midocean ridges, looking much like modern-day bar codes. The first such “stripe maps” were produced at the Scripps Institute of Oceanography in Southern California by Roger Mason and Arthur Raff in 1958 and published in 1960. At that time, no one knew what the stripes meant, and the maps were quietly put aside along with reams of other marine data for later investigation. As so often happens, a young graduate student was given the task of figuring it all out. That student was Fred Vine. Ted Irving had already established that the Earth’s magnetic field (where the North Magnetic Pole is in the north) flips (“reverses”) over the course of thousands of years to take up a new position at the South Magnetic Pole, where it can stay for sometimes millions of years before switching back to its normal position in the north (“normal” polarity). This was thought to be a product of convection within Earth’s core, and by the early 1960s the timing (and duration) of the reversals was broadly known by dating layers of volcanic rocks on land. Vine and his supervisor, Matthews, proposed that the magnetic stripes discovered on either side of midocean ridges were the result of sea floor spreading, where new magma rising and cooling along the ridge crest locks in the polarity of the Earth’s magnetic field but is promptly pushed to

Solving the Mystery of the Magnetic Stripes Throughout the 1950s, ocean-going geoscientists were routinely towing geophysical instruments behind ships to collect data from the ocean floors many kilometres below, allowing Marie Tharp to map high mountains along their centres and very deep trenches around parts of their outermost margins. But these surveys also mapped patterns on the ocean floors that were much less easy to understand.

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Solving the “riddle of the stripes” in 1963, by Fred Vine and Drummond Matthews at Cambridge University and independently by Larry Morley at the University of Toronto, was instrumental in demonstrating sea floor spreading along midocean ridges, and thus the movement of ocean floors and continents. Continuous welding on of new ocean crust by the cooling of magma rising along the centre lines of midocean ridges combined with gravitational sliding away from the high standing ridge is known as “ridge push” and helps to drive oceanic crust away from the ridge. Earth’s magnetic field experiences episodic changes when the “polarity” of the field reverses and the North Magnetic Pole becomes the South and vice versa. Cooling magma at the crest line of the ridge retains a record of the contemporaneous magnetic field, giving rise to “stripes” of normal and reversed polarity in oceanic crust, which are symmetrical either side of the ridge, such as seen here along the Mid-Atlantic Ridge south of Iceland. The timing of the changes in magnetic polarity is known from the study of volcanic rocks found onshore.

Fred Vine at Princeton University in 1968, explaining how magnetic stripes form at midocean ridges; spreading is continuous but the Earth’s magnetic field changes abruptly, resulting in stripes of previous fields preserved in now cooled magma that has moved away from the ridge on either side. Courtesy of Fred Vine, as featured on www.bl.uk/voices-of-science.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

either side of the ridge by new magma intruding into the ridge as dikes. As is so often the case in science, there were other people working on the very same problem who had arrived at the same result simultaneously. Vine and Matthews’s innovative solution of the origin of magnetic stripes had been foreshadowed by the work of one of Tuzo’s graduate students at Toronto. In 1949 Tuzo began to supervise Lawrence “Larry” Morley, a young ex-naval lieutenant, who had spent the Battle of the Atlantic as a radar officer working onboard destroyers escorting convoys of slowly moving merchant ships. His expertise in electronics and desire to do geology saw him develop an interest in the magnetic characteristics of iron-rich rocks that had cooled from fluid magma. Morley designed and built his own instrument in the laboratory and began work on billion-year-old rocks he had collected from the Canadian Shield near Bancroft, a short drive from Toronto. He began to see patterns of “normal” and “reversed” magnetism and other anomalies recorded in the ancient rocks. Upon graduation in 1952, Morley left the University of Toronto to become the first geophysicist to be employed by the Geological Survey of Canada, eventually becoming chief of the Geophysics Division. By 1960 he had become the leading expert in the interpretation of so-called aeromagnetic data collected by aerial surveys of ancient shields and advised other countries on how to conduct such surveys. The airborne data were no different from those collected by marine surveys of ocean floors in water several kilometres deep. By 1963 Morley and his colleague André Larochelle had grasped that the

puzzling magnetic stripes of alternating normal and reversed polarity found on either side of midocean ridges provided a timeline of magnetic reversals recording the outward movement of cooling magma from the ridge. There was also the added potential of being able to date large parts of the ocean floors by reference to known ages of reversals. Morley and Larochelle presented their ideas at a conference in Quebec City in June 1963. They were excited at having found what they considered to be the “key to an enormous jig-saw puzzle,” but their talk failed to arouse the audience and not a single question was asked of the speakers. Undeterred, they attempted to have their findings published in a scientific journal and thus claim ownership of their idea. This was to prove a step too far, as one journal editor after another (Nature and then Journal of Geophysical Research) rejected their hypothesis as being far too extravagant for such junior scientists. Nature claimed it had no room, and another reviewer scoffed that it might be “more appropriate over martinis, than in the Journal of Geophysical Research.” To Morley and Larochelle’s dismay, Nature published Vine and Matthews’s breakthrough paper in September 1963, beating the two Canadians to the finish line in receiving public recognition at having solved the “riddle of the stripes.” Vine would remain unaware of the Canadian’s contributions for another four years. Morley later wrote of being “cowed and frustrated by the self-assurance of recognized experts” and having been shunned as a young scientist. Today, he is given joint credit for the discovery, but Andy Larochelle’s contribution is all but forgotten.

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But there is an upside to this story. By the time he left the Geological Survey in 1969, Morley had supervised the collection of aeromagnetic data across the entire Canadian Shield from flights logging more than 15 million km and had generated more than 7,000 maps showing the changing magnetic characteristics of rocks across its surface. Newly released maps became hot items, eagerly sought by prospectors and miners. Magnetic patterns and anomalies identified by Morley’s surveys proved crucial in guiding exploration and drilling by mining companies and would eventually help target billions of dollars of mineral deposits ranging from diamonds to zinc – resources that underpinned the nation’s postwar economic development.

The Great Alaskan Earthquake Shakes Things Up Good Friday, 27 March 1964, was anything but good to Alaskans and is the darkest day in that state’s recent history. The most powerful earthquake ever recorded in North America, a devastating magnitude 9.2 tremor triggered at a depth of 20 km, shook the area below Prince William Sound for five minutes and generated powerful tsunamis that washed away much of the Port of Valdez and the native village of Chenega, killing 139 people. The city of Anchorage in Cook Inlet was heavily damaged by landslides that destroyed many city blocks, and geologists learned for the first time of the dangers posed by “liquefaction,” when thick, seemingly solid clay beds that underlie the city’s downtown buildings suddenly fissured and

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turned to a mush that flowed down into Cook Inlet, carrying buildings and roads with it. Near Cordova, the famous “Million Dollar Bridge” across the Copper River, collapsed, severing the busy fishing port’s sole means of communication with the outside world. The effects of the earthquake were felt around the Pacific Basin as the tsunami spread outwards like a giant ripple, damaging coastal communities in British Columbia, California, Hawai’i, and Japan. Water levels in wells in places as far away as Australia and England sloshed up and down as seismic waves reverberated around the globe. However, the Great Alaskan earthquake wasn’t all bad news, as its analysis helped solve several mysteries about the deep-water trenches that surround the Pacific Ocean just when the debate about continental mobilism was reaching fever pitch. The deep submarine trenches that surround the Pacific Ocean mark what is now called the “Pacific Rim of Fire” in reference to the hundreds of dangerous volcanoes and powerful earthquakes associated with the ocean’s boundary. In the 1920s the Dutch geophysicist Felix Vening Meinesz showed that trenches are associated with anomalies in the regional gravity field that suggested that they were the sites where dense ocean floor rocks were being pushed down to great depths below adjacent land masses. Working simultaneously and independently, the American geophysicist Hugo Benioff and the Japanese geophysicist Kiyoo Wadati demonstrated in the early 1950s that the distribution of many thousands of earthquakes triggered at depth in the vicinity of trenches picked out a continuous sloping surface consistent with slabs of ocean floor crust being driven down under the continents to depths of almost

Remains of the “Million Dollar Bridge” over the Copper River in southern Alaska. The span dropped into the river during the Great Alaskan earthquake of March 1964.

Reproduction of George Plafker’s map of crustal deformation resulting from the March 1964 Great Alaskan earthquake. Some areas were raised; others sank, and the edge of North America also moved as much as 25 m oceanward. It was a timely demonstration of subduction at a time when the idea of continental mobility was still being debated.

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700 km. These were initially termed “Benioff Zones” (Wadati’s contribution was acknowledged later), but no one knew precisely how they worked or what their bigger role might be. That changed abruptly in 1964. The Great Alaskan earthquake was recognized as a “megathrust subduction earthquake,” produced along the eastern end of the Aleutian Trench where a thick slab of heavy oceanic crust making up the floor of the Pacific Ocean is being shoved down into the mantle below North America. The descending slab needs to overcome intense friction against the overlying continent and moves downward in an erratic stick-slip fashion where stress is slowly built up, often for centuries when all movement is stopped, and then suddenly breaks free to continue its descent into the mantle, producing a powerful megathrust earthquake. Here was the explanation of how Benioff-Wadati Zones worked and their wider role; ocean floor crust produced by sea floor spreading at midocean ridges was eventually consumed along subduction zones hundreds or thousands of kilometres distant. But there was more to come. Fieldwork along the coast of southern Alaska by George Plafker of the United States Geological Survey revealed unusual patterns in how the edge of the North American continent had buckled during the 1964 earthquake. A broad belt of the Alaskan coast around Prince William Sound had been raised up in seconds by as much as 9 m, exposing the sea floor and elevating coastal cliffs above sea level. Conversely, a broad area further inland had sunk, resulting in eerily quiet “ghost forests” of dead trees killed when their roots were drowned by encroaching seawater.

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Plafker had an elegant explanation: uplift occurred where the outermost edge of the overriding North America crust had suddenly freed itself from the grip of the descending slab, and subsidence occurred inland where the continent was still coupled to the descending slab and was dragged down with it, to be freed later by slippage during a future earthquake. It showed that continents were not entirely rigid blocks but could flex along their margins. But the more pressing need was to answer the question on the minds of the concerned residents of Anchorage. How often did massive subduction earthquakes occur, and when might be the next one? The answer was discovered by Plafker working some 70 km offshore in the Gulf of Alaska on Middleton Island; no more than 15 km long and 4 km wide, and no higher than 120 m in elevation, the island is a mere speck in the vastness of the North Pacific Ocean. Though uninhabited by any humans, it is densely populated by thousands of rabbits whose ancestors were escapees from now abandoned blue fox fur farms. During the 1964 earthquake, the whole of Middleton Island was bodily uplifted out of the sea by almost 4 m, creating new land below the old – and now raised – sea cliffs. The sudden upheaval brought the wreck of an old Second World War Liberty ship (the USS Colebrook) out of the sea, where it now hosts thousands of seabirds on its rigging and rusting gun placements. A staircase of older, higher cliff lines inland records previous “1964-sized” earthquakes, which Plafker determined to occur every thousand years or so. This is known as their “recurrence interval.” The concerned citizens of Anchorage had their answer.

TOP: Middleton Island in the Gulf of Alaska. Staircases of former sea cliffs, now raised above sea level, record repeated episodes of crustal uplift every thousand years or so, during large earthquakes when the floor of the Pacific Ocean is violently shoved down (subducted) below North America, and the edge of the continent pops up, suddenly freed of the drag of the descending plate. BOTTOM: The wreck of USS Colebrook lifted above sea level in seconds during the 1964 Great Alaskan earthquake.

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Computing Pangea: The “Bullard Fit’’ The game of the jigsaw puzzle has been played by many geologists. L.U. De Sitter, 1959

Initially trained at Cambridge as a nuclear physicist, Edward “Teddy” Bullard gained his PhD in 1932 and was then lured into the study of geophysics by the prospect of travelling the globe on geological field research. We have already seen how Tuzo had been disappointed at being unable to work with Bullard at Cambridge in 1930 because of his absence abroad conducting fieldwork on the structure of the East African Rift, but later they would become very good friends. Teddy was noted for his ability to design and build electronic instruments. During the Second World War he was attached to HMS Vernon near Portsmouth in southern England, a shore-based naval establishment (a “stone frigate” in naval slang) operated by the Royal Navy, which housed its magnetic experts. Bullard’s task was to make ships less vulnerable to the thousands of submerged German magnetic mines anchored by cables to the sea floor, where they lay in wait for unsuspecting victims to float by in the busy sea lanes around Great Britain. Bullard’s solution was to “degauss” ships’ hulls by wrapping them with charged electrical cables, making them magnetically invisible; it was a lifesaver and proved of immense practical and psychological value in the congested waters of the English Channel during the evacuation of Dunkirk and later during the D-Day landings. Bullard was an unsung hero of the Second

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World War and countless men and women owe their lives to him. Bullard had also specialized in the science behind anti-submarine warfare and developed seismic (sonar) methods, akin to the technology behind modern-day fish finders, to hunt submerged submarines. There were important spinoffs from this technology for understanding the ocean floors. The speed of sound in water is about 1,500 m/sec; acoustic energy released from a vessel on the ocean surface is reflected back to the source from the ocean floor and from harder sediment and rock layers that the sound waves encounter under the ocean floor. Determination of the time needed for emitted waves to reach these “reflectors” and return to the ship-board source (“two-way travel time”) not only allows the depth of the ocean to be determined but also the geological structure and layering at greater depth. Bullard’s “seismic reflection” measurements revealed substantial differences between the geology and rocks of the ocean floors and those of the surrounding continents; the oceans were not simply the result of the foundering of land bridges, as the permanentists had argued earlier. Their floors now needed to be explored and rocks recovered, triggering a program of ocean floor drilling that continues to this day. Bullard’s work in the early 1950s had also identified significant spatial variations in the amount of heat escaping from the Earth’s mantle and ushered in systematic surveys of “heat flow” across entire ocean floors. This initiative quickly established that their centre lines were areas of anomalously high heat flows – areas that were later recognized as midocean

Tuzo: The Unlikely Revolutionary of Plate Tectonics

ridges with active sea floor spreading where hot new magma rose to the surface. Bullard was noted for a dry sense of humour, and a running joke of his at Cambridge was to make fun of himself at not having a physical law named after him, the traditional hallmark of an accomplished physicist. In jest, his colleagues formulated Bullard’s Law, which simply states, “Never take a second heat flow measurement within 20 km of the original lest it differ by several orders of magnitude.” Geophysicists had long known that more heat escaped from the planet’s interior through the ocean floors than from the much thicker and cooler continents, but the heat loss along the centre lines of oceans was highly variable and not well understood. This variation was later found to be the result of superheated mineral-rich waters escaping like clouds of steam from midocean ridges through chimney-like vents named “smokers” in reference to their similarity to belching smokestacks. It is a classic case in science of how data once seen as useless “noise” take on a whole new significance as other information is collected. Bullard was to make his most well-known (and perhaps the most compelling) contribution to the debate on continental drift by using the power of early computers in the mid-1960s. This was a complete volte-face because Bullard, like Tuzo, had opposed mobilism for much of his career. He now would put Wegener’s postulated Pangea to the test by using modern technology to fit the continents together. Wegener had reconstructed his 1915 map of Pangea by matching the coastlines and geology of continents now separated by wide oceans. His

map was elegant but crude, and to many geologists the completed jigsaw puzzle was unconvincing because, as Wegener admitted, it needed some slight fudging to fit its pieces together. An improved map was made by the French geologist Boris Choubert in 1935, which showed that parts of Europe, such as Spain, had rotated after the breakup of the supercontinent. In one of the first applications of computers to geological mapping, Bullard and his colleagues Jim Everett and Alan Smith set out to assess the fit of now-scattered continents. It was laborious work, as each data point along a coastline was read off the chart and then “georectified” and rotated around the Earth’s surface back to its former position at the time of Pangea. The geometrical calculations for this exercise are complex and employ Euler’s classic theorem of “spherical geometry,” developed in Switzerland in 1776 to describe the movement of spherical “caps” rotating about a fixed point on the surface of a sphere – think of large pieces of a broken shell sliding around the surface of an egg. Matching the coastlines did indeed fully support the reconstruction of Pangea, but the best fit overall was found if the outermost edges of the continents, now deep under water at the base of the so-called continental slope, were brought together. In places there was some overlap because of deposition of thick piles of sediments that had slumped down the slope, and also there were some small gaps because of erosion. Nonetheless the computer-generated fit was convincing; all the jigsaw pieces of the present-day continents could be rotated and fitted together.

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The “Bullard Fit” of 1965, which convinced many previous skeptics of the existence of Wegener’s Pangea. Areas in black are overlaps created by the deposition of sediment along the margins of continents (“continental shelves”) after the supercontinent began to break up about 180 million years ago.

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Of course, a wealth of geological evidence for the matching of continents to form Pangea had already been meticulously assembled and published by Taylor, Wegener, Suess, Du Toit, Choubert, Carey, and others several decades prior to 1965, but permanentists yet remained to be convinced. Bullard’s computer-drawn map with its complex mathematical underpinnings was much more credible to many and had the added allure of apparent scientific sophistication. Permanentists were now seen as Luddites defying the results and implications of the new technology. In 1963, as the Space Race was heating up between the USSR and the United States, the British prime minister, Harold Wilson, made a speech to the British Labour Party that lauded new technological developments, arguing that the country could only prosper in the “white heat” of a new scientific revolution. New “red-brick” universities were built to accommodate the ever-increasing numbers of students enrolled in science and technology programs (including the author). Bullard’s computer-drawn map was a poster child for its time, and it became the widely used image of “One World” on T-shirts and other assorted paraphernalia as a graphic representation of the reality of the drift of continents. Bullard’s sophisticated computer-generated reassembly of Pangea finally convinced many previous doubters that Wegener’s thesis of a former supercontinent was correct, and if this were indeed the case, then the present-day continents must have moved apart to form new oceans. But exactly how and why had this happened?

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Geology Is Transformed during Tuzo’s Annus Mirabilis

stroke of luck, included lengths of the active Juan de Fuca midocean ridge just off Vancouver Island. At Cambridge, Tuzo collaborated with Fred Vine to work up this dataset and compare it with the now improved geomagnetic timescale. The results published in Science not only confirmed that crust was spreading away from the Juan de Fuca ridge but went one very significant step further. Because the timing of the magnetic reversal and the duration of each magnetic event was known, thanks to Cox and Doell, then the width of any one magnetic stripe on the ocean floor is determined by the rate of spreading; about 3 cm a year it turned out, or enough to form 60 km of new ocean crust on each side of the ridge in 4 million years. Tuzo and Vine had not only confirmed the reality of sea floor spreading, but they had also established how fast it was happening and, by extension, the rate at which oceans could widen and continents move. It was quickly shown that this is precisely the same rate of movement along major faults such as the San Andreas Fault in California. This breakthrough, in turn, set the scene for yet another profound discovery about how midocean ridges worked. Tharp and Heezen’s 1957 topographic map of the ocean floors revealed long fractures that dissected midocean ridges into shorter segments that are offset from each other, creating a distinct zig-zag pattern on the ocean floor. Initially Tuzo identified (incorrectly) the long fractures as active “transcurrent faults,” where rocks slide past each other along their entire length of the fracture. In a subsequent Nature article of 1965, he threw away his former interpretation and argued instead for a previously undiscovered type of fault, which he called “transform faults.”

As recently as five years ago the hypothesis that the continents had drifted apart was regarded with considerable skepticism particularly among American investigators. The hypothesis has gained so much support its critics may now be said to be on the defensive. P.M. Hurley, 1968

If broadly speaking, these ideas are correct, the whole of historic geology needs re-writing, and all the standard textbooks are to a greater or lesser extent out of date. J. Tuzo Wilson, 1970

In January 1965, Teddy Bullard invited Tuzo and Harry Hess to Cambridge for a six-month sabbatical leave that Tuzo later remembered as “stimulating and fruitful.” It produced a cascade of innovative discoveries, each one quickly building on its predecessor; Tuzo’s creativity was in full flow. Ongoing work by the paleomagnetist Allan Cox and his colleagues Richard Doell and Brent Dalrymple had greatly refined understanding of the “flips” in Earth’s magnetic field and determined exactly when reversals had occurred and how many times. There was now a detailed geomagnetic polarity timescale for the last 4 million years detailing the sequence of flips. This was the breakthrough needed to finally test the Vine–Mathews–Morley model of 1963, explaining the magnetic stripes on ocean floors. It quickly became apparent that magnetic data already collected from the floor of the northeast Pacific Ocean had, by a complete

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LEFT: Midocean ridges are cut into segments by long fractures, which were a striking feature on the maps of the ocean floors made by Marie Tharp and Bruce Heezen. Courtesy of the Lamont-Doherty Earth Observatory and the estate of Marie Tharp. RIGHT: Initially fractures were interpreted as simple “transcurrent faults” separating crust moving in opposing directions. In 1965, however, Tuzo and Alan Coode recognized that the fractures are inactive and thus are not faults. Independently, they identified the role of much shorter “transform faults” (named by Tuzo) that offset the ridges themselves.

Ever conscious of the need to simplify things, Tuzo built a paper model of how the newly recognized transform faults worked. John Dewey recalls the moment just prior to publication of the Nature article in 1965 when Tuzo strolled into his office at Cambridge and boldly declared that he had discovered an entirely new type of fault on the ocean floors. Dewey was initially unconvinced, but Tuzo proceeded to demonstrate his paper model, “repeatedly opening and closing it under my nose” while jokingly referring to it as “do-it-yourself transform fault-kit.” Dewey was sufficiently inspired

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by Tuzo to pursue tectonics as a career, and they would later collaborate in Toronto in 1974, Dewey going on to become a founding father of the new science of plate tectonics. Walfried Schwerdtner, a colleague of Tuzo’s at Toronto, recalls him using the model while giving a talk in a large lecture theatre filled to capacity at the University of Saskatoon. It was a favourite tool of Tuzo’s, and he would carry it around in the breast pocket of his suit. His wife, Isabel, referred to it as Tuzo’s “happy origami.” Alan Ruffman, a now-­ retired marine geologist, was a fourth-year honours

Tuzo: The Unlikely Revolutionary of Plate Tectonics

undergraduate student in Tuzo’s 1963–4 geophysics class at 49 St. George Street. He recalls that his lasting image of Tuzo is of him “standing in front of our small class of seven or eight in a lecture while holding his simple paper and cardboard model painted with the ocean’s midocean ridge and their magnetic stripes. Then, with a magician’s touch and a mischievous smile, slowly pulling the edges of the model to visually demonstrate the opening of a transform fault. It was so logical, and it made sense. He was a practical showman.” Tanya Atwater, a young graduate student at the time, similarly remembers Tuzo as a “wonderful showman” handing out duplicate copies of the model at a conference in Ottawa in 1965 and being amazed at the sight of the audience, consisting mostly of grey-haired senior academics, all playing with their model as if in kindergarten while listening to Tuzo’s instructions to “cut here, fold here and pull here.” She was the youngest person in the room (it was her first scientific meeting) and, feeling slightly embarrassed, she took the model to her hotel room and, after following the instructions, “several light bulbs went off in my brain.” During a long career, she went on to pioneer the exploration of spreading centres on the floor of the Pacific Ocean and how they function. If Tuzo’s hypothesis of how transform faults worked was correct, then earthquakes would occur only along their length, not along the fractures that extended hundreds of kilometres on the ocean floors either side of ridges. Once again, the needs of the military with its huge resources came to the aid of civilian science. The 1963 Nuclear Test Ban Treaty signed in Moscow by the United States, Russia, and the UK prohibited testing of nuclear weapons, but policing it depended

on a sophisticated global seismic monitoring system that could detect distant explosions. Fortuitously, this network also created the opportunity for geophysicists to map the location and size of earthquakes worldwide. Tharp and Heezen had already established that small earthquakes occur along the crests of midocean ridges, and sure enough, when the much larger global compilation of earthquake epicentres was painstakingly compiled by Lynn Sykes and placed over a map of Tuzo’s transform faults, the role of the faults became crystal clear: they are seismically active, but the long fractures that extend for hundreds of kilometres away on either side are not. Tuzo’s recognition of transform faults along midocean ridges presented yet other questions about their larger planetary role. He realized that “transform faults cannot exist unless there is crustal displacement, and their existence would provide a powerful argument in favour of continental drift.” Tuzo realized joining up the world’s midocean ridges from one ocean to another outlined the margins of a planet-wide system of large crustal slabs (resembling the panels on a soccer ball) bounded by subduction zones and chains of high mountains such as the Alps and Himalayas. In the introduction to his 1965 paper, Tuzo wrote of a “continuous network of mobile belts around the Earth which divide the surface into several large rigid plates.” What had started with Frank Taylor’s concept of crustal flakes in 1910 had now, more than a half-century later in 1965, been transformed into tectonic plates. Tuzo would write that “continents are incorporated with surrounding ocean floor into a plate that is larger than the continent, just as a raft of logs can be frozen into a sheet of ice. These plates have repeatedly collided,

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Transform faults are a very elegant mechanical device that permits sea floor spreading on either side of midocean ridges, which are highly sinuous, such as that running up the axis of the Atlantic Ocean. They also accommodate variation in spreading rates from one segment of a ridge to another.

broken apart and rejoined in different patterns. Ocean floors have been reabsorbed but the continents have been modified and remain.” Here was a profound breakthrough in understanding how Earth’s surface worked. Continents didn’t drift like giant icebergs by plowing across the ocean floors, as Wegener had proposed in 1915. Instead, the entirety of Earth’s crust was on the move as a series of jostling, interlocked plates that carried continents as giant rafts. It was an enormous jigsaw puzzle where pieces move, grow, and, as we shall see, are also destroyed.

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By visualizing crustal plates, Tuzo had intuitively seen a recurring pattern on the Earth’s surface that no one else had – yet another example of his ability to clearly see the big picture from a cloud of data and information. His key discovery was the role of transform faults and recognition of their global importance in defining the edges of large lithospheric plates that carried entire continents; it made him famous and was to change the science of geology overnight. Scientific progress is seldom linear or straightforward and can often be haphazard and messy, resulting in disputes about who can claim credit for a discovery. Scientists in different laboratories often produce simultaneous discoveries, but only those publishing first can claim the prize. Such is the case of transform faults, and the story is worth recounting, as it illustrates how science often works. In the spring of 1965, well before Tuzo had identified and named transform faults, a young Canadian graduate student, Alan Coode, working on his PhD in Keith Runcorn’s laboratory at the University of Newcastle upon Tyne in northeastern England, submitted a short manuscript to Nature identifying the basic function of the newly identified faults, but without giving them a name. Unfortunately, his paper was not considered substantial enough to publish because the editor of the journal did not recognize its author as an established scientist, and it was returned as “rejected,” a similar experience to that of Larry Morley when he tried to publish his groundbreaking work on the origin of magnetic stripes as an as-yet unknown researcher. Coode never stated in his submission that he had identified a new, hitherto unrecognized type of fault, which would certainly have helped make the case for publication. Undaunted, he then resubmitted

Tuzo: The Unlikely Revolutionary of Plate Tectonics

his manuscript to Canadian Journal of Earth Sciences, a newly created journal issued four times a year, where it was accepted but not finally published until August. Tuzo beat him to the punch by submitting his own manuscript to Nature, the much better known and more widely read journal with a weekly publication rate and whose editor, recognizing the name of its famous author and its scientific significance, sped it through the editing process and had it published a month earlier than Coode’s. This allowed Tuzo to claim the all-important right of having first discovered the faults and give them the name that stuck. Tuzo had been aware of Coode’s work and he had learned much from the junior scientist when the two had briefly met at the University of Newcastle upon Tyne in February 1965. The occasion was an invited lecture given by Tuzo, and in the ensuing discussion on the floor of the lecture hall, Coode generously told him of his own ideas, even correcting serious errors and misconceptions in Tuzo’s model. Tuzo was adamant, however, that his own interpretations, not Coode’s, were correct. They agreed amicably there and then to publish their work separately, but Tuzo then used Coode’s comments to improve the paper that he would shortly submit and publish in Nature. Today, more than fifty years later, Alan Coode harbours no ill will at being scooped by Tuzo and admitted to the author to having then been “stuck between the devil and the deep blue sea.” Like any graduate student with a great idea, he could have submitted a joint paper with his supervisor Keith Runcorn, which would likely have guaranteed publication in Nature, but then his supervisor would have taken the credit.

Tuzo theorized that midocean ridges (areas of active sea floor spreading), transform faults (where crust slides past other crust), and subduction zones (where oceanic crust is consumed) are all connected and together demarcate the margins of large plates of crust that move. Continents are embedded in the larger plates and together, much like passengers on a raft, they both drift across the underlying mantle interacting with surrounding plates. It was the elegant explanation of how continents moved that Alfred Wegener’s grand concept of continental drift lacked when proposed in 1915 and that had been seized on by the permanentists as a fatal flaw in the whole model. Tuzo wrote, “The surface of the Earth is like the hard shell of a turtle broken into plates, but unlike the turtle, Earth’s plates can move.”

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In 1979, Tuzo received the Albatross Award from a group of US-based oceanographers who humorously labelled themselves as the American Miscellaneous Society. The stuffed bird was presented to “someone with an albatross-like ability to make conceptual leaps on the scale of an ocean” and recognized Tuzo’s discovery of transform faults (“faults that ran backwards” reads the citation) which was key in identifying the boundaries of tectonic plates. At right is Arthur E. Maxwell. On the left is Sir Edward “Teddy” Bullard, the previous recipient of the award in 1976 for his contributions to "unintelligible paleomagnetism," who had also produced the first computerized reconstruction of Pangea in 1965.

