Ediacaran-Paleozoic Rock Units of Egypt: Their Correlation with Adjacent Countries and Their Depositional Environments (Earth and Environmental Sciences Library) 3031273192, 9783031273193

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Earth and Environmental Sciences Library

Mohamed Abdel Ghany Khalifa

EdiacaranPaleozoic Rock Units of Egypt Their Correlation with Adjacent Countries and Their Depositional Environments

Earth and Environmental Sciences Library Series Editors Abdelazim M. Negm, Faculty of Engineering, Zagazig University, Zagazig, Egypt Tatiana Chaplina, Antalya, Türkiye

Earth and Environmental Sciences Library (EESL) is a multidisciplinary book series focusing on innovative approaches and solid reviews to strengthen the role of the Earth and Environmental Sciences communities, while also providing sound guidance for stakeholders, decision-makers, policymakers, international organizations, and NGOs. Topics of interest include oceanography, the marine environment, atmospheric sciences, hydrology and soil sciences, geophysics and geology, agriculture, environmental pollution, remote sensing, climate change, water resources, and natural resources management. In pursuit of these topics, the Earth Sciences and Environmental Sciences communities are invited to share their knowledge and expertise in the form of edited books, monographs, and conference proceedings.

Mohamed Abdel Ghany Khalifa

Ediacaran-Paleozoic Rock Units of Egypt Their Correlation with Adjacent Countries and Their Depositional Environments

Mohamed Abdel Ghany Khalifa Geology Department, Faculty of Science Menoufia University Shiben El Kom, Egypt

ISSN 2730-6674 ISSN 2730-6682 (electronic) Earth and Environmental Sciences Library ISBN 978-3-031-27319-3 ISBN 978-3-031-27320-9 (eBook) https://doi.org/10.1007/978-3-031-27320-9 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

On the soul of my father and my mother Dedication to my wife and my sons (Motaz, Hythium and Mona)

Preface

Said (1971) made the first attempt to describe the Paleozoic sedimentary rock stratigraphic units in his explanatory notes that were included with the geological map of Egypt. Issawi et al. made a second attempt in 1999 and 2009. Additionally, the Paleozoic rock stratigraphic rock units in Sinai were described by El Kelani et al. in 1999. Additionally, the Sinai Peninsula’s Cambrian rocks were categorized by Kora (1991). The primary focus of Egypt’s Ediacaran-Paleozoic stratigraphic rock units is: 1) To include and update new rock units that have been discovered on Egyptian geologic maps over the past forty years, either by the Egyptian Geological Survey or by researchers who have travelled to and explored new original references. Therefore, we apply the rules of the North American code for stratigraphic nomenclatures (1983) in choosing a proper and suitable name for rock unit in different regions in the extreme south Western and Eastern Deserts, as well as the Sinai Peninsula, 2) To restore or give credit for the rock units’ names. This book began its description of the rock units from south to north across the Egyptian Territory, arranging the description of the rock units according to their ages (from older to younger). 3) to provide the readers the opportunity to follow the changes in facies, thickness, depositional settings, and ancillary structural components that occurred during the sedimentation of these rock units t. 4) To get back or attribute the names of the rock units to their original name. This book arranged the description of the rock units according to their ages (from older to younger) and started the description from south to north all over the Egyptian Territory. This arrangement will allow the reader to follow the facies changes, thickness changes, depositional environments and the accompanying structural elements that culminated during the sedimentation of these rock units. The rules of the North American code on stratigraphic nomenclature (1983), which are discussed in this book, are crucial for settling the controversy surrounding the repetition of multiple rock units with the same age. Additionally, it will disregard any terms for rock units that do not adhere to the North American code for stratigraphic nomenclatures (1983). New rock units are introduced in this book, e.g. the Ediacaran Abu Haswa Formation, which contains stromatolitic dolomitic limestone, the Devonian Tadrart Formation, the Upper Permian Wadi Dome Formation (exposed), the vii

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Upper Permian Misawag Formation (in the subsurface), and the Ordovician-Silurian Gabgaba Formation. This book describes each rock unit: definition, stratigraphic contact, lithology, thickness and distribution, age assignment, and correlation with adjacent countries, e.g. Libya, Jordan, Saudi Arabia and Iraq. Each rock unit has a lithostratigraphic column representing the type locality and nearby localities in the Western and Eastern Deserts and Sinai. Also, each rock unit is provided by field lithologic description, field photographs, faunal association and map illustrating the possible depositional environments. The exposed and subsurface Paleozoic rock units mentioned in this lexicon correlate with their corresponding rock units inside Egypt and adjacent countries (Libya, Jordan, Saudi Arabia and Iraq). The data mentioned in this book are based on the published papers from the Egyptian Geological Society, the explanatory notes to accompany the geological map of Egypt (Said, 1971), the Geology of Egypt (Said, 1962, 1990), Phanerozoic Geology of Egypt (Issawi et al. 1999, 2009), the geology of the Egyptian Nubian Shield (Hemimi et al., 2021), published papers from the International Conference on the Geology of the Tethys (Cairo University), the Geology of the Arab World (Cairo University), Annals of the Egyptian Geological Survey and its unique publication papers and the Geological conference of Africa (Assuit University). Moreover, it is used in other published papers by researchers who published papers on the Geology of Egypt. In addition, the author used his field experience from his work in the Geological Survey of Egypt (1975–1978), his field experience during his supervising on M.S and PhD Theses and his published research articles in local and international journals. Mohamed Abdel Ghany Khalifa Geology Department, Faculty of Science Menoufia University Shiben El Kom, Egypt

Acknowledgements

The author expresses his deep gratitude to Prof. Abdel Azeem Nagm, Faculty of Engineering, Zagazig University for his advice during the proposal of this book. Also, my deep appreciation is due to the German Scientists of them, Prof. E. Klitzsch, Peter Wycisk, Lejal-Nicol, and Olaf Elicki. They provide me with field photos of the Paleozoic rocks taken from the Gilf El Kebir plateau, southwestern Desert and Sinai. My thanks also go to Dr. Ezzat Abdallah, and Dr. Ali Khudeir, Geology Department, Assuit University for their supply of the published papers on the Ediacaran Hammamat. My thanks to Dr. Mohamed Foad, the remote sensing authority who provided me with field photographs and Satellite images of the Hammamat sediments in the central Eastern Desert. Also, I would like to thank Dr. Ashraf Boghdady, Geology Department, Ain Shams University, for providing me with field photographs of the Hammamat sediments. My appreciation is oriented to Dr. Tarek Foad and Dr. Walid Makled, Exploration Department, Egyptian Petroleum Research Institute, Nasr City for providing me with the Paleozoic subsurface data in the northwestern Desert. Last but not least, my profound thanks to my colleagues and my students in the Geology Department, Menoufia University, who prepared the needed drawings for this book, and especially mention Dr. Motaz Khalifa, Dr. Amr Zaki, Ahmed El Feky, Fatma Abd El Geleil, and Mohamed Shaban, all of them have from me many thanks and appreciation.

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Contents

1 Introduction and Back Ground History . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 6

2 The Ediacaran Rock Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 The Hammamat Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 2.3 The El Urf Formation (Volcanoclastic Sediments) . . . . . . . . . . . . . . . 2.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 2.4 The Abu Haswa Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 Ediacaran Rocks in Adjacent Countries . . . . . . . . . . . . . . . . . . . . . . . . 2.6.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7.1 Depositional Environments of the Hammmat Formation . . . Depositional Environment of the El Urf Formation (Volcanoclastics) . . . Depositional Environments of the Abu Haswa Formation . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9 9 12 12 12 13 14 17 17 17 20 21 21 21 22 22 22 22 22 24 24 26 26 26 27 28 34 35 36 xi

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3 The Cambrian Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.4 Tectonics and Paleogeography . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 The Araba Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.2 Stratigraphic Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 3.3 The Shifa Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 3.4 The Cambrian Rock Units in Adjacent Countries . . . . . . . . . . . . . . . . 3.4.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43 43 43 44 44 45 46 46 46 47 48 51 53 53 54 55 55 56 56 56 56 57 58 58 64

4 The Ordovician Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.4 Paleogeography and Tectonics . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Ordovician Rocks in Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 The Karkur Talh Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 4.2.1.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 4.2.2 The Naqus Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2.2 Stratigraphic Contacts . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 4.2.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . .

69 69 69 70 70 71 71 71 71 72 72 75 75 76 76 77 77 79 82

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4.2.3 The Gabgaba Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 4.2.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 4.2.4 Ordovician Rocks in Adjacent Countries . . . . . . . . . . . . . . . . 4.2.4.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.4.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.5 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

83 83 84 84 84 84 85 85 85 86 86 87 91

5 The Silurian Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.4 Tectonics and Paleogeography . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 The Silurian Rocks in Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1 The Um Ras Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1.4 Thickness and Distribution . . . . . . . . . . . . . . . . . . . . 5.2.1.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 5.3 The Kohla Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.4 Thickness and Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 5.4 The Basur Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.4 Thickness and Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.5 Age Assignment and Correlation . . . . . . . . . . . . . . . . . . . . . . . 5.5 Silurain Rocks in Adjacent Countries . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

95 95 95 96 96 96 98 98 98 98 98 99 100 101 101 101 101 104 104 105 105 106 106 107 109 109 109 110 110 111 111 114

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6 The Devonian Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1.2 Calssification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1.4 Tectonics and Paleogeography . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 The Devonian Rock Units in Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1 The Tadrart Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.1.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 6.2.1.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 6.2.2 The Zeitoun Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 6.2.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 6.2.3 Devonian Rocks in Adjacent Countries . . . . . . . . . . . . . . . . . . 6.2.3.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

119 119 119 120 120 120 122 122 123 123 124 125 125 125 125 125 127 128 129 129 129 130 130 131 131 135

7 The Carboniferous Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1.4 Tectonic and Paleogeography . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Lower Carboniferous Rock Units in Egypt . . . . . . . . . . . . . . . . . . . . . 7.2.1 The Umm Bogma Formation . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.2.1.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.2.2 The Abu Thora Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.2.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . .

139 139 139 140 141 141 141 142 142 142 143 144 146 146 146 148 149 151 152

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7.2.3 The Wadi Malik Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.2.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.2.4 The Desouqy Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.4.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.4.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.4.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.4.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.2.4.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.2.5 The Dhiffah Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.5.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.5.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.5.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.5.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.2.5.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3 Upper Carboniferous Rock Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1 The Abu Durba Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.1.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3.2 The Rod El Hamal Formation . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.2.2 Stratigraphic Contacts . . . . . . . . . . . . . . . . . . . . . . . . 7.3.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3.3 The Abu Darag Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.3.2 Stratigraphic Contacts . . . . . . . . . . . . . . . . . . . . . . . . 7.3.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3.4 The Aheimer Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.4.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.4.2 Stratigraphic Contacts . . . . . . . . . . . . . . . . . . . . . . . . 7.3.4.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.4.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.4.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3.5 The North Wadi Malik Formation . . . . . . . . . . . . . . . . . . . . . . 7.3.5.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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153 153 154 154 154 155 156 156 157 158 158 160 160 160 160 160 161 161 161 161 161 161 162 164 164 165 165 166 166 166 167 167 167 167 167 168 169 169 169 169 169 170 171 171 171

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7.3.5.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.5.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.5.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.5.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.3.6 The Safi Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.6.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.6.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.6.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.6.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 7.3.6.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 7.4 Carboniferous Rocks in Adjacent Countries . . . . . . . . . . . . . . . . . . . . 7.4.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

171 172 172 172 173 173 174 174 175 175 175 175 176 176 177 177 183

8 The Permian Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.2 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.3 Fauna and Flora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.4 Tectonics and Paleogeography . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Permian Rock Units in Egypt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2 The Wadi Dome Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.2.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 8.2.2.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 8.2.3 The Misawag Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.3.1 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.3.2 Stratigraphic Contact . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.3.3 Lithology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2.3.4 Distribution and Thickness . . . . . . . . . . . . . . . . . . . . 8.2.3.5 Age Assignment and Correlation . . . . . . . . . . . . . . . 8.3 Permian Rocks in Adjacent Countries . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.1 In Libya . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.2 In Jordan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.3 In Saudi Arabia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3.4 In Iraq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 Depositional Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

189 189 189 190 190 191 192 192 193 193 193 193 194 194 197 197 197 198 198 198 198 198 199 199 200 200 205

About the Author

Mohamed Abdel Ghany Khalifa received his B.S. in geology from Geology Department at Cairo University in 1972. He obtained a master’s degree in geology from the Faculty of Science, Cairo University, in 1977. He received his Ph. D. in sedimentology and stratigraphy from the Faculty of Science, Cairo University, in 1981. His dissertation concentrated on the facies analyses and depositional setting of the Lower, Middle, Upper Eocene and Oligocene rock units (West Beni Mazar and south Fayium region). Five years were spent with the Egyptian Geological Survey from 1973 to 1978. During this period, he drew geological maps using aerial photographs and made a regional correlation between the Mesozoic and Cenozoic rock stratigraphic units in the Western and Eastern Deserts. He taught at the geography department of Imam Mohamed ben Saud University at Al Qasim branch, Saudi Arabia, from 1995 to 1999. He also taught at Geology Department, Omar Al Mokhtar University (Libya) at the Topruck branch from 2009 to 2015. He introduced five-rock units in the geology of Egypt: The Turonian Khashm El Galala Formation (Northern Galala, Eastern Desert, 2004), the Turonian Naqb El Sellim Formation (Bahariya Oases, 2003), the Campanian Ain Giffara Formation (Baharyia Oases, 1977), the lower Eocene Nashfa Formation (south of Fayium, 1984), the Pleistocene El Reis Formation (Bahariya Oases, 2004). He introduced different rock stratigraphic units in Saudi Arabia such as, A) Al Adgham Formation (Late Triassic), Al Qasim Province, Saudi Arabia (Khalifa, 1992; Khalifa, 2010). B) Rukhman Formation (Late Triassic), Al Qasim xvii

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Province, Saudi Arabia (Khalifa, 1992). C) Anz Formation (Early Ordovician), Al Qasim Province, Saudi Arabia (Khalifa, 1993, 2015), D) Al Watah Formation (Early Triassic), Al Qasim Province, Saudi Arabia (Khalifa, 1993, 2010) and E) Al Arid Formation (PermoTriassic), Al Qasim Province, Saudi Arabia (Khalifa, 2010). Moreover, He introduced a new terms in sedimentary cycles such as A) Emergence, submergence, gradual, non-gradual and truncated cycles (Khalifa, 1996), B) complete and incomplete cycles (Khalifa, 2005), C) Monolithic, diad and triad cycles (Khalifa and Tanner 2017). He published 87 research papers in sedimentology, stratigraphy, diagenesis, cyclicity and sequence stratigraphy of the Paleozoic, Mesozoic and Cenozoic rocks from Egypt, Saudi Arabia, Yemen and Jordon. Now, he is an emeritus Professor at the Geology Department, Faculty of Science, Menoufia University, Shiben El Kom, Egypt.

Chapter 1

Introduction and Back Ground History

Abstract This chapter discusses the recognition and classification of Ediacaran and Paleozoic rocks in Egypt. It also sheds light on the Ediacaran rock classification, which includes the Hammamat and El Urf formations in the Easter Desert and Sinai. Furthermore, it provides geologic information about the Nubia Sandstone and its division into various rock units in the Western Desert. It connects Paleozoic rocks from the Western and Eastern Deserts, as well as the Sinai Peninsula. It depicts the distribution of Ediacaran and Paleozoic rocks on the surface and in the subsurface. Keywords Paleozoic · Egypt · Ediacaran · El Urf Formation · Hammamat Formation · Western Desert · Eastern Desert · Sinai

Nobody knew the exact age of the Ediacaran rock in Egypt before the advent of age-dating methods used to determine the exact age of these rocks 40 years ago. Uranium-lead dating (U–Pb dating) is one of the first methods used for determining the exact age of the Ediacaran rocks (Boltwood 1907). Since then, the Ediacaran rocks in Egypt that were named before as the Hammamat sediments in the centre of the Eastern Desert and the volcanoclastic rocks in the northeastern Desert have been dated and described. The first authors estimated the age of the Hammamat deposits to be between 616 and 590 Ma (Ries et al. 1983). Then, the age dating (U–Pb dating) analysis continued to determine the possible age of the Hammamat sediments at Wadi Hammamat in the central Eastern Desert and the volcanoclastic rocks at Gebel El Urf in the northeastern Desert. They are both of the same age periods ranging from 615 to 585 Ma (Willis et al. 1988; Fowler and Osman 2013; Wilde and Youssef 2002). The Hammamat sediments are named herein as the Hammamat Formation, while the volcanic rocks are termed the El Urf Formation. Before 1972, stromatolitic dolomite rocks of the Ediacaran Period were not identified in Egypt. Later, Omara (1972) first noticed these rocks in the Sinai Peninsula and dated them to the Lower Cambrian period. The author discovered the stromatolitic dolomitic limestone in 2006 at the entrance of Wadi Mokattab from Wadi Feiran in southwest Sinai. It occurs above the basement rocks and below the Cambrian Araba Formation. On the Quseir-Qift Road in 2020, the author saw the stromatolitic dolostone occurring between the Precambrian basement rocks below the Cambrian Araba Formation above. These © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_1

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1 Introduction and Back Ground History

rocks have been treated here as separate rock stratigraphic units, named the Abu Haswa Formation. Carboniferous rocks’ earlier and easy differentiation from those from the Paleozoic sandstone is due to numerous index mega fossils and plant remains in these rocks. The Carboniferous rocks recorded in numerous locations west of the Suez Gulf and Umm Bogma in Sinai was the first Paleozoic rocks identified in Egypt (Walther 1890). Schweinfurth (1885) made the first discovery of the Carboniferous rocks described in detail by Walther (1890) in Wadi Araba, west of the Suez Gulf, and attributed the entire succession to the Lower Carboniferous. Bauerman initially found the Carboniferous rocks in Sinai in 1869, and because of their proximity to economically significant manganese mines, they drew many distinguished geologists. Later, the Lower Carboniferous sandstones from northeast Gebel Uweinat near Karkur Murr were discovered by Menchinkoff (1926, 1927). The unfossiliferous brown coarse-grained sandstone that restricted between the Precambrian basement rocks below and the Cenomanian rocks above was named the Nubian Sandstone (Russgger 1837). The stratigraphy, petrology, and possible mode of formation of this rock unit were studied by Bauerman (1869), Ball (1907), Hume (1911), Beadnell (1927), Seward (1935), Andrew (1937), and Shukri and Said (1944, 1946). Since then, the term Nubia Sandstone has become the mainstream and the famous term and became the common name among eminent geologists until 1978 (Ouda 2021). After then, when German geologists (Barthel and Boettcher 1978; Klitzsch 1978, 1979, 1986; Klitzsch et al. 1979; Barthel and Herrmann-Degen 1981; Klitzsch and Lejal-Nicol 1984; Klitzsch and Wycisk 1987; Klitzsch and Schandelmeier 1990), studied northern Sudan, southern Egypt, and southern Libya. They classified the Nubian Sandstone into several independent rock stratigraphic units based on the radical difference in lithology and identification of index trace fossils. They divided the lower part of the Nubian Sandstone (Paleozoic part) in the southwestern Desert at Gebel Uweinat into Karkur Talh Formation (Ordovician, Klitzsch and Lejal-Nicol 1984), Um Ras Formation (Silurian, Klitzsch and Lejal-Nicol 1984), Tadrart Formation (Devonian, Klitzsch and Wycisk 1987), Wadi Malik Formation (Early Carboniferous, Klitzsch 1979), North Wadi Malik Formation (Late Carboniferous, Klitzsch and Wycisk 1987), Lakia Formation (Permian, Klitzsch and LejalNicol 1984) (Table 1.1). At the same time, the Upper part of the Nubian Sandstone (Meszoic part, Cretaceous) was classified into Six Hills Formation (BarrisianBarremian, Barthel and Boettcher 1978), Abu Ballas Formation (Aptian, Barthel and Boettcher 1978), Sabaya Formation (Aptian-Albian, Barthel and Boettcher 1978), Maghrabi Formation (Cenomanian, Barthel and Herrmann-Degen 1981) and Taref Sandstone (Turonian-Santonian, Awad and Ghobrial 1965) (Table 1.1). These rock units were observed in the great sand Sea by Ouda (2021). The same party of German geologists visited the Nubain Sandstone in the central Eastern Desert at Marsa AlamIdfu road and Quseir-Qift road, notwithstanding the subdivision mentioned above of the Nubian Sandstone in the southwestern Desert. At these locations, they attempted to classify the Nubian Sandstone into independant rock units resembling those in the Western Desert. They were unsuccessful, but Nubian Sandstone remains on Egypt’s