Coode admits, too, that he “may have been naive in talking to Tuzo after the lecture in Newcastle, trying to correct his presentation which violated simple laws of geophysics and geology, which I had learned as an undergraduate at UBC. Later, I was told that Tuzo often tried to sort out his problems by bouncing his thoughts off graduate students.” Indeed, he was well

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known for this habit at Toronto, and in the author’s opinion it reflected his earlier wartime training and modus operandi. He would quiz soldiers and engineers in the field and hurriedly write reports on how well this piece of equipment or that had functioned in combat, or what was evident on a reconnaissance flight over enemy defences, immediately passing the findings up the chain of command to his superiors. It was the same with Operation Musk Ox, where Tuzo’s responsibility was to test men and machines in the Arctic and write voluminous reports in short order. There was usually an urgent problem to solve requiring diverse information to be collected from many different sources and assessed for its importance and quality, then a recommendation written up quickly for immediate action. He was to later comment, “As fast as I saw these multitudinous developments I had to borrow or sketch plans and write reports for dispatch post-haste.” His ability to quickly produce short reports learned in the army was of immense help in academia. It is also apparent from discussions with his colleagues, and especially his daughter Susan, that Tuzo was not greatly bothered with establishing personal ownership of ideas that he published, and instead regarded them as simply part of a greater pool of knowledge for the common good. Nonetheless, he should have acknowledged the help of his fellow Canadian in formulating his Nature paper. It also must be said that Coode’s illustration of a transform fault is simpler and more elegant compared to that shown in Tuzo’s Nature paper. Looking back, the discovery of transform faults by both Alan Coode and Tuzo Wilson in 1965 was the key

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Tuzo Closes and Reopens the Atlantic Ocean

step that would ultimately lead to a comprehensive theory of plate tectonics and would in turn finally unlock the history of the continents and oceans. Tuzo’s unique contribution lay in painting a clear and comprehensive picture of the significance of data that had remained buried and unseen by those who had themselves collected the data. He returned to this issue in 1985, writing that “in trying to assemble information on a worldwide scale from data collected by others I felt like a far-ranging scavenger, but the geological and geophysical evidence I compiled from these sources was the background of fact that produced the theory of plate tectonics.” Alan Coode generously admitted to the author that he thought Tuzo the much better salesman, highly adept at publicizing the wider global importance of the newly named faults. Tuzo reinforced this skill in numerous well-publicized lectures across North America and in a series of short, high-impact papers in late 1965. The central message was simple and elegant: when the faults were traced away from midocean ridges, they merged (became transformed) with subduction zones and high mountains that together identified the active boundaries of large plates on the Earth’s surface. Tuzo Wilson and Alan Coode had independently discovered the missing link that brought everything together, but only Tuzo had recognized their global significance. Earth’s outermost shell was not intact and unmoving, but broken into large crustal pieces, much like crazy paving, that drifted relative to each other. This dramatic turning point in thinking marked the beginning of the end of the long debate that had polarized the entire science of geology, pitting one geologist against another, since 1910. Tuzo, the longtime permanentist, had shown the way.

Tuzo’s travels around the world and his deep knowledge of global geology and geography now came to the fore, giving him a unique advantage unmatched among his peers. He would now test his new ideas on continental mobilism by taking another look at the origins of the oceans. As we have already seen, Tuzo had toyed with the idea that the Atlantic Ocean was of relatively recent geological ancestry, when in 1962 he proposed that the Cabot Fault of Nova Scotia and the Great Glen Fault of Scotland were one and the same and had been separated by the breakup of Pangea when the Atlantic Ocean had formed. Four years later he proposed the existence of an older ancestral ocean prior to the Atlantic that had closed when Pangea had formed. The basis for the idea was again matching the geology of the coastlines on either side of the Atlantic, but this time the focus was on ancient mountain ranges. Tuzo argued in his 1966 Nature paper that the Appalachian Mountains in North America and their equivalent in Scotland and elsewhere in Africa (the Caledonides) had once been together. They had formed as a long continuous chain when a proto-Atlantic Ocean (named “Iapetus” in reference to the father of Atlantis in Greek mythology) had closed, bringing North America and Europe together. In one stroke, Tuzo’s model of a long-dead ancestor of the Atlantic Ocean solved a long-standing controversy, finally making sense of evidence collected by paleontologists such as Charles Schuchert and Charles Walcott that pointed to the existence of land bridges across fixed

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Tuzo Wilson’s 1966 schematic depiction of how the closing of an ancestral Atlantic Ocean (Iapetus) brought together North America and Europe, juxtaposing rocks with very different trilobites and brachiopods that lived along their opposing shorelines. The opening of the modern Atlantic Ocean after the breakup of Pangea some 180 million years ago left slivers of European rocks (with their “Atlantic” fossils) stranded in North America, and similarly North American rocks and their “Pacific” fossils in Europe. The puzzle that had eluded Carl Schuchert and other permanentists in the 1920s (that we described earlier in this book) was finally solved without the need for land bridges between fixed continents.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

oceans. Amadeus Grabau had been banished to China for his opposition to the whole idea of land bridges, and Tuzo acknowledged his ideas by demonstrating how the collision between ancestral North America and Europe and the death of the Iapetus Ocean had brought together rocks of the same age that formerly had been on either side of the ocean. But these contained very different types of fossil trilobites and brachiopods. Later, as the modern Atlantic Ocean slowly opened and Pangea broke apart, slivers of European and African crust and their respective fossils were left behind on the “wrong” side of the Atlantic in North America. Barrie Clarke, a former student of Tuzo’s, now a retired emeritus professor, recalls, “Tuzo could never have imagined when he was working with the Geological Survey of Canada in the late 1930s while mapping the geology of Nova Scotia that he was essentially mapping the geology of North Africa, specifically Morocco or what some geologists have famously called Nouvelle Maroc!” Similarly, pieces of American rocks had been abandoned in Europe, resulting in their very different fossils being juxtaposed with European cousins. With his ability to simplify, Tuzo used the example of a broken dinner plate: “The Atlantic Ocean had then reopened but not exactly in the same place as before and some slivers along the coast had been switched from one side to the other as though one had cemented two halves of a broken dinner plate together and then broken it again nearly, but not exactly, in the same place.” The grand story of the closing of the Iapetus Ocean to form Pangea and the later opening of the Atlantic Ocean all came together in the small community of

Gander, in eastern Newfoundland, during a now famous conference, “Geology and Continental Drift: A Symposium,” in August 1967. Long known as the “crossroads of the world,” Gander lies roughly halfway between the major cities of North America and Europe, and for many years served as a refuelling stop for transatlantic flights. But it was also a fitting location for geologists to meet and talk about a time when there had been no Atlantic Ocean. During a series of field trips, the evidence was laid out for all to see that the geology of Newfoundland and the Appalachian belt of eastern North America is composed of far-travelled rocks brought together by continental collision during closure of an earlier ocean that predates the Atlantic. Remnants of the floor of the former Iapetus Ocean are now preserved across much of Newfoundland. Ancient ocean crust and even rocks of the Earth’s upper mantle can be seen at the World Heritage–listed Gros Morne National Park and the Tablelands on the island’s west coast. These had been thrust onto North America as the ocean closed. It was the tangible evidence that finally convinced many previously skeptical American permanentists that the geology of eastern North America recorded the opening of the ancestral Iapetus Ocean, its later closing as Pangea came together, and that their own continent had drifted westward after Pangea broke apart. Ironically, the meeting was organized, and the proceedings published, by the American Association of Petroleum Geologists, the very same organization that had organized the infamous symposium in New York in 1926 (with virtually the same title) that had brought together many of Wegener’s most vocal permanentist

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opponents who had stifled any further debate about continental drift. The convenor of the Gander conference was Marshall Kay, who had, unlike his colleagues, been able to shrug off his earlier permanentist convictions and very publicly accept mobilism in the 1960s. A senior professor at Columbia University, from which Amadeus Grabau had been abruptly terminated in 1919, he had long advocated for the permanency of continents and their growth by the repeated sinking and filling of geosynclines, which, as already noted, he had classified into many tongue-twisting sub-types. Kay declared that it was now “generally agreed that continental separation had taken place in the North Atlantic, and that the geologic data indicate how, as well as when, drift occurred.” The world of North American geology would never be the same. As the new mobilism began to overcome the last remaining pockets of permanentist resistance, pre-existing data collected decades earlier now took on an entirely unexpected significance. As we have shown in this book, geological and geophysical research after 1945 had largely been conducted from ships passing backwards and forwards collecting vast amounts of electronic data from the deep ocean floors. This had revealed that today’s oceans postdate Pangea, contain rocks that are no older than about 180 million years, and are still evolving. In 1970, a landmark paper written by Tuzo’s longtime colleague John Dewey (whom we met earlier) and Jack Bird refocused geologists’ attention back on land to areas they had painstakingly traversed on foot, hammers and notebooks in hand, for more than a century. The history of old oceans lay high and dry within the crumpled rocks of mountain chains. Suess, Taylor, and

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Wegener had been proven correct, but their work had lacked a convincing mechanism for moving continents around. Now, under the spotlight of the new mobilism, mountains were seen as crumple zones, made of the wreckage of old ocean floors, pinched and shoved on land during their closure, like flotsam thrown up on a beach during a storm. In Charles Schuchert’s great book, The Stratigraphy of the Eastern and Central United States, published a year after his death in 1942, he had argued that the eastern margin of a permanently fixed North America had grown outwards during the Paleozoic by the filling of three successive geosynclines, which he called the “Taconican,” “Acadian,” and “Appalachian,” named after the mountain ranges supposedly thrown up by the filling and contraction of each one. It quickly became apparent that these mountains and their rocks, so patiently recorded by Schuchert, Kay, and their many colleagues over their long careers, marked distinct phases in the protracted collision of Europe and Africa with North America. This had occurred when a much older ocean (named the Iapetus Ocean) had closed when continents collided to form Pangea. The mountain ranges were simply enormous crumple zones of deformed rock pushed onto North America. Their counterparts lay on the other side of the Atlantic in the Scottish Highlands, where Tuzo had famously declared his opposition to mobilism in 1948 in the company of Sir Edward Bailey. A much larger global synopsis emerged as work progressed: that ocean opening and closing had been a recurring process in Earth’s history. In fact, it described the life cycle of all oceans as continents came together to form supercontinents, squeezing oceans shut in the process, to later separate and form brand new

Tuzo: The Unlikely Revolutionary of Plate Tectonics

ones. This was a breakthrough that would provide the impetus for exploring Earth’s geological history, which, as we shall see subsequently, would be named the “Wilson Cycle” in Tuzo’s honour.

Bay Company. As the fur trade dwindled, the Shield was given away to the new, three-year-old country of Canada in 1870, but only later, and then largely by chance, was its vast mineral potential discovered as transcontinental railways sliced through its ancient rocks. A full century after Confederation, the nation celebrated at Expo 67, the World’s Fair held that summer in Montreal. At Expo’s opening, the prime minister, Lester B. Pearson, declared that “we are witness today to the fulfillment of one of the most daring acts of faith in Canadian enterprise and ability ever undertaken.” Visited by Queen Elizabeth II, Robert F. Kennedy, and Charles de Gaulle (who famously upset his hosts by declaring “Vive le Quebec Libre”), Tuzo was invited to give a lecture (sponsored by Noranda Mines, for whom he had worked as a young geological assistant fifty years earlier) and to take part as the personification of how Canadian expertise had finally deciphered how the planet worked. To reach Montreal, Tuzo sailed his boat, a Chinese junk, with his brother as crew, east from his cottage on Georgian Bay all the way to Montreal. John Lear attended Expo 67 as the science correspondent for the Saturday Review and reported on what he saw as Canada’s role as an “unappreciated scientific innovator.” He concluded that amidst all the many spectacular exhibits at Expo, the one that had the most profound meaning was not Habitat 67 or Buckminster Fuller’s geodesic American Pavilion, but rather “a pot of boiling tomato soup.” Tuzo gave his lecture in Montreal on mantle convection and had devised an ingenious prop for demonstrating to his audience the basic mechanism driving plate tectonics.

Expo 67: “A Pot of Boiling Tomato Soup” In 1967, I felt like a mountain climber who had safely reached a terrace but was uncertain of the will or the strength to attempt another peak. J. Tuzo Wilson, 1993

By 1967, Tuzo was the most famous living scientist in Canada, the face of the new geology with its gripping tales of drifting continents and long-dead oceans, and a well-known public intellectual. It was a time of great optimism across Canada, and its citizens found themselves, a full century after Confederation in 1867, as inheritors of the young country occupying an immensity of space and still-uncharted landscapes, enormously rich in resources and potential. Many factors led to so few people becoming guardians of such a large area of the planet, but as the author has argued elsewhere, this situation owes much to the vast, rocky wastes of the Canadian Shield, the largest piece of Precambrian crust anywhere on the planet that no one initially realized held so much mineral wealth. At first, the Canadian Shield was seen as a remote, rock-strewn wilderness of limited value, incapable of being farmed and with commercial access strictly controlled by the British fur traders of the Hudson’s

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With his characteristic flair, Tuzo boiled a pot of soup on stage and showed his audience how a white froth “that had risen from below, piled on its surface and grown through time” was analogous to how the earliest continents might have formed as a surface scum by stirring of the primeval mantle. Simple it may have appeared, but Tuzo had experimented many times in his kitchen (usually with porridge) to ultimately find the right mix of soup and other additives needed to thicken it and make it perform as intended, much to the chagrin of his wife, Isabel, at the waste of good food and to the great amusement of his daughters Patty and Susan. In due recognition of his industrial sponsors, Tuzo stressed how the new theory of plate tectonics was the key to unlocking Canada’s mineral wealth. He highlighted the role of superheated crustal fluids in circulating through rocks, leaving metal-rich veins, using the analogy of William Harvey’s seventeenth-century discovery of the body’s circulatory system, which had triggered numerous medical and biological innovations. Tuzo finished his lecture by stressing that existing ideas in geology, geophysics, and geochemistry were now in need of urgent revision in the light of the new model of how the planet functioned. His work in deconstructing the geophysical heart of Canada – the Shield – showing how it was a mosaic of immigrant rocks comprising far-travelled exotic crust, was a fitting metaphor for a settler country where everyone has arrived at some time or another from elsewhere. Northrop Frye, another famous contemporary scholar from the University of Toronto, had recently posed the rhetorical question

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about Canadian culture: “Where is here?” Tuzo was now able to provide a definitive answer drawn from its rocks: “From someplace else.”

Confirmation of Sea Floor Spreading One of the greatest triumphs in geology. H.W. Menard, 1986

Study of the magnetic stripes discovered in the oceans’ crust had revealed that ocean basins progressively widened with time by sea floor spreading, and in the process, continents were pushed apart. In the minds of many geologists, however, definitive proof of the drift of continents could come only when the ocean floors had been sampled and the rocks systematically dated on either side of midocean ridges, an undertaking that would need large ocean-going ships capable of drilling into the crust in waters many kilometres deep. This mission beneath the surface of the planet was a fitting counterpart to the Apollo program, which at the same time was trying to leave the surface of the planet altogether. Beginning in 1968, the Texas-built drillship Glomar Challenger began a series of global voyages (each one called a Leg) to various sites where it would drill into the ocean floor. It was Leg 3, completed in late 1968 and early 1969, that will go down in history. Held in position in swirling ocean currents and swells by powerful electric thrusters controlled by a satellite navigation system, the Glomar carried enough length of drill pipe to work in 5 km of water and then drill

By the late 1960s, the dating of magnetic stripes on the ocean floor, combined with drilling and dating of ocean floor rocks, showed that the oceans are no older than about 200 million years and resulted from the breakup of Pangea. Their floors get older with distance from midocean ridges, which are sites of active spreading where new ocean crust is forming today. The resulting map clearly revealed that ocean basins have progressively widened from narrow rifts. Note the absence of oceanic crust older than 50 million years in the eastern Pacific – this huge expanse of “missing” ocean crust has been lost by subduction below the westward-moving North and South American Plates. Over the next 250 million years, the current ocean floors will shrink and disappear entirely as continents continue to converge to form the next supercontinent, Pangea II.

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2 km into the ocean floor rocks below. On the ship’s third leg it drilled a series of holes right across the Mid-Atlantic Ridge at 30° south latitude. Ken Hsu, then a well-known skeptic of sea floor spreading, was the onboard geologist and later wrote of his painful “emotional shock” as data came in hole by hole showing increasingly older rocks and thickening sediment covers with increasing distance away from the midocean ridge, just as the hypothesis of sea floor spreading had predicted. When the Glomar finally berthed in Rio de Janeiro in January 1969 it had completed, with very little fanfare, one of the greatest voyages of discovery ever made, and the resulting map of the varying age of the ocean floors is a true masterpiece. The voyages of the Glomar Challenger demonstrated that nowhere in any ocean is the crust older than about 200 million years, dispelling the long-held notion that the ocean basins were permanent features of the planet. The evidence suggested they were in fact no older than Pangea and had formed after the breakup of the supercontinent. The width of the oceans as they slowly expanded through time after the breakup of Pangea, and the corresponding shifts in position of the continents, could be precisely determined from the Jurassic to the present day. Unfortunately, this stunning confirmation of the age of the oceans was eclipsed in the public’s eye by the lunar landing, for understandable reasons. The astronauts Neil Armstrong and Buzz Aldrin stood on the Moon in July 1969 and brought back 21 kg of rocks to Earth, but it was not until 1973 that Earth-bound geologists made the first exploration of an active midocean ridge. This landmark event was undertaken by a joint US–French

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team near the Azores in the Atlantic Ocean and was quickly followed by expeditions to the Galapagos Islands and Hawai’i in 1977. There they documented active underwater eruptions of pillowed basalt lavas and active hydrothermal vents called “smokers” that spout jets of superheated, mineral-rich water that support thriving communities of organisms living 3 km beneath the ocean surface. Hydrothermal activity also chemically alters sea-floor basalts, creating rich metal deposits. The mineral-rich pillow lavas that Tuzo had seen as a young geological assistant in 1929 working with the Geological Survey of Canada at Abitibi in Quebec had formed in the same fashion. These rocks formed the extensive “greenstone belts” now locked deep within the Canadian Shield and had formed billions of years ago on the floor of an ancient ocean. During the 1960s Tuzo had discovered transform faults, recognized lithospheric plates, showed that oceans had closed and then reopened, and all but finished off permanentism. It had been an exhausting achievement opening new fields of study, but his own frenetic pace of research was about to slow down and go in a very different direction.

A Change of Pace In 1968, Tuzo was asked to head up the newly opened Erindale College (now the Mississauga campus) of the University of Toronto and become its principal. The new position offered a change in pace and heralded the end of his active research career. Despite Tuzo’s long-held aversion to bureaucracy, it would give him a platform

Tuzo: The Unlikely Revolutionary of Plate Tectonics

to inspire a much larger group of students than he ever could in the more narrowly focused geophysics group on the St. George campus. There had also been friction generated among his downtown colleagues by his proposal to unite the warring factions of geology and geophysics into a single Institute of Earth Sciences, which predictably pleased no one, so a break would be welcome. At the time, however, Tuzo wasn’t easily convinced of the value of moving across the city.

attitudes were symptomatic of a wider revolt against sweeping postwar societal norms sweeping across both the West and the other side of the Iron Curtain. It required a very delicate and unconventional touch in leading Erindale, but Tuzo was up to the task. He later recounted that “it wouldn’t have been much fun to run a college that was already running. But to build a college, that was different.” Widely recognized and admired as an administrator, he attributed his success to his wartime experiences with the Canadian Army, “which were so varied, camping out and living with men in various circumstances including a lot who were pretty tough characters, and also scientists. This was a very good training for Erindale which I didn’t run in any conventional way at all.” On the many occasions he was away, Tuzo would leave the daily running of the campus to his secretary. Things ran very smoothly, and no one noticed the changes in command, but his frequent absences directly interfered with the weekly demands of lecturing. Henry Halls, Tuzo’s former colleague, recounts the challenges of being the replacement instructor for Tuzo’s courses.

The president of the university took me out to lunch and beforehand we went swimming. We went to Hart House pool, and I thought it wise not to beat him swimming, so I just kept pace with him. Then he said would I care to go to Erindale. I said I didn’t want to go to Erindale and do administration. He asked if I’d ever been there. It was fifteen or twenty miles out of town. I said no. He said, “Why don’t you go – it’s a nice spring day. Go out there and take Isabel and see what she thinks.” So, I went out and Isabel thought it would be just great to be chatelaine of a lovely estate which is three hundred acres altogether. I was then persuaded to accept the job. I was very glad I did.

Trying to sit him down even for a few moments to

And so too was Erindale. It was his first major administrative position at the university and Tuzo proved to be a popular and highly effective leader. The Erindale campus prospered and grew under his tutelage, and he was heavily involved in the design of new buildings specifically intended to foster openness between professors and students at a difficult time in education, when students were often dismissive of the status quo and staged numerous “sit downs” and “demos.” These

talk about the content of an upcoming lecture was almost impossible, while the great man himself, ever dismissive of mere details, mused about greater issues of the moment, such as where North America had been 200 or 60 million years ago. On one occasion when he was just beginning to plan Planet of Man (a series of films for TV Ontario and far more exciting prospect than undergraduate teaching!) I asked Tuzo “What should we teach tomorrow?” His response was,

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Seismic Shift “Well I think a series of earth science films is needed;

you think?” After suitable bromides from me, he left to

Newfoundland has excellent ophiolites, the Sudbury

repeat the production further along the corridor in the

impact structure would obviously be a topic, and I can

next available faculty office. About an hour and a half

be shown in my junk at the beginning of each episode;

later he was back in my office and much to my surprise

what do you think, mmm?”

and delight there was another identical performance. Tuzo had obviously been all around the entire campus

During the research that he had completed for the US Air Force on dating ocean floor rocks, Tuzo became acquainted with the names of hundreds of islands in the Pacific; at Erindale, he was well known for being able to remember the names of every student sitting before him in large classes. Henry Halls vividly remembers the very first lecture in one such course when, in typical fashion, Tuzo swept into the lecture room before about a hundred first-year undergraduates. Before we went in, Tuzo had gathered a pile of textbooks and gave them to me to carry, the stack almost being higher than my head,

on this rather immature venture and had forgotten his starting point! The performance was quite in tune with Tuzo’s flair for bonhomie and sense of fun.

It has been estimated that by the end of his seven years at Erindale, Tuzo and Isabel had entertained some 10,000 people in the Principal’s House, a staggering number but illustrative of the Wilsons’ energy and hospitality. Tuzo’s retirement from the University of Toronto was celebrated by a cabaret organized by undergrads, and Halls received a phone call just the day before with an invitation to portray the great man, as

with me trailing behind him as he entered the room. So, when I was introduced by Tuzo to the class as the

I was quite well known around the college for mimicry

main lecturer for the course, giggles and snickers floated

and particularly my Tuzo rendition. The script had to be

around the room because I was hidden behind the stack

completely re-written because only I knew his manner-

of books and was very clearly in a subservient role!

isms and humorous foibles. The following night about a thousand people turned up, and my entrance, while

Halls was also witness to Tuzo’s frequent acts of showmanship. One time, Tuzo

wearing a bald wig and a pillow to fatten me out, brought the house down. One skit dwelt on Tuzo’s position as Chair of the College Council and the famous occasion when,

unexpectedly came into my office sporting a new T-shirt

faced with a thorny item on a council agenda, he had his

presented to him by students at the University of Okla-

secretary enter the meeting to loudly declare “Professor

homa. On the front it said “Tuzo, we love ya” and on the

Wilson, your flight to China is about to leave shortly.”

back a coloured cartoon of two continents breaking apart.

Ironically, but perhaps not surprisingly, given his work ethic, it wasn’t long after his grand send-off

With a little twirl like Pierre Trudeau’s famous pirouette behind the Queen in 1977, he exclaimed “Well, what do

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Tuzo: The Unlikely Revolutionary of Plate Tectonics

that Tuzo found himself busily occupied again, but this time in a new role at a very different institution, which would allow him the opportunity to travel and lecture to a global audience.

Unlike Alfred Wegener, who preferred to let his writing do the talking, Tuzo walked the talk and believed in the crucial importance of taking the plate tectonic revolution on the road. He remarked that “whatever the cause of my conversion, the result was a display of missionary zeal common to the newly converted. I barn-stormed around North America trumpeting the new gospel on a lecture tour of the lower forty-eight states sponsored by the Geological Society of America.” In his role as trumpeter-in-chief, echoing his earlier grand tour of the planet in 1950 to “see as many Precambrian shields as possible,” Tuzo went on tour “selling” mobilism (in Henry Menard’s words) in the heartland of the former permanentists and beyond. Eventually he lectured on plate tectonics in a grand total of seventy-three countries, and by this stage he had lost count of how many times he had now circled the globe. In 1978 Tuzo returned to his Arctic roots and organized a historic meeting of more than forty explorers of the Canadian Arctic at the Ontario Science Centre. These included Evelyn Stefansson, the widow of his father’s old friend Vilhjalmur, and Punch Dickins, the intrepid ex–First World War combat pilot and bush pilot. It was Punch who had shown Tuzo the potential of using planes for geological mapping and mineral prospecting across the vast expanse of the Canadian Shield. Tuzo now had the opportunity to develop another great interest of his, that of China and Chinese culture. Unlike the hostile reception that plate tectonics received in the Soviet Union, Chinese geologists warmly embraced the new thinking and its principal Canadian disciple. Of all the countries he visited, Tuzo developed

Spreading the Gospel: Tuzo at the Ontario Science Centre A new idea must be advertised and sold. H.W. Menard, 1986

Officially in retirement from the University of Toronto in 1974, Tuzo found himself for the first time in decades without an office or secretary, “forcing me to learn the mechanics of getting someone on the telephone but I could not even find the directory.” However, the interlude was to be just a few months long, and for the following eleven years until he retired for good, Tuzo was the director of the Ontario Science Centre. He had been personally asked to run the new facility by William Davis, the premier of Ontario, and under Tuzo’s leadership, science education greatly expanded in the province. A sister facility, Science North, was opened in Sudbury, and Tuzo ensured that geology was made a significant focus of its exhibits – on a practical level, this reflected the importance of mining to the surrounding community and province. Above all, however, the Ontario Science Centre gave Tuzo a platform to spread the word about the revolution that had just swept through the world of geology, and, with his infectious enthusiasm, he became the chief diplomat for the new science of plate tectonics.

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Tuzo in his cluttered office at the Ontario Science Centre in 1979 surrounded by piles of papers and books that required careful navigation. He would remain director of OSC until 1985 and referred to his years there as some of most fascinating of his entire life. Note the absence of a typewriter; he never learned to type, always requiring the services of a secretary. Late in life he was dissuaded by his family from learning to type on the grounds that it was not a good use of his time.

a special affection for China and its vast and varied culture. He had, as related above, first visited there in 1958, and his second visit in 1971, hard on the heels of the Cultural Revolution, was eased by Canada’s formal recognition of the People’s Republic of China. Potential political tensions during Tuzo’s visit were calmed not only because of his nationality but because he was a geologist and a member of a profession that enjoyed a favoured status among the communist hierarchy. Scientific research in China carried the risk of creating highly educated elites whose interests, if unchecked, might work against those of the proletariat. To avoid

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toxic counter-revolutionary seeds from germinating in universities, the so-called 7th May Directive issued by Chairman Mao in 1968 ordered university professors to work in the field, live among the masses, and become better acquainted with manual labour. This is what geologists do anyway and so the discipline had prospered, also benefitting from its economic importance for mapping natural resources. In Communist China, then and now, being a geologist has its advantages, and Tuzo was well received as the discipline’s most senior and internationally recognized spokesman. Much to Tuzo’s delight, all administrative work in the universities and research institutes had been taken over by revolutionary committees, thereby freeing up research scientists to continue their work unburdened by the day-to-day running of their departments, still only a pipe dream for their colleagues in the West. At the time of Tuzo’s visit in 1971, the leading Chinese geologist was J.S. Li, who had been briefly trained in the United States in the 1940s and, while very supportive of large lateral movements of the Earth’s crust, was not a “drifter.” Tuzo noted that Chinese geologists still had access to Sir Harold Jeffreys’s book The Earth, which had retarded acceptance of continental mobility by several decades in many Western universities. However, the Chinese scientists overall were a very receptive audience for Tuzo’s new and revolutionary ideas on plate tectonics. China is cursed by what Tuzo referred to as “killer earthquakes,” and its 3,000-year history is punctuated by major tremors arising from the northward drift of the Indian subcontinent and its collision with the Eurasian Plate. India is a giant wedge being driven

For the last 15 million years, India has been shoved northwards into the Eurasian Plate; the enormous crumple zone between them now forms the Himalayan Mountains. Fossil-rich limestones deposited below sea level are now found on top of high mountains such as Mount Everest. India is said to form an “indenter,” displacing Eurasian crust west and east along numerous faults to escape the collision, in turn producing deadly earthquakes in China. Tuzo wrote after his visit to Peking University in 1971, “On the wall of the room was a map of the geology of China. I could immediately see structural lines that appeared to correspond with the belts of earthquakes.” On that occasion, while speaking through an interpreter, he gave an impromptu lecture on plate tectonics that lasted three and a half hours.

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into the heart of Asia, and violent earthquakes result in large losses of life. Correspondingly, much effort has been spent by Chinese scientists in manufacturing seismographs for detecting and measuring earthquakes (the oldest one in the world was made in China in 132 CE). Tuzo was captivated by Chinese culture and its contributions to global technology since the dawn of history, and he focused on these contributions in his second book, Unglazed China (1973). Pre-communist China under the emperors had been run by a system of scholar-administrators, and this scheme had great personal appeal to Tuzo, given his own successful career as a soldier-administrator in the Second World War and later as a senior statesman for plate tectonics. The culmination of Tuzo’s fascination with China came in 1982 when he organized one of the most ambitious exhibitions ever mounted at the Ontario Science Centre: “China: 7000 Years of Discovery.” Visiting Chinese artisans showed off their skills in ceramics, bronze casting, paper making, printing, and the construction of earthquake-resistant buildings, all amid huge public interest. Tuzo was disinterested in the political divisions between East and West but was a keen observer of how different societies and their peoples adapt to living on the surface of a dynamic and often dangerous planet. Looking back on his career he commented, “I had not devoted my life to becoming an expert in any particular branch of science but rather to try to understand how the Earth as a whole operated and how this has affected life and people.” Although he did not share his Chinese colleagues’ political views, he had re-energized and reorganized an entire academic discipline, and in that sense was a revolutionary of a different kind. 203

Tuzo was an avid photographer capturing images of society still hidden from the West behind the Bamboo Curtain. TOP: 1971 photograph of a young teenaged Red Guard holding aloft the “little red book,” Quotations from Chairman Mao Tse-tung. The revolver stuffed in his waistband is a wooden dummy. BOTTOM: Hundreds of Chinese labourers working at a construction site.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

A Chilly Reception in Russia

In August 1968, almost at the very moment that Beloussov and Tuzo were arguing with each other, nearly 3,000 geologists from all over the world gathered in Prague for a major international congress, a month-long calendar of meetings, presentations, field trips, and beer. That week, however, Russian troops crossed the border, and the harsh sound of tank tracks echoed and rumbled through the city’s narrow, cobbled streets. Western geologists wore black stripes on their name tags in mourning for the violated country and Russian geologists quietly slipped away. The congress was abruptly cancelled, and the potential for exchanging ideas between West and East was lost for more than decade. In the light of recent events in Ukraine, “what’s past is prologue,” as Shakespeare so aptly put it. Russian geology was to be dominated until the early 1990s by an ageing gerontocracy isolated from Western science, devoted to permanentism, and concerned with the practical, everyday search for mineral deposits and oil. It was entirely isolated from the “blue sky” thinking about global dynamics that had emerged in the West from studying the oceans. Much of the geology of Russia consists of vast platform-like areas, like the Plains of North America, underlain by thick layer-cake successions of rocks laid down in former seas. Beloussov’s ideas on the importance of vertical movements of the Earth crust as the mantle and core slowly consolidated under gravity, and the corresponding waxing and waning of vast interior seaways, seemed to explain everything. It was not until 1987, just four years before the fall of the Berlin Wall, that the first conference devoted to plate tectonics was held in Russia. For Soviet geologists, it had been one revolution too many.

The reaction to the plate tectonic revolution was very different in other parts of the communist world. The Cold War delayed acceptance of the theory east of the Iron Curtain, creating what was then known as the “Russian Rift” between its geologists and those of the West. Plate tectonics was, after all, the child of military funding by the Western Allies and thus was suspect in communist minds. In 1967, the Russian geophysicist E.N. Lyustikh, of the Institute of the Physics of the Earth in Moscow, rejected any notion of continental movement, declaring, “We have to agree with Sir Harold Jeffreys’ opinion that the articles of drifters are remarkable for fallacious data, misinterpretation of the data, and omission to mention any objections.” The geophysicist Vladimir Vasilievich Beloussov, head of the Department of Geodynamics in the Academy of Sciences at Moscow, succeeded Tuzo as president of the International Union of Geodesy and Geophysics in 1960. He was a frequent traveller to the West, spoke and wrote English fluently, and was a frequent sparring partner of Tuzo. We have already noted the strained relationship between the two, stemming from the 1957 meeting of the IUGG at Toronto. The Russian referred to “the total vacuousness and sterility” of the hypothesis of continental mobilism, arguing that it “explained nothing of what must be explained in the first place,” but Beloussov was guilty of being highly selective of those aspects of plate tectonics that he found objectionable. He famously wrote a highly critical “open letter” to Tuzo in late 1968 in Geotimes, and Tuzo responded that his Russian colleague’s comments were notable only for what they had left out rather than what they had addressed.

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The New World of Plate Tectonics

It has always puzzled me as to how Jeffreys could be wrong in a matter that dealt with physics, and another physicist who was denigrated for so long, Alfred Wegener, was proved to be more nearly correct. J. Tuzo Wilson to D.C. Skeels, 1981

Plate tectonics describes how the entire planet works. It shows how the geography of continents and oceans is constantly refashioned because of ­convection in the mantle and the formation, migration, and ­destruction of lithospheric plates on its surface. Making the final step in understanding this process was a source of great personal satisfaction to Tuzo, but it was a bittersweet moment because others would beat him to giving the new theory its name. While Tuzo had been the first to identify lithospheric plates, it was others such as Xavier Le Pichon, Dan McKenzie, Jack Oliver, Bryan Isacks, John Dewey, Lynn Sykes, and Jason Morgan who forged the study of Earth’s shifting crust into a coherent field of quantitative geoscience that came to be called plate tectonics. Tuzo’s work had been the inspiration for

the new theory, but the naming rights for the newborn child had gone to others; the term first appears in a landmark paper by Morgan and McKenzie in 1968. Tuzo revealed his disappointment at that time when he later wrote that he was still rueful at “not nailing it.” He also admitted that his use of the term “plates” was not entirely appropriate – they are not the flat, slab-like paving stones that the name implies and as they appear on two-dimensional maps. Instead, they are gently curved, resembling large pieces of broken eggshell, and their movement around the Earth’s surface follows strict rules, each one slowly rotating as it migrates, just as Bullard had determined in 1965. Reassembling ancient supercontinents and predicting the future pathways of future continents is a complex mathematical task and needs physics, after all.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Earth’s tectonic plates, with their direction of movement depicted by arrows (with lengths proportional to velocity), and the types of plate boundaries. The total global length of midocean ridges on the planet is about 65,000 km, forming an interconnected network like seams on a baseball. The rates of plate movement vary widely; fast rates in the Pacific are related to pulling forces as oceanic crust is subducted around the Pacific Rim. Pulling forces are absent in the Atlantic, where there are no subduction zones, and the mid-Atlantic spreading centre is pushing the North America and Eurasian Plates apart much more slowly.

Alfred Wegener had been right all along: continents do migrate, but in a manner very different from what he had proposed. They move not by ploughing across oceans like giant icebergs, as he had suggested, but instead are embedded within moving lithospheric plates that slide across a hot soft layer in the uppermost mantle created by an abrupt change in the physical properties of rocks. Travel down into a deep mine and the temperature increases by about 2.5°C for every 100 m depth. The key temperature is approximately 1,300°C, at which point, at depths of more than 50 km,

hot rock under enormous pressures begins to soften and become toffee-like, creating a soft plastic layer called the “asthenosphere,” over which colder and much stiffer lithospheric plates can slide. The plates are largely rigid, with earthquakes mostly limited to their edges, and in 1968 Bryan Isacks and Lynn Sykes showed that the global distribution of earthquakes, revealed by policing of the Nuclear Test Ban Treaty of 1963, outlines some fifty-two individual plates. Seven large plates account for 95% of the entirety of the Earth’s surface, the largest being the Pacific Plate,

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Earth’s outermost rigid crust is composed of two types: one is heavy, relatively thin, and underlies the oceans (oceanic crust); the other is light and thicker (continental crust). The lower limit of both types is marked by the Mohorovičić Discontinuity. Crust is bonded to an underlying thin, rigid layer (lithospheric mantle) that together make up a lithospheric plate, able to slide across the Earth’s surface over a hot plastic layer called the asthenosphere. Lithospheric plates are moved by weak pushing forces arising from sea floor spreading at midocean ridges, and by stronger pulling forces where plates dive down into subduction zones. The role of huge mantle convection currents in stirring the mantle and driving plates across the Earth’s surface is still debated.

which is entirely oceanic and thus completely under water, followed by the Eurasian and North American Plates, which carry high-standing continents as passengers. The largest number of plates occurs in the southwest Pacific Ocean; these are now being amalgamated into a larger crustal collage marking the beginnings of the next supercontinent, Pangea II. The smallest lithospheric plate is the Juan de Fuca Plate, which is getting smaller each day as it is being subducted below the western margin of North America. Small as it is, however, it still packs a heavy punch, and analysis of the plate’s seismic history reveals that it will send

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the cities of Vancouver and Seattle reeling very soon from “the next big one.” Geologists refer to “plate tectonic settings” and, in time-honoured fashion, use knowledge of the rocks that are accumulating in each setting today as a blueprint to interpret ancient rocks. Using this principle of uniformitarianism, it is possible to reconstruct plate tectonic processes and plate interactions over billions of years of Earth history. Geologists currently recognize some six different plate tectonic settings, based largely on the composition of the plates, whether they are composed of light continental crust or much heavier oceanic crust, and whether they are converging or moving apart.

The global distribution of past earthquakes and their depths (known as the earthquake “focus”) reveals the outlines of Earth’s major plates. Divergent boundaries (along midocean ridges) are marked by shallow-focus earthquakes along transform faults, whereas subduction zones are characterized by shallow, moderate, and deep-focus earthquakes that track the descent of plates of oceanic crust into subduction zones to depths than can exceed 700 km, notably around the margins of the Pacific Ocean – the so-called Pacific Rim of Fire.

Plates interact with each other in different ways, creating different tectonic settings. 1 When plates of light, low-density continental crust collide, their boundaries form a crumple zone

younger plate. Sediment is scraped off the descending plate to form accretionary wedges.

(an obduction zone) marked by high mountains made

4 Passive margins occur on the trailing edges of continents

of deformed and thrust continental rocks. These “suture

and are marked by continental shelves underlain by thick

zones” may include remnants of oceanic crust from

sediment.

oceans that died in the collision. 2 When a plate of oceanic crust converges with a continent, the heavier oceanic plate is driven down below the land mass in a subduction zone, giving rise to a magmatic arc of volcanoes along the edge of the continent.

5 Divergent plate boundaries occur within ocean basins at midocean ridges offset by transform faults with active sea floor spreading. 6 Rifting of a continent may ultimately result in a young ocean that widens by sea floor spreading, producing

3 When two plates of oceanic crust converge, the heavier

a divergent plate boundary and eventually passive

(older) one is driven below the lighter, younger plate,

margins along the edges of now widely separated

forming an island arc of volcanoes along the edge of the

land masses.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

New discoveries in science always invite yet more questions and, despite the apparent elegance of plate tectonic theory, geologists still do not know what gives rise to midocean ridges and what precisely drives sea floor spreading. The basic idea of outward spreading of new crust away from the ridges is still valid, but in the classical model of Hess and Dietz, midocean ridges are deep-rooted and fed by huge plumes of hot rock rising through the mantle. Satellite data, on the other hand, now reveal that ridges also migrate while spreading, suggesting that they are shallow-rooted and independent of what is happening deep in the mantle. Their ability to push entire plates around is also now in doubt, contrary to the classic sea floor spreading model of strong forces pushing crust away from midocean ridges. Some geologists argue that the primary actor behind sea floor spreading and plate motion is the enormous pulling force exerted by long slabs of thick ocean crust sliding down into the mantle in subduction zones. These slabs act as powerful tractors pulling the rest of the huge plate trailing far behind them; midocean ridges may simply be long rips in the ocean floors where oceanic crust has been torn apart by the strong pulling force of subduction zones. The ripping process may trigger local upwelling and melting of shallow mantle rocks, causing the upward intrusion of new magma into ridges. Midocean spreading centres are composed of newly formed hot and buoyant rock and so stand high above the surrounding ocean floor. Newly created oceanic lithosphere thickens as it moves away from the ridge by cooling

The anatomy of a typical midocean ridge and site of active sea floor spreading. Modern textbooks continue to show large mantle plumes rising under the ridges, but this is now questioned. Recent work also shows that ridges themselves migrate; the central rift is essentially a rip in the Earth’s crust.

downwards from its base, slowly sinking into the mantle under its own weight. Correspondingly, ocean water depths increase systematically from about 3 km above midocean ridges to more than 6 km along the outer margins of ocean basins where the underlying oceanic lithosphere can be as much as 30 km thick, and as much as 200 million years old, having formed when Pangea began to break up and the ocean began to open. Much thickened

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The New World of Plate Tectonics

and very heavy, the weight of the old crust slowly causes the onset of subduction. In turn, the ocean then begins to slowly close as the oceanic plate is progressively consumed by subduction, pulling in the surrounding continents as a result. Ocean basins are ephemeral features of the Earth’s surface, architects of their own demise, and once opened, are ultimately doomed to close and die, unlike continents, which are geologically long-lived and contain rocks as old as 4 billion years. Being much lighter, continental crust cannot be subducted and destroyed.

Plate Tectonics and the Ancient Past Oh God! That one might read the book of fate, And see the revolution of the times Make mountains level, and the continent, Weary of solid firmness, melts itself into the sea. William Shakespeare, Henry IV, 1597

Oceans come and go. J. Tuzo Wilson, 1993

Once supercontinents crack, they go to pieces. Unsuccessful undergraduate attempt at humour on a U of T geology exam

By the beginning of the 1970s, the war of words between the permanentists and mobilists that had begun sixty years earlier with Frank Taylor’s bold idea of “Earth’s Plan” and moving crustal flakes, and Alfred

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Wegener’s controversial theory of continental drift in 1915, was finally over. The existence of Pangea had been confirmed, and it had been clearly shown by drilling of the ocean floors that its breakup had given birth to today’s oceans and now separated continents. But science never sleeps, and geologists now turned their attention to applying plate tectonic theory to how Earth had evolved long before Pangea. It is a long and complex story; in the words of one eminent geologist, “It’s just one d— thing after another” and a source of frustration for students required to become familiar with all the details and dates. But the advent of plate tectonics has overcome the tedium of time because there is now a very simple conceptual framework that divides the long rock opera of the planet into distinct chapters. Plate tectonics brings order to the chaos of Earth history. Earth history is really about the history of its oceans, which close when continents collide to form supercontinents, only to be reborn when supercontinents break up. In 1968 Tuzo had referred to the “life cycle of oceans,” and in 1974 Kevin Burke and William Kidd, whom Tuzo had recruited to work at the University of Toronto at Erindale, formally named this the Wilson Cycle in his honour. Geologists now also refer to a “supercontinent cycle” that describes the comings and goings of these crustal behemoths. Tuzo had shown in the mid-1960s how the modern Atlantic Ocean is the successor to an earlier ancestral Ocean (the Iapetus) that had closed when North America joined Europe to form Pangea some 350 million years ago. But what of earlier oceans and supercontinents? How many have there been? The answer was to come out of the laboratory.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

The Magic Numbers By 1970, evidence was mounting for the existence of a supercontinent about 1 billion years old, to which was given the name “Rodinia.” This is a word of Russian origin meaning “the motherland,” because it appeared to be the original parent supercontinent. But this idea was quickly determined to be premature when geologists found evidence of yet older supercontinents. In fact, the Dutch geologist J.H.F. Umbgrove had anticipated this idea in his 1947 book Pulse of the Earth, but his idea only gained wider acceptance in the early 1970s as improved technology allowed for the continued refinement in dating rocks. By 1972, Derek York and Ron ­Farquhar, two colleagues of Tuzo at the University of Toronto, had plotted all the then available ages from around the world. Planet Earth was determined to be 4.567 billion years old, and, much to their amazement, they found that the ages of igneous rocks, as determined by analysis of lead in zircon crystals, formed distinct clusters at around 2.6, 1.8, and 1.0 billion years ago, and then again around 500 and 350 million years ago. York and Farquhar called these the “magic numbers,” but what was their meaning? The magic numbers tell us that these were times in the planet’s history when plate collisions, and thus volcanic activity and the formation of zircon crystals, were especially frequent. Specifically, the magic numbers identify episodes of supercontinent formation. Today, fifty years later, the number of dates produced from analysis of zircons has increased exponentially,

TOP: Cross-section through a 2.7-billion-year-old zircon crystal (as wide as a human hair) showing growth rings. The quantity of lead within the crystal, produced by the decay of unstable radioactive uranium, creates a geological clock. Courtesy of Mike Hamilton, University of Toronto.

BOTTOM: The magic numbers refer to distinct spikes in the frequency of the ages of zircon crystals preserved in volcanic rocks worldwide. Courtesy of Chris Hawkesworth, Ian Campbell, and colleagues.

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The New World of Plate Tectonics

but still identifies the same clustering (and gaps) first identified by York and Farquhar. Four supercontinents are currently recognized with some certainty, the oldest being a large land mass variably called Superia or sometimes Sclavia (also known as Kenorland among some geologists) around 2.6 billion years ago, followed by Nuna at 1.8 billion (possibly part of a supercontinent some call Columbia), Rodinia at 1.0 billion, and Gondwana-Pangea at 600–350 million years before present. There are probably more to be discovered, given that the oldest continental crust on Earth is more than 4.1 billion years old. However, the early planet was much hotter, and its plates may have been thinner and moved much faster, so our current understanding of plate tectonics may not apply to the very remote past. Plate tectonics also alters and destroys evidence of more ancient land masses, making the task of forensic reconstruction more difficult. Not surprisingly, there are many outstanding questions, not the least of which is the precise configuration of past supercontinents and whether their formation is a repetitive process that fully deserves the name “supercontinent cycle.” Nonetheless, the basic cycle appears to divide the hard rock opera we call “Earth history” into long approximately 750-million-year-long acts that involve all continents, whereas the Wilson Cycle, strictly speaking, describes the much shorter life history of numerous individual ocean basins. The most recent supercontinent cycle commenced with the breakup of Pangea about 200 million years ago, and as of today, we are roughly halfway through

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The supercontinent cycle: individual continents come together to form giant land masses, which are then torn apart by plumes of hot rock moving upwards in the mantle.

Sea. We shall briefly explore these different oceanic settings to show what happens in each stage of a supercontinent cycle.

Birth The beginning of a new cycle starts with the breakup of a supercontinent such as Pangea and gives rise to the creation of many new narrow oceans. Today in East Africa, the Somalian and Arabian Plates are breaking away from the African Plate, tearing wide rifts that will widen and deepen to eventually become oceans. Rifting and tearing of continental crust occurs in an orderly manner, in the form John Dewey and Kevin Burke called “triple junctions,” consisting of three radiating rift valleys, much like the arms of a Mercedes-Benz logo. Only two of the three arms become oceans; one is said to “fail” because its further growth is arrested.

Rodinia about 1 billion years ago: geologists are still not agreed on the precise shape of the supercontinent, and different reconstructions have been proposed based on tracing former mountain ranges and their highly deformed rocks from one continent to another.

it; the next supercontinent (Pangea II) is estimated to be complete in some 250 million years. Illustrating the various stages of an entire cycle on today’s planet needs a large degree of scientific latitude because continents are widely dispersed, separated by large oceans. Nonetheless, the different stages can be approximated by looking at today’s oceans. Today, there are oceans that are being born by rifting of the African plate (in East Africa), there are oceans that are mature (the Atlantic Ocean), one beginning to close resulting in plate collisions (the Pacific Ocean), and one that is near death (Tethys) whose remnant waters we call the Mediterranean

Maturity The Atlantic Ocean is a “mature” ocean. Sea floor spreading along its midocean ridge is hidden deep underwater, usually at depths of 3,000 m or more, but in Iceland the Mid-Atlantic Ridge pops up on land, and one can comfortably hike from one plate (the North American) to another (the Eurasian) in a day. The highest part of the midocean ridge can be climbed at Snaefellsjökull, a high volcano

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The birth of a new ocean begins with a narrow rift (seen in present-day East Africa), which widens (as in the Red Sea) to form a mature ocean such as the Atlantic. In turn, mature oceans die when their cooled and much-thickened ocean floor crust is pulled back into the mantle into a subduction zone (e.g., the Pacific Ocean).

The breakup of Pangea, beginning some 200 million years ago, saw the birth of the present oceans. In the geological near term, within the next 100 million years or so, the sequence will go into reverse. Oceans will close and continents will converge to reassemble as Pangea II some 250 million years in the future.

New oceans form by the breakup of supercontinents warmed by rising mantle plumes. Initial doming above the plume is followed by formation of three-armed rifts called “triple junctions.” 

Today’s Red Sea, Gulf of Aden, and East African Rift are three arms of a complex rift system formed by the breakup of the African Plate above the upwelling African mantle plume. Opening of the Red Sea is pushing the Arabian Plate into the Eurasian Plate and pushing Turkey (the Anatolian Plate) into the Mediterranean Sea – all that is left of the ancient Tethys Ocean. Pieces of its oceanic crust are scattered around the Mediterranean as mineral-rich rocks called ophiolites.

(Top left) Stretching and rifting of continental crust is occurring today along the East African Rift, producing staircases of upstanding blocks (called horsts) and down-dropped blocks (grabens). Upwelling magma from the mantle invades the rift zone and leaks enormous volumes of fast-flowing basaltic lava called “flood basalts” in recognition of their fluidity and ability to move quickly (centre right). These volcanoes cannot grow as steep cones like stratovolcanoes, instead forming “shield volcanoes,” so named after their resemblance to the dome-like form of a warrior’s shield placed on the ground. Continued rifting and subsidence results in eventual invasion by the sea to form an embryonic ocean.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

The 1783 eruption along the 30-km-long Laki fissure between the Myrdalsjökull and Vatnajökull ice caps was massive, spewing out some 15 km3 of lava and throwing volcanic ash as high as 13 km into the atmosphere. An estimated 120 million tonnes of sulphur dioxide created an acidic haze that slowly drifted across Europe, causing many deaths, destroying crops, and fostering riots and unrest that lead to the French Revolution in 1789. Currently, the North American Plate is moving about 3 cm westward every year, and the European Plate by a similar amount eastward, creating 6 cm of new oceanic crust every year. But the fate of the Atlantic is already sealed; in the long term, dramatic changes will someday occur along its opposing coasts as heavy oceanic crust starts to subduct and volcanoes emerge under New York and London.

The North Atlantic midocean ridge is raised above sea level in Iceland, and its central rift is seen here at Thingvellir. The high ground in the background at left is the edge of the North American Plate, which is moving away from the edge of the Eurasian Plate at right. The rate of divergence between the two is being measured here by Professor Freysteinn Sigmundson of the University of Iceland, using GPS.

Death Some 250 million years ago, the Tethys Ocean was a large C-shaped embayment on the eastern margin of Pangea. Today, the Mediterranean Sea is all that remains of the former ocean, having been crushed like a car in a scrapyard by the northward movement of Africa, India, and Australia against Eurasia. Its former floor is now preserved as deformed rocks within a major mountain chain that extends for more than 8,000 km in a belt from Spain to Nepal from the Atlas, Taurus, Caucasus, and Zagros Mountains to the high Himalayas, where more than 100 mountain peaks are higher than 7,200 m – the greatest concentration anywhere on the planet. The rise of the Himalayas triggered the onset of Ice Ages of the last 2.5 million years, and the great seasonal land-ocean “sea

north of Reykjavik, where the fictional Professor Lidenbrock and his nephew in Jules Verne’s 1864 classic novel Journey to the Centre of the Earth began their journey by climbing into its crater. Iceland’s Mid-Atlantic Ridge is famous for its fissure eruptions, when highly fluid basalt magma floods out of the fractured ground like blood from a deep wound. Cooling of magma in fissures creates vertical wall-like dikes, and their repeated intrusion assists in pushing the crust away on either side just as Reginald Daly had surmised in 1926 in his book Our Mobile Earth.

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The New World of Plate Tectonics

LEFT: Sea floor spreading on land in Iceland involves the formation of long deep cracks (fissures) into which magma moves up from the mantle and is intruded to form thousands of dikes, first noted by Reginald Daly in 1926. RIGHT: Enormous lava flows result from fissure eruptions of fast-flowing basaltic magma. This is oceanic crust in the making, and Iceland is slowly being stretched as the North American and Eurasian Plates drift apart.

breeze,” known as the monsoon, which dumps copious volumes of rain over the foothills and plains of India toward the end of May each year. The monsoon affects a large part of surrounding Southeast Asia including China and Japan, where one third of the world’s population depend on it to sustain the annual rice crop. Today, like the Tethys Ocean before it, the Pacific Ocean is showing the unmistakable signs of terminal decline, marked by the Pacific Rim of Fire where enormous volumes of oceanic crust are being recycled back into the mantle in subduction zones. The melting of heavy basaltic oceanic crust and large amounts of seawater, together with parts of the upper mantle, is ironically a key process in building continents. Melting

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of subducting crust produces very different magmas, which, when erupted at the Earth’s surface, form low density, silica-rich rocks such as andesite, named from the Andes of South America, adding to the mass of the overriding continent. The continents are in effect the tectonic winners of Earth history, always growing in extent, at the expense of the oceans, which come and go. The Pacific Rim of Fire is a very dangerous place because subduction unleashes powerful “megathrust” earthquakes (like what occurred in Alaska in 1964), destructive tsunami, and massive volcanic eruptions and ash falls. Indeed, the tectonic violence around the Rim of Fire can at times affect the entire planet, as was seen with the eruption of the Indonesian volcanoes

High mountains that extend from the Alps of Western Europe through to the Himalayas and beyond are composed of the buckled rocks of the former Tethys Ocean. The limestones on top of Mount Everest that puzzled Noel Odell in 1924 originated on the floor of the ancient ocean.

The crater of Lascar Volcano in the Andes of northern Chile reaches almost 6,000 m above sea level. It is a typical Pacific Rim stratovolcano growing in height during explosive eruptions when broken andesitic rock and magma are thrown out of the volcano and dropped on its flanks. The collapse of the steep sides results in clouds of burning hot gas and broken rock that avalanche downslope as “nuée ardentes” (glowing clouds). These volcanoes are dangerous because their magmas contain silica and the resulting andesite lavas are stiff and do not flow as readily as the flood basalts produced by volcanoes in areas of rifting and sea floor spreading. The great height of stratovolcanoes eventually prevents magma reaching the throat of the volcano; gas pressure builds up and is released in a catastrophic eruption that throws many cubic kilometres of pulverized rock (popularly called ash, but more correctly referred to as pyroclastic debris) into the atmosphere, obliterating the volcano and leaving a volcanic caldera. These volcanoes are huge factories for recycling subducted heavy oceanic crust into much lighter continental crust.

The New World of Plate Tectonics

The Pacific Ocean is slowly dying as the Pacific, Cocos, and Nazca Plates are being subducted below encroaching continents, creating the dangerous Pacific Rim of Fire some 40,000 km in length, marked by deep trenches and more than 400 stratovolcanoes – three quarters of all volcanoes on Earth – and powerful earthquakes.

Tambora in 1815 and Krakatau in 1883. Tambora threw 100 km3 of pulverized rock and ash into the atmosphere during what is now considered to be the largest volcanic cataclysm on the planet in the last 10,000 years. Simultaneous eruptions of ash from several large Pacific Rim volcanoes in the mid-fourteenth century triggered a planet-wide climate cooling that lasted as the “Little Ice Age” until around 1900. Such global cataclysms can and will happen again, possibly stopping global warming in its tracks.

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In Search of Ancient Continents Geologists are still not quite sure when and how Earth’s first continents formed, but it has been proposed, somewhat strangely, that it would not have been possible without first having water on the planet’s surface. No Water, No Granites – No Oceans, No Continents is the title of a now-famous publication written in 1983 by Ian Campbell of the University of Toronto (working with Tuzo) and Stuart Taylor of the Australian National University in Canberra.

Continents are made of relatively light rocks rich in silica, such as andesite and granite, in contrast to lithospheric plates of much heavier oceanic crust that underlie the ocean floors and are made of iron-rich basalt. Ironically, the formation of the first continental andesites and granites on planet Earth required water, since these rocks are largely the product of the “wet” melting of ocean floor basalt containing sea water and upper mantle rocks. Consequently, the essential precondition for making the first continent was the first ocean. Granitic rocks are rare in the crust of Mars and the Moon because they lack water, and our wet planet is the only one in the solar system with continents. What Earth’s surface may have looked like just after its formation is unknown, but it may have appeared as a glowing red-hot “magma ocean” under heavy bombardment by giant meteorites, which prevented cooling and stabilization of an early crust. Outgassing of water vapour and the ponding of surface water created the first proto-oceans, giving a radically new face to the planet, cooling the hot magma ocean to form a stiffer “protocrust.” At the same time, the Earth’s core began to consolidate as the result of iron-rich nickel slowly sinking under gravity through the depths of the mantle. The trinity of crust, mantle, and core was now in place. On the floors of the brand-new oceans, the nowcooled, hardened, and much-thickened basaltic crust began to sink back (subduct) into the softer hot mantle below, carrying with it vast volumes of water – the essential ingredients of continental crust when melted at depth with mantle rocks. The newly formed and much lighter granitic magma rose from the depths to the Earth’s surface as huge rafts, creating the first protocontinents, perhaps appearing from space as light-coloured islands in

Subduction around the Pacific Rim of Fire recycles oceanic crust into continental crust. Descending slabs of oceanic crust melt at depth, sending magma back to Earth’s surface by building volcanic arcs. Subduction zones are sites of powerful megathrust earthquakes that now threaten Seattle and Vancouver. Both these cities, and Tokyo, are overdue for the next “big one,” the last one happening in the Pacific Northwest around 1700, and in 1923 in Tokyo. The angle of descent of the Pacific Plate below Japan is so steep it is pulling the island nation away from the Eurasian Plate, in the process opening the Japan Sea as a “back arc basin.” In the Great Tōhoku earthquake of 2011, Japan was moved instantaneously as much as 50 m eastward, marking another step in the eventual closure of the Pacific Ocean.