1 Introduction and Back Ground History

3

Table 1.1 Classification of the Nubian Sandstone or Nubia Group in different rock units by German geologists (Barthel and Boettcher 1978; Klitzsch 1978, 1979, 1986; Klitzsch et al. 1979; Barthel and Herrmann-Degen 1981; Klitzsch and Lejal Nicol 1984; Klitzsch and Wycisk 1987; Klitzsch and Schandelmeier 1990) and Issawi et al. (1999) allover Egyptian territory

geologic map. However, the author and his PhD students’ thorough geological examination of the Nubian Sandstone along the Quseir-Qift Road led to the subdivision of the Nubian Sandstone into four rock units, based on lithology and trace fossils. These rock units are: Araba Formation (Cambrian), Abu Thora Formation (Carboniferous), Malha Formation (Early Cretaceous), the Bahariya Formation (Cenomanian) and the Taref Sandstone (Turonian) (Table 1.1). Another classification of the Nubian Sandstone was suggested by Issawi and Jux (1982) and Issawi et al. (2009) in the southwestern Desert (Table 1.1). In general, the Ediacaran Hammamat and El Urf formations are exposed in different localities in the central and northeastern Desert (Fig. 1.1). While the exposed rocks of the Cambrian Araba Formation occur at Wadi Abu Agag (Khedr et al. 2010), Idfu-Marsa Alam road, Qift-Quseir road (the present work), Wadi Qena (Klitzsch 1990), and in Sinai (Kelani et al. 1999; El-Kelani 2001; Khalifa et al. 2006) (Fig. 1.1). The Ordovician Karkur Talh Formation occurs at Gilf Kebir plateau, and northeast Gebel Uweinat (Klitzsch and Lejal-Nicol 1984), the Ordovician Naqus Formation occurs as discontinuous exposure in Sinai. The Gabgaba Formation, equivalent to the Naqus Formation, only occurs in the southeastern Desert (Issawi 2005; Osman et al. 2002). The Um Ras

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1 Introduction and Back Ground History

Fig. 1.1 Location map showing the distribution of the exposed Ediacaran and Paleozoic rock units in the Western and Eastern Deserts and Sinai Peninsula of Egypt

Formation occurs at Gilf Kebir Plateau, northeast Gebel Uweinat, In Wadi Araba and east of Northern Galala, and in Umm Bogma, southwestern Sinai (Fig. 1.1). The Paleozoic rocks in the subsurface of the northwestern Desert were encountered in 31 wells, five of which are uncertain (Keeley 1989; Hantar 1990) (Fig. 1.2). Their identification and the boundaries between rock units are difficult due to the monotonous composition of clastic rocks. However, they can be determined based on their stratigraphic position and the presence of index mega and microfossils. These rocks units are the Shifa Formation (Cambrian-Ordovician), Kohla and Basur formations (Silurian), Zeitoun Formation (Devonian), Desouky, Diffah, and

1 Introduction and Back Ground History

5

Fig. 1.2 Location map showing the subsurface drilled wells in the northern Western Desert (After Keeley 1989)

Safi formations (Carboniferous) (Keeley 1989), and Misawag Formation (Permian, present work) (Table 1.2). Although the exposed thicknesses of the Paleozoic rocks either in the Western, Eastern Deserts and Sinai are reduced (ranging from 300 to 500 m), they show maximum thickness in the subsurface in the Western Desert basins reaches up to 2500 m at Faghur.1, 2416 at Zeitun.1, and 2406 at Siwa.1 (Hantar 1990). The Correlation of the exposed Paleozoic rocks with their equivalent subsurface rock units is summarized in Table 1.2.

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1 Introduction and Back Ground History

Table 1.2 The distribution and correlation of the Paleozoic rock units in the surface and the subsurface in the Western and Eastern Deserts and the Sinai Peninsula

References Andrew, G., 1937. On the Nubian sandstone of the Eastern Desert of Egypt. Bull. inst. Egypte, 19: 93–115. Awad, G.H.; Ghobrial, M.G., 1965. Zonal stratigraphy of the Kharga Oasis, Egypt. Geol. Surv. Egypt, paper 34, 77 pp. Ball, J., 1907. A description of the first or Aswan cataract of the Nile. Egypt. Survey Dept., Cairo, 121 pp. Barthel, K. W; Boettcher, R., 1978. Abu Ballas Formation: a significant lithostratigraphic unit of the former “Nubian Series”. Mitt. Bayer. Staats, Paleontol. Hist. Geol. 18:155–166.

References

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Barthel, K. W.; Herrmann-Degen, W., 1981. Late Cretaceous and early Tertiary stratigraphy in the great Sand Sea and its SE margins (Farafra and Dakhla Oasis), SW Desert, Egypt. Mitt Bayer. Staats, Paleontol. Hist. Geol., 21: 141–182. Bauerman, H., 1869. Note on a geological reconnaissance made in Arabia Petraea in the spring of 1868. Quart. J. Geol. Soc. London, 25: 17–38. Beadnell, H. J. L., 1927. The wilderness of Sinai. Arnold, London, 180 pp. Boltwood, B. B., 1907. “Ultimate disintegration products of the radioactive elements; Part II, Disintegration products of uranium”. American Journal of Science. 23: 78–88. EL-Kelani, A., 2001. Contribution to the geology of Paleozoic in Sinai, Annals of the Geological Survey of Egypt, XXIV: 233–255. Fowler A, Osman A. F., 2013. Sedimentation and inversion history of three molasse basins of the western Central Eastern Desert of Egypt: Implications for the tectonic history of Hammamat basins. Gondwana Res 23:1511–1534 Hantar, G., 1990. Northwestern Desert. In Said. R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 293–320. Hume, W. F., 1911. The effects of secular oscillation in Egypt during the Cretaceous and Eocene periods. Quart. J. Geol. Soc. London, 67: 118–148. Issawi, B., 2005. Archean-Phanerozoic birth and development of the Egyptian land. First Inter. Conf. Geology of the Tetheys Cairo Univ. 2: 401–450. Issawi, B.; Jux, U. 1982. Contribution to the stratigraphy of the Paleozoic rocks in Egypt. Geol. Surv. Egypt. paper 64, 24 pp. Issawi, B.; El Hinnawi, M. Francis, M.; Mazhar, A. 1999. The Phanerozoic Geology of Egypt: A Geodynamic Approach. Egypt. Geol. Surv. Paper No. 76, 462 pp. Issawi, B.; Francis, M. H.; Youssef, E.A. A.; Osman, R.A., 2009. The Phanerozoic Geology of Egypt. A Geodynamic Approach. Min. Petrol. Egyp. Min. Reso. Authoity, Special Publ. No. 81. 589 pp. Keeley, M. L., 1989. The Paleozoic history of the Western Desert of Egyp. Basin Research, 2: 35–48 pp. Khedr, E., Abou Elmagd, K., Khozyem, H., 2010. Tectono-stratigraphic subdivision of the clastic sequence of Aswan area, southern Egypt. Fifth Int. Conf. Geology of the Tethys Realm, South Valley University, P. 197–216 Khalifa, M.A., Soliman, H. E., Wanas, H. 2006. The Cambrian Araba Formation in northeastern Egypt: Facies and depositional environments. Journal of Asian Earth Sciences 27 (2006) 873–884. Klitzsch, E., 1978. Geologische Bearbeitung Sudwest Agyptens. Geol. Rundschau 67: 509–520 Klitzsch, E., 1979. Zur Geologie des Gilf Kebir Gebietes in der Ostsahara. Clausthaler Geol. Abh. 30: 113–132 Klitzsch, E., 1986. Plate tectonics and cratonal geology in northeast Africa (Egypt/Sudan). Geol. Runschau 75:755–768 Klitzsch, E. 1990. Paleozoic. In Said. R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 393–406. Klitzsch, E.; Lejal-Nicol, A., 1984. Flora and fauna from a strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Berl. Geowiss. Abh. 50 (A):47–79. Klitzsch, E.; Schandelmeier, H., 1990. Southwestern desert. In Said, R. (Ed.): The Geology of Egypt. Balkema, Rotterdam, Brookfield: 249–257. Klitzsch, E.; Wycisk, P., 1987. Geology of sedimentary basins of northern Sudan and bordering areas. Berl. Geowiss. Abh. 75 (A)1: 97–136. Klitzsch, E.; Harms J. C.; Lejal-Nicol A.; List, F. F., 1979. Major subdivisions and depositional environments of Nubia strata, southwestern Egypt. Bull. Am. Assoc. Petrol. Geol. 63: 974–976. Menchikoff, N., 1926. Observations geologiques faites au cours de l’Expedition de S.A.S. Ie Prince Kemal El-Dine Hussein dans Ie desert de Libye (J925-192~ompt. rend., 183: 1047–1049. Menchikoff, N., 1927. Les roches cristallines et volcaniques du centre du desert de Libye. Compt. rend., 184: 215–217.

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Omara, S. 1972. An Early Cambrian outcrop in southwest Sinai, Egypt. N. Jb. Geol. Palaont. Mh. Stuttgart, 306–314. Osman, R., Ahmed, S.M., Khater, T., 2002. The stratigraphy and facies of Wadi Gabgaba and its surroundings with an emphases on the Lower Paleozoic glaciation. Sixth Inter. Conf. Arab World, Cairo Univ. Egypt, 2:469–482. Ouda, K., 2021. The Nubia Sandstone (Nubia Group), Western Desert, Egypt: An Overview. International Journal of Trend in Scientific Research and Development (IJTSRD) 5: 2456–6470. Ries, A. C.; Shackelton, R. M.; Graham, R.H., Fitches, W.R., 1983. Pan-African structures, ophiolites and melange in the Eastern Desert of Egypt: a traverse at 26° N. J. Geol. Soc. London, 140:75–95. Russegger, J. R., 1837. Kreide und Sandstein: Einfluss von Granit auf letzteren. Neues Jahrb. Mineral., 1837:665–669. Schweinfurth, G., 1885. Sur la decouverte d’une faune paleozoique dans Ie Gres d’Egypte. Bull. inst. Egypte (Ser. 2), 6: 239–255. Seward, A. C., 1935. Leaves of Dicotyledons from the Nubian sandstone of Egypt. Geol. Survey Egypt, Cairo, 21 pp. Shukri, N. M.; Said, R., 1944. Contribution to the geology of the Nubian sandstone, part I: Field observations and mechanical analysis. Bull. Fac. Sci. Cairo Univ., 25: 149–172. Shukri, N. M.; Said, R., 1946. Contribution to the geology of the Nubian sandstone. Part II, Mineral analysis. Bull. illst. Egypte, 27: 229–264. Walther, J. K., 1890. Ueber eine Kohlenkalk-Fauna aus der agyptisch-arabischen WListe. Z. deut. geol. Ges., 42: 419–449. Wilde, S.A.; Youssef, K. A, 2002. Re-evaluation of the origin and setting of the late Precambrian Hammamat Group based on SHRIMP U-Pb dating of detrital zircons from Gebel Umm Tawat, North Eastern Desert, Egypt. J. Geol. Soc. Lond. 2002, 159, 595–604. Willis, K. M.; Stern. R. J; Clauer, N., 1988. Age and geochemistry of Late Precambrian sediments of the Hammamat series from the Northeastern Desert of Egypt. Precambrian Res 42:173–187.