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The North American Plate is moving westward and extends from its eastern margin deep underwater along the MidAtlantic Ridge, where new oceanic crust is added by sea floor spreading, to its western margin bordering the Pacific Ocean, where it is overriding and sliding past oceanic crust of the Pacific and Juan de Fuca Plates. The North American Plate, formed by the breakup of Pangea some 200 million years ago, carries the North American continent, made of rocks as old as 4 billion years.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

the vastness of the one blue ocean; these were the seeds from which all the modern-day continents would eventually grow – much like the froth seen on Tuzo’s experiments with pots of boiling tomato soup. Once formed, continents cannot be destroyed or recycled; their granitic crust is too light to be thrust down a subduction zone. The North American continent is not a single homogenous piece of crust but a complex mosaic, what the Canadian geologist Paul Hoffman describes as the “United Plates of America.” As we have related, the continent has grown by accretion of far-travelled crust around its original nucleus – the Slave Craton in Northwest Canada, whose rocks are at least 4 billion years old. The continent is now 25 million km2 in area, which is an astonishing seventy times larger than it was 4 billion years ago. The continent grew in size spasmodically as the supercontinents Superior-Sclavia (2.7 billion), Nuna (1.8 billion), Rodinia (about 1 billion), and Pangea (350 million) assembled, so oceans were destroyed and their floors subducted; in the process, large slabs of oceanic crust and their thick covers of sedimentary rock were accreted to the edges of continent. A clearer picture of how continents grow has come from the work of the geologist Tanya Atwater (you will remember she had been inspired by Tuzo, when he showed off his famous transform model in Ottawa). In 1970 she recognized that the geology of most of the western United States and Canada is the result of the subduction of huge expanses of the former floor of the Pacific Ocean (that part called the Farallon Plate) in the last 200 million years. All that is left of the doomed plate is the remnant Juan du Fuca Plate, now being subducted under Vancouver and Seattle. Like

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The North American continent is a mosaic of crustal blocks (variably called terranes, cratons, and provinces) added during the formation of past supercontinents (Superior-Sclavia, Nuna, Rodinia, and most recently, Pangea). The continent is now seventy times larger than it was 4 billion years ago when it consisted simply of the Slave Craton in northwest Canada.

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Continents grow from small nuclei of old rock such as shields, more than 4 billion years old, by repeated accretion of far-travelled crust (called terranes).

ships pulling up to a quayside, small oceanic islands carried along by the doomed Farallon Plate docked with western North America as “terranes.” Painstaking fieldwork by geologists such as David Howell, Stephen Johnston, and Peter Coney and their many students in the rugged mountains stretching from Mexico through Canada to Alaska (collectively known as the Cordillera) reveals that some terranes originated thousands of kilometres away, some from China, all carried across the Pacific Ocean by the eastward moving Farallon Plate. The same story applies to the geology of the Appalachian Mountains in eastern North America, which is largely made up of blocks of far-travelled crust that were scraped off subducting ocean floor crust. In the north, the Yakutat terrane in Alaska is in the process of docking, the collision throwing up the tallest mountains in North America. Once a terrane collides, its journey is not over, being then moved northwards by sliding along the edge of the continent for hundreds of kilometres (a process called “collide and slide”). The largest of these terranes in western

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Much of the western part of the North American continent is the result of crustal accretion in the last 200 million years. In this time, the westward moving North American Plate has scraped off landmasses being carried by the Farallon Plate, which has now almost all but been subducted, leaving the Juan de Fuca Plate as a remnant. Baja California is moving north as a terrane along the San Andreas Fault to join Canada.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

The world at it may appear 250 million years in the future: one supercontinent (Pangea II) surrounded by one ocean.

North America is “Wrangellia,” which originated in Central America. It docked some 145 million years ago in present-day California and slid northwards like a car crashing into and careening along a guard rail. Fragmented during its journey, its pieces have been carried as far north as Alaska – the largest piece is known today as Vancouver Island. In the same fashion, the entire Baja California peninsula is being moved northward along the San Andreas Fault en route to its final resting place in Canada. Subduction and crustal accretion of terranes along the western boundary of North America created powerful pushing forces that deformed older continental rocks like a bow wave as far inland as present-day Calgary and Denver, creating the folded and thrusted rocks of the Rocky Mountains. As we saw earlier in this book, these were once seen as a record of a contracting, cooling planet, but are now appreciated as the product of terranes being shoved onto the leading edge of

North America as the plate moves westward following the breakup of Pangea. The Beartooth Mountains of Montana – Tuzo’s study area from his PhD years at Princeton in the 1930s, which permanentists argued were the product of buckling of a deep geosyncline – resulted from crustal shortening as oceanic plates and terranes collided with western North America.

Back to the Future: Pangea II So far, much of this book has been focused on peering in the rear-view mirror of geologic history and seeing how geologists came to determine how continents and oceans have changed over billions of years. But what have we learned that has any predictive value for what the future Earth might look like? As it turns out, we can forecast future plate tectonic activity much better than next month’s weather because the global satellite

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positioning system accurately tracks the drift of plates and continents in real time, such that their movement can be predicted. Today, lithospheric plates and their continental passengers are converging on Southeast Asia and the western Pacific region. North and South America will lie along its western margins cozied up against Antarctica, and Australia will be reunited, having been brought together by the death of the Pacific Ocean. Africa will nestle against Eurasia, and the Atlantic Ocean will have been long destroyed by subduction.

The Limits of Plate Tectonics One can only conclude that the difficult problem of what mechanism drives the plates is far from settled. Plate tectonics seems to provide a tenable theory of what is happening to the Earth, but it offers no explanation of why, and the search goes on. J. Tuzo Wilson, 1985

Today, more than fifty years after it was first formulated, geologists are still not entirely sure how plate tectonics works. There are major geological features on the surface of our planet that the theory simply does not explain. There is also lingering uncertainty about the precise boundaries of some plates (such as that between the North American and Eurasian Plates). Geologists also argue about how and when plate tectonics first started (about 3 billion years ago is the modern consensus), how it got going, and how the Earth may have functioned prior to the onset of plate tectonics. Much argument still surrounds the long-standing issue of what processes move plates. The relative importance of pushing forces

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exerted by the outward movement of sea floor spreading on either side of midocean ridges (“ridge push”) and the tremendous pulling forces exerted by great slabs of oceanic plates being dragged down subduction zones (“slab pull”) is still much debated. The balance of evidence suggests that slab pull is the much more important process and that the pulling of cold wet plates back into the mantle contributes to mantle convection, and in turn, the movement of hot mantle rock up to the surface to feed midocean ridges. Basically, nothing comes up until something goes down. The deepest hole ever drilled is a mere 12 km long. Diamonds give some idea of processes at work as much as 800 km underground. But beyond that, our knowledge of Earth’s interior is limited to the analysis of seismic energy waves triggered by earthquakes passing through the planet. Tuzo was convinced that “hot spots” (classically represented by the Hawai’ian Islands) are the surface expression of deep mantle plumes, tall columns of hot mantle rock rising to the Earth’s surface from the core-mantle boundary, that remain fixed in position like bunsen burners piercing the overlying plate. New work suggests that plumes are not deep seated in the mantle but result from local and relatively shallow melting of the upper mantle (“melt spots,” according to Gillian Foulger) and are not fixed but move. The debate continues. Other enigmatic features are the so-called Large Igneous Provinces (LIPs) that record vast outpourings of magma, both on land and on ocean floors, that appear to be unexplainable by Tuzo’s plate tectonic theory, since they occur in the middle parts of plates remote from their more active edges. LIPs, too, have long been associated with mantle plumes, but this has also been questioned and some argue, controversially, that the larger

Tuzo: The Unlikely Revolutionary of Plate Tectonics

Large areas of volcanic rock on the surface of planet Earth are unrelated to plate boundaries. Instead, they record hemorrhaging of magma from the mantle. These are called Large Igneous Provinces (LIPs).

ones might be the product of giant meteorite impacts that shattered the Earth’s crust, releasing magma from below. They point to the giant impact crater and related volcanism that happened at Sudbury, Ontario, some 1.8 billion years ago. Others relate LIPs to rips and tears within plates that allow mantle rocks to escape upwards and begin to melt. The giant dike swarms criss-crossing the Canadian Shield (and all others) that Tuzo mapped from the air in the 1930s are also now recognized as LIPs, perhaps related to unusual episodes when the continent was being stretched. Other types of volcanic activity that are not readily fitted within a plate tectonic framework are “super-volcanoes,” each capable of throwing more than 1,000 km3 of pulverized rock into the atmosphere. At least four such “super-eruptions”

are known to have occurred in the last 2.5 million years. That at Yellowstone is the most well known and it threw out an estimated volume of 2,500 km3 of ash and rocky debris about 2.2 million years ago. There is much theorizing and debate about these astonishing “big bangs,” which are thought to occur somewhere on the planet about every 100,000 years. A key question is whether plate tectonics as we understand it today has always operated in precisely the same fashion earlier in Earth history. Here the jury is still out. Some, notably Robert J. Stern and his colleagues, argue that long phases of “normal” plate tectonics characterized by the formation and breakup of supercontinents alternate with long-lived “pauses” in activity with a much thicker and more rigid “lid-like”

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lithosphere. He and others suggest that the last two supercontinents Rodinia and Pangea followed a long period (nicknamed by some geologists as the “Boring Billion” between 1.85 and about 800 million years ago) where the lithosphere may have been too thick and strong to allow subduction. This would also have prevented crustal rupturing from forming midocean spreading centres, halting the formation and movement of plates. In this respect, Venus, Mars, and Io are modern illustrations of normal plate tectonics being paused and “on hold.” In contrast, normal plate tectonic activity as we know it today may have operated on a hot early Earth but at much faster rates. The modern consensus, voiced by Chris Hawkesworth and others, is that plate tectonics was underway by at least 3 billion years ago. The biggest challenge to resolving these and other questions is our inability to peer into the inner workings of the machine: Earth’s interior. Understanding its anatomy is still reliant on studies of how seismic waves produced by earthquakes travel through the interior of the planet, a technique referred to as “seismic tomography.” Geophysicists Trond Torsvik and Kevin Burke, formerly an early recruit of Tuzo at the University of Toronto, recognized the presence of huge slabs of hot dense rock at depths approaching 3,000 km, far below Africa and the Pacific Ocean (one of which has been named “Tuzo”). These may be the remnants of ancient ocean floor crust subducted into the mantle, and their boundaries appear to delineate the location on the Earth’s surface of hot spots, implying that mantle upwelling is only happening around their edges. This is a reminder that what happens on the Earth’s surface is controlled by the deep structure of the mantle. More definitive answers about the working of plate tectonics will be found in the “inner space” of Earth’s

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mantle by a new generation of geophysicists armed with better technology, and by forensic examination of long-dead lithospheric plates now buried in continental shields. The scientific journey started in 1968 by Tuzo’s vision of plate tectonics has only just begun.

Why Plate Tectonics Matters Almost nothing in geology makes sense except in the light of plate tectonics. M.D. Simmons, 2020

Thinking like a geologist can save the world. Marcia Bjornerud, 2018

Tuzo was fond of stressing that while huge sums of money were being spent on space programs and lunar exploration (and now Mars), much of the Earth’s surface remained terra incognita. Ironically, several decades later the data collected remotely from the red planet have led to profound scientific insights into the history of life here on Earth. We now appreciate that life on Earth would be impossible in the absence of plate tectonic processes, which act as a thermostat regulating extremes in surface temperatures, resulting in a habitable planet. Mantle convection and sea floor spreading along midocean ridges release enormous volumes of water vapour, oxygen, and carbon dioxide. Mantle outgassing filled the first ancestral oceans with water and created a protective atmosphere able to burn up incoming meteorites. In the deep oceans, dissolved nutrients in the superheated waters spewing out from midocean ridges and their

Tuzo: The Unlikely Revolutionary of Plate Tectonics

“smokers” sustain simple aquatic life forms that support more complex pyramidal food chains, including humans. Those same hot waters are the source of the metals now preserved in ancient oceanic rocks, bequeathed by the deaths of former oceans such as Iapetus and Tethys, and allowed us to build civilizations, fuel the Industrial Revolution, and create modern prosperous economies. Convection in the Earth’s core also acts as a large dynamo that creates an electromagnetic field (the magnetosphere), which protects us from the solar wind and its high-energy particles. Without that shield, the oceans, the atmosphere, and all life would be vaporized and stripped from the planet’s surface. Gaze up at the moon to see what Earth would look like without mantle convection. Convection in the core and mantle, the movement of lithospheric plates, and life are all intimately interconnected. The first-ever land masses and their rocks billions of years ago were exposed to the chemically corrosive effects of rain – a weathering process that consumes carbon dioxide, scrubbing it from the hot early atmosphere, cooling the planet, and preventing runaway global warming. In a similar fashion, in the last 15 million years, the formation of high mountains such as the Himalayas and the weathering of their debris scrubbed huge amounts of carbon dioxide from the atmosphere, cooling the planet and helping create oscillations between warm climates and Ice Ages. These swings in climate gave rise to wet and dry cycles in the East African Rift and were the background to human evolution. The lesson is that a dynamic planet with active plate tectonics allows organic life to evolve and flourish, and this simple rule now guides the search for other habitable planets among many distant exoplanets.

The recurring opening and closing of oceans accompanying the growth and later breakup of supercontinents has driven the long-term evolution of the Earth’s changing climates and atmosphere and its biosphere over billions of years. The abrupt emergence of complex multi-cellular marine animals, including those with protective shells and backbones, at the end of the Precambrian about 540 million years ago is closely linked to the breakup of the supercontinent Rodinia. New oceans formed by the breakup of this huge land mass created new habitats for life to diversify. Plate tectonics and the origin and history of life on Earth are inextricably linked.

Plates of Wrath: Cities on the Edge Earthquakes alone are sufficient to destroy the prosperity of any country. Charles Darwin, 1835

Life needs plate tectonics, but the same life-giving processes also threaten destruction. The year 2007 saw human society pass an evolutionary milestone, thousands of years in the making: most of us now live in a city or its suburbs, not in the country. The “age of construction” has created nearly forty megacities that individually are home to more than 10 million people each, and some are up to four times larger. These megacities house some of the world’s most dynamic economies and as massive consumers of raw products, and producers of wastes, will determine the environmental future of our species. Plate tectonics created opportunities for cities to prosper and expand. Old rocks, often mineral-rich, are

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uplifted into mountains. These are eroded by rivers that carry vast volumes of sediment to sustain fertile floodplains and their rich soils before flowing out to coastlines with deep, sheltering, and strategically located harbours. Cities have grown rapidly by having access to mineral wealth, lumber and other construction materials, productive soils, and plentiful food supplies. But there is a deadly catch. It is estimated that by 2050, two thirds of the global population will be concentrated in cities sprawled across active plate boundaries, highly vulnerable to volcanic activity and earthquakes. They are cities living precariously on the edge. Great earthquakes have a way of shaking up societies and destroying economies. The Lisbon earthquake, which rocked the pious Portuguese “City of Light” on 1 November 1755, killed as many as 50,000 people. Its traumatized inhabitants questioned how a munificent god could be so destructive, especially on All Saints Day. The French philosopher Voltaire wrote about the disaster, as did Immanuel Kant, who attributed it to natural – not divine – processes, reflecting the rationalist approach of the Enlightenment movement then taking root in Europe. Lisbon lies on continental crust broken during the breakup of Pangea, a victim of its rifted past. The Lisbon disaster helped trigger the beginnings of the science of seismology in the West, and earthquake-resistant buildings were designed for a newly reconstructed city laid out with large squares and wide streets. But the economy was so badly bruised that the financial prominence of the city was never re-established. It had been dealt a mortal blow by tectonics. Today, billions of people live and work around the Pacific Rim in some of the world’s most dynamic economies threatened by the violent tectonic forces

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accompanying the death throes of an entire ocean. The effects of the 1891 Nobi earthquake in Japan, for example, had far-reaching social and political consequences, revealing the weakness of Western-inspired buildings and of the government’s response, ultimately strengthening the military’s grip on society, resulting in a belligerent Japan in 1941. The 1906 San Francisco earthquake affected a relatively small city of 400,000 people, yet the aftereffects cut the gross national product of the United States by as much as 2%, raised interest rates in Britain as insurance companies paid out massive claims, and tipped the United States into recession in 1907, creating what has been called a “monetary aftershock.” The western margin of the Pacific Rim of Fire is one of the deadliest places on the planet. Greater Manila in the Philippines is home to some 22 million people, and Jakarta has more than 30 million inhabitants expected to increase to 36 million by 2030. The two cities lie right on the front line of an ongoing war between rival tectonic plates, held hostage to forces beyond their control. The Great Tōhoku earthquake of 2011, which affected northeastern Japan, was the costliest natural disaster in history and triggered a nuclear accident. To the south, the area around Tokyo is home to 40 million people and is overdue for a large, damaging earthquake that will shortly rock the global financial system. Tokyo uniquely lies above the intersection of four lithospheric plates, and geologists have determined that a major earthquake occurs every century on average; the mathematics are not good, as the last one was in 1923. In China, the Tangshan earthquake of 1976 killed half a million people. Today, earthquake-prone China has many of

Tuzo: The Unlikely Revolutionary of Plate Tectonics

The world’s largest cities and earthquake risks. Red circles are sites of recurring moderate-to-high-magnitude earthquakes. About 40% of the world’s urban population is concentrated around the Pacific Ring of Fire marking the closure of the Pacific Ocean, and along the seismically active tectonic zone of the Tethyan Belt extending from the western Mediterranean to the western Pacific Ocean marked by high mountains recording the closure of the former Tethys Ocean. This is where the African, Pacific, and Eurasian Plates are colliding to form the next supercontinent.

the largest cities on the planet: Guangzhou, with close to 45 million inhabitants in its greater metropolitan area, followed in size by Shanghai, Chongqing, and Beijing. Great changes are in store. Globally, almost 40% of the planet’s entire economy is hosted in countries scattered along the length of the west–east collision zone between the Eurasian, African, and Pacific Plates that extends some 9,000 km from Spain to China. Like the Pacific Rim today, this belt marks the ancient Tethys Belt, where a former ocean died. Global resilience is threatened as supply chains across the world are so closely interconnected, but plate tectonic theory helps identify the most vulnerable

populations and how risk can be lessened by appropriate monitoring and planning. Worldwide, about seventy volcanoes erupt every year, and about twenty are active at any one time, but very few of the remaining hundreds of dormant volcanoes are closely monitored and watched. A heavily debated topic among geologists has been the role of supervolcanoes and their possible influence on global climate and human evolution. Some argue that the massive eruption of Toba in Sumatra, Indonesia, about 75,000 years ago, which released an estimated 3,000 km3 of magma and ash, cooled global climates for as much as 1,000 years and substantially reduced the 232

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human population of the planet. This debate mirrors that about the end-Permian extinction event about 252 million years ago when the bulk of marine species died off and land-dwelling organisms were reduced by as much as 70%. One theory states that the extinction event was related to vast outpouring of basalt magma in the “Siberian Traps,” which is a Large Igneous Province. Even small volcanic eruptions can have widespread effects on our society, as we saw in 2010, when ash from Iceland’s Eyjafjallajökull Volcano resulted in disruption of flights for months. The island has another thirty-two as yet still sleeping giants. Volcanic ash in the atmosphere not only interferes with plane travel, but scientists now increasingly appreciate the effect such eruptions have on global climate as they examine the global record of major eruptions and their influence on climate, recorded in ice cores recovered by drilling deep into the Greenland and Antarctic ice sheets.

Plates of Plenty At the end of the Precambrian era some 540 million years ago, the supercontinent Rodinia broke apart to create many small but expanding oceans, making incubators for new forms of marine life to evolve and flourish, in what has become known as the “Cambrian explosion.” By the Silurian period some 100 million years later, the continents had finally been colonized by algae and shortly afterwards by the Carboniferous some 325 million years ago; densely forested coastal swamps became giant factories where peat was compressed into coal when buried under younger sediments. At the same time, organic material derived from marine organisms such as phytoplankton and 233

algae were trapped in the sediments on sea floors. Buried at depths of several kilometres or more, and in the process warmed and cooked, these were the chemical feedstocks for oil and gas. Coal was once king, and it fuelled the Industrial Revolution, and in turn the chemical and urban revolutions, which have transformed the quality and length of human life. Coal is relatively easy to find, occurring in well-defined layers that commonly outcrop at surface, giving clues to the riches below. The beginnings of the international oil industry can be traced to Oil Springs, near Petrolia in southwestern Ontario, Canada, where it was first exploited from shallow dug wells in 1858, although Indigenous people had recognized its value long prior and used it to waterproof canoes and for medicines. For oil to be present underground in sufficient volumes to be developed commercially it must be trapped in “reservoirs,” typically comprising rocks that have open pores that are interconnected (much like a sponge) that allow hydrocarbons to migrate into the rock and accumulate. The early days of oil exploration focused on areas where potential reservoir rocks had been gently folded or faulted, where a sandstone “trap” was underlain by a “source rock” (organic-rich shale) and overlain by a “seal,” ideally of thick salt beds. The easy targets were soon found and depleted, which presented a question: Where else could we find oil? It eventually became clear that there was a link between oil and Pangea. After 1968, plate tectonic theory provided a coherent framework for the mapping and exploration of sedimentary basins worldwide. Geologists now recognize a wide suite of basin types, all defined by their plate tectonic setting, which gives rise to a predictable range of trap types, what are called “reservoir models.” Some of the

Tuzo: The Unlikely Revolutionary of Plate Tectonics

most prolific reservoirs and oil-bearing basins are those that formed during the breakup of Pangea and are now preserved deep under continental shelves, such as those of the North Sea and Hibernia off Canada’s east coast. The vast oil wealth of Saudi Arabia, Oman, and Iran is a gift of the Tethys Ocean, where enormous thicknesses of salt, organic-rich source rocks, and thick limestones accumulated in tropical climates over hundreds of millions of years. As Pangea broke up, and Africa moved north to collide with Eurasia, marine rocks of the Tethys Ocean were creased into large anticlinal structures trapping huge quantities of oil and gas.

next decades demand will increase by as much as 1,000%; other studies conclude, bleakly, that future demand exceeds all known reserves discovered to date. Yet remarkably little attention has been paid to how we might find the resources required, or whether it is even possible. Traditional energy sources – n ­ uclear, coal, oil and gas – still need to be be developed to guarantee energy security in the face of enormous obstacles to powering rapidly expanding cities and industry solely from renewable energy sources and unforeseen geopolitical events. Finding those in the quantities required and ensuring ethical sourcing of supplies will require a massive transformation in public attitudes, and there is no quick fix. We do know that the road map to a greener economy lies with the application of plate tectonic theory to ancient rocks, and knowledge of the different tectonic settings in which resources are to be found. The planet’s metal deposits, for example, are the gifts of ancient volcanoes and ocean floors, and it is no coincidence that the first classical metal-working civilizations in human history developed around the shores of the Mediterranean, in the ancient mineral-rich crust of the former Tethys Ocean. A new “age of mining” and resource development now beckons, and with it a heightened demand for new geophysical tool and technologies for finding the mineral wealth hidden in Earth’s crust. As this book has shown, understanding of plate tectonics was the offspring of data gathered by wartime technology, and massive investments in science and technology. Meeting the challenge of finding new resources in the quantities now required will need a mobilization of geoscientific expertise on the same scale.

Plate Tectonics, a Green Future, and the New Age of Mining Most of us now live in an urban bubble where the prevailing attitude is that nature is under control, and where it is easy to lose sight of the origins of the resources that house us, move us, allow us to grow food and feed us, keep us healthy, and allow us to communicate; all these resources ultimately come out of the ground. “If it isn’t grown, its mined” is an old adage, yet we are still living in the Stone Age, needing more and more of the metals and resources that can only come from rocks. “Going green” is the mantra of the times, yet the shift to renewable energy sources and the advanced technologies on which they depend compounds our reliance on metals – and mining. The ominous phrase “geological scarcity” is now being voiced by geologists familiar with the supply of strategic metals and rare earth elements. The World Bank estimates that in the

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The complexities of the Earth and the difficulty of studying it have prevented geology from becoming precise. It still retains more of the quality of an art to be gained by long experience than physics does. Where calculations will not avail, imagination and judgement must do. J. Tuzo Wilson, 1956

The greatest impediment to progress in research is not lack of funds but the universal challenge all humans share of opening the mind to fresh ideas – of conceiving the possibility that a new theory might have merit over accepted views. J. Tuzo Wilson, 1993

In the Marvel comic books, Captain America, the Second World War superhero, is trapped in ice for nearly seventy years before being thawed out to resume his global adventures. Another hero, Lieutenant Alfred Lothar Wegener, is still frozen, buried to this day within the Greenland Ice Sheet, but his grand theory of continental drift re-emerged in the late 1960s and, reborn and reconfigured as plate tectonics by Tuzo Wilson, has gone on to conquer the world. The birthplace of this great idea is in Hawai’i, where

in August 1961 Tuzo had his revelation fittingly enough on top of an active volcano. Tuzo had visited Hawai’i in 1950 on his way back from Australia, but possessing a fixed permanentist mindset he could not see what was so obvious a decade later: what he called a “long straight string of volcanic islands” that got progressively older with distance, implying that the Earth’s surface layer had moved across a hot spot where magma rises as a column from the Earth’s interior. The solution to the great debate

Tuzo: The Unlikely Revolutionary of Plate Tectonics

about Earth’s behaviour triggered in 1910 by Frank Taylor’s hypothesis of “Earth’s Plan” and moving “crustal flakes” was now finally in view. It is in Greenland’s snowy wastes that the contributions of Alfred Wegener and Jock Tuzo Wilson merge and become a single narrative. Wegener’s final resting place high on the ice sheet lies close to the northern boundary of the so-called Nagssugtoqidian Orogen, consisting of highly deformed rocks between 2 and 1.8 billion years old, hidden deep below the ice sheet and only exposed along the coast. In a nod to Tuzo, these rocks record a complete Wilson Cycle of continental rifting, opening of the so-called Manikewan Ocean and its later closure. The highly deformed rocks found in Greenland are perfectly matched with those of the Torngat Orogen of Labrador in eastern Canada and the Trans-Hudson Orogen in northwest Canada, that taken together record the assembly of an early North American land mass within the supercontinent Nuna. Greenland is now the largest island in the world but for most of its existence has been part of the Canadian Shield until it was torn away from North America about 80 million years ago during the breakup of Pangea. The vivid story of continent building and oceans that are born and die, developed into a coherent theory by Tuzo Wilson, lies near Wegener’s icy gravesite, which is being carried westward by the continental drift he had predicted but never lived to see confirmed. Plate tectonic theory as it evolved in the 1960s was in many ways the gift of new electronic technology developed in the Second World War and the Cold war. Funded by the Allied military, geologic data could be collected and processed on a scale hitherto impossible by newly developed computers. Just as the availability

Alfred Lothar Wegener lies buried at Eismitte high on the Greenland Ice Sheet. That part of the ice sheet lies close to the Nagssugtoqidian Orogen, a broad belt of deformed rocks that record the opening and closing of a 2-billion-year-old ocean during the building of the supercontinent Nuna. It is a fitting tectonic memorial to the father of continental drift, for the orogen records a complete Wilson Cycle, named after the Canadian father of plate tectonics.

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of surplus warplanes and air photography after the First World War changed the science of geology for good, so too did the huge investments made during and after the Second World War by the US Navy and the Royal Navy in equipment and personnel needed to explore the planet’s oceans and find enemy submarines. In retrospect, it is deeply ironic that the clearest evidence for mobilism was derived not from the study of easily accessible thrusted and pushed rocks on land, such as in mountains, but by shipboard geologists working remotely high above the floors of the deep and dark ocean floors where no human has ever walked. The Swiss geologist Rudolph Trumpy has humorously admitted that the failure of his European colleagues to see what was hidden in plain sight in their own Alps was a consequence of the “modest tonnage of the Austrian and Swiss navies.” The long journey from continental drift to plate tectonics and the battles of the permanentists and mobilists told in this book illustrate the inbuilt resistance of the scientific establishment to embrace bold new ideas, especially when proposed by students and those perceived as scientific outsiders. Looking back at the poor treatment of Alfred Wegener by many of the world’s leading geologists, but especially those in North America, Ted Irving wrote, “It was unconscionable that an atmospheric physicist should so confidently propose a radical overhaul of their ideas about their solid Earth.” In their turn, the ideas of Frank Taylor, Amadeus Grabau, Alex Du Toit, Reginald Daly, Arthur Holmes, Inge Lehmann, Marie Tharp, Ted Irving, and Larry Morley were all discounted and dismissed in the face of the prevailing political orthodoxy of permanentism that pervaded the geological elites and their universities.

Taught dogmatically as late as 1960 for more than a century since the time of James Dana, permanentism crumbled in much less than a decade, virtually overnight. A constant refrain seen in the recollections of the then-young geologists at the time was one of amazement at the whirlwind pace of discovery, and the seemingly bewildering explosion of ideas. All were aware they were living through a special time in the history of geology, even if they couldn’t see exactly where the science was heading. New data would often be presented at meetings that no one could then interpret before it all suddenly came together at last in 1968. Old data and maps generated by cohorts of long-dead geologists were similarly revaluated to glean entirely different answers. An entire science had been turned upside down. Rapid revolutionary changes in science are known as “paradigm shifts,” and while there are other examples of transformative debates in geology, none are so grand as plate tectonics. During the Annual Meeting of the Canadian Institute of Mining and Metallurgy in March 1967, Tuzo felt bold enough to proclaim a revolution in earth sciences had just occurred, suggesting that it should be called the Wegenerian Revolution. The name never caught on; it reminded geologists of the earlier, sometimes ugly chapter in the history of their science when the German had been grossly misrepresented (or just ignored). Tuzo and his colleagues, especially John Jacobs, tried to get the new mobilism, with its heavy reliance on physical laws governing the behaviour of the planet, renamed “geonomy,” but that too failed; it had been the title of a book published on 1858 by James Stanley Grimes that attributed the creation of

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the continents to dissection of a large land mass by powerful ocean currents. Revolutionaries are always impatient for change, and Tuzo was no exception. Susan relates how “you either got on board or got left behind” by her father, and Tuzo’s nickname at Toronto was the “benign cyclone of science” in recognition of his extraordinary physical and mental energy. He could also be highly critical of those who hadn’t realized that geology had been irrevocably refashioned and who, in his opinion, were still pursuing “rather unimaginative studies based on pedestrian interpretations of natural phenomena.” The long war between permanentists and mobilists may have finally been decided as the 1960s ended, but there were still local skirmishes within individual university departments where some senior faculty now found themselves out of touch, pursuing outdated research and isolated from the new world order. The very public spats Tuzo had with the chair of the Geology Department at Toronto, Les Nuffield, are illustrative of the lingering tension among geologists. Tuzo gave a well-attended talk in the Geology Department in 1967 as a dry run for his upcoming William Smith Lecture to the Royal Society in London. Henry Halls remembers “people hanging on the rafters of the seminar room in the Mining Building. Tuzo opened his lecture by saying something like ‘mineralogy, geochemistry and petrology have been studied for over a hundred years and most of them are now well known’ … to which Nuffield jumps out of his seat and shouts ‘That is simply not true!’ To which Tuzo responds ‘of course it is – it’s perfectly obvious!’” Nuffield was so furious that afterwards he called Tuzo into his office

and threatened to dismiss him from the department, to which Tuzo is supposed to have answered, “You can’t. I’m appointed by the dean.” Geoffrey Norris, now an emeritus professor of geology at Toronto, also remembers another noisy run-in between Tuzo and Nuffield. Norris had been working in Oklahoma, the epicentre of the 1960s oil boom in the United States, and was lured north to an academic position at Toronto in 1967, where part of his teaching duties in geology involved a broad introductory course in which the then-emerging theory of plate tectonics loomed large. Norris invited Tuzo to give a guest lecture on his work. On later learning of the invitation that had been extended to Tuzo, Nuffield angrily and very loudly berated Norris (so that others could clearly hear and take heed) for having the nerve to “invite Tuzo into the Geology Department.” Many of Tuzo’s colleagues were conducting highly sophisticated laboratory experiments on rocks and minerals, but on rereading their results today, one is struck by the lack of any reference to how the findings might throw light on plate tectonic processes. Tuzo wrote in 1970 that “these studies are too limited to solve by themselves the major problem of how the earth behaves.” As a result, students at Toronto needed to steer a fine line between professors who distrusted each other because of their allegiance, or otherwise, to Tuzo. Undergraduates occupied a dangerous noman’s-land, unsure of which professor to listen to, and they had to develop the skill of unlearning what they had gained from Tuzo to pass exams in more conventional courses taught by other professors. Barrie Clarke, then a student, distinctly remembers one professor’s exhortation to his class in 1963 “not to

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pay any attention to Professor Wilson. He’s crazy!” He also provides an example of the retrograde learning required to survive:

had to unlearn everything that Tuzo had taught us and

In our first class, Tuzo asked us to go to the bookstore

Another student at the time, Peter Reynolds (now a retired emeritus professor of geology), vividly recalls that “it was very hard to take notes from Tuzo because he was so eager to tell the class what he’d just seen, or heard on his travels, scribbling things on the blackboard and not finishing the sentence, as yet another thought crowded in.” Above all, Tuzo had a natural feel for new ideas that would prove fertile for further discoveries, and with his great industry (and close ties to the editorial boards of leading scientific journals), he could get his ideas out quickly. His wartime success in bringing a scientific efficiency to bear on operational research with the Canadian Army, and the imperative need to collect, assess, and act promptly on emerging information, underlay his ability to move fast as an academic. In 1961 he had set aside the permanentist doctrines and beliefs that had governed his earlier career, recalibrated and “adopted a new revolution.” In the end, while he bemoaned his earlier inability to embrace mobilism, he changed his mind decisively – and didn’t flip-flop – and so escaped the suspicion of opportunism that can befall academics who change their minds too frequently to fit the current mode of thinking. In 1975 Tuzo presented the Massey Lectures on the Canadian Broadcasting Corporation’s radio broadcasts consisting of six one-hour talks on the “Limits of Science.” With typical humility he downplayed his own role in developing plate tectonics, stressing instead his inability to recognize the limits

replace it with outmoded concepts from the textbook that he himself had co-written but had recently rejected.

and buy a copy of Physics and Geology by Jacobs, Russell, and Wilson as our textbook. We then settled into a pattern that involved two types of lectures: In the first, we would arrive in the lecture room at the appointed time and sit there and sit there, and then finally the secretary would come in and say, “Didn’t Professor Wilson tell you? He’s in Europe/Russia/ China (whatever) this week” and off we’d go to an early lunch. In the second type of lecture, we’d sit in the room until we heard footsteps on the stairs, and then in would come Tuzo with a big globe under his arm and a wide grin on his face and he’d say, “You’ll never guess what I thought about last night.” And then for the next hour he would share with us his latest ideas, well before plate tectonics became the new paradigm. It was fun, it was inspiring, but it was confusing because it didn’t fit into the framework of what we were learning from other geology professors. And that created problems when we attended the final lecture. We heard footsteps on the stairs, but it was Professor Farquhar that entered our classroom. He told us that Professor Wilson was away in Europe/Russia/ China/Antarctica (or wherever) and that Tuzo had asked him to set the exam, but because Dr. Farquhar did not know what we had been doing in our classes he said that he would simply base the exam on the textbook we had bought in the first week, and never used. We were stuck in limbo between two completely different geological-geophysical worlds and for the exam we

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of the old permanentism, declaring, “I had shut my eyes to the new evidence and followed the pack.” Tuzo had been a member of the innermost ruling elite for almost thirty years, and yet he ultimately caused the entire pre-existing edifice that had stood for more than a century to abruptly collapse. It was a palace coup by a former insider and most unlikely revolutionary.

her father were when she and Tuzo hiked through the ravines that lead down to the Don River valley in Toronto, while he walked to work following his appointment to the Ontario Science Centre. This domestic situation was not unusual for a senior academic of Tuzo’s era and standing and is indeed typical of the absent-minded professor living in a parallel universe. He was unable to talk about anything other than geology even at family dinners; not out of a selfish need to dominate the conversation, but because he was so intrigued by what he had just discovered. Patty and Susan have fond memories of the great man at home, particularly of his experiments in the kitchen with oranges and hard-boiled eggs to show how their peeled skins and broken shells resemble the Earth’s crustal plates, and his paper models of the workings of transform faults. Susan remembers frequent exclamations of “Isn’t this exciting!” and “Look at this!” from her father, seeing him as a “kid at heart,” totally fascinated by what he was doing, much to the exclusion of anything else, even pressing family matters or urgent medical appointments. Not surprisingly, Tuzo had few hobbies other than a love of classical music and stamp collecting, which is ironic, given that physicists had earlier used that term to dismiss the work of geologists, an attitude that had stalled acceptance of Wegener’s work in the early years of the twentieth century. When not travelling, the family spent summers on the east shore of Lake Huron a few hours north of Toronto, where in 1952 Tuzo and Isabel had restored a derelict cottage on the rocky shores of Go Home Bay, in the 30,000 Islands area of Georgian Bay on the Canadian Shield. In hindsight, it was a fitting location for the forefather of plate

Remembering Tuzo Look at all the other things you can see and do! J. Tuzo Wilson, on the advantages of a career in geology, 1993

Jock Tuzo Wilson is to earth science what Charles Darwin is to biology and Galileo and Copernicus to astronomy: all transformed their own sciences and humankind’s view of the world at large, and our place in it. But in addition to being a scientific heavyweight, Tuzo was also a much-loved family man and friend. At times he could be challenging to live with, frequently away for long periods of time and exhausted when he returned, preoccupied with what he had just learned. Heavily involved with his lecturing, writing, and travelling, it fell to his wife, Isabel, not only to keep the home fires burning but also to edit and polish his public writings. She made Tuzo’s life possible, declaring that she and their daughters, Patty and Susan, always “came second to the bowels of the Earth.” Susan relates that her father was incapable of small talk or even discussing his emotions and seemed on many occasions to be remote and insensitive to the needs of the family. Her longest conversations with

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Tuzo and Isabel relaxing aboard Mandarin Duck, his fiveton Chinese junk, amid the many islands of Georgian Bay in the summer of 1966. The boat was later used as a platform for a twelve-part television series The Planet of Man in 1975 in which he related the importance of the new discoveries in plate tectonics.

The Wilsons on their 50th wedding anniversary in October 1988. Isabel was the rock, the one unmoving, permanent fixture in Tuzo’s constantly shifting world, and kept him functioning when preoccupied with research and all too often oblivious to family matters. While he travelled the globe, often for many months at a time, it took resilience to raise two daughters and manage and host the neverending round of formal events for the many visitors drawn to Toronto by her husband’s achievements.

Tuzo: The Unlikely Revolutionary of Plate Tectonics

tectonics, because the rocks are highly deformed gneisses like those he had worked on as a young man in the Northwest Territories. Today, we now know that they illustrate processes operating many tens of kilometres underground near the base of tectonic plates, as hot rock under great pressures and temperatures slowly creeps like hot wax, allowing the rigid plate above to move. Now exposed to view by deep erosion of the crust and high mountains that once marked a giant collision zone during the building of Rodinia 1 billion years ago, these rocks are the smoking gun of the role of plate tectonics in building the North America continent. Tuzo would sail his Chinese junk Mandarin Duck, which had been specially imported from Hong Kong. Barrie Clarke remembers the excitement and commotion surrounding the arrival of the boat when it was unloaded from a freighter in Toronto Harbour in 1964.

me. After all, I had only just recently graduated with a B.Sc. and I felt insignificant.

As a former colonel in the Canadian Army, Tuzo cut an authoritative and charismatic figure that spoke of self-confidence, yet he was always very approachable. He believed and would frequently exclaim that “science is for everyone!” and possessed the rare ability to easily move from the very formal atmosphere of a boardroom or conference into the classroom or public forum to capture the imagination of old and young alike with his many “hands on” demonstrations and passion about geology. His sudden storm of ideas and exuberance would leave no one untouched; heads turned as he entered a room. He was an inspired teacher with the skill, enthusiasm, and creativity to motivate others to take up geology, never missing the opportunity to share his knowledge with others, whether in the laboratory, classroom, field, or just talking over a beer. Henry Halls was recruited by Tuzo as a young graduate student at a conference held at the Royal Society in London in 1964 entitled “Continental Drift.” He recalls,

I was working in the Chemistry Building in a lab strewn with equipment needed for that summer’s fieldwork on Baffin Island with Tuzo; tents, sleeping bags, Coleman stoves, hammers, rope, etc. I was just minding my own business studying some air photographs when the door suddenly burst open. It was Tuzo. “Barrie, come quickly. My junk has arrived.” I really had no idea what he was talking about. Was

Everybody who was anybody was there including

he referring to his own field gear? It was only as we

well-known scientists such as Runcorn, Girdler, and

were in his car tearing down Bay Street that I found

Irving, and of course, Tuzo. For a young, sheltered

out what it really was. We went out in the harbour and

graduate student in the middle of a master’s degree it

watched a crane lift a real Chinese junk off the ship’s

was all rather overwhelming to be in the presence of

deck and lower it into the waters of Lake Ontario.

such famous people. I first approached Runcorn who

Tuzo was characteristically beaming from ear to ear.

kept looking past me and then said “Ah! There you are

When I look back on this event, I am still amazed, and

Jock I need to talk to you” and without so much as an

honoured that he shared this special moment with

apology left me stranded in mid-sentence. After a few

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Barrie Clarke, whom we met earlier, also described to the author how just “one brilliant idea Tuzo dropped into an undergraduate lecture” in 1963 eventually became his own life’s work at Dalhousie University. Barrie was just about to work with Tuzo in Baffin Island investigating how Greenland had drifted away from Canada during the opening of the northern Atlantic about 60 million years ago.

minutes, the next person I tried was Tuzo himself, who was surrounded as always, by an audience. I timidly went up to him and asked to talk about graduate studies at Toronto. Immediately he broke out of the encirclement with apologies and took me to one side and was friendly and very interested at the prospect of me working with him.

Tuzo’s love for teaching and his ability to relate to all age groups is highlighted by Oliver Bertin, a young high school student in Toronto in the early 1970s.

Everybody knew about the early Tertiary volcanic province in West Greenland, but only Tuzo had made the connection with some obscure volcanic rocks on

I was president of Jarvis Collegiate Institute’s Sci-

Baffin Island. I was infatuated with anything Arctic,

ence Club in Grade 10 or 11. We were looking for a

so a year later I timorously knocked on Tuzo’s door

good speaker and my friend John Burka suggested

and asked him if he wanted anyone (specifically me!)

a famous scientist, “Mr. Wilson,” who lived next

to go and look at those rocks. A few months later, in

door. We really had no idea who he was or what he

the summer of 1964, off we went together, but before

did, but that didn’t bother us. John went over one

going, I had determined that we would buy our food

day when he was on his knees planting tulips in his

supplies at the Hudson’s Bay Post on Broughton

front garden. John looked down and said: “Excuse

Island. When we got there, I had my shopping list of

me, Mr. Wilson, would you speak at our science

canned meat, canned spaghetti, canned vegetables,

club, please?” Tuzo looked up and said: “Certainly,

powdered milk, powdered eggs, etc. But Tuzo would

young man. When would you like me to come?” We

have none of it, being determined that we were going

organized a date, looked up this guy and suddenly

to “live off the land” in deference to his old friend

realized that he was a world-famous geophysicist!

the Arctic explorer Vilhjalmur Stefansson’s views on

Oh no! We rushed around, cleaned up the chemistry

how to survive in the Arctic. The only purchase Tuzo

lab, grabbed some cookies and made sure we had a

permitted for himself was pilot biscuits (hard tack),

kettle and some tea. He came on time and took us all

and it wasn’t long before he was hungry and ate into

very seriously. He gave a very impressive talk that I

our canned spaghetti! Ironically, only after he returned

still remember almost 50 years later. He was so polite

to Toronto did we have some Arctic char, seal, walrus,

he didn’t complain when we poured the hot tea into

and even polar bear (all hunted by our Inuit guides).

wax paper cups. I remember the hot wax floating on

It was there in Baffin Island that Barrie learned that despite Tuzo’s standing as an internationally respected

the surface of the tea, and I’m sure he noticed it too, but he didn’t say anything.

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scientist with numerous prestigious awards, he was at heart a highly modest individual. “Tuzo and I spent 24 hours a day together for 2–3 weeks on Baffin Island, and he never once told me any stories about his geological or wartime activities when he could have done so continuously, and without repetition, during that entire time. Today, I own a cottage in the middle of one of the areas that Tuzo had mapped in southwestern Nova Scotia from the 1930s (one of the best outcrops on the lake is on our property, so he must have seen it) and wish that he had told me his accounts of the days he spent here. It’s special to think that his footprints are on our land.” Many others have spoken to the author about Tuzo in the same vein, and it may be that his slim unpublished autobiography with its notable gaps and disappointing omissions about his signature scientific achievements simply reflects his own fundamental humility and deference to the role played by others in the development of plate tectonics.

lead the organization. He was also appointed chancellor of York University in Toronto (1983–7). As his health began to deteriorate in the early 1990s and his memory began to fade, Tuzo was unable to complete several research projects, and there is a sense from his correspondence written shortly before his death in early 1993 that he regretted the time spent away from research. As a man of tremendous vitality and energy, in his view his life’s work could never be completed, as there were always new projects and discoveries to be made, places to go, and people to meet. This zeal trumped any consideration of what he considered more mundane matters, such as his own well-being and mortality. In his last years he became interested in his old stomping ground from his Princeton days and proposed that volcanic activity of the Yellowstone area reflected the drift of North America over a mantle hot spot (now seen as the product of a tear in the subducting Farallon Plate). The fabulous silver deposits of Nevada, he suggested, were also related to upwelling mantle plumes and the metal-rich fluids they expelled. These ideas were the topic of Tuzo’s last lecture at the University of Toronto in early 1991, which the author remembers vividly. The grand occasion was “Rockfest,” an event still held every Friday afternoon, when faculty and students assemble and describe their latest projects, usually with a beer in hand. A large circular table occupied the middle of the seminar room and every chair crammed around its periphery was taken, with others standing in the corridor outside hanging on to his every utterance. You could have heard a pin drop. Somehow or other, we all instinctively knew a geological era was coming to

“With Zest to Go, in Quest to Know” During his tenure at the Ontario Science Centre, Tuzo’s organizational skills were much in demand and took him away from geological research. He was a member of the Science Committee of NATO in Brussels from 1976 to 1986 and chaired the Canadian Commission on Aluminum Wiring, which produced a lengthy volume in 1981 that he largely compiled and wrote. He was the first non-American president of the American Geophysical Union (1980–2), which had to rewrite its constitution to allow a Canadian to

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an end and what he said seemed much less important than being in his presence. Tuzo’s farewell lecture to the public was given at the Ontario Science Centre in February 1992, entitled “With Zest to Go, in Quest to Know,” in which he recounted his career and his vast global travels. A year later, Susan took him on a trip to Roy Thomson Hall to hear the Russian Philharmonic Orchestra. He was very frail:

Canada has produced many eminent scientists, but Tuzo stands tall amongst their company, having also served his country with great distinction in wartime. He never won a Nobel Prize for his discoveries (it is not given to earth scientists) but was awarded its geological equivalent, the prestigious Vetlesen Prize by Columbia University in 1978 for “scientific achievement resulting in a clearer understanding of the Earth, its history, or its relation to the universe.” First awarded in 1960, the list of past laureates reads like a “Who’s Who” of plate tectonics and includes Tuzo’s early mentors Sir Harold Jeffreys and Sir Arthur Holmes. Like his mother, Hetty, Tuzo was fascinated by mountains, and in fact both are memorialized by having peaks named after them: Mount Tuzo in Alberta for his mother, and the Wilson Mountains in Antarctica for her son. These mountains are on the Weddell Sea coast of Palmer Land of the Antarctic Peninsula and were named in honour of his visit during Operation Deep Freeze in 1958. Fittingly, they lie adjacent to the Du Toit Mountains. His name is also given to the Wilson Seamounts, which are active sea floor volcanoes in deep water some 200 km west of Vancouver Island and lie, appropriately enough, above a mantle hot spot just like Hawai’i where he had made his momentous discovery in 1961. A large part of the Earth’s lower mantle deep below Africa from which plumes have been derived for much of the planet’s history and which may control plate movement is also named after Tuzo. He had written in 1961, in his book IGY: The Year of the New Moons, that “it is strange that the only substance from the dark interior of the earth which most people ever

Mum had refused to go because she was so worried about his health, but I thought it worth the risk. Dad had never heard that orchestra live before and badly wanted to hear it play. He was also thrilled that the program contained his two favourite symphonies. To save his strength, I treated him to a leisurely dinner on King Street and I began to regret my decision to go out with him that winter night. I felt sure too that being now exhausted he would sleep through the entire evening, as he rarely could stay awake after dinner at the best of times. I was wrong. He was alert and elated throughout the entire evening and at the end was totally buoyed up by the experience. I remember his chuckling with delight before the performance began when the harpist, who turned out to be the only female member of the orchestra, came onstage with a mane of golden curls cascading down her back. Dad said something like “Well there’s the cat among the pigeons!” Mum remarked that the next day he hardly moved from his chair, but he was beaming with pleasure all day.

Tuzo died six weeks later. An early hand-drawn map of Earth’s tectonic plates was found under his bed.

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notebook on that fateful day in Hawai’i atop Mauna Loa volcano. Its thickness is equivalent to the distance that the crust on which you live will have moved by this time tomorrow. Scarcely noticeable, but over the course of a year, it is equivalent to the thickness of decent-sized book, over an average lifetime it is more than 2 m, and in a million years it is as much as 40 km. Given the vastness of Earth’s history, where time is measured in billions of years, the slow shift of Earth’s plates, their destruction by subduction and their creation by sea floor spreading, has reconfigured the face of the planet many times over; entire oceans have been squeezed shut and new oceans born again by the rupture of immense supercontinents, a process that will continue for the next few billion years, taking the continents on their long unfinished journeys. Tuzo’s name is forever associated with this fundamental rhythm that describes the changing face of an entire planet and its geological history. In truth, Tuzo needs no memorial; the ground over which we walk, the planet on which we live are testament to this eminent Canadian geoscientist and teacher who showed us how the Earth’s surface moves, why and how mountains are uplifted, how continents are made, why they migrate, and why oceans open and eventually must die. Tuzo revealed to all of us how our planet works.

Tuzo’s achievements are commemorated by a large iron spike at the Ontario Science Centre in Toronto, symbolically driven down right through the North American plate and embedded in the underlying mantle; the torn pavement to the left of the spike provides a graphic image of the distance the plate and the Science Centre have moved westward (to left) over the mantle and thus around the spike during Tuzo’s lifetime – about 2.3 m.

see is the brilliant diamond.” A newly discovered diamond-bearing kimberlite near the Gahcho Kué diamond mine, some 250 km northeast of Yellowknife in the Northwest Territories, is named after him. Much more accessible to the public is the memorial to Tuzo located just outside the Ontario Science Centre on Don Mills Avenue in Toronto. As you near the end of this book, take a moment to ponder the thickness of the page ripped from Tuzo’s

Si monumentum requiris circumspice. If you seek his monument, look around.

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Appendices

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Appendix I: Medals and Awards

On receiving the Vetlesen Prize from Columbia University in 1978, Tuzo stated, “Many do the work and only one gets the award. It’s not fair.”

1930:

Coleman Gold Medal in Geology, University of Toronto

1930–2: Massey Fellowship to University of Cambridge 1946:

Order of the British Empire; Officer, Legion of Merit, United States

1950:

R.M. Johnston Medal, Royal Society of Tasmania

1958:

Willet G. Miller Medal, Royal Society of Canada

1959:

S.G. Blaylock Medal, Canadian Institute of Mining and Metallurgy

1960:

Civic Award of Merit and Gold Medal, City of Toronto

Appendix I: Medals and Awards

1968: Logan Medal, Geological Association of Canada; Bancroft Award, Royal Society of Canada; Bucher Medal, American Geophysical Union; Penrose Medal, Geological Society of America 1970: Order of Canada, Officer 1974: Order of Canada, Companion 1975: J.J. Carty Medal, US National Academy of Sciences 1978: Gold Medal, Royal Canadian Geographical Society; Wollaston Medal, Geological Society of London; Vetlesen Prize, Columbia University; J. Tuzo Wilson Medal, Canadian Geophysical Union; Joseph Priestley Award, Dickinson College; Rennie Taylor Award, American Tentative Society (Science ­Writers of United States) 1979: Albatross Award, American Miscellaneous Society 1980: Ewing Medal, American Geophysical Union; M. Ewing Medal, Society of Exploration Geophysics 1981: Huntsman Award, Bedford Institute of Oceanography 1983: Citizenship Award, Ontario Association of Professional Engineers 1986: Encyclopaedia Britannica Medal and Award 1989: Wegener Medal, European Union of Geosciences; Killam Award, Canada Council 2005: Inducted into the Canadian Mining Hall of Fame

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Appendix II: Select Primary Sources

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– 1926. Ice Ages Recent and Ancient. New York: MacMillan. – 1932. “Glaciation and Continental Drift.” Geographical Journal 79:252–5. Coode, A.M. 1965. “A Note on Oceanic Transcurrent Faults.” Canadian Journal of Earth Sciences 2:400–1. – 2011. “Part of the History of the Origin of Transform Faults.” Earth Sciences History 30:58–62. Daly, R.A. 1926. Our Mobile Earth. New York: Charles Scribner and Sons. Dana, J.D. 1895. Manual of Geology. 4th ed. New York: American Book. Dewey, J.F., and J.M. Bird. 1970. “Mountain Belts and the New Global Tectonics.” Journal of Geophysical Research 75:2625–47. Dewey, J.F. 2016. “Marking 50 Years of the Wilson Cycle.” Geoscience Canada 43:283–5. Dietz, R.S. 1961. “Continent and Ocean Basin Evolution by Spreading of the Sea Floor.” Nature 190:854–7. – 1994. “Earth, Sea, and Sky: Life and Times of a Journeyman Geologist.” Annual Review of Earth and Planetary Sciences 22:1–32. Dott, R.H. 1997. “James Dwight Dana’s Old Tectonics: Global Contraction under Divine Direction.” American Journal of Science 297:283–311. Du Toit, A.L. 1937. Our Wandering Continents: An Hypothesis of Continental Drift. Edinburgh: Oliver and Boyd.

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– 1944. “Tertiary Mammals and Continental Drift: A Rejoinder to George G. Simpson.” American Journal of Science 242:145–63. Evans, D.A.D., Z.X. Li, and J.B. Murphy. 2016. FourDimensional Context of Earth’s Supercontinents. London: Geological Society of London, Special Publication, no. 424, 1–14. Eyles, N. 1987. “The Life and Times of Arthur Philemon Coleman: Geologist, Mountaineer and Artist.” Geoscience Canada 14:183–92. Eyles, N., and A.D. Miall. 2018. Canada Rocks: A Geologic Journey. 2nd ed. Markham, ON: Fitzhenry and Whiteside. Foulger, G.R. 2010. Plates vs Plumes: A Geological Controversy. Hoboken, NJ: Wiley-Blackwell. Frankel, H.R. 2016. The Continental Drift Controversy. 4 vols. Cambridge: Cambridge University Press. Friedman, G.M. 2007. “In Memory of Professor Amadeus William Grabau (1870–1946) on the Semicentennial of His Death.” Carbonates Evaporites 22:86–91. Garland, G.D. 1995. “Obituary: John Tuzo Wilson.” Biographical Memoirs of Fellows of the Royal Society 41:534–52. Grabau, A.W. 1921. A Textbook of Geology. Boston: D.C. Heath. – 1940. The Rhythm of the Ages. Peking: H. Vetch. Greene, M.T. 2015. Alfred Wegener: Science, Exploration, and the Theory of Continental Drift. Baltimore, MD: Johns Hopkins University Press. Haughton, S.H. 1949. “Alexander Logie du Toit. 1878– 1948.” Obituary Notices of the Fellows of the Royal Society 6:385–7. Hawkesworth, C.J., P.A. Cawood, and B. Dhuime. 2020. “The Evolution of the Continental Crust and the Onset of Plate Tectonics.” Frontiers in Earth Science 8:326. https://doi.org/10.3389/feart.2020.00326 Heezen, B.C. 1960. “The Rift in the Ocean Floor.” Scientific American 203:98–110. Hess, H.H. 1946. “Drowned Ancient Islands of the Pacific Basin.” American Journal of Science 244:772–91.

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Appendix II: Select Primary Sources Kuhn, T.S. 1962. The Structure of Scientific Revolutions. Chicago: Phoenix Books. Lake, P. 1923. “Wegener’s Hypothesis of Continental Drift.” Geographical Journal 61:179–87. See also discussion 188–94. Lane, A.C. 1944. “Frank Bursley Taylor (1860–1938).” Proceedings of the American Academy of Arts and Sciences 75:176–8. Laudan, R., A. Leviton, and M. Aldrich. 1985. “Frank Bursley Taylor’s Theory of Continental Drift.” Earth Sciences History 4:118–21. Le Pichon, X., J. Francheteau, and J. Bonnin. 1973. Plate Tectonics. Amsterdam: Elsevier Scientific. Letsch, D. 2015. “R.A. Daly’s Early Model of Seafloor Generation 40 Years before the Vine-Mathews Hypothesis.” Canadian Journal of Earth Sciences 52:1–10. Lewis, C. 2000. The Dating Game: One Man’s Search for the Age of the Earth. Cambridge: Cambridge University Press. Lyustikh, E.N. 1967. “Criticism of Hypotheses of Convection and Continental Drift.” Geophysical Journal of the Royal Astrophysical Society 14:347–52. Marvin, U. 1985. “The British Reception to Alfred Wegener’s Continental Drift Hypothesis.” Earth Sciences History 4:138–59. McKenzie, D.P., and R.L. Parker. 1967. “The North Pacific: An Example of Tectonics on a Sphere.” Nature 216:1276–80. Menard, H.W. 1986. The Ocean of Truth. Princeton, NJ: Princeton University Press. Military Engineers Association of Canada. 1966. The History of the Corps of Royal Canadian Engineers. Vol. 2, 1936–1946. Ottawa: MEAC. Morley, L.W., and A. Larochelle. 1964. “Palaeomagnetism as a Means of Dating Geological Events.” Royal Society of Canada Special Publication 8:39–50. Nance, R.D., and J.B. Murphy. 2013. “Origins of the Supercontinent Cycle.” Geoscience Frontiers 4:439–40. Natland, J. 2006. “R.A. Daly: Eclectic Theoretician of the Earth.” GSA Today 16:24–6.