Chapter 2

The Ediacaran Rock Units

Abstract This chapter sheds more light on the description of the Ediacaran rocks in Egypt. Three rock units are introduced in this chapter; two of them (the Hammamat and the El Urf formations) belong to the Ediacaran Neoproterozoic, while the third (Abu Haswa Formation) belong to the Ediacaran sedimentary rocks. The Hammamat Formation refers to the Ediacaran clastic rocks found in an isolated basin within the Neoproterozoic rocks of Egypt’s central Eastern Desert. The El Urf Formation describes the Ediacaran volcanoclastic rocks found in the northern Eastern Desert and Sinai. In contrast, the Abu Haswa Formation describes the Ediacaran stromatolitic dolostone found at Gebel Abu Haswa, south of Gebel Ekma in southwestern Sinai, which is restricted between the basement rocks below and the Cambrian Araba Formation above. The lithofacies that make up the rock units mentioned above are described, and their depositional environments are interpreted. These rock units are correlated to neighbouring countries such as Libya, Jordan, and Saudi Arabia. Keywords Ediacaran · Abu Haswa · Hammamat · El Urf · Volcanoclastics · Sinai · Gebel Ekma · Wadi Queh · Egypt

2.1 Introduction The Ediacaran period is the most recent, occurring at the end of the Neoproterozoic. It only exists between the Cryogenian and Cambrian periods (Fig. 2.1). It spans 94 million years, beginning with the end of the Cryogenian Period (635 million years ago) and ending with the beginning of the Cambrian Period (541 million years ago) (Knoll et al. 2004a, b). It represents the Proterozoic Aeon’s end and the Phanerozoic Aeon’s start (Knoll et al. 2004a). It is named after the Ediacaran Hills in south Australia (Knoll et al. 2004a, b, 2006). The International Union of Geological Sciences designated the Ediacaran Period as an official geological period in 2004 (IUGS). It has been designated the first new geological period in the last 120 years (Knoll et al. 2006). Sprigg (1947) was the first to discover fossils of the eponymous Hoffmanns in this period, even though the period was named after the Ediacaran Hills in Australia. Due to a lack of underlying dating igneous material, it is complicated © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_2

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and ambiguous to date the rock type from the Ediacaran Period in South Australia. Thus, the Ediacaran period’s actual age ranges from 635 to 542 million years based on U–Pb (uranium-lead) isochron dating from Namibia (Hoffmann et al. 2004) and China (Condon et al. 2005). The age of the top in the Ediacaran Era is the same as the recognized age for the base of the Cambrian Period (542 0.3 Mya), resulting in a misalignment, as the end of the Ediacaran Period should have marked the start of the Cambrian Period. Applying this age to the Ediacaran base assumes that the cap of the carbonates is laid down synchronously around the world and that the appropriate cap carbonate layers have been selected in places as diverse as Australia and Namibia. This assumption is controversial because glacial rocks in Tasmania have been dated around 580 million years, which some scientists tentatively assign to those just beneath the Ediacaran Fig. 2.1 Geological chart shows the Ediacaran period’s position in the geological column (Knoll et al. 2004a)

2.1 Introduction

11

rocks of the Flinders Ranges. In the Ediacaran Era, multicellular organisms (with specialized tissues) that resembled segmented worms, fronds, discs, or immobile sacks were most common. In recent Ediacaran strata in western Siberia, a few hardshelled agglutinated foraminifera have been discovered (Kontorovic et al., 2008). Some essential Ediacaran biotas discovered include Arkarua, Charnia, Dickinsonia, Edicaria, Marywadea, Cephalonega, Pteridinium, and Yorgia. In Egypt, the Ediacaran sediments are divided into two types: (1) nonmarine sediments, which include uppermost Neoproterozoic sediments such as the Hammamat sediments and volcanoclastic rocks, and (2) marine sediments. The nonmarine sediments are found in the central and northeastern Deserts, as well as Sinai (Fig. 2.2). The Hammamat sediments are referred to as the Hammamat Formation in this context. At the same time, volcaniclastics are referred to as the El Urf Formation. The marine facies (stromatolitic dolomitic limestone) are named the Abu Haswa Formation in this work. Fig. 2.2 Location map illustrating the distribution of the Hammamat and the El Urf formations in the Eastern Desert and Sinai (After Eliwa et al. 2010; Abd El-Rahman 2021)

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2.2 The Hammamat Formation 2.2.1 Definition Hume (1934) was the first to refer to the Hammamat sediments as the Hammamat series. It takes its name from the pharaonic quarries of Wadi Hammamat. Wadi Hammamat, near the Quseir-Qift Road in the central Eastern Desert, was designated as the type locality (Wadi Hammamat). Although the thickness of Wadi Hammamat (4000 m, Akaad and Noweir 1969, 1980) is less than that of Wadi Arak (5000 m, Assaf 1973) and Wadi Kariem (6000 m, Abdel Aziz 1968), this may be due to the area’s accessibility due to its location along the Qift-Quseir road. This road is one of the oldest and closest roads connecting the Nile Valley to the Red Sea. Different nomenclature has been assigned to these sediments. They named the Hammamat Series (Hume 1934), the Hammamat Formation (Grothaus et al. 1979), the Hammamat clastics (Ibrahim et al. 2013), the molasse sediments (Abd El Rahman 2021; Fowler and Osman 2013; Ibrahim et al. 2013; Khudeir and Ahmed 1996), Hammamat Group (Ahmed et al. 1989; Akaad and Noweir 1969; Eliwa et al. 2021; Holail and Moghazi 1998), and the Hammamat sediments (Abd El Rahman 2021). The Hammamat Group was divided into two rock units by Akaad and Noweir (1969): the older is the Igla Formation, and the younger is the Shihimiya Formation. The Igla Formation is distinguished by its purple-to-red colour due to the abundance of hematite, hematitic clay, and detrital hematite volcanic (Akaad and Noweir 1969). The molasse term is inappropriate for describing the Hammamat sediments because this term in geological dictionary terms (Bates and Jackson 1983) implies that the molasse sediments are partly marine and partly continental. Furthermore, they stated that the molasse facies is a deltaic sedimentary facies composed of ungraded fossiliferous conglomerates, sandstones, shales, and marls. As a result, molasses is inconvenient for describing the Hammamat sediments of Egypt’s central and eastern deserts. Following Grothaus et al. (1979), the Hammamat sediments are studied in one rock unit under the term Hammamat Formation in this work. This nomenclature refers to the previously mentioned rules of the North American Stratigraphic Code (1983), which state that the formation has a unified and closely similar facies association mapped on the aerial photographs and has a wide geographic distribution.

2.2.2 Stratigraphic Contact In Wadi Hammamat, this formation unconformably overlies metasediments and metavolcanics (Grothaus 1979), whereas, at Wadi Queh, this formation nonconformably overlies the Dokhan volcanic (Fig. 2.3). The contact is commonly irregular or undulated and generally dips toward the south (Ahmed et al. 1989). In Wadi Abu Shiqieli, the basal conglomerate of the Hammamat Formation is exposed southwest of port Safaga and nonconformably overlies the Dokhan volcanic (Khudeir and Ahmed

2.2 The Hammamat Formation

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Fig. 2.3 Geologic map showing the occurrence of the Hammamat Formation, at Wadi Queh, central Eastern Desert (After Ahmed et al. 1989; Khudeir and Ahmed 1996)

1996). Such nonconformable contact is locally exposed, but sometimes it is downfaulted against the Dokhan volcanic. In Gebel Kharaza, the central Eastern Desert, the Hammamat Formation nonconformably overlies the Dokhan volcanic and is intruded by the younger granites (Azzaz 2015). However, in Wadi Hammamat, neither the base nor the top of the Hammamat Formation is unexposed (Abd El Rahman 2021). In general, the Hammamat Formation either overlies the Dokhan Volcanics (Akaad and Noweir 1969; Ries et al. 1983) or underlies the Dokhan Volcanics (Willis et al. 1988). The succession of the Hammamat Formation nonconformably overlies the tectonic mélange, intruded by collision-related granites and invaded by post-tectonic Phanerozoic trachytes (Ibrahim et al. 2013).

2.2.3 Lithology In different locations, the Hammamat Formation has different types of sedimentary facies association. Grothaus et al. (1979) identified four lithofacies at Wadi Hammamat: conglomerate, pebbly conglomerate, sandstone, and siltstone. The sediments at Wadi Queh are classified as a coarse red conglomerate, fine red conglomerate, fine green conglomerate, red sandstone, green siltstone, and red siltstone

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(Ahmed et al. 1989). Wadi Abu Shiqieli are classified as a matrix-supported conglomerate, clast-supported conglomerate, greywacke, and Siltone (Khudeir and Ahmed 1996). The current investigation will focus on the Wadi Queh. The coarse red conglomerate and fine red conglomerate usually occur in the northwest of Wadi Queh and show fining-upward cycles. Each cycle begins with a coarse red conglomerate and is capped by a fine red conglomerate (Fig. 2.4). This sequence constitutes the whole of section 1, which represents the Proximal fan (Fig. 2.4, section 1). The coarse conglomerate (massive and graded types) (Fig. 2.5a) is most commonly found in the basal part and the northwest of Wadi Queh and constitutes the majority of the section in the proximal fan. It ranges in thickness from several centimetres (for lens formation) to several hundred metres (Ahmed et al. 1989). Fine-grained conglomerates are also massive and polymictic. Each bed ranges in thickness from 1 to 2 m (Fig. 2.5b). At the central part of the Wadi Queh, the sequence comprises two lithofacies, pebbly sandstone and fine conglomerate. They exhibit a fining-upward cycle, each begins with a fine conglomerate and is capped by pebbly sandstone (Fig. 2.4, section 2, Fig. 2.6). This sequence build-up by itself section 2, which represents the Mid-fan lithofacies (Fig. 2.4, section 1). The pebbly sandstone outcrops in conglomerate filling channels. Its thickness ranges from 10 to 30 m. The sandstones are mostly cross-bedded planners with fining-upward cycles (Fig. 2.7). The sandstone lithofacies are massive, cross-bedded, and lenticular bedding. Some thin to lenticular mudstone lithofacies are less common. The conglomerate associated with the sandstone is closely similar to that found in section 1 (proximal fan lithofacies). The finest lithofacies in the Hammamat Formation are massive and thin laminated siltstones (Fig. 2.8a) and rippled mud-cracked siltstone (Fig. 2.8b). They are the most abundant lithofacies and occur at the southeast of Wadi Queh consisting sections 3 and 4. They are typically green to red and occur in the outer fan lithofacies (Fig. 2.4). They are found in the middle and upper sections of the section. They show fining-upward cycles. Each cycle starts with capped pebbly sandstone, sandstone, and siltstone.

2.2.4 Distribution and Thickness The Hammamat Formation occurs as isolated exposure in the central Eastern Desert. It appears less frequently in the southern parts of the central Eastern Desert until it disappears entirely south of 25° N. (Fig. 2.2) (Williams and Stern (1998). It is exposed in the northeastern Desert as relatively low hills and masses within Dokhan volcanic at Gebel Kharaza and Gebel El Urf. The Hammamat basin in the central Eastern Desert has the most exposure to the Hammamat Formation (150 m thick). On the other hand, the second most significant exposure of the Ediacaran Hammamat Formation occurs in the Wadi Kariem basin (150 m thick), where it covers an area of about 130 Km2 (Abd El-Wahid 2010, 2021). It can also be found in Wadi Queh and Wadi Abu Shiqieli.

2.2 The Hammamat Formation Fig. 2.4 Measured lithologic sections of the Hammamat Formation at Wadi Queh (After Ahmed et al. 1989). Section 1 (proximal fan lithofacies). Section 2 (Mid-fan lithofacies) and section 3, 4 (outer fan lithofacies)

15

16 Fig. 2.5 a Field photograph showing the coarse red massive polymictic conglomerate at the base of the Hammamat Formation (Proximal fan, section 1) northwest of the Wadi Queh (Taken from a field report, in Geol. Surv. Egypt, Dr. Mohamed Foad, personal communication. b. Field photograph showing the fine red conglomerate intercalated with coarse red conglomerate (Proximal fan, section1), the Hammamat Formation at northwest Wadi Queh (Fowler et al. 2020)

Fig. 2.6 Field photograph showing the fining-upward cycles of the fine conglomerate and sandstone (section 2). Each cycle begins with fine conglomerate at base, capped by sandstone at the top (Middle fan). Wadi Queh, central Eastern Desert (Taken from a field report, in Geol. Surv. Egypt, Dr. Mohamed Foad, personal communication)

2 The Ediacaran Rock Units

2.3 The El Urf Formation (Volcanoclastic Sediments)

17

Fig. 2.7 Field photograph showing the cyclic sequence of the massive pebbly sandstone siltstone lithofacies that constitute the entire sequence of the Hammamat Formation (middle fan, section 2) at the southeastern part of Wadi Queh (Fowler et al. 2020)

2.2.5 Age Assignment and Correlation Different authors determined the Hammamat Formation’s age, ranging from 616 to 590 Ma (Ries et al. 1983). It is concluded that the age of Hammamat sediments, as well as their date of deposition, occurred between 615 and 585 Ma (Fowler and Osman 2013; Wilde and Youssef 2002; Willis et al. 1988) and that both the Hammamat and Dokhan Volcanics were affected by rapid uplift between 595 and 588 Ma (Fritz et al. 1996; Loizenbauer et al. 2001). This formation can be correlated to the Mourizidie Formation in Libya, the Saramuj and Haiyala formations in Jordan, and Umm Al Asiah and Jifin formations in Saudi Arabia (Fig. 2.9).

2.3 The El Urf Formation (Volcanoclastic Sediments) 2.3.1 Definition The volcanoclastic sediments are studied herein under one independent rock stratigraphic unit called El Urf Formation. It describes the mixed terrestrial continental sediments associated with volcanic eruption and detrital sediments from volcanic sources. The nomenclature of volcanoclastic sediments in the El Urf Formation may

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Fig. 2.8 a Field photograph showing the massive and thin laminated siltstone lithofacies that constitute the most of the sequence of the Hammamat Formation (outer fan, sections, 3, 4) at the southeastern part of Wadi Queh (Fowler et al. 2020). b. Field photograph showing the rippled siltstone lithofacies that intercalated with the massive siltstone sequence (outer fan) of the Hammamat Formation (sections, 3, 4) at the southeastern part of Wadi Queh (Fowler et al. 2020)

refer to the following reasons, (1) it is well-preserved and has a maximum thickness of the Ediacaran volcano-sedimentary deposits at Gabal El Urf in the Northeastern Desert of Egypt (Khalaf et al. 2000). (2) These sediments only occur in the northeastern Desert and southern Sinai, (3) These volcanoclastic sediments in the northeastern Desert are unlike the Hammamat Formation in the central Eastern Desert as it is characterized by the lack of the intra-oceanic island arc and ophiolitic assemblages and the predominance of Ediacaran crust (Stern and Hedge 1985;

2.3 The El Urf Formation (Volcanoclastic Sediments)

19

Fig. 2.9 Correlation of the Hammamat Formation with the Mourizidie Formation in Libya, Saramuj and Haiyala formations in Jordan and with Umm Al Asiah and Jifin formations in Saudi Arabia

Abdel Rahman 2021). (4) the El Urf Formation contains more than 50% of the total thickness of volcanic (ignimbrite), volcanoclastic breccia, and metavolcanic (Eliwa et al. 2021). (5) It mainly comprises volcanoclastic associated with detrital sediments that significantly differ from the Hammamat Formation. This type of facies is considered Ediacaran terrestrial successions comprise intercalations of Hammamat sediments associated with the Dokhan Volcanics (Willis et al. 1988; Khalaf et al. 2000; El-Gameel 2010; Eliwa et al. 2010; Breitkreuz et al. 2010). The type locality of El Urf Formation occurs at Gebel El Urf, Ras Gharib segment, northeastern Desert (Fig. 2.2), where its lower and upper boundaries are well defined and the maximum thickness is observed (2000 m, Eliwa et al. 2021).

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2.3.2 Stratigraphic Contact The lower boundary of the El Urf Formation varies depending on location. It nonconformably overlies granitoid rocks or metavolcanic rocks at Gebel El Urf and east of Gebel El Kharaza (Fig. 2.10). The contract is between the granitoid rocks below and the sandstone of the basal El Urf Formation above (Fig. 2.10, Eliwa et al. 2021). In contrast, at Gebel Abu Had, the lower boundary is between the subvolcanic intrusion and lava at the base and siltstone at the base of the El Urf Formation. At Wadi Abu Hammad, the contact is between the ignimbrite rocks at the base and s (Eliwa et al. 2021). The upper boundary is between the sandstone of the uppermost El Urf sandstone and the ignimbrite rocks (Fig. 2.10, Eliwa et al. 2021). At the Hamid area, the lower contact nonconformably overlies the older granite, and it is placed between the older granite below and the massive conglomerate of basal El Urf Formation above. The latter locality’s upper boundary is between the bedded polymictic conglomerate and the welded ignimbrite rocks (Khalaf 2013). In Sinai, at Ferani locality, the lower boundary of the El Urf Formation is placed between the basaltic andesite below (603 Ma) and the undifferentiated conglomerate (590 Ma) of the basal El Urf Formation above. At Rutig area, the lower boundary lies between rhyolite and ignimbrite rocks below (619 Ma, Eliwa et al. 2021) and Kathrina volcanic (583 Ma, Eliwa 2021). The upper boundary at the Ferani area lies between the ignimbrite rocks. Fig. 2.10 Measured sections of the El Urf Formation at Gebel El Urf and east of Gebel Kharaza northeastern Desert (After Eliwa et al. 2021)

2.3 The El Urf Formation (Volcanoclastic Sediments)

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2.3.3 Lithology The El Urf Formation is composed of intercalations of Dokhan Volcanics and terrestrial sedimentary rocks of the Hammamat Formation (Fig. 2.10). The Dokhan Volcanics are made up of pyroclastic deposits, volcaniclastic mass flow deposits, and lava flows. The pyroclastic deposits include pyroclastic fallout deposits and pyroclastic density current flow deposits (Fisher and Schmincke 1984; Orton 1996; Eliwa et al. 2021; Schmincke 2004). The volcaniclastic mass flows comprise breccia (agglomerate), massive, matrix-supported sandstone rich in pumice fragments, and polymictic volcanic pebbles (Eliwa et al. 2021). The lava flows have an aphanitic to porphyritic texture and are primarily composed of andesite to rhyolite. The formation at Gebel El Urf consists of massive and well-rounded clasts, clast-supported conglomerate (up to 100 cm), pelitic to sandy-turbiditic lacustrine and cross-bedded fluvial sandy deposits with occasional volcanic glassy fragments. The El Urf Formation’s upper part is dominated by alternating ignimbrites and synvolcanic sedimentary mass flow deposits (Eliwa et al. 2021, Fig. 8.2). The main lithological features of Sinai’s volcanoclastic sediments are calc-alkaline intermediate to acidic volcanic associated with immature conglomerates, sandstones, and mudstones (Samuel et al. 2001; El-Gaby et al. 2002; Azer 2007; El-Bialy 2010; Stern et al. 2010).

2.3.4 Distribution and Thickness Volcanoclastic successions are found throughout the northeastern Desert (Ras Gharib segment), and Sinai (Fig. 2.2). The most common and thickest occurrences of the volcanoclastic sequence have been recorded at Gebel El Urf (Eliwa et al. 2010; Breitkreuz et al. 2010), Gebel Abu Had (El Gameel 2018), Gebel El Kharaza (Azzaz et al. 2015; Khalaf et al. 2000), Wadi Abu Hammad, Wadi Bali, and Gebel Nuqara (Fig. 2.2). They have been observed in Wadi Malhak, Ferani, Rutig, and Khashabi areas in southern Sinai (El-Gaby et al. 2002; Samuel et al. 2001; Azer and Farahat 2011; Khalaf and Obeid 2013; Andresen et al. 2014).