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Newman, R.P. 1995. “American Intransigence: The Rejection of Continental Drift in the Great Debates of the 1920s.” Earth Sciences History 14:62–83. Oreskes, N. 1999. The Rejection of Continental Drift: Theory and Method in American Earth Science. New York: Oxford University Press. – 2001. Plate Tectonics: An Insider’s History of the Modern Theory of Plate Tectonics. Boulder, CO: Westview. Runcorn, S.K. 1962. Continental Drift. Cambridge, MA: Academic. Scheidegger, A.E., and J.T. Wilson. 1950. “An Investigation into Possible Methods of Failure of the Earth.” Proceedings of the Geological Association of Canada 2:167–90. Schuchert, C. 1932. “Gondwana Land Bridges.” Geological Society of America Bulletin 42:875−915. – 1955. Atlas of Palaeogeographic Maps of North America. New York: Wiley. Schuchert, C., and C.O. Dunbar. 1941. Textbook of Geology. Part 2: Historical Geology. 4th ed. John Wiley & Sons. Şengör, A.C. 2015. “The Scientific Work and Legacy of Eduard Suess.” Geoscience Canada 42:181–246. Stäblein, G. 1983. “Alfred Wegener: From Research in Greenland to Plate Tectonics.” GeoJournal 7:361–8. Stacey, C.P. 1955. Six Years of War: The Army in Canada, Britain and the Pacific. Ottawa: Ministry of National Defence. Stern, R.J. 2020. “The Mesoproterozoic Single-Lid Tectonic Episode: Prelude to Modern Plate Tectonics.” GSA Today 30:4–10. Swettenham, J. 1968. McNaughton. 3 vols. Toronto: Ryerson. Taylor, F.B. 1910. “Bearing of the Tertiary Mountain Belt on the Origin of the Earth’s Plan.” Bulletin of the Geological Society 21:179–226. – 1923. “The Lateral Migration of Land Masses.” Proceedings of the Washington Academy of Sciences 13:445–57. – 1930. “Correlation of Tertiary Mountain Ranges in Different Continents.” Geological Society of America Bulletin 41:431–73.

Appendix II: Select Primary Sources Torsvik, T.H., and L.R.M. Cocks. 2017. Earth History and Paleogeography. Cambridge: Cambridge University Press. Trumpy, R. 2001. “Why Plate Tectonics Was Not Invented in the Alps.” International Journal of Earth Science 90:477–83. Umgrove, J.H.F. 1947. Pulse of the Earth. The Hague: Martinus Nijhoff. van Waterschoot van der Gracht, W.A.J.M. 1928. Theory of Continental Drift: A Symposium on the Origin and Movement of Land Masses as Proposed by Alfred Wegener. Tulsa, OK: American Association of Petroleum Geologists. Vine, F.J. 1966. “Spreading of the Ocean Floor: New Evidence.” Science 154:1405–15. – 2003. “Ophiolites, Ocean Crust Formation, and Magnetic Studies: A Personal View.” Geological Society of America, Special Papers 373:65–75. Vine, F.J., and D.H. Matthews. 1963. “Magnetic Anomalies over Oceanic Ridges.” Nature 199:947–9. Vine, F.J., and J.T. Wilson. 1965. “Magnetic Anomalies over a Young Oceanic Ridge off Vancouver Island.” Science 150:484–9. Wegener, A. 1915. Die Entstehung der Kontinente und Ozeane. Braunschweig: Vieweg & Sohn. – 1966. The Origins of Continents and Oceans. New York: Dover. West, G.F., R.M. Farquhar, G.D. Garland, H.C. Halls, L.W. Morley, and R.D. Russell. 2014. “John Tuzo Wilson: A Man Who Moved Mountains.” Canadian Journal of Earth Sciences 51:xvii–xxxi. Wilkinson, B.H., B.J. McElroy, and C.N. Drummond. 2017. “Broken Sheets: On the Numbers and Areas of Tectonics Plates.” GSA Today 28:4–9. Willis, B. 1928. “Continental Drift.” In Theory of Continental Drift: A Symposium, edited by W.A.J.M. van Waterschoot van der Gracht. Tulsa, OK: American Association of Petroleum Geologists, 76–82. – 1944. “Continental Drift, ein Märchen.” American Journal of Science 242:509–13.

Wilson, J.T. 1938. “Drumlins of Southwest Nova Scotia.” Transactions of the Royal Society of Canada, 3rd ser., 32:41–7. – 1939. “Eskers Northeast of Great Slave Lake.” Transactions of the Royal Society of Canada, 3rd ser., 33:119–29. – 1941. “Structural Features in the Northwest Territories.” American Journal of Science 239:493–502. – 1946. “Winter Manoeuvres in Canada.” Canadian Geographical Journal 32–3:88–93. – 1947. “Exercise Musk Ox: 1946.” Polar Record 5:14–27. – 1957. “Origin of the Earth’s Crust.” Nature 179: 228–30. – 1959a. “Geophysics and Continental Growth.” American Scientist 47:1–24. – 1959b. One Chinese Moon. New York: Hill and Wang. – 1961a. “Discussion of R.S. Dietz: Continent and Ocean Basin Evolution by Spreading of the Sea Floor.” Nature 192:125–8. – 1961b. IGY: The Year of the New Moons. Toronto: Longmans. – 1962. “Cabot Fault: An Appalachian Equivalent of the San Andreas and Great Glen Faults and Some Implications for Continental Displacement.” Nature 195:135–8. – 1963a. “Continental Drift.” Scientific American 208:86–100. – 1963b. “Evidence from Islands on the Spreading of Ocean Floors.” Nature 197:536–8. – 1963c. “Hypothesis of Earth’s Behaviour.” Nature 198:925–9. – 1963d. “A Possible Origin of the Hawai’ian Islands.” Canadian Journal of Physics 41:863–870. – 1965a. “Evidence from Ocean Islands Suggesting Movement in the Earth.” Philosophical Transactions of the Royal Society London 258:145–67. – 1965b. “A New Class of Faults and Their Bearing on Continental Drift.” Nature 207:343–7. – 1966. “Did the Atlantic Close and Then Re-open?” Nature 211:676–81.

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Appendix II: Select Primary Sources – 1968a. “A Revolution in Earth Science.” Canadian Mining and Metallurgical Bulletin 61:185–92. – 1968b. “A Revolution in Earth Science.” Geotimes 13:10–16. – 1973. Unglazed China. Toronto: MacMillan. – 1976. Continents Adrift and Continents Aground. San Francisco: W. H. Freeman. – 1982. “Early Days in University Geophysics.” Annual Reviews of Earth and Planetary Sciences 10:1–14. – 1985. “Development of Ideas about the Canadian Shield: A Personal Account.” In Geologists and Ideas: A History of North American Geology, edited by E.T. Drake and W.M. Jordan. Centennial special vol. 1. Boulder, CO: Geological Society of America, 143–50.

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Wilson, J.T. 1975. The Planet of Man (TV series). https:www .youtube.com/playlist?list=PL1CC57D3ECC4B2B13. Wilson, J.T., G. Falconer, W.H. Mathews, and V.K. Prest, V.K., compilers. 1958. Glacial Map of Canada. Toronto: Geological Association of Canada. Wilson, R.W., G.A. Houseman, K.J.W. McCaffrey, A.G. Doré, and S.J.H. Buiter, eds. Fifty Years of the Wilson Cycle in Plate Tectonics. Special publication 470. London: Geological Society of London. Winchester, S. 2001. The Map That Changed the World. New York: Harper-Collins Publishers. York, D. 2001. “Rock Stars: J.T. Wilson.” GSA Today, September, 24–5.

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Appendix III: The Geological Timescale

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Glossary

absolute age Age of a rock in millions or billions of years as determined by radiometric dating techniques. Contrast with relative age. accretion Principal process by which continents grow by the addition of crustal blocks (terranes) during collisions with other continents. accreted terrane Block of crust that was formerly a land mass or a piece of the ocean floor that eventually collided with and adhered to the margin of a continent. accretionary wedges Unstable piles of marine sediments scraped off an oceanic plate as it descends into a subduction zone. When shaken by large earthquakes they slump and create damaging tsunamis.

andesite Igneous rock with greater than 50% silica content. Andesitic magmas are stiff, trap gas, and do not flow readily (unlike flood basalts) and are typical of highly explosive volcanoes. andesitic volcano Highly explosive, steep-sided volcano above a subduction zone and characterized by explosive eruptions of stiff, silica-rich andesitic magma that produce huge volumes of pyroclastic debris. Commonly described as a stratovolcano because it grows in height by the layer-by-layer accumulation of debris and lava flows on its flanks. anticline Rocks bent into bent into arch-like folds by compression (contrast with syncline).

active margin Leading edge of a lithospheric plate where it collides with another plate; also known as a convergent margin. Contrast with passive margin.

apparent polar wander (APW) pathway Map showing the migration pathways of continents through time determined by study of remnant magnetism in igneous rocks.

aeromagnetic survey Airborne magnetic geophysical survey designed to identify buried geological structures such as faults and mineral deposits.

asthenosphere Plastic layer of the Earth’s outermost mantle about 50–300 km below the surface where rocks begin to soften under heat and pressure. It

Glossary

forms the basal part of the much cooler and much more rigid lithosphere, broken into plates that move by gliding across the asthenosphere.

the term “displacement theory.” Continents are embedded in much larger lithospheric plates that move across the softer asthenosphere below.

atoll Circular, halo-like reef around the rim of an extinct midocean volcanic island that slowly sank below sea level as underlying crust cooled, to become underwater seamounts or guyots.

contractionism The belief that as the planet cools it shrinks, wrinkling its surface to produce mountain ranges.

basalt Igneous rock lacking in silica and enriched in heavier iron and magnesium. Typical of oceanic crust formed on the ocean floor at midocean ridges and hot spots (see pillow basalt). Typically associated with gabbro, which cooled more slowly at depth and is more coarsely crystalline.

convection Internal circulation within the mantle driven by differences in temperature and density; think of the workings of a lava lamp. convergent plate margin Tectonically active zone between two colliding plates (also known as an active plate margin). There are three types, depending on which type of plates are involved: ocean-ocean, ocean-continent, and continent-continent. Contrast with passive margin and divergent margin.

batholith Large mass of molten magma intruded into rocks at depth that cools slowly to produce granite. When eroded and exposed at surface they form rounded sugar loaf mountains. body waves Energy released by earthquakes that moves through the interior of the Earth (contrast with surface waves).

craton Oldest, innermost, and most stable part of a continent composed of Precambrian rocks, e.g., the Canadian Shield. The term is also used for component parts of shields, along with province and terrane.

Cambrian explosion Sudden appearance of abundant multicellular animals near the beginning of the Cambrian period, about 540 million years ago.

crust Outermost layer of Earth consisting of either lower density, relatively light continental crust or heavier, more dense oceanic crust. The base of the crust is the Mohorovičić Discontinuity.

continental crust Thick, relatively low-density granitic crust, low in iron and relatively enriched in silica, ranging from 40–100 km thick. Contrast with denser oceanic crust.

crustal rebound Increase in elevation of Earth’s surface when the crust with its underlying much softer mantle is freed from the weight of a large ice sheet (glacial rebound) as ice melts, or when large mountain ranges are worn down by erosion.

continental drift Term attributed (incorrectly) to Alfred Wegener to describe the movement of continents across the Earth’s surface after the breakup of the supercontinent Pangea. He used

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crystalline Appearance of igneous rocks and the size of their component crystals which reflect the rate at which parent magma cooled.

other (also called transcurrent, strike-slip, or wrench faults by geologists). felsic Igneous rocks such as granite and andesite, typically containing more than 50% silica, ­depleted in magnesium and iron. They are of lower density than mafic rocks such as basalt and gabbro that dominate oceanic crust.

dike Vertical wall-like igneous intrusion that cross-cuts older rocks and/or other structures; also spelt as dyke. Contrast with sill. divergent plate boundary The boundary where two plates move away from each other from a midocean ridge.

flood basalt Name given to magma noted for its fluidity and ability to flow long distances from volcanic vents.

docking Collision of one far-travelled piece of crust (terrane) with a continent.

focus Zone below the Earth’s surface where an earthquake is generated. Contrast with epicentre.

drumlins Long streamlined hills formed under a glacier that resembles an upturned boat with the bow (the sharp end) facing up glacier. They can be several kilometres in length and up to 50 m high.

fold Rock layers that have been crumpled by tectonic activity (see also syncline and anticline) because of tectonic activity. fold and thrust belt Region of deformed rocks produced during plate collisions or accretion of terranes (orogeny). They are associated with crustal thickening and high mountains formed during orogenies (such as the Rocky Mountains and Appalachians).

epicentre Point on Earth’s surface lying immediately above the focus of an earthquake. esker Long sinuous ridge of sand and gravel deposited by water flowing in tunnels under a glacier or ice sheet. expansionism The belief that the planet Earth is slowly expanding.

Ga Abbreviation for Giga-annum, referring to the age of an event or rock measured in billions of years (1,000,000,000 years or 109 years). See also Ma and ka.

extrusive igneous rock Molten rock (magma) that reaches Earth’s surface forming a lava flow. Contrast with intrusive igneous rock.

gabbro A coarsely crystalline igneous rock with same chemical composition as basalt and typical of heavy oceanic crust.

fault A fracture or break where blocks of rock have been markedly offset and displaced on either side. They can result from compression of Earth’s crust (reverse faults) or stretching (normal faults), or simply where blocks slide past each

geodesy That branch of Earth sciences concerned with the measurement of the planet’s surface, shape, and gravity field.

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geology Study of planet Earth and its history (also referred to as Earth science or geoscience).

nineteenth-century marine geologist (also known as a seamount). They often form distinct linear chains known as a hot spot track.

geophysics Application of physics to geology to further understand Earth’s origins and evolution. Widely used to explore Earth’s deep interior and search for mineral deposits just below the Earth’s surface.

hot spot Area on the Earth’s surface lying directly above a mantle plume. Marked by volcanoes that occur in the middle of lithospheric plates (e.g., Hawai’i) rather than, as normal, at their margins.

geosynclinal theory Now abandoned concept formerly used by permanentists to explain the growth of fixed continents by the repeated filling and uplift of deep, moat-like sedimentary basins (geosynclines) around their margins.

hot spot track Linear chain of extinct volcanoes on land or on the sea floor resulting from the movement of the lithosphere over a mantle plume whose position remains fixed (hot spot).

glacial rebound Upward movement of the Earth’s rigid crust after having been previously pressed down into the softer mantle by the weight of a large ice sheet (see also crustal rebound).

hydrothermal activity This refers to the effects of hot superheated waters in altering ocean floor rocks along mid-ocean ridges, often forming rocks rich in metals.

Gondwana Southern part of the supercontinent Pangea composed of what is now South America, Africa, Australia, and Antarctica.

ice sheet A glacier that is large enough to cover all or part of a continent, such as the Laurentide Ice Sheet that once covered much of Canada and northern parts of the United States between approximately 100,000 and 10,000 years ago.

graben Steep-sided trough formed by the subsidence of large blocks of rock between faults.

igneous rock Rocks formed from the cooling of magma, either at the Earth’s surface such as lava flows (extrusive igneous rock) or underground (intrusive igneous rock) in the form of dikes, sills, or plutons.

granite A coarsely crystalline felsic igneous rock formed deep underground in the form of plutons, which cooled slowly from parent magma. greenstone belt A common component of the Canadian and other shields where large volumes of basalt were erupted on a former ocean floor (as pillow lavas) and altered chemically by hydrothermal activity. The term refers to the green colour of metamorphosed basalt.

index fossils Remains of organisms that quickly evolved such that the time range of any one type is short. They are used for correlating rocks found in one area with another.

guyot Flat-topped extinct underwater volcano on the ocean floor named after Arnold Guyot, a

intrusive igneous rock Molten rock (magma) that was injected into other rocks underground in the

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lithosphere Relatively rigid outermost layer of the Earth, broken into plates that move over a weak layer in the upper mantle called the asthenosphere.

form of a dike, sill, or pluton. Contrast with extrusive igneous rock. island arc Curved line of volcanic islands that forms where older oceanic crust is subducted below younger, more buoyant oceanic crust, e.g., Aleutian Arc and those of the Caribbean (contrast with magmatic arc).

lithospheric plate Rigid plates composed of continental or oceanic crust that, together with the uppermost mantle, move around the Earth’s surface in response to convection in the mantle. Each plate has a passive margin where new crust is being formed (at midocean ridges) and an active margin where crust is being destroyed (subduction) below adjoining plates or being compressed against other plates (obduction). Some plates simply slide past each other along transform plate boundaries.

isostasy Vertical movements of lithospheric plates resulting from changing weight on the plate imposed by ice sheets, changes in crustal thickness, and especially the formation and later erosion of large mountains. ka Shortened version of kilo-annum (a thousand years). Unlike the prefixes Mega and Giga, the k is not capitalized. See also Ga and Ma.

Ma Abbreviated form of Mega-annum meaning “a million years.” The initial letter is always capitalized (unlike ka). See also Ga and ka.

lahar Indonesian word for mudflow moving down the slopes of a volcano and composed of large volumes of ash and other pyroclastic debris; can be extremely destructive in populated areas.

mafic Type of igneous rock containing less than 50% silica, with iron and magnesium, such as basalt and gabbro, typical of dense oceanic crust (contrast with felsic rocks, such as granite and andesite, typical of lighter continental crust).

Laurentia Name given to the ancestral North American continent that broke out from the supercontinent Rodinia shortly after about 750 million years ago.

magma Molten igneous rock either underground or flowing on the Earth’s surface as lava.

lava Molten volcanic rock (magma) flowing as a liquid over the Earth’s surface and resulting in a wide variety of extrusive igneous rocks when cooled.

magmatic arc Line of volcanoes produced along the edges of continents by subduction of oceanic crust (contrast with island arc), e.g., the Cascade volcanoes of western North America and the many volcanoes along the Andes.

LIP Acronym for Large Igneous Province recording a short-lived volcanic event when enormous volumes of magma were erupted on the floor of the oceans (oceanic plateau), on land (as continental flood basalts), or intruded (such as dikes).

magnetic anomaly Deviation in the strength of Earth’s magnetic field from the average regional

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Glossary

value identified by an instrument called a magnetometer.

rise to “ridge push” that drives sea floor spreading (see also slab pull).

magnetic north Point on the Earth’s surface to which a magnetic compass needle points.

mobilism Belief held by some geologists in the early decades of the 1900s that continents could migrate. Then widely rejected, it was confirmed during the plate tectonic revolution of the late 1960s. The opposite view is permanentism.

magnetic reversal Change in the polarity of the Earth’s magnetic field when the North Magnetic Pole becomes the South Magnetic Pole and vice versa.

moho Abrupt boundary between the Earth’s crust and the underlying mantle; short for Mohorovičić Discontinuity, named after its discoverer. Energy waves released by earthquakes show an abrupt change in velocity (from 7 to 10 km/sec) across the contact that occurs at about 6 km depth under the oceans and at least 40 km and more under continents.

magnetic stripes Alternating bands of normal and reversed polarity either side of midocean ridges. Each band can be age dated according to the magnetic polarity timescale. magnetometer An instrument used to measure very small variations in the Earth’s magnetic field. It can be towed behind a boat (a marine magnetometer) or used from an airplane (an airborne magnetometer).

nuée ardente Cloud of incandescent volcanic ash and debris flowing down the slopes of a volcano (also called a pyroclastic flow).

mantle Largest zone in Earth’s interior lying between the crust and the core and composed of hot plastic rock.

Nuna Inuit word for “northern lands” used for an early North American continent including much of Northern Europe between 1.9 and about 1.3 billion years ago. Nuna may have been part of an ancient supercontinent called Columbia.

mantle plume Column of hot plastic rock rising in the mantle toward the Earth’s surface because of large-scale convection in the mantle (think of a lava lamp). metamorphism Transformation of pre-existing rock into a new, much-altered rock by pressure and temperature, without the rock melting.

nappe Derived from the French word for “tablecloth” and refers to a large sheet of rock that has been pushed laterally over other rocks for many kilometres, often being folded and complexly buckled in the process. It is common in mountain ranges formed by plate collisions (e.g., Alps, Himalayas).

midocean ridge Continuous submarine mountain range up to 3 km high, extending through the middle of the ocean basins. It commonly has a central rift valley marked by the eruption of new oceanic crust (dominantly pillow basalt). Repeated intrusion of igneous dikes into the ridge gives

obduction Collision and over-thrusting of continent crust over other continental crust to produce

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Glossary

Pangea Last supercontinent about 350 million years ago, which broke apart some 200 million years ago to form the present continents and oceans.

large mountains; subduction and related volcanic activity does not occur. oceanic crust Relatively heavy, high-density crust composed mainly of iron-rich, silica-poor basalt formed at midocean ridges by sea floor spreading. Contrast with continental crust dominated by granite which is iron-poor, has more silica, and is less dense.

Pangea II Next supercontinent that will be finally assembled about 250 million years in the future. passive margin Trailing edge of a lithospheric plate or continent that lies opposite to its active margin. Eastern North America is a passive continental margin; western North America is the active plate margin where it is colliding with the Pacific Plate.

ophiolite Ancient oceanic crust thrust onto c­ ontinents during closure of ancient oceans (see suture).

permanentism Belief that continents are fixed in position and have never moved. Contrast with mobilism.

ore Rocks containing minerals in sufficient quantity to mine. orogenic belt (also called orogen) Regionally extensive zone of highly metamorphosed rock, typically gneiss, that has undergone folding and deformation during an orogeny. Ancient “fossil” orogens whose mountainous topography has long since been flattened by erosion criss-cross the Canadian Shield, marking collisions and amalgamation of smaller crustal pieces (terranes).

pillow basalt Bulbous, pillow-shaped masses of basalt erupted underwater such as at midocean ridges forming the uppermost part of oceanic crust. plate tectonics Grand theory that describes the formation, movement, and destruction of lithospheric plates on planet Earth. It recognizes that Earth’s crust and underlying mantle are in constant motion.

orogeny Large-scale deformation within Earth’s crust arising from the collision of lithospheric plates. Continents grow during orogenies by accretion of terranes.

plume Narrow column of molten magma that is rising in the Earth’s mantle (see hot spot and pluton). pluton Large body of intrusive igneous rock dominated by granite, formed by slow cooling underground (see also batholith).

paleogeographic maps Maps showing what geologists consider the surface of Earth to have looked like at various times in the past including the location and shape of continents, ancestral oceans, etc.

polar wander Slow movement of the position of the North Magnetic Pole over time (contrast with apparent polar wander).

paleomagnetism Study of past changes in the Earth’s magnetic field as recorded by fossil (remnant) magnetism in rocks and sediments.

Precambrian Long-time interval before the Paleozoic era (i.e., older than 541 million years before the present).

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protocontinent Small embryonic continents composed mainly of granitic rocks that formed very early in Earth’s history. They are preserved today as very old pieces of crust within shields (e.g., Slave Craton of the Canadian Shield).

Mapping of data from successively younger rocks defines an apparent polar wander path recording the migration and rotation of continents. ridge push Forces exerted by sea floor spreading at midocean ridges that push newly formed ocean

province Long-standing term used by geologists to refer to distinct regions within shields where rocks are similar but very different from ­surrounding areas. Broadly synonymous with craton and terrane.

floor and entire lithospheric plates across the asthenosphere. Contrast with slab pull, which is generally regarded as the more important process in moving plates. rift Large, often kilometres-wide crack in the Earth’s

pyroclastic An umbrella term for debris pulverized by powerful volcanic eruptions and either thrown up into the atmosphere (tephra) or dropped onto the flanks of volcanoes (see also stratovolcano and lahar). Popularly (and incorrectly) known as volcanic ash.

surface resulting from the crust being stretched and pulled apart (see graben). Rodinia Supercontinent that existed between about 1,100 and 750 million years ago. sea floor spreading Refers to the formation of new

radiometric age dating Calculation of the age of a rock or mineral (typically zircons) in years based on the known decay rates of unstable isotopes (e.g., Uranium-238) that produce stable daughter products (such as Lead-206) that can be precisely measured in the laboratory to determine the age of a rock.

ocean crust at midocean ridges resulting in outward movement of the ocean floor either side of the ridge. sedimentary rock Rocks formed either from compaction and cementation of sediment (such as sandstone), precipitation from water (such as

relative age Age of a rock or event when compared to another rock or event, e.g., this layer is older than that one, or younger. Commonly based on distinctive fossil types present in each layer or by mapping of how layers are arranged, e.g., this layer underlies that one or has been intruded into that one, etc. Contrast with absolute or radiometric age dating.

rock salt), or consolidation of plant material (such as coal). seismic reflection Geophysical method where artificially created energy is released at surface. The energy returns to the surface after reflecting from layers of rock or sediment below the ground surface. Returning waves are recorded on

remnant magnetism Magnetic properties of ancient rocks that record position of continents relative to North Magnetic Pole at the time of their formation.

an instrument that depicts layering of strata at depth.

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seismic stratigraphy Mapping of deeply buried rock layers and geological structures based on seismic reflection surveys.

sill Horizontal, sheet-like igneous intrusion. Contrast with dike. slab pull This refers to the force acting to pull lithospheric plates over the asthenosphere, created by sinking of cold, dense oceanic crust at a subduction zone. Thought to be a more powerful process in moving lithospheric plates than ridge push.

seismic wave Waves of energy produced naturally by an earthquake or artificially by an explosion or other device. seismograph Recording instrument designed to detect seismic waves and earth motions resulting from earthquakes. Also used to identify buried strata using manufactured energy sources (e.g., an exploration seismograph).

strata Layers of rock such as exposed in a cliff. The study of strata, their age, and their distribution regionally or globally is the subject of the branch of Earth sciences called stratigraphy.

shield Large area of exposed Precambrian igneous and metamorphic rocks formed between 4 billion and about 600 million years, that form tectonically stable areas within the inner parts of continents. Shields (also referred to as cratons) are formed by crustal accretion during continental collisions during successive ­supercontinent cycles. Younger sedimentary rocks cover their outermost margins.

stratovolcano Classical, steep-sided cone-like volcano built up by successive eruptions that deposited ash and volcanic debris on the slopes of the volcano. Also referred to as an andesitic volcano because of the dominant rock type. stratigraphy Subdiscipline of geology concerned with establishing the order and age of rock strata, whether igneous, metamorphic, or sedimentary in origin.

shield volcano Low-mounded volcano associated with very fluid lava flows, called flood basalts. Contrast with steep-sided stratovolcanoes, dominated by stiffer andesitic magma.

striations Scratches and elongate gouges on the surface of a rock formed by debris dragged below a sliding glacier or ice sheet.

silica A dominant mineral on planet Earth (e.g., quartz) and the building block of silicate minerals (e.g., feldspar, mica, etc.). Igneous rocks are classified according to their silica content into low-density, silica-rich felsic rocks (granite, andesite) typical of continental crust, and much heavier, silica-poor mafic rocks, such as gabbro and basalt, typical of oceanic crust.

subduction Downward sliding of denser oceanic plate into the mantle under a continent (forming a magmatic arc), or under another thinner plate of oceanic crust (an island arc). subsidence Sinking of Earth’s crust. supercontinent A large land mass formed by collision of continents and the closure of oceans.

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supercontinent cycle Repetitive formation of supercontinents by plate tectonic collisions, followed by their eventual breakup when continents disperse (see also Wilson Cycle, which describes the history of individual oceans) and the reforming of a new supercontinent hundreds of millions of years later.

terrane “Exotic” piece of crust within a continent that originated from another plate and collided with and stuck to the continent’s margin. Continents are commonly a complex mosaic of many terranes (see also accreted terrane and province).

Superior-Sclavia Ancient supercontinent possibly as old as 3 billion years.

till Poorly sorted, concrete-like admixture of clay, silt, sand, and gravel, often with large boulders deposited by a modern glacier or ice sheet. Ancient tills, now rocks, are called tillites.

supervolcano Large and potentially very dangerous volcano that erupts more than 1,000 km3 of rock and ash during any one eruptive event typically every 100,000 years.

transform faults These faults cut across and offset midocean ridges. They allow sea floor spreading to take place along sinuous, meandering ridges and across the curved surface of the Earth.

surface wave Seismic wave that travels outward from the focus of an earthquake by travelling along the surface of the Earth (contrast with body wave).

trench Very deep water (as much as 9 km) formed over the down-going oceanic plate at a subduction zone. triple junction Three-armed rift formed where a continent begins to break apart. Only two arms will widen to form future oceans, leaving a “failed rift.”

suture Boundary between former land masses, such as terranes brought together by plate collisions. Seen as a belt of highly deformed rocks commonly including ancient oceanic crust preserved as ophiolites.

unconformity Missing layers within rock strata, resulting from non-deposition and the erosion of older underlying strata. Unconformities are common and result in gaps in the geological record.

syncline Rock layers bent into a U-shape. Contrast with anticline. tectonics Motion and deformation of rocks on a regional to global scale, resulting from the movement of lithospheric plates.

uniformitarianism Guiding principle that assumes that Earth history can be interpreted using modern-day geological processes. “The present is the key to the past.”

tephra Airborne pyroclastic debris (ash) thrown out of erupting volcanoes.

uplift Upward movement of the Earth’s crust.

terrain Areas of the Earth’s surface of distinct topography, e.g., mountainous terrain. Easily confused with terrane.