2.3.5 Age Assignment and Correlation Ediacaran Dokhan Volcanic activity in the northeastern Desert and southern Sinai lasted 630–590 Ma, according to geochronology (Eliwa et al. 2021). The Hammamat Formation was formed around the same time as the Dokhan Volcanic activity (625– 596 Ma) (Eliwa et al. 2021).

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2.4 The Abu Haswa Formation 2.4.1 Definition The Abu Haswa Formation is defined in this work as the first attempt to describe Ediacaran carbonate sediments, which are restricted between Precambrian basement rocks below and the Cambrian Araba Formation above (Fig. 2.11). The author recorded it in 2006 at Wadi Mokattab. Omara (1972) identified the same stromatolitic limestone at the base of Gebel Abu Durba for the first time and attributed it to the Early Cambrian period (Fig. 2.11). Its type locality is at the base of Gebel Abu Durba, between Precambrian basement rocks and beneath Araba Formation sandstone overlooking Belayim Bay (Fig. 2.11). Kora (1992) also recorded the same stromatolitic dolomitic limestone above the basement rock and below the basal Araba Formation at Gebel Abu Durba, southwest Siani. This observation is considered as solid evidence for the occurrence of Ediacaran stromatolitic dolomitic limestone of the Abu Haswa Formation in the Sinai Peninsula.

2.4.2 Stratigraphic Contact This formation is sandwiched between the Precambrian basement rocks below and the conglomeratic sandstone and siltstone of the basal Araba Formation above (Fig. 2.12). Its base nonconformably overlies the metamorphic rocks at Quseir-Qift Road (Fig. 2.12).

2.4.3 Lithology The main lithology is dark grey to light grey, very hard stromatolitic dolomitic limestone (Fig. 2.13a). Three bands or layers of stromatolitic dolostone are separated by sharp and uneven contact (Fig. 2.13b). It contains some elongated striations and or fossils traces? On its top (Fig. 2.14). This rock consists of wavy lamination in thin section, including micron-sized dolomite rhombs (5–10 um). Such rhombs are commonly idiotopic without zoning.

2.4.4 Distribution and Thickness Its occurrence is sporadic and discontinuous in southwest Sinai. It is first encountered at the base of Gebel Abu Durba, overlooking Belayim Bay, by Omara (1972). The author also encountered in 2006 and 2022 at the entrance of Wadi Mokattab from

2.4 The Abu Haswa Formation

23

Fig. 2.11 Geologic map showing the distribution of the Ediacaran carbonate rocks, Gebel Abu Durba, southwestern Sinai, Egypt) (After Omara (1972) with modification)

Wadi Feiran, southwest Sinai (Fig. 2.13a). It may occur at other localities in southwest Sinai. It assumes to be about 6 m thick at Gebel Abu Durba (Omara 1972, Fig. 2.12), it decreases in thickness at the entrance of Wadi Mokattab, measuring about 80 cm. Furthermore, dolostone rocks belonging to this formation are restricted between the Precambrian rocks below and the Araba Formation above in Quseir-Qift Road, measuring a few decimeters in thickness (Fig. 2.12).

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2 The Ediacaran Rock Units

Fig. 2.12 Measured lithostratigraphic sections show the Ediacaran Abu Haswa Formation’s stratigraphic position and boundaries at Gebel Abu Haswa, Wadi Mokattab (southwest Sinai), and Quseir-Qift road (central Eastern Desert)

2.5 Age Assignment and Correlation The age of the Belayim Bay Formation is based on its stratigraphic position. As it is restricted between the Precambrian basement rocks below and the basal Araba Formation above, it could be attributed to the top of Neoproterozoic. The lithology of the Abu Haswa Formation can be correlated with the Ediacaran Fatima Formation, which crops out along t he northern flank of Wadi Fatima about 15–55 km northwest of Jeddah, Saudi Arabia (Abu Seif et al. 2018).

2.6 Ediacaran Rocks in Adjacent Countries The Ediacaran rocks are scattered sporadically in the rifted basins on the AraboNubian Shield in the north African craton. They are encountered on the surface and in the subsurface in Libya, Egypt, Jordan, and Saudi Arabia.

2.6 Ediacaran Rocks in Adjacent Countries Fig. 2.13 a Field photograph illustrating the stromatolitic dolomitic limestone of the Abu Haswa Formation at Quseir-Qift road, central Eastern Desert. b Field photograph illustrating the wavy lamination, massive grey dolostone of the Abu Haswa Formation at Quseir-Qift road, central Eastern Desert. Notice the presence of three bands of stromatolitic dolostone separated by sharp and uneven contacts

Fig. 2.14 Field photograph illustrating the presence of some elongated striation that may indicate indefinite trace fossils? On the top of stromatolitic dolostone

25

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2 The Ediacaran Rock Units

2.6.1 In Libya The Ediacaran rocks are studied under the term Mourizidie Formation (700 m thick), defined by Jacque (1962) and named infracamberian (Algonkian). This formation nonconformably rest on the basement rocks and unconformably underlies the Cambrian Hasawnah Formation (Aziz 1998) (Fig. 2.9a). Shales, siltstones, and sandstones of possibly Infracambrian age have been encountered in the subsurface, in southern Cyrenaica in northeast Libya, and in the Murzuq Basin in southwest Libya. Infracambrian conglomeratic, shaly sandstones and siltstones occur at outcrop beneath Cambrian strata along the eastern margin of the Murzuq Basin in southwest Libya (Jacqué 1962). Additionally, exposures of Infracambrian sedimentary rocks have been reported from the eastern and western margins of this basin (Selley 1971; El-Mehdi et al. 2004).

2.6.2 In Jordan The Ediacaran sediments are recorded in southwest Jordan and given two rock units, the Saramuj conglomerate at the base and the Haiyala Formation (volcanoclastic sediments) at the top (Fig. 2.9c). The Saramuj Conglomerate was named by Blanchenhorn (1912). Its lower contact noncoformably rest on the granitoid, while its upper contact unconformably underlies the volcanoclastic Haiyala Formation (Jarrar et al. 1991) (Fig. 2.9). The Saramuj conglomerate assumes about 200 m in thickness. It comprises an immature, poorly sorted polymictic thick, bedded boulder conglomerate with some intercalation of pebbly-sized conglomerate and sandstone (Jarrar et al. 1991). The Haiyala Formation. McCourt (1987) that overlies the Saramuj conglomerate measures about 200 m thick and consists of intercalation of tuffaceous rocks, pyroclastic rocks, and green siltstone and shale (Jarrar et al. 1991; Bandel and Salameh 2013). It unconformably underlies the Cambrian sandstone.

2.6.3 In Saudi Arabia The Ediacaran rock units are named the Jibalah Group (Delfour 1977; Hadley 1974, 1986). It crops out in small, isolated basins adjacent to Najd faults (Fig. 2.9d). This group nonconformably overlies the Shammar Group (basement rocks), which mainly consists of rhyolites, older granitic and volcanic flows (Al Husseini 2011). Its upper boundary unconformably underlies the Siq Sandstone (Al Husseini 2011). The group attains a thickness of more than 3,300 m, which exhibits some difference in thickness from basin to basin. The Jibalah Group is divided into two rock units, Umm Al Asiah Formation at the base and the Jifn Formation at the top (Fig. 2.9d). The former

2.7 Depositional Environments

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formation consists of a polymictic conglomerate, followed upward into sandstone, mafic volcanic rocks, or cherty limestone. The Jifin Formation comprises sandstone with subordinate to minor siltstone, conglomerate, and limestone dominating the succession in most basins. Some of the thickest algal mat limestone occurs in Jibalah basins in the northwestern shield (Miller et al. 2008).

2.7 Depositional Environments Between 1000 and 525 Ma, the Late Neoproterozoic to Early Cambrian (“Infracambrian or Ediacaran”) period in North Africa was distinguished by major extensional movements (Craig et al. 2008). Structures from this period are thought to have formed as a result of shearing along the Trans-African lineament, as well as pull-apart basins associated with the westward continuation of the Arabian Najd fault system (Johnson et al. 2013). Furthermore, it contains half-graben, which is linked to the Pan-African orogen’s extensional collapse (Greiling et al. 1994). The Ediacaran basins are common and widespread in the Nubian Africa Shield, and their sediments were deposited atop regional and local unconformities formed on arc assemblages in the basement (Johnson et al. 2013). The Mourizidie Formation filled these basins in Libya, the Hammamat Formation and the El Urf volcanoclastic rocks in Egypt’s central and northern Eastern Desert, the Saramuj Conglomerate and the Haiyala Formation in southwest Jordan, and the Jibala Group in Saudi Arabia. The basin assemblages are Cryogenian to Ediacaran in age, ranging from approximately 785 Ma (Hali Group) to approximately 560 Ma (Jibalah and Saramuj groups). These basins range in size from large aggregates (72,000 km2 ) to small isolated basins (200 km2 ) (Johnson and Kattan 2012). The Murdama and the Jibalah Groups fill the largest basins in the northeastern Arabian Shield. While the Atura Formation, Amaki Formation fills the smaller basins of the far southern Arabian Shield and the south-central Nubian Shield respectively. The Hammamat and El Urf formations (in Egypt) fill a smaller basins in the central and northern Eastern Desert, respectively. Some basins are entirely or partially filled by volcanic or volcaniclastic rocks that contain basalt, andesite, rhyolite flows, agglomerates, ignimbrites, and tuffs, such as the El Urf Formation in Egypt’s northeastern Desert (El Gameel 2010; Eliwa et al. 2021). Other basins are dominated or filled by sedimentary rocks like conglomerate, pebbly sandstone, sandstone, and siltstone, such as the Hammamat Formation in the central Eastern Desert (Ahmed et al. 1989; Khudeir and Ahmed 1996; Johnson et al. 2013). The Hammamat Formation of Egypt’s Eastern Desert was deposited in isolated basins formed during an early stage of orogen parallel N-S extension (650– 580 Ma) (Fowler and Osman 2013; Wilde and Youssef 2002; Willis et al. 1988). The El Urf Formation consists of mixed detrital sediments and volcanic erruptions that were deposited in two stages. The earlier stage was the eruption of the Dokhan volcanic (602–593 Ma), while the late stage was supply of detrital clasts to the basins (Osman et al. 2001; Eliwa et al. 2010; Khalaf 2013; El-Gameel 2018). The sedimentary rocks of Wadi Hammamat were composed of 30% mafic, 25% granodiorite,

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25% intermediate, and 20% felsic (Holail and Moghazi 1998). They stated that the Wadi Hammamat sedimentary rocks were deposited in an intra-arc basin formed by the creation of significant topographic and structural relief following the development of a continental arc. The source rocks were continental arc volcanic (Dokhan Volcanics), older oceanic tholeiites that had been uplifted, and island arc assemblages (Holail and Moghazi 1998).

2.7.1 Depositional Environments of the Hammmat Formation Many hypotheses are advocated to explain the possible depositional setting of the Hammamat Formation in the Eastern Desert. It was deposited in a large foreland basin (El Gaby et al. 1988; Fritz et al. 1996), fluvial systems of a continental regime (Wilde and Youssef 2002), in isolated intermountain basins (Grothaus et al. 1979; Khudeir and Ahmed 1996; Rice et al. 1993; Abdel Wahid 2009), a strike-slip pullapart basin, in the El Mayah basin (Shalaby et al. 2006a, b), terrestrial basins (Johnson et al. 2013) and fault-bounded basins (Fowler and Osman 2013). Previous studies on the Hammamat Formation indicate that this formation is younger than the Dokhan volcanics and even volcanoclastic sediments (Akkad and Noweir 1980; El Ramly and Akkad 1960). While other authors suggested that the deposition of the Hammamat Formation and the volcanoclastic are synchronous during their deposition (El Gaby et al. 1984, 1988; Ahmed et al. 1989; Eliwa et al. 2021). The Hammamat Formation was deposited in intermontane separate disconnected basins found in the Wadi Hammamat basin, Wadi El Queh basin and Abu Shiqieli basin in the central Eastern Desert. These basins usually extend in east–west to northwest directions. In the present work, we concentrated our interpretation of the Hammamat Formation on the Wadi Queh. According to the stratigraphic position, vertical and lateral lithofacies changes, and types of lithofacies, we proposed a cross-section showing the lateral facies changes from the proximal fan, middle-fan and outer fan of the Hammamat Formation in Wadi Queh (Fig. 2.15). The proposed depositional model of the Hammamat Formation is the alluvial fan at Wadi Queh. The Wadi Queh has considered a half-graben basin that extends in an east–west direction, bounded by the Dokhan volcanic from the north (upthrown side) and felsite and Dokhan volcanic from the south (downthrown side, Ahmed et al. 1989) (Fig. 2.3). The term alluvial is derived from the Latin word alluvio, meaning “to overflow” or “to inundate”. Therefore, the alluvial definition draws upon this derivation and refers to the process of alluvial fan formation, in which an outwash of water causes the alluvial fan to form. Alluvial fans are distinguished by their conical or tongue-shaped masses of clastic deposits. It is commonly developed where drainage catchment outlets are connected to a topographic transition from high mountains or plateaus to subdued, open terrains (Blair and McPherson 1994; Ventra and Clarke 2018). These fan sediments register changes in palaeoclimate,

2.7 Depositional Environments

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Fig. 2.15 Cross-section of the alluvial fan extending northwest-southeast direction, manifesting the lithofacies types in Proximal, middle and outer fans, Hammamat Formation, Wadi Queh, central Eastern Desert

tectonic effect and landscape evolution across a variety of environments on Earth (Hornung et al. 2010; De Haas et al. 2015). Coarse conglomerates dominate the alluvial fan from its proximal to distal parts. Based on lithofacies types, grain size, primary sedimentary structures and their stratigraphic position, four depositional environments have been proposed to interpret the Hammamat Formation at Wadi Queh. These are: (1) proximal fan, (2) Mid-fan, and (3) distal fan (Fig. 2.15). In the geological record, two types of alluvial fans are recognized, arid and wet alluvial fans (Yu et al. 2018). The absence of plant remains, coals and vegetation and lacking debris flow in the Hammamat Formation can suggest the term dry alluvial fan for describing the Hammamat Formation (Fig. 2.16). Some factors are essential in developing an alluvial fan. The significant characteristics of an arid fan include the development of coarse clastic sediments that become finer rapidly toward the end of the fan, and fan thickness decreases rapidly (Yu et al. 2018). Modern and ancient large alluvial fans are usually developed at the footwall of a peripheral fault and fluctuations in climate (Yu et al. 2018). The Hammamat alluvial fan is subdivided into three synchronous environments, proximal fan, middle fan and outer fan, as illustrated in Figs. 2.15 and 2.16. Proximal fan environment Proximal fan lithofacies are found near the top zone of an alluvial fan. It has a sedimentary slope angle of 2–3°. Its sediments are either conglomerate and gravel

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2 The Ediacaran Rock Units

Fig. 2.16 Schematic diagram showing the imagined depositional model of the Hammamat Formation at Wadi Queh, central Eastern Desert (After Grothaus et al. (1979), with modification)

with an imbricate structure or conglomerate with poor sorting, no structure, and a mixed size. As a result, debris flow sedimentation and braided channel sedimentation are prevalent in this region (Yu et al. 2018). Two types of conglomerate were observed: red coarse-grained conglomerate and fine red conglomerate (Fig. 2.4a, 2.13a and 2.16). They created their proximal facies environment. They were stacked vertically to form fining-upward cycles (Fig. 2.4a and 2.13a). Each cycle started with a red coarse-grained conglomerate and was capped with a delicate green conglomerate (Fig. 2.4a). The red coarse-grained conglomerate is poorly sorted and unstratified, with rounded to avoided metasediments, metavolcanics, intrusive lava, andesitic and dacitic clasts, and a polymict texture (Ahmed et al. 1989). Clasts range from 5 to 35 cm and float in a sand-silt matrix. There are no sedimentary structures. They have long axes that exceed 6 cm, and some are boulder-sized (more than 30 cm). Each conglomerate unit has a thickness of 4–5 m. The fine green conglomerate is usually found at the top of the cycle. Interpretation: The coarse conglomerate, in conjunction with poorly sorted and bimodal size distribution, suggests high hydrodynamic energy in response to crustal instability in the Juvenile Pan-African crust (Jarrar and Zellmer 1991; Grothaus

2.7 Depositional Environments

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et al. 1979). The coarse, massive represent the proximal fan conglomerate and clastsupport conglomerates (Haughton 1989). Debris flow deposits on alluvial fans are typically characterised by angular clasts, weak to chaotic fabrics, gradational bed contacts, poor sorting, and a typically massive, ungraded structure (Nemec and Steel 1984; Shultz 1984; Harvey et al. 1999). The presence of a very coarse conglomerate in association with debris flow indicates steep slopes and proximity to the source area (Rust 1979). The high capacity of the formative floods to transport sediment is indicated by the high concentration of the coarsest clasts in this facies association (Field 2001). Lack of stratification and cross-stratification movement rejected by traction current and possibly deposited debris flow, rock fall, or grain avalanche sedimentation (Steel 1974; Ahmed et al. 1989). These deposits’ poor sorting, large maximum clast-sized, and thick bedding suggest that competent high-energy flows quickly deposited them. The upward fining cycle in the proximal conglomerate indicates that sedimentation occurred in several episodic phases. Every phase began with a reddish conglomerate and ended with a fine reddish conglomerate. The retreat of the provenance escarpment the decline of ground surface and lateral movement or migration of the fan body, because large-scale fining-upward sequences (Ethridge and Wescott 1984). When the sediment accumulation rate is slower than the basin’s subsidence rate, coarser grain sediments are retrograded and settled at the bottom of the cycle, followed by finer-grained sediments at the top, forming a fining-upward cycle (Yu et al. 2018). Based on their causes and characteristics, the cycles can be classified into two types: autocycles and allocycles (Yu et al. 2018). Internal factors such as fan body migration, abandonment, and progradation caused by flooding create autocycle mechanisms. They are typically small-scale sequences with thicknesses ranging from one to several metres and can be caused by fining and coarsening upward (Heward 1978; Yu et al. 2018). Sedimentation usually forms autocycle mechanisms when the base level does not change and has no direct connection with tectonic activity. In contrast, the allocycle mechanism generates large sequences with thicknesses ranging from tens to hundreds of metres due to periodic changes in climate and tectonic activity (Heward 1978; Yu et al. 2018). The autocyclic mechanism may be enhanced, resulting in the formation of meter-scale fining-upward cycles in the Hammamat Formation. Suppose the process of provenance uplift or basin sedimentation slows or stops for a short period. In that case, sequence fining and thinning upward occurs, and asymmetric or nearly symmetric depositional cycles can form. Simple sequence fining and thinning upward are typically caused by faulting and gradual depletion in the denuded zone (Yu et al. 2018; Ethridge and Wescott 1984). The reddish colour in sediments is recorded in several depositional environments, either marine or nonmarine, and has a broad distribution throughout the stratigraphic record (Van Houten 1968, 1973). The presence of finely dispersed hematite pigments in sediments is responsible for the red colour. Two hypotheses have been proposed to explain the origin of hematite pigment (Van Houten 1968, 1973; Turner 1980; Pye 1983; Einsele 1992). One hypothesis argues that hematite is detrital derived from lateritic soils (Folk 1976). The other suggests that hematite forms naturally after deposition through altering iron-bearing detrital grains (Walker 1967; Eren and Kadir 1999). Weathering and erosion of purple-red porphyries of the Dokhan