Wilson Cycle Life cycle of individual oceans, from initial rifts to broad mature oceans, to dying oceans that are closing, named in honour of J. Tuzo Wilson.

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Index

Note: The abbreviation JTW is used to refer to John “Jock” Tuzo Wilson. Page numbers appearing in italics refer to pages containing illustrations. Acadian mountain building, 47, 193 Adams, Frank Dawson, 61–2 aerial photography: of Canadian north, 29, 103, 127; considered “cheating” in mapping geology, 104; mapping geological features, 14, 15, 19, 92, 98, 99, 127, 135, 140, 200; national index of, 15; optical instruments, 15; types of planes required, 15, 16; during wartime, 104, 116–17, 159, 237 African Plate, 214, 216 Age of the Earth, The (Holmes), 69 Agricola, Georgius, 147 Air Board Act, 13 airplanes: Bristol biplanes, 90, 91; bush pilots, 13, 15, 17; cathode ray tubes used, 15–16; exploration flights, 19; first flights, 13, 17, 17, 19; Imperial Airship Scheme, 17, 18, 19; for mapping forest fires, 13; for mineral resource surveys, 15; in sub-zero temperatures, 15; as workhorses post–First

World War, 13. See also aerial photography Airy, George Biddell (astronomer), 63 Alaska: Canadian Arctic Expedition (1913–18), 19; crustal blocks, 225; earthquakes, 63, 177–9, 178, 180; wartime, 120 Albatross Award, 189 Alpine Club of Canada, 9, 10, 11, 82 Alps: formation of, 28, 30, 31, 33, 76, 137, 220; framework for mapping, 134; marine fossils in, 28; nappes as evidence of lateral movement, 33, 35 American Association of Petroleum Geologists, 43, 44, 75, 192–3 American Geophysical Union, 159, 244 Ami, Henri, 22 Anderson, Ernest M. (geologist), 139 Andes, 42, 219, 220, 220, 221, 222 animals, long-distance migration of, 28, 49, 78

Antarctica: evidence of contiguous land masses, 27, 40–1; exploration by Mawson, 148; Imperial Trans-Antarctic Expedition (1914), 89; Operation Deep Freeze, 156, 245; scientific research in, 155, 156; Wilson Mountains, 245. See also magnetic poles Antin, Mary, 50 Appalachian mountain building, 47, 193 Appalachians: formation of, 55, 137, 138, 148, 192, 225; as part of continuous chain, 47, 134–5, 190, 193 Arctic: aerial survey of coast, 19; Canada’s presence in, 20, 120, 123; Canadian Arctic Expedition (1913–18), 19–20; Distant Early Warning (DEW) line, 16, 123; Inuit communities, 87, 125; mapping oil and coal deposits, 15; scientific research in, 125, 155, 243; vehicles for traversing, 121, 123. See also glaciers; ice sheets;

Index magnetic poles; Nunavut; Operation Musk Ox Arctic Institute of North America, 125 Argand, Emile (geologist), 33, 76, 137 Ashbury College, 22 asthenosphere, 207 Astor, William, 85 Atlantic Ocean: closing of, 163, 170; as mature ocean, 214, 215, 218; opening of, 191, 192; similarity of coastlines on either side, 25–6, 26, 27, 39, 47, 48; subsidence of floor, 28; as vestige of rupture, 25; width, 42. See also land bridges; Mid-Atlantic Ridge; midocean ridges; sea floor spreading atlases, first world, 25 atolls, 63, 64, 164, 172 Atwater, Tanya, 186, 224 Australia: Australian National University, 145; effects of ice sheet, 83, 148–9, 149; geology, 76, 148, 149, 164; JTW’s lecturing in, 145, 149; movement, 218, 227; Tasman Fold Belt, 148; University of Adelaide, 148, 149. See also Gondwanaland Bacon, Francis, 25 Bailey, Edward B. (geologist), 110, 132–3, 134, 169 Bailey bridges, 117–18, 118 Baird, P.D. (geologist), 124, 140 BBC Senior Geography course, 127 Beartooth Mountains (Montana), 12, 92–4, 94–5, 226 Beaumont, Élie de (geologist), 28 Bell, Mackintosh, 23 Beloussov, Vladimir Vladimirovich (geologist), 154, 204

Benioff, Hugo (geophysicist), 177–9; Benioff trenches, 179 Berry, Edward, 43 Bertin, Oliver, 243 Bethune, Norman, 154 biological sciences, and debate about evolution, 58 biosphere, 29, 230 Bird, John (geologist), 193 Bjornerud, Marcia, 229 Bleeker, Wouter, 102 Bombardier, Joseph-Armand, 121, 123 Bowen, Norman (geologist), 33 brachiopods, 45–50, 46, 48, 191, 192 Brant, Arthur (geophysicist), 130 bridges. See land bridges Bristol biplanes, 90, 91 British Commonwealth Air Training Program, 109–10 British Empire, 17, 22, 76, 145 Brooke, A.F., 116 Bryce, R.A., 105 Bullard, Edward (geophysicist), 44, 88, 181–4, 183; Bullard’s Law, 182 Burke, Kevin, 211, 214, 229 Burton, W.K., 66 bush pilots, 13, 15, 17 Bushveld Complex, 148 Cabot Fault, 169, 170, 190 Cadell, Henry M., 134 Calcutta/Kolkata, 54, 56 Caledonides, 190 Cambrian explosion, 10, 12 Campbell, Colin, 105 Campbell, Ian, 221 Campbell, W.W. (astronomer), 44

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Canadian Arctic Expedition (1913– 18), 19–20 Canadian Army: Army Operational Research, 120, 127; combat engineers in Sicily, 119; invasion of Sicily, 116, 117, 118, 119; JTW’s OBE citation, 126; losses, 115. See also Second World War Canadian Institute of Mining and Metallurgy, 237 Canadian Journal of Earth Sciences, 187 Canadian Legion Educational Services, 131 Canadian Shield: aeromagnetic data, 176, 177; Beartooth Mountains, 93–4; deforming of rocks, 62, 87, 93; dikes of volcanic rock, 99–100, 101, 139, 152, 228; faults or gashes in, 99, 100, 101; formation of, 86, 99–100, 135, 136–7; gneisses, 99, 100, 240–1; greenstone belts, 86, 86–7, 197; mapping, 16, 81, 92, 98, 99, 135, 200; mineral deposits along fault lines, 99, 127; nucleus, 136, 138; patterns of magnetism in rocks, 176; pillow basalt, 86, 86–7; Precambrian rocks, 22, 62; recent history, 194; Tectonic Map of Canada, 135, 169 Chamberlin, Rollin T., 60 Chamberlin, Thomas C. (geologist), 33, 136, 137 Chile, 63, 64, 220. See also Andes China: and Amadeus Grabau, 155, 168; culture, 203, 203; earthquakes, 201–3, 202, 231; geologists, 155, 200, 201; JTW’s visits, 50, 154–5, 200–1, 202; and Norman Bethune, 154; scientific

Index research, 201; Unglazed China (Tuzo Wilson), 203 Choubert, Boris (geologist), 182 cities. See megacities Clarke, Barrie, 127, 192, 214, 215, 218, 238, 242, 243–4 climate: affected by removal of carbon dioxide, 230; affected by volcanic eruptions, 222, 231, 232; belts across Pangea, 40, 42; effect on glaciers, 143; interglacials, 83; Köppen classification, 42; and plate tectonics, 5; significance in sand and mud layers, 83; swings, 230; weather forecasting, 16 Cloos, Hans, 39 coal, 15, 26, 42, 76, 133, 233 Cold War: need for oceanographic data, 157–8; Operation Musk Ox, 121–6, 122, 124, 125; tools developed, 4 Coleman, Arthur Philemon (geologist): about, 82, 82–3; feature named after, 82; identifying Ice Age and interglacials, 83; influence on JTW, 82, 83, 84, 101, 132, 140; publications, 82, 83; on role of geology, 56, 82 Collins, W.H. (geologist), 62, 90, 91, 92 Columbia University (New York), 95, 158, 159 Coney, Peter (geologist), 225 continental drift: collisional event, 57, 62, 193; continents as rafts of lighter rocks, 1, 42, 63; forces causing movement, 71, 72; horizontal mobility of plates, 36; and longitudes, 75; mechanism not

explained, 42, 135, 145; opposition to theory, 56, 57, 60, 62, 69, 71, 72, 77, 83, 204; rocks as evidence, 71, 160, 163, 163–4, 168, 195–7; support of theory, 110, 133, 149, 193; as Taylor-Wegener theory, 76; theory reconfigured as plate tectonics, 235; timeline, 169; and transform faults, 186; “wander paths,” 160, 163. See also Bullard, Edward; Hess, Harold; mobilism; plate tectonics; sea floor spreading; Wegener, Alfred Continental Drift (Runcorn), 162 continents: attempts to explain origin, 26; centre, 54, 137, 223; as clustered together and then moved apart, 25, 26, 26, 30, 36, 57; considered immutable, 3, 25, 28, 137; continental shelves, 160, 182, 183, 209, 209, 233; as evidence of divine plan, 3, 56, 58; floating higher on the mantle, 63, 139; formation of first continents, 221–6; fragmentation, 25, 164; growth by crustal accretion, 54, 55, 57, 164, 219, 223, 225; margins, 63, 137–9, 138, 168, 179; movement, 30–1, 36, 42, 43, 74, 184; rifting, 209, 209; rocks, 39, 62, 63, 221–2. See also Gondwanaland; North American continent; supercontinents; tectonic plates convection currents: in Earth’s mantle, 70, 194–5, 207, 227, 230; Holmes’s model, 70, 139, 164; JTW’s soup demonstration, 194–5; moving continents, 70, 72, 135; and ocean floors, 170; opening

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new oceans, 70; rising from Earth’s core, 67, 70, 230 Coode, Alan, 185, 187–90 Cooke, H.C. (geologist), 86 Cooke, Lester, 92 Cordillera, 42, 137, 138, 225–6 Cordilleran ice sheets, 142 Cox, Allan V. (paleomagnetist), 162–3, 167 cratons. See crustal blocks Crawford, C., 82 Création et ses mystères dévoilésm, La (The creation and its mysteries unveiled) (Snider-Pellegrini), 26 creationism, 3, 56, 58, 82 Creer, Ken, 160 crustal blocks (terranes): Baja Peninsula, 225, 225; in Canadian Shield, 100, 101, 135; collide and slide, 224; composition of North American continent, 224, 224; on contracting Earth, 28, 76; and formation of greenstone belts, 86; illustration, 225; pushing forces, 225; slip on faults in, 66; Vancouver Island, 226; Wrangellia, 225 crustal flakes: evidence in Nunavut, 32; idea ignored by permanentalists, 36; possible gliding of, 30, 31, 139; Wegener’s interest in, 39 Curtis, Lionel, 82 Dalrymple, Brent, 184 Daly, Reginald Aldworth (geologist): about, 71, 71; on crustal mobility, 71, 72, 91, 164, 218; on dikes and dike swarms, 99–100, 101, 139, 219; on imaginative thought, 160; objections to his concept of continents,

Index 72; support of Wegener’s theory, 43, 61, 69, 71; theory of pushing and pulling forces, 73, 74 Dana, James Dwight (geologist), 3; about, 53, 56; and creationism, 3, 56; on Hawai’ian Islands, 53, 168; permanentist model of Earth’s evolution, 54, 55; support of geosyncline theory, 57, 137–9, 138 Darwin, Charles, 3, 59, 63, 80, 164, 230 Das Antlitz der Erde (Suess), 27 Davy, Humphrey, 25, 133; Davy safety lamp, 133 Dawson, George (geologist), 80, 101 De Sitter, Lamoraal (geologist), 44 Derry, Duncan, 135 Dewey, John, 185, 193, 205, 214 Dickins, “Punch” (bush pilot), 13, 15, 200 Die Klimate der Geologischen Vorzeit (The climates of the geologic past) (Köppen & Wegener), 42 Dietz, Robert (geologist), 39, 57, 72, 164, 168 dirigibles, 17, 18, 19 “Disappearance of the Huronian, The” (Quirke & Collins), 62 disintegration theory (Rutherford & Soddy), 69 displacement theory. See continental drift Distant Early Warning Line (DEW Line), 16, 123 Doell, Richard (paleomagnetist), 162–3, 184 Don Valley Brickyard, 83 drumlins, 96–7, 102, 103, 139, 140, 141, 141 DSV Alvin (submersible), 158

Du Toit, Alex (engineer), 36, 76–8; Du Toit Mountains, 245 Dunbar, Carl, 58 Dynamics of Faulting (Anderson), 139 Earth: age, 59, 69, 212, 212; biosphere, 29, 230; consumption of carbon dioxide, 230; as cooling and contracting, 28–9, 30, 33, 35, 53, 59–60, 65, 76, 96, 137–8, 152; effects of evolution, 230–1, 233; extinction events, 233; as formed by upwelling magma, 152; geological timescale, 257; holistic study of, 60, 94; horizontal displacements, 33; interior, 5, 59, 60, 65, 69, 70, 78; lithosphere, 29, 173, 206; magnetic field, 162, 163 (see also magnetic poles). See also continents; Earth’s core; Earth’s crust; Earth’s mantle; plate tectonics; seismic waves Earth, Its Origin, History and Physical Constitution, The (Jeffreys), 59–60, 61, 62, 62n, 201 earthquakes: in Alaska, 177–9, 178, 180; along continental margins, 156–7, 177–9, 207; along ocean midlines, 156–7, 186; along transform faults, 186; Benioff zones, 179; caused by Earth’s contraction, 29; causing crustal deformation, 178; in Chile, 63; in China, 231; effect on megacities and economy, 230–1; energy released, 66, 177; epicentres, 66, 67, 156, 186; focuses, 67, 208; global distribution, 186, 206, 208, 232; in island and magmatic arcs, 137; in Japan, 66, 66, 67, 222, 231; and

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liquefaction, 177; megathrust subduction, 179, 180, 220, 221, 222; at plate margins, 206; in Portugal, 231; predictions, 67, 179, 222; records used to build picture of Earth’s mantle, 88; resistant buildings, 231; San Francisco, 231; and seismic gap theory, 66–7; and submarine trenches, 177–9; and tsunamis, 177, 219; and upward movement of crust, 63, 64. See also seismic waves Earthquakes and Other Earth Movements (Milne & Burton), 66 Earth’s core, 65, 67, 230 Earth’s crust: age, 196, 197; crustal blocks, 224; crustal slabs, 186, 190; deformation, 63, 134; evidence of sinking and uplift, 65, 65, 83; evidence of stress, 59, 61, 137, 139; magma intrusions, 139; Mohorovičić Discontinuity, 152, 207; movement, 2, 62, 69, 70, 171; normal faults, 139; recycling of, 219, 222; role of rock extension, 139; stretching and rifting, 214, 217; types of crust, 63, 207. See also earthquakes; tectonic plates Earth’s mantle: asthenosphere, 173, 206, 207; convection currents, 70, 194–5, 207, 227, 229; heat leaking from, 67, 181–2; hot spots, 171, 228; melt spots, 227; outgassing, 230; as plastic and mobile, 31, 32, 61, 65, 67, 69, 83, 227; as solid, 83, 88; strength, 61. See also magma “Earth’s Plan” (Taylor), 30, 31, 39, 58, 84, 140, 236 East African Rift, 146, 147, 215, 217

Index Ediacaran fossils, 10 Egypt, JTW’s visit to, 145–7, 146, 147 Einstein, Albert, 92 Elementary Geology (Coleman & Parks), 83, 84 Empress of Australia (ship), 107 England, JTW’s visits to, 20, 22 Everett, James, 182 Ewing, Maurice, 91–2, 95, 156, 159 exploration geophysics, 81–2 Expo 67 (Montreal), 194–5 Eyles, Albert, 113n Eyles, Alfred, 113n Face of the Earth, The (Suess), 27, 29 Falconer, George, 140 Farquhar, Ronald M., 143, 212, 239 faults: Cabot/Long Range, 169, 170, 190; Great Glen, 133, 169, 170, 190; rate of movement along, 184; relationship to earthquakes, 64; San Andreas, 169, 226; strike-slip type, 169; transform faults, 184–6, 185, 187, 187, 189. See also magma Field, Richard (geologist), 94 First World War: aerial photography, 104, 237; artillery intelligence map, 14; Canadian national fighting force, 104; Hill 70, 104; tunnelling techniques, 105; Vimy Ridge, 14, 104, 105 Fisher, Osmond (geophysicist), 33 Flint, Richard (geologist), 58, 140 forestry, 22–3 fossils: brachiopods, 45–50, 46, 48, 191, 192; discovery of oldest, 80; Ediacaran, 10; as evidence of contiguous land masses, 26, 27, 38, 39, 40, 42, 45, 47, 78, 191, 192, 230;

fossiliferous limestones at Everest summit, 23, 24, 202; JTW’s search near Ottawa, 22; marine fossils in Swiss Alps, 28; in sedimentary rocks in Wales, 133; in Southern Hemisphere, 78; Tuzoia, 12 Foulger, Gillian, 227 Foulkes, Charles, 126 Frye, Northrop, 195 Gastil, Gordon (geologist), 163–4 Geikie, Archibald, 61 Geological Association of Canada, 140–1, 142 Geological Society of America: meetings, 43, 71, 84, 200; opposition to continental drift theory, 57; presidents, 56, 57, 82; publications, 30, 49, 49, 56 Geological Structure of the Northwest Highlands of Scotland, The (Peach & Horne), 133–4 Geological Survey of Canada: Geographic Bureau, 20; Geophysics Division, 176; JTW’s fieldwork in Northwest Territories, 96–102, 98; JTW’s fieldwork in Nova Scotia, 90, 96, 96–7, 169; JTW’s fieldwork in Quebec, 85, 86, 97, 98; JTW’s postwar views on, 129–30; JTW’s reimbursement to, 105; mapping methods, 83, 99; publications, 62; Tectonic Map of Canada, 135, 169 Geological Survey of Great Britain, 133 Geologische Rundschau, 39 geologists, generally: about, 54, 59, 60, 80; and cancellation of Prague conference, 204; female geologists,

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158–9; JTW’s view of, 59, 61, 96; new focus, 157; in North America vs. elsewhere, 76; on purpose of study of geology, 58; recognition of paleomagnetic data, 162; resistance to new ideas, 237. See also mobilists; permanentists Geology: Earth History (Chamberlin & Salisbury), 136 geology, science of: about, 81, 131–2, 135, 145, 235, 240; and adherence to accepted beliefs, 77; broadening of scope, 29, 129, 235; comparative geology, 77; and creationism, 56; dangers in the field, 97; effect of wars on, 236–7; effects of plate tectonics theory, 5, 6; “Highland Controversy,” 133–4; imperial science, 76; instructional booklets postwar, 131, 131; interpreting data, 4, 128; JTW’s first interest in, 22, 23, 79; as “Made in America,” 4, 57, 157; oldest known map, 147, 147; paradigm shifts, 6, 237; at Princeton University, 94–5; in Russia, 204; strategic and economic importance of, 3, 76, 234; survey departments in British Empire, 76; as taught in universities, 3, 54, 58, 59, 80, 92; textbooks, 6, 136, 184, 239; uniformitarianism, 54, 65. See also continental drift; mobilism; permanentism; plate tectonics “Geology and Continental Drift: A Symposium,” 192–3 geophysics: attitude towards, 91, 131–2; International Geophysical

Index Year, 155–7, 160; interpreting data, 128; JTW’s studies, 81; ownership of research discoveries, 126–7; real-time monitoring, 156 geosynclines: and Beartooth Mountains, 93; Dietz’s view of concept, 168; and expansion of North American continent, 55, 57, 137, 157; filling of, 193; Ganges river example, 54; slipping of crust below, 72, 74; theory, 56, 57; types, 56–7 Germany: anti-German sentiment, 44, 57 Gibson, Colin, 19 Gilbert, Walter, 19 Gilchrist, Lachlan (physicist), 81, 82, 87, 129, 132 Girdler, Ron W., 174, 242 glacial geology: about, 139; Glacial Map of Canada, 140–3, 141, 142; JTW’s interest in, 83, 143; study of Salmon Glacier, 143 Glacial Geology and the Pleistocene Epoch (Flint), 140 glacial striations, 41 glaciers: aerial photographs, 143; Canadian government inventory, 143; early research, 10; Glacial Map of Canada, 140–1, 142; on Gondwanaland, 27; ice flow directions, 40–1; indicators of climate change, 143; Salmon Glacier, 143; Saskatchewan Glacier, 143; scouring of Great Glen Fault, 169; striations and tillites on bed, 40–1, 148–9; Thompson Glacier, 144; as water source, 143 Glaciers of the Canadian Rockies and Selkirk (Sherzer), 10

Glomar Challenger (drill ship), 195, 197 glossary of terms, 259–68 Glossopteris, 27 gneisses, 62, 99, 100, 134, 240–1, 242 Godfrey, Albert, 19 Gondwanaland: breakup, 28, 38, 149; evidence of, 27, 38, 147–8; included in Pangea, 36; influence on Taylor’s theory, 30; naming, 27, 28; reconstruction, 28, 77; as southern land mass, 27, 77, 149. See also Pangea Goudin, Urey (geophysicist), 153, 154 Gould, Stephen Jay (biologist), 49 Government of Canada, Glaciology Division, 143 Grabau, Amadeus William: about, 45, 46, 50; and anti-German sentiment, 50; battle with Schuchert over land bridges, 45–51, 192; Chinese students, 155; Grabau Gold Medal, 50; on historical geography, 45; influence on JTW, 50–1, 168, 192 Granatstein, J.L., 116 gravimeters, 63 gravity: effects of, 204, 222; measuring changes in, 63, 158; and surveys of rock density, 88, 177 Great Depression, 90, 92–3 “Great Earthquake of Japan, 1891, The” (Milne & Burton), 66 Great Lakes region, 29, 31 Great Trigonometrical Survey, 62–3 Greenland: ice sheet, 37, 74–5, 76; Nagssugtoqidian Orogen, 236, 236; and plate tectonics theory, 236; rate of drift between Europe and, 74 greenstone belts, 86, 86–7, 197

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Grenville Orogeny and Province, 61–2 Grimes, James Stanley, 237 Gutenberg, Beno (seismologist), 67 Gutenberg Discontinuity, 67 Guyot, Arnold (geologist), 164 guyots, 164, 171, 173, 245 Hall, James, on continental growth, 54 Hallam, Joe (engineer), 118 Halls, Henry, 136, 198–9, 238, 240–1 Hawai’ian Islands: ages, 1; as chain of volcanoes, 53, 173; Dana on, 53; evidence of ocean floor movement, 53, 173; JTW’s revelation in, 1, 53, 168, 235, 246; as mantle hot spots, 171, 173, 173 Hawkesworth, Christopher (scientist), 229 Hearne, Samuel (explorer), 96, 113 Hees, Harold, 72 Heezen, Bruce, 158–9, 160, 184, 185 Heim, Albert (geologist), 33 Hess, Harold (geologist): about, 94, 164; “geopoetry,” 165; innovative discoveries, 184; mapping sea floor, 72, 164; on ocean origins, 95; theory on seamounts, 164, 171 Hills, G.S.F., 139 Himalayas: effects, 219, 230; formation, 31, 54, 56, 202; measuring height, 62–3; Mount Everest, 2, 23, 24, 24, 82, 202, 220 Historical Geology (Schuchert et al.), 58 Hoffman, Paul (geologist), 223 Holmes, Arthur (geologist): about, 69, 69, 245; correspondence with JTW, 135–6; on earthquakes, 157; on mantle processes causing

Index movement, 174; on midocean ridges, 159, 164, 171; model of drifting continents, 70, 139; publications, 70, 72, 113n; radiometric dating, 135 Home of the Blizzard (Mawson), 148 Hooker, Joseph (botanist), 148 Horne, John (geologist), 33, 133–4, 134 “hot spot” volcano, 172 Howell, David (geologist), 225 Hsu, Ken (geologist), 155, 197 Humboldt, Alexander von (geographer), 26 Hurley, P.M., 184 Huronian rocks, 62 “Hypothesis of Earth’s Behaviour” (Tuzo Wilson), 173–4 Iapetus Ocean, 134, 190, 191, 192, 193 Ice Ages, 31, 83, 101, 219, 221. See also Canadian Shield; glaciers Ice Ages Recent and Ancient (Coleman), 83 ice sheets: in Australia, 83, 148–9, 149; Cordilleran, 142; drumlins left by, 96–7, 102, 139, 140, 141, 141; eskers, 101–2, 139, 140; flow direction, 141, 141; glacial sediments, 142; in Greenland, 37, 74–5, 76; Lake Agassiz, 142; Laurentide, 101, 140, 142, 143; mapping, 83, 140–3, 141; monitoring changes in, 156; on Pangea, 83. See also glacial geology Iceland, 214, 218, 218, 219, 233 igneous intrusions. See magma IGY: The Year of the New Moons (Tuzo Wilson), 155–6, 160, 245 Imperial Airship Scheme, 17, 18, 19 Imperial Oil, and aerial photography, 15

imperial science, 76 Imperial Trans-Antarctic Expedition (1914), 89 India: fossil flora and fauna, 27, 38, 39, 148; Ganges river sediments, 54, 56; Ice Age deposits, 83; indigenous group, 27; jute, 6; monsoon, 219; movement into Eurasian Plate, 201, 202, 203, 218; part of Gondwanaland, 28, 36, 149. See also tectonic plates Indian Geological Survey, 54 International Council of Scientific Unions, 151 International Geophysical Year, 155–7, 160 International Union of Geodesy and Geophysics (IUGG), 127–8, 151, 152, 154, 156, 204 Irvine, Sandy (mountaineer), 23, 24 Irving, Edward A. (geologist), 161–2, 174, 237, 242 Isacks, Bryan, 205, 206 isostasy, theory of, 63 isthmian links. See land bridges Jacobs, John A., 143, 237 Japan: balloon bombs, 120; earthquakes, 66, 66, 67, 222, 231; monsoon, 219; tsunamis, 177 Jeffreys, Harold (physicist): about, 59, 60, 60, 88, 89, 245; on contractionism, 59–60; flaw in his work, 61; JTW’s studies under, 84, 88–9, 132, 167; opposition to continental drift, 62, 88, 89, 162; use of earthquake records to picture Earth’s mantle, 88 Jenness, Diamond (anthropologist), 20 Johnston, Stephen (geologist), 225

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Joly, John (geologist), 54 Journal of Geology, 33, 137 Kant, Immanuel, 231 Karcher, John C., 104 Kay, Marshall, 56, 57, 193 Kay, Suzanne, 57 Keevil, Norman B. (geophysicist), 130, 156 Kelvin, 1st Baron (William Thomson) (physicist), 59, 65 Kidd, William, 211 Kipling, Rudyard, 17 Kolkata/Calcutta, 54, 56 Köppen, Wladimir (climatologist), 40, 42 Kuhn, Thomas (philosopher), 6 LaBine, Gilbert, 17 Lake, Philip, 43, 60, 88 Lake Iroquois, 83 Lambert, W.D., 71 lamp shells, 46 land bridges: about, 49; Coleman on, 84; dismissed by Wegener, 39; flaw in theory, 148; map, 49; and origin of oceans, 95, 190–2, 191; Schuchert and Grabau battle over, 46, 48, 49–50; Simpson’s belief in, 78 Lapworth, Charles, 133 Large Igneous Provinces (LIPs), 227, 228, 232 Larochelle, André, 176 Lascar Volcano, 220 Laurasia, 36, 77 Laurentia, 29 Laurentide Air Services Company, 13 Laurentide Ice Sheet, 101 Le Pichon, Xavier (geophysicist), 205

Index Lear, John, 194 LeGrand, H.E., 148 Lehmann, Inge (seismologist), 67; Lehmann Discontinuity, 67 Lenox-Conyngham, Gerald, 88 Li, J.S. (geologist), 201 lithosphere, 29, 173, 206 Loewe, Fritz (meteorologist), 74–5 Logan, R.A. (pilot), 15 Logan, William, 80 Long Range Fault, 169, 170, 190 Longwell, Chester, 3, 58 Lyell, Charles (geologist), 65, 65 Lyustikh, E.N. (geophysicist), 204 MacClintock, Paul, 139 MacDonald, Gordon (geophysicist), on Harold Jeffreys, 89 magma: ascending through older rocks, 71–2; dikes and dike swarms, 72, 99–100, 101, 139, 152, 227; flood basalts, 217, 220; forming volcanic islands, 171, 172; greenstone belts, 86, 86–7, 197; Large Igneous Provinces (LIPs), 227, 228; magnetic characteristics, 160; and melting of subducting crust, 219, 222; moving up through faults, 137, 138, 139, 152, 219; plumes, 172, 174, 227; pushing force of, 73. See also sea floor spreading; volcanoes magnetic poles: changes, 175; geomagnetic polarity timescale, 184; movement of, 161, 162, 163, 174; North Magnetic Pole, 19, 160, 163; timeline of magnetic reversals, 176, 184 Malloch, George (geologist), 20