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2 The Ediacaran Rock Units

Volcanics, which are rich in iron oxides, caused the red–purple colouration in the Hammamat Formation (Akaad 1957; Abdel Rahman 2021). The reddish coarsegrained conglomerate accumulated in the early phase during a high flash flood or as a result of uplifting in the source area. Their reddish colour was most likely derived from older reddish rocks or pre-existing minerals’ oxidation. In this case, the deposition may take an extended period to complete the thematization processes. Because fan sediments are formed under arid and semi-arid conditions and oxidizing conditions that lack organic matter and sediments with reducibility, the rocks in an arid fan have a red hue (Yu et al. 2018). The finer green conglomerate at the cycle tops represents the late deposition phase during the waning process. Middle Fan environment The middle fan is located in the middle and is distinguished by a medium to low sedimentary slope and developed braided channels (Fig. 2.14). As a result, it is primarily composed of sandstone, conglomeratic sandstone, and conglomerate (Benvenuti 2003). Sand and gravel have higher textural maturity compared to the proximal fan’s depositional facies. Trough bedding is formed (Yu et al. 2018). The sediments in the middle fan have a slower slope than the proximal fan, with a decrease in coarse conglomerate and the appearance of sandstone (Bull 1972; Heward 1978). The midfan lithofacies are made up of two different lithofacies: red fine-grained conglomerate and red sandstone (Fig. 2.4b and 2.13b). These sediments form fining-upward cycles, with each cycle beginning with fine red conglomerate and ending with red sandstone and red siltstone lenses (Fig. 2.4b and 2.13b). The fine-red conglomerates are invariably massive, forming the cycle bases and individual beds ranging in size from 3 to 4 m. They can sometimes form units up to 6 m thick. They consist primarily of metavolcanic, metasedimentary, and granite clasts with long axes less than 4 cm. The presence of red hematite pebbles indicates that most, but not all, conglomerates have been oxidised. The red sandstones that make up the cycle tops are usually massive and range from 50 cm to 1.5 m. Sandstone beds range in size from coarse sand to granule. The sandstone bed boundaries are typically sharp, however, in some cases, the contacts are gradational. Interpretation: Sandstone beds are thought to be the result of ephemeral fluvial channels, whereas conglomerates are the result of unconfined flows associated with sheet flood events (Chakraborty et al. 2009; Barkat et al. 2020). However, tectonics and climate are the primary factors in the evolution of alluvial fans (Bull 1977; Ritter et al. 1995). According to Bull (1977), mid-fan evolution is influenced by climatic and tectonic processes at different time scales. In this environment, the average particle size decreases down the fan and the sand-to-gravel ratio increases toward the fan toe, indicating mid-fan facies (Grothaus et al. 1979). A common observation in mid-fan is an intergradational relationship between sheet flood and stream channel deposits, which is regarded as a positive feature for alluvial fan succession (Rust and Koster 1984). Allocyclic mechanisms may be used to activate the fining-upward cycles. Active faulting and tectonic stages in this process produced a local uplift rate of about 0.7 mm/yr in the source area, causing the mid-fan to widen and, as a result, the development of the fan system (Boenzi et al. 2004). The mid fan is

2.7 Depositional Environments

33

represented by the vertical stacking pattern of sandstones and conglomerates and channelized conglomerates in decreasing order of abundance (Ritter et al. 1995). In contrast, an intergradational relationship between sheet flood and stream channel deposits is typical in the mid-fan and is a defining feature of alluvial fan succession (Rust and Koster 1984). During high-magnitude flood events, Surges of coarsegrained, highly concentrated flows generated during high-magnitude flood events either remain confined within channels or spread out beyond the margins of shallow ephemeral channels (Benvenuti 2003; Deynoux et al. 2005). Outer Fan environment: The outer fan environment occurs at the toe of an alluvial fan and is distinguished by low sedimentary slopes or gentle terrain (Yu et al. 2018) (Fig. 14.2). Its sediments typically consist of sandstone, pebbly sandstone, siltstone, and clay rock. Furthermore, gypsum-salt layers can be seen locally. Furthermore, these sediments could have deformation structures like mud cracks and raindrop imprints. Thus, sheet flood deposits in the outer fan are typically siltstone with parallel bedding and massive mudstone (Yu et al. 2018). This environment can be found southeast of Wadi Queh, overlapping on felsic rocks (Fig. 2.3) (Ahmed et al. 1989). It has a surface area of about 22 km and is composed of red, green, and rippled sandy siltstone with some lenses or lenticular beds of fine conglomerate (Figs. 2.4c and 2.13c). They construct 90% of the measured sections (Figs. 2.4c and 2.13c) on their own, assuming a thickness of 95 m. The ripple marks are straightly crested with undulated crests. Although siltstones and mudstones are typically massive and structureless, wavy or horizontal bedding can be identified locally. Red siltstone is the most common lithofacies, while green siltstone accounts for 40–45% of the total thickness, particularly in the south and west. Siltstones are typically massive, non-erosive boundary-graded bedding, laminated, and rippled. Interpretation: The association of fine-grained conglomerate with siltstone indicates an alluvial fan inundation flash flood (Steel 1947; Ahmed et al. 1989). The presence of well-preserved ripple marks and mud cracks in the siltstone suggests subaerial deposition (Grothaus et al. 1979). Thin ripple marks and mud cracks are common in cutoff channel deposits, whereas greater thicknesses, such as those found in the Wadi Queh, are interpreted as playa or lake deposits (Grothaus et al. 1979). The massive siltstone was most likely formed in low-energy depositional environments (Hillier et al. 2011). Furthermore, the wavy ripples and wavy bedding in the siltstone are most likely the results of subaqueous traction processes such as lower regime flow (Cain and Mountney 2009; Hillier et al. 2011). According to Miall (1978), mud and silt are typically carried out in suspension. Mud and silt layers are thus most commonly found in overbank (floodplain) areas where fine sediment settled out of suspension from slowly moving or stagnant flood waters (Hiller et al. 2011). The scarcity and absence of root traces in these deposits at the top of the studied series indicate a dry climate. The siltstone’s non-erosional basal boundaries were most likely formed by the vertical settling of detrital suspensions in standing water (Miall 1977, 1978; Horton and Schmitt 1996). Furthermore, the absence of floodplain features such as typical crevasse-splay deposits or mud cracks indicates that they were deposited from suspension fallout in relatively large and long-lived bodies of fresh water (Miall 1977, 1978; Horton

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2 The Ediacaran Rock Units

and Schmitt 1996). Massive to crudely laminated muds, parallel-laminated sands and silts are thought to form from settling from suspension in ponded water (Levson and Rutter 2000). Red and purple rocks have pervasive hematite grain coatings and crystals intergrown with clay, while brown rocks have faint or localised iron-oxide grain coatings (McBride 1974).

Depositional Environment of the El Urf Formation (Volcanoclastics) The Gabal El Urf volcano-sedimentary succession is a typical example of intercalation between the Hammamat Formation and the El Urf Formation and Dokhan Volcanics (Breitkreuz et al. 2010; Eliwa et al. 2010). This location has a deformed and asymmetrical syncline fold or structurally controlled intermontane basin (Eliwa et al. 2010; Breitkreuz et al. 2010). The Gabal El Urf, located in Egypt’s northeastern desert, is a well-preserved example of Neoproterozoic volcano-sedimentary deposits. It consists of inter- and syn-eruptive facies formed by various depositional processes, such as debris flows, sheet floods, lacustrine flood flows, and pyroclastic ash falls/fissure-fed ignimbrites (Eliwa et al. 2021). The formation of El Urf volcanoclastic sediments occurred in two major stages. The vertical facies arrangement found in the measured sections at East Gebel Kharaza and Gebel El Urf (Eliwa et al. 2021) indicates presence of two phases of sedimentation (Fig. 2.10). The first phase occurs at the El Urf Formation’s base, as seen at Gebel El Urf and Gebel Kharaza (Fig. 2.10). The lithofacies in this sedimentation phase are essentially the intercalation of sandstone and siltstone, which is more similar to the Hammamat Formation. The thickness of this sequence ranges from 60 m at Gebel Kharaza to around 600 m at Gebel El Urf. This sequence was stacked vertically into finingupward cycles, with each cycle beginning with sandstone and ending with siltstone, and was deposited in an alluvial fan setting (Eliwa et al. 2021). These cycles were most likely formed by an autocyclic mechanism (Yu et al. 2018). Autocycle mechanisms are created by internal factors such as fan body migration, abandonment, and progradation caused by flooding. They are typically small-scale sequences with thicknesses ranging from one to several metres, and they can be caused by both upward fining and coarsening (Heward 1978; Yu et al. 2018). When the base level does not change, autocycle mechanisms form and have no direct relationship with tectonic activity (Yu et al. 2018). These cycles were most likely formed in the mid-fan setting. There was no volcanic activity during this sedimentation period. The upper phase is dominated by volcanic rocks such as ignimbrite, thin conglomerate beds, and sandstone (Fig. 2.10). Such a sequence would be approximately 90 m thick at Gebel Kharaza and 200 m thick at Gebel El Ufr. The upper phase includes three cycles, each cycle begins with volcanic lava at the base and conglomerate at the top. The second eruption produced dacitic-rhyolitic non-welded ignimbrite layers and one bedded

Depositional Environments of the Abu Haswa Formation

35

tuff deposit. The volcanic lava eruptions produce ignimbrite-forming caldera eruptions (Eliwa et al. 2021). The variable thickness of the ignimbrite layers indicates emplacement in a structurally controlled basin. In contrast, the bedded tuff deposits indicate emplacement in low-concentration aqueous flows (i.e. turbidity flows or currents) where ash-sized materials are present (Eliwa et al. 2021). After the postamalgamation of Ediacaran volcano-sedimentary basins wid widely distributed in the northern part of the Arabo-Nubian Shield, the development of the volcanoclastic rocks in the El Urf basin occurred (Khalaf et al. 2000).

Depositional Environments of the Abu Haswa Formation The transitional period from the Ediacaran to the Cambrian records significant changes in the geosphere and biosphere. This period corresponds to the final Rodinia break-up and Gondwana assembly (Meert et al. 2016; Robert et al. 2017). Oceanic deep-water redox conditions accompanied palaeogeographic changes (Grotzinger et al. 2011). The stromatolitic dolostone’s deposition can be explained by its presence above the basement rocks and below the Cambrian Arab Formation. It occurs in Sinai and the northeastern Desert in irregular and spatial patterns. The restricted, shallow basins, lagoons, and tidal flats provided the best depositional setting. Most of the sedimentation occurred in the photic zone, as evidenced by the extensive development of algal laminites and stromatolites (Logan et al. 1964). The smooth laminated texture suggests precipitation onto the surface of microbial mats rather than mat trapping and binding of carbonate clasts. They were most likely in the shallow intertidal zone (Grotzinger 1986; Grotzinger and knoll 1999; Riding 2000). They can also be formed in lagoonal fines facies, which include mudstone and laminated dolosiltite and represent low-energy deeper water parts of peritidal cycles like the Khufai Formation (Osburn et al. 2014). Two major factors may have contributed to the formation of stromatolitic dolostone during the Ediacaran period. The first is the very early dolomitization of pre-existing sediment, whether lime mud or micritic grains, as well as marine cement, provided that microbes that promote dolomite precipitation are present (Van Lith et al. 2003; Vasconcelos et al. 2006). Thus, the bacteria or microbes create a suitable micro-geochemical environment for early dolomite precipitation and replacement of the pre-existing dominantly high-Mg calcite sediment of lime mud and stromatolites Mastandrea et al. (2006). The discovery of mineralized bacteria in Dolomia Principale stromatolites indicates a microbial origin for the dolomite (Perri and Tucker 2007). The second factor required for early dolomitization in Ediacaran time is seawater chemistry. Tucker and Wright (1990) stated that two factors, such