Mallory, George (mountaineer), 23, 24 Mandarin Duck (Chinese junk), 194, 199, 241, 242 Manifest Destiny, 9 Manikewan Ocean, 236 Manual of Mineralogy (Dana), 53 marine geology, 94, 95, 158 marine organisms. See brachiopods; fossils Martin, Paul Sr, 23 Mason, Roger, 174 Massey Lectures, 239–40 Matthews, Drummond, 174, 175, 176 Maupiti atoll, 64 Mawson, Douglas (geologist), 148, 149 May, Wilfrid Reid “Wop” (bush pilot), 15 McConachie, Grant, 17 McConnell, Richard (geologist), 33, 34 McKee, James, 19; McKee Trophy, 19 McKenzie, Dan (geophysicist), 205 McLennan, John Cunningham (physicist), 79–80 McNaughton, Andrew M.: about, 103; “McNaughton tube,” 108–9, 109, 111; military service, 18, 103–5, 108, 109, 115, 116; National Research Council, 15, 104–5 Mechanics of Appalachian Structure, The (Willis), 33 Mediterranean Sea. See Tethys Ocean megacities: about, 230; along westeast collision zone of plates, 231; vulnerability on plate boundaries, 230–2, 232 Meinesz, Felix Vening (geophysicist), 63, 157, 177

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Menard, H., 200 Mesosaurus, 27 meteorite impacts, 39, 222, 227, 228 Mid-Atlantic Ridge: collecting data, 197; composition, 159, 160; as evidence of continental drift, 168; in Iceland, 214, 218, 218; magnetic stripes, 175; as original place of continental fracture, 30; pushing plates apart, 206, 218, 223; transform faults, 185, 187. See also midocean ridges; sea floor spreading midocean ridges: as evidence of sea floor spreading, 196, 197; first geological exploration, 197; formation of magnetic stripes, 175; formation theories, 210–11; fractures dissecting, 184; functioning of, 174, 210; heat flows, 181–2; Juan de Fuca ridge, 184; maps, 159, 160; migration, 210; as parts of world rift system, 174; ridge push, 164, 168, 175, 226; smokers, 182, 197, 230; timeline of magnetic reversals, 176; total global length, 206; transform faults, 184–6, 185, 187, 189; worldwide joining of, 186. See also Mid-Atlantic Ridge; ocean floors; sea floor spreading military service by JTW: air photograph analysis, 116–17; bomb disposal, 112–13; buying books, 113; communication skills, 127; demolition and use of explosives, 109, 111; as director of Army Operational Research, 119, 120, 121–6, 122, 124, 125; enlisting, 103, 105, 106, 109; with First Canadian Tunnelling Company, 107–8, 109, 110– 11, 111, 112; London residences,

Index 114; overseeing design and testing of equipment, 119; planning new airstrips in France, 119; regimental life, 107–8; return to Canada, 119; sleep ability, 127; social life, 113, 114; writing reports, 115, 117, 118–19, 126–7, 189, 239 Milne, John, 66 mineral resources: airplanes for surveys, 15; in ancient oceanic rocks, 229; copper mining in Butte, 93; diamonds, 82, 177, 227, 245–6; drilling in wartime, 110–11; geological scarcity, 234; instructional booklets postwar, 131, 131; iron deposits in Labrador, 82; laboratory experiments, 238; mapping, 76, 81, 82, 130–1, 141, 177; nickel deposits in Ontario, 82; and plate tectonics theory, 195; search for, 43–4, 81–2; silver deposits in Nevada, 244; in South African banded rocks, 148. See also oil and gas exploration mining: attitude towards women, 158–9; Davy safety lamp, 133; JTW as geological assistant for, 23; mapping by bush pilots, 13, 15; Turin mining map, 147, 147; use of drilling techniques in wartime, 105 mobilism: JTW’s conversion to, 152, 167–70, 170, 171, 200, 239–40; naming of, 237; opposition to, 57, 204, 237; re-evaluation of data, 193, 237. See also continental drift; Daly, Reginald; plate tectonics; Wegener, Alfred mobilists: about, 2; debate among, 72; debate with permanentists, 2,

4, 24, 30, 36, 45, 72, 133, 162, 211, 237, 238. See also Bullard, Edward; Du Toit, Alex; Irving, Edward; Taylor, Frank Mohorovičić Discontinuity, 152 monsoon, 219 Montgomery, Bernard, 116, 118, 155 Moon, 30, 39 Moorehead, Alan, 107 Morgan, Jason (geophysicist), 205 Morley, Lawrence “Larry” (geophysicist), 175, 176–7, 187 Mount Everest: Capt. Crawford, 82; composition of summit, 23, 24, 202, 220; expedition (1924), 23, 24; movement, 2 Mount Tuzo, 9–10, 11, 245 mountain chains: continuity of, 190; as crumple zones, 193, 202, 209, 209; crustal blocks, 224–5; ending on opposing coastlines, 39, 42, 47; formed by buckling along continent edges, 57, 168; formed by compressive stresses in crust, 137; formed by pulling forces, 74; and former Tethys Ocean, 218, 220 mountains: as evidence of lateral displacements of Earth’s crust, 33; and formation of geosynclines, 55, 56; formed by being pushed up as Earth cooled, 28, 33, 54, 135; formed by the moving and colliding of continents, 30, 31, 42; framework for mapping structure of, 134; and gravitational pull, 63; phases of mountain building, 47, 70; rapid uplift of, 29. See also specific mountains Murchison, Roderick Impey (geologist), 133

277

Nagle, Ted, 17 nappes, 33, 35, 56 nationalism, 4, 75 Nature (journal), 173, 174, 176, 187, 188 Nevada, silver deposits of, 244 New Guinea, 149 Newfoundland, 47, 120, 192–3, 199 Ninnis, Belgrave, 148 No Water, No Granites – No Oceans, No Continents (Campbell & Taylor), 221 Noranda Mines, 194 Norris, Geoffrey (geologist), 238 North America, 56, 57–8, 80, 120, 121, 140 North American continent: composition and growth, 223, 224, 225, 225; creation of interior lowlands, 55; drift, 74, 75, 192, 244; earthquakes, 179, 222, 231; as God’s plan of creation, 56; oceanic crust moving into the mantle below, 179; outward growth of eastern margin, 193; as type continent, 53. See also crustal blocks North American Geosynclines (Kay), 56 North Magnetic Pole, 19, 160, 163 Northern Aerials Mineral Exploration, 15 Northwest Staging Route, 19 Northwest Territories: JTW’s fieldwork, 96–102; mapping methods in, 96, 97, 98, 99 Nova Scotia: Bedford Institute of Oceanography, 170; Cabot/ Long Range Fault, 169, 170, 190; deformed rocks, 96; fossils, 47; JTW’s fieldwork, 90, 96, 96–7, 169

Index Novum Organum (Bacon), 25 Nuclear Test Ban Treaty, policing of, 186, 206 Nuffield, Edward “Les” (geologist), 238 Nunavut: Baffin Island, 243–4; Inuit communities, 87, 125; raised beaches caused by crustal uplift, 32; Thompson Glacier, 144 ocean floors: convection flow of, 170; and crumple zones, 193; dating of, 176, 197; geological research, 95, 170–3, 174, 181, 193, 195–7; and greenstone belts, 87; heatflow surveys, 181–2; magnetic rock stripes, 174–6, 175, 176, 184; mapping, 157–61, 164, 174; mobility of crust, 2, 53, 168, 170, 173; rocks beneath, 63, 67; seamounts, 164, 171, 173, 245; sinking of, 64, 196; submarine trenches, 177. See also midocean ridges; sea floor spreading oceanography, 157–61, 170, 174, 189, 193 oceans: age, 196, 197; Cambrian explosion, 233; considered immutable, 3, 53; creation of new oceans, 214, 215, 216, 217, 222; depths, 211; effect of continental drift, 42; formed by foundering of continental crust, 28; horizontal mobility, 36; life cycle (“Wilson Cycle”) of, 193–4, 211, 213; marine organisms, 232–3; mature oceans, 214, 215, 218; oceanic lithosphere, 211; oceanographic survey data, 157, 193; opening and closing of, 96, 190–4, 191, 218–20; Rheic

Ocean, 134; widening rate, 184. See also Iapetus Ocean; specific oceans Odell, Noel “Noah” Ewart (geologist): influence on JTW, 23, 24, 81, 85, 85, 86; Mount Everest Expedition (1924), 23, 24 oil and gas exploration: attitude towards women, 158–9; beginnings, 233; and geologic knowledge, 43–4; locations, 160, 233, 234; use of sound waves to locate oil, 104, 131, 153, 154 Oliver, Jack (geologist), 205 Omori, Fusakichi (seismologist), 66–7 On the Origin of Species (Darwin), 3 One Chinese Moon (Tuzo Wilson), 155 O’Neill, John (geologist), 20 Ontario Provincial Air Service, 13 Ontario Science Centre: exhibition “China: 7000 Years of Discovery,” 203; JTW as director, 200–3, 201, 245, 246, 246; meeting of Arctic explorers, 200; science education, 127, 200 Operation Deep Freeze, 156, 245 Operation Husky, 116 Operation Musk Ox, 121–6, 122, 124, 125, 128, 189 Oreskes, Naomi, 56 Origin of Continents and Oceans, The (Wegener), 36, 39, 42, 75, 76 Origin of the Alps, The (Suess), 28 Ortelius, Abraham (geographer), 25 Ottawa Field Naturalist Society, 22 Our Mobile Earth (Daly), 71, 72, 91, 218 Our Wandering Continents: An Hypothesis of Continental Drifting (Du Toit), 77

278

Pacific Ocean: age of oceanic crust, 196; amalgamation of plates, 207; closing and death of, 219, 221, 221, 222; crustal block movement, 224; plate movement, 206, 221, 224. See also ­Hawai’ian Islands Pacific Rim of Fire: earthquakes, 208, 231, 232; marked by submarine trenches, 177; and Omori’s map, 66; subduction effects, 206, 219, 221, 221, 222; volcanoes, 219, 220 Palaeogeography of North America (Schuchert), 47 Palaeomagnetism and Its Application to Geological and Geophysical Problems (Irving), 162 paleogeographic maps, 3 paleomagnetic data, 161, 162, 163 paleomagnetists, on continental drift, 162–3 Pangea: animals and plants on, 78; breakup, 42, 134–5, 170, 190, 192, 211, 213, 233; climate belts, 40, 42; creation, 77, 134–5, 191, 224; drift rates, 42; effects of assemblage, 223; formation of Pangea II, 196, 207, 213–14; geological evidence, 36, 39, 47, 134, 162, 169, 183; ice sheets, 83; JTW’s broken dinner plate example, 192, 240; “One World” image, 138; opposition to theory, 38, 42, 59–60, 74; reconstruction using computers, 44, 163, 182–3, 183; support of theory, 160; as urkontinent, 36, 169; Wegener’s theory, 4, 36, 37, 38. See also Gondwanaland; supercontinents Pangea II, 196, 207, 213–14, 215, 226, 226

Index Panthalassa, 36 Papua New Guinea, 150 paradigm shifts, 6 Parks, W.A., 83 Peach, Ben (geologist), 33, 133–4, 134 Pearson, Lester B., 123, 194 permanentism: about, 3–4, 60, 197, 237; American school, 43, 56, 75, 84, 140; concept, 33, 72, 93, 137; and JTW’s conversion to mobilism, 152, 167–70, 170, 171, 200, 239–40; Wilson–Scheidegger’s model, 137–9, 138, 145. See also land bridges permanentists: about, 2, 3–4; about Beartooth Mountains, 93, 225; acceptance of Bullard’s Pangea reconstruction, 183; control over university curricula and scientific journals, 58, 70, 72, 77, 78, 237; debate with mobilists, 2, 4, 24, 30, 36, 45, 72, 133, 162, 211, 237, 238; inability to accept basic premise of continental movement, 44, 50, 57, 77; JTW as permanentist, 84, 88, 96, 132, 134, 135, 137, 151, 167–8, 239; at University of Cambridge, 88–9. See also Chamberlin, Thomas; Coleman, Arthur; Dana, James; Heezen, Bruce; Jeffreys, Harold; Schuchert, Charles; Simpson, George; Suess, Eduard Perry, John (mathematician), 59 Physical Geology (Schuchert et al.), 58 physicists, generally, 59, 60–1 physics, 22, 80 Physics and Geology (Jacobs, Russell, & Wilson), 239 Physics of the Earth’s Crust (Fisher), 33 Pioneer Mining Corporation, 84–5

pitchblende discovery, 17 Placet, François, 25–6 Plafker, George, 179 Planet of Man, The (TV series), 198, 241 plate tectonics (theory): about, 205, 234, 246; application for greener economy, 234; application to Earth’s evolution, 211–14, 212, 213, 214; “Earth’s Plan” as early version, 140; effects of the theory, 5, 195; enabled by geological data, 236–7; evolution of, 1–2, 170, 173– 4, 195, 235–40; first use of term, 205; as framework for mapping and exploring sedimentary basins, 233; identification of lithospheric plates, 205; plate tectonic settings, 207, 209, 209, 210, 233; processes acting as Earth’s thermostat, 229– 30; promotion and support of, 57, 200, 201, 241; rift between Russian and West geologists, 204; role of mantle convection currents, 207; theories of plate motion, 210–11, 226–7; unanswered questions, 226–9. See also supercontinents; tectonic plates plates. See plate tectonics (theory); tectonic plates Plumstead, Edna, 147 polar flight (movement of continents), 43 Precambrian shields, and evidence of continental drift, 163–4 Princeton University, 84, 92–5, 93, 94, 95 Principles of Geodynamics (Scheidegger), 137 Principles of Geology (Lyell), 65

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Principles of Physical Geology (Holmes), 70, 113n Project Habakkuk, 120 Promised Land, The (Antin), 50 prospecting, instructional booklets for, 131, 131 Prospector North of Sixty, The (Nagle & Zinowich), 17 provinces. See crustal blocks Pulse of the Earth (Umbgrove), 212 pushing forces, 33, 72, 73, 74, 225 Pyke, Geoffrey, 119; pykcrete, 119–20 Quebec: airships, 18; ice sheet, 31, 83; JTW’s fieldwork, 13, 22, 85, 96, 97, 98, 197; Noranda Mines, 86, 194; in wartime, 105, 107 Queen Elizabeth (as troop carrier), 119 Quirke, T.T. (geologist), 62 R-100 and R-101 airships, 17, 18, 19 Raff, Arthur, 174 Ralston, James, 111 religion, 3, 51, 56, 58, 82 Reynolds, Peter (geologist), 239 Rhythm of the Ages, The (Grabau), 47, 50, 155, 168 “Rift Valleys, Continental Drift and Convection in the Earth’s Mantle” (Girdler), 174 Rockcliffe Preparatory School, 22 rocks: ability to deform and flow, 62; andesite, 219, 220, 221, 222; on Baffin Island, 243; banded rocks in South Africa, 148; Cambrian, 48; density, 62–3; evidence of continental collision, 192; evidence of continental mobility, 71; evidence of Pangea, 39, 40, 191, 192; faults in, 99; glacial tillites, 27, 40–1, 42;

Index granite, 222; JTW’s broken dinner plate example, 192; laboratory experiments, 238; magnetic characteristics, 160, 176, 177; mapping, 97, 177; nature of mantle rocks, 61; oldest in centre of continents, 54; Paleozoic, 138; practical studies of, 81; Precambrian, 62, 96; radiometric age-dating of, 59, 69, 70, 135, 136, 154, 212; and requisite water, 222; uniformitarianism, 54. See also fossils; oil and gas exploration Rocky Mountains: formation, 33, 55, 93, 225; mapping, 82, 134; Saskatchewan Glacier, 143; structure, 34; tourism, 9, 10; “writing table” mountains, 34 Rodina, 62 Romania, 152–3 Royal Canadian Air Force, 13, 15, 127 Royal Canadian Engineers, 105, 106 Royal Canadian Navy, 170 Royal Society, 44, 238, 242–3 Royal Society of Canada, 127 Ruffman, Alan (geologist), 185–6 Runcorn, Stanley “Keith” (geophysicist), 161, 162, 187, 188, 242 Russia: JTW’s travel in, 153–4, 154, 155; science of geology in, 204 Rutherford, Ernest, 69 Salisbury, Rollin D. (geologist), 33, 136 Scheidegger, Adrian (mathematician), 137, 145 Schuchert, Charles (paleogeographer): about, 30, 45–6, 46, 157; criticism of Wegener’s theory, 38, 43, 44, 46, 69; geology

textbooks, 58; on land bridges, 29, 47, 48, 49, 190–2, 191; on ocean basins, 53; paleogeographic maps, 47, 48; phases of mountain building, 47; review of continental drift theory, 56, 72; Schuchert Medal, 47 Schwerdtner, Walfried, 185 Science North, 200 scientific journals, influenced by permanentists, 4, 58, 70, 72, 78 scientific revolution, 183 scientists: and independent rediscovery, 165, 176, 187–8; viewed as objective and rational rather than passionate, 4, 57 Scopes, John T. (geologist), 58 Scopes Monkey Trial, 58 Scottish Highlands: formation, 33, 134–5; Great Glen Fault, 133, 169, 170, 190; “Highland Controversy,” 133–4; JTW’s fieldwork, 132–5; Lewisian Gneiss, 134; Moine Thrust, 134, 134; as part of continuous chain, 190 Scripps Institute of Oceanography, 158, 174 sea floor spreading: causing continental drift, 71, 72, 74, 165, 168, 195–7; causing magnetic stripes, 174–6, 175, 184; driving force behind, 170, 210–11; evidence of, 168, 171, 196, 197; and Mid-Atlantic Ridge, 159; rate, 184; and spreading force of dikes, 101, 219; transform faults, 184–6, 185, 187, 187, 189; vapours released, 230. See also midocean ridges seamounts, 164, 171, 173, 245 Sears, Mary (oceanographer), 157

280

Second World War: aerial photography and equipment, 116–17, 159; after-action damage assessments, 116; Americans’ control over Canadian airports, 110; aptitude tests, 120; Bailey portable bridges, 117–18, 118; Battle of Britain, 111, 115; the Blitz, 112, 113n, 114; British Commonwealth Air Training Program, 109–10; building aircraft carriers from pykcrete, 119–20; coastal defences in southern England, 108; collecting oceanographic data, 157, 237; degaussing ships’ hulls, 181; drilling and tunnelling, 105, 107, 108, 110–11, 112; fighting in arctic conditions, 121; German invasions, 108; getting equipment into the field, 115; inflatable boats and tanks, 119; League War Cup, 113n; Mechanised Transport Corps, 114; Operation Husky, 116; Operation Spartan, 116; postwar studies and employment for servicemen, 131, 131; soldiers’ distrust of scientists, 118–19; troop transport, 107, 119; typical Canadian recruits, 107, 115; weapons, 4, 108–9, 109, 111, 111–12, 117, 120, 181; wearing good-conduct medals, 108. See also Canadian Army; military service by JTW seismic gap theory, 66–7 seismic waves: to map structure of New Jersey coast, 92; seismic reflection methods, 131, 181; seismic tomography, 229; seismographs, 203; shadow zones, 67, 68; sound waves, 104, 131, 158, 181; traversing Earth’s interior, 66, 152, 227, 229; types, 67, 68

Index seismology, science of, 66, 227, 229 Sherzer, William, 10 sial, 42, 63 Silurian Period, 133, 134 silver mines, JTW’s visit to, 22 sima, 42, 63 Simmons, M.D., 229 Simonds, Guy, 116 Simpson, George Gaylord (biologist), 78 slab pull, 71, 74, 226–7 Slave Craton, 100, 102, 136, 223, 224 Smith, Alan, 182 Snider-Pellegrini, Antonio (naturalist), 26, 26 snowmobiles, 121, 123 society, in the sixties, 5 Soddy, Frederick, 69 sound waves, 104, 131, 158, 181 South Africa, banded rocks in, 148 spherical geometry theory, 182 Stacey, Charles P., 113 Stefansson, Vilhjalmur (ethnologist), 19–20, 123, 125, 200, 243 stereoscopes, 15 Stern, Robert J. (geologist), 228 Stille, Hans (geologist), 56 Stratigraphy of the Eastern and Central United States (Schuchert), 47, 193 Strength and Structure of the Earth (Daly), 72 strike-slip faults, 169 subduction: effects, 157, 206, 219, 221, 221, 222; evidence of, 178; force behind continental movement, 72; megathrust, 179, 180, 220, 221, 222 subduction zones, 63, 209, 209, 211, 221, 222 Sudbury Basin, impact origin of, 39

Suess, Eduard (geologist), 26–9, 27, 77, 193 supercontinents: ages, 212, 213; Columbia, 213; cycle, 211, 213, 213– 20, 246; episodes of formation, 212, 227–8; Gondwana-Pangea, 213; “magic numbers,” 212; Nuna, 213, 223, 224, 236, 236; Pangea II, 196, 207, 213–14, 215, 226, 226; Rodina, 62, 212, 213, 214, 223, 224, 230, 232; Superia/Sclavia/Kenorland, 213, 223, 224. See also Pangea Sykes, Lynn, 186, 205, 206 Taconic mountain building, 47, 193 Taylor, Frank Bursley (geologist): about, 29–31, 30; communication with Du Toit, 77; publications, 30, 31, 39, 58, 84, 140; responses to his hypotheses, 36; Taylor-Wegener theory, 76, 193; theory, 32, 236 Taylor, Stuart, 221 tectonic plates: about, 186–7, 206, 207; African Plate, 214, 216; Anatolian Plate, 216; Arabian Plate, 216; continents embedded in, 186, 188, 206; crumple or suture zones, 209, 209; discovery, 29, 66, 186–90, 189; effect on cities, 230–3; Eurasian Plate, 202, 216, 218; European Plate, 218; Farallon Plate, 224, 225, 244; future activity, 226; and gneisses, 240, 242; Indo-Australian Plate, 202; JTW’s demonstration of mechanism, 194–5; Juan de Fuca Plate, 207, 223, 224, 225; lectures on, 190, 200; lithospheric plates, 207, 207; maps, 196, 202, 206, 232; margins, 188, 206; movement, 187, 188,

281

206, 210–11, 225, 246, 246; North American Plate, 218, 218, 223, 225, 225; Pacific Plate, 173, 207, 222, 223; passive margins, 209, 209; plate interactions, 209, 209, 216, 218, 219, 222, 223, 232; subduction zones, 209, 209, 221; Tectonic Map of Canada, 135, 169; as thermostat, 229–30; unanswered questions about, 226–9. See also Dewey, John; plate tectonics (theory) Temple of Serapis, 65, 65 Termier, Pierre (geologist), 75 terranes. See crustal blocks Tethys Ocean: closing, 28, 214; collision zone along rim, 232; map, 28; metal deposits, 234; naming, 27; and oil and gas, 234; remains of, 216, 218, 220; rocks from, 28 Textbook of Geology (Chamberlin & Salisbury), 33 Textbook of Geology (Schuchert et al.), 58 Tharp, Marie (geologist), 158–9, 160, 174, 184, 185 Theatrum Orbis Terrarum (Theatre of the world) (Oretlius), 25 Thirty Thousand Islands, gneisses on, 62 Thom, William, 92 Thompson, J.J., 88 tidal forces, 30, 65 till, 41 Torngat Ocean, 236 Toronto, geological map of, 83 Trans-Hudson Orogen, 236 transform faults, 185 trilobites, 47, 48, 191, 192 Trosvik, Trond (geophysicist), 229

Index Trumpy, Rudolph (geologist), 132, 237 Tuzo, Henry Atkinson (grandfather), 8–9 Tuzoia fossil, 10 Umbgrove, J.H.F. (geologist), 212–13 Unglazed China (Tuzo Wilson), 203 uniformitarianism, 54, 65 University of Cambridge, 88–90, 91, 132, 184 University of Toronto: Ajax campus, 131; boundaries of physics and geology, 130; Department of Geology, 80, 81, 238; Department of Geophysics, 132, 143; Department of Mathematics, 80; Department of Physics, 79–80, 81, 130, 132; effect of disagreements on students, 238–9; exploration geophysics, 81– 2; 49 Club, 136; JTW as principal of Erindale College, 197–9; JTW in dramatics and debating, 81; JTW’s studies, 22, 24, 78–84, 87, 87; JTW’s summer fieldwork, 80–1, 84–7, 85, 87, 242; JTW’s teaching, 130, 132, 186, 189, 198–9, 238–9, 244–5; life at Trinity College, 80; Rockfest, 244–5; salaries, 130; Science Club, 81; student veterans postwar, 130–2; tuition, 81 university programs: controlled by permanentists, 58, 72, 78, 237; re-energized by plate tectonics theory, 5. See also specific universities uranium ore discovery, 17 urban geology, 29 USS Colebrook, 179, 180 USS Thresher, 158

Vaux, Mary, 10 Vetlesen Prize, 245 Vickers Vedette (plane), 15, 16 Villumsen, Rasmus (Inuit), 74–5 Vimy Ridge, 14, 104, 116 Vine, Frederick (geologist and geophysicist): findings on ocean floors, 174, 175, 176, 184; and Jeffreys’s opposition to continental drift, 62n volcanic islands: dikes, 72, 73; geology, 71–2; as mantle hot spots and hot spot tracks, 171, 172, 173, 227, 235; movement, 172; sinking, 63, 64, 164; underwater eruptions, 197. See also Hawai’ian Islands volcanoes: collapse causing tsunamis, 173; distribution in island and magmatic arcs, 137, 138, 139, 209; effect on climate, 231, 232; hot-spot type, 1, 171, 172, 173; in Iceland, 218, 232; and megathrust earthquakes, 219, 221; monitoring, 231; in New Guinea, 149, 150; shield type, 217; stratovolcanoes, 220; supervolcanoes, 227, 231; Tambora and Krakatau, 221; Toba Volcano, 231. See also magma Voltaire, 231 Wadati, Kiyoo, 177–9 Walcott, Charles Doolittle (geologist), 10, 47, 190 Wallis, Barnes (aircraft designer), 17 Waterschoot van der Gracht, Willem A.J.M. van (geologist), 43–4 Wegener, Alfred Lothar (physicist): about, 4, 37, 37–8, 44, 57, 58, 75;

282

anti-German sentiments towards, 4, 44, 57, 75; conference to review his theory, 43, 44, 75; continental drift theory, 4, 36, 42–3, 44–5, 74, 75; flaws in theory, 42, 57, 60, 74, 168, 188, 193; on formation of mountain chains, 57; German use of his theory, 75; ignored in textbooks, 58, 83; later test of his theory, 162; lecture on Taylor’s “Earth’s Plan,” 39; military service, 39; opposition to his theory, 38, 42–4, 46, 56, 59–60, 78, 82, 88, 237; support of his theory, 43, 70–1, 77, 84; surveying and death in Greenland, 74–5, 76, 89, 235, 236, 236. See also continental drift; Pangea Wegener, Kurt, 37, 75, 76 Wegmann, Eugene (geologist), 76 West, Gordon, 132 Wiechert, Emil, 65 Willis, Bailey (geologist), 33, 36, 49, 49–50, 53, 75 Wilson, Harold, 183 Wilson, Henrietta “Hetty” Tuzo (mother), 6, 7, 7–10, 11, 12, 12, 245 Wilson, Isabel Jean Dickson (wife): assisting JTW with maps and reports, 100, 240; on Hetty Wilson, 10; on JTW’s career choices, 130, 198; marriage, 100, 114, 241; military service, 113–14 Wilson, James Tinley (geophysicist), 96 Wilson, John Armitstead (father): about, 6–7, 8; in aeronautics and air transport, 13, 17, 17, 18; in Australia, 149; awards, 19, 110; and Canadian Arctic Expedition, 19–20;

Index connections, 19, 20; employment, 12–13; marriage, 7–8, 12; military service, 103, 109–10, 113–14 Wilson, John “Jock” Tuzo (JTW): about, 5; awards and medals, 88, 126, 189, 245, 249, 249–50; character, 19, 20, 61, 79, 99, 125, 162, 238, 240, 244; cooking during fieldwork, 84–5; daughters’ memories of, x, 12, 153, 167, 168, 189, 195, 238, 240, 245; family life, 5, 12, 240; features named after, 245–6; five-month world tour, 145–9, 146, 148, 149, 150; hobbies, 240, 245; last years and death, 244–5; leadership skills, 126, 128, 198; marriage, 5, 102, 241; military service (see military service by JTW); organizations led, 5, 125, 127–8, 151, 244; parents, 6–10, 7, 11, 12, 12–13, 19,

21; on politics, 153; postgraduate studies, 87–8; rum aversion, 90; schools, 5, 22, 84; showmanship, 199; sports, 21, 22, 89–90, 194; summer cottage and sailing, 194, 199, 240, 241, 242; teaching techniques, 5, 242, 243; travels, 8, 20, 22, 80, 89, 120, 152, 240 (see also specific countries); use of the name Tuzo, 8, 96; writings, 6, 115, 126–37, 155, 168, 170, 173–4, 239, 240. See also Geological Survey of Canada; Ontario Science Centre; Princeton University; University of Cambridge; University of Toronto Wilson, Patty (daughter), x, 12, 154, 195, 240 Wilson, Peter (brother), 21 Wilson, Susan (daughter), x, 12, 153, 167, 168, 189, 195, 238, 240, 245

283

Wilson Cycle, 193–4, 211, 213, 236, 236 Wilson Seamounts, 245 “With the Night Mail” (Kipling), 17 women, in fieldwork, 158–9 Wopmay Orogen, 15 Wordie, James M. (geologist), 89 World Bank, on demand for metals and elements, 234 World War I. See First World War World War II. See Second World War Wright, Harry (science teacher), 22 “writing table” mountains, 34 Yellowstone, volcanic activity of, 244 York, Derek, 212 Zinowich, Jordan, 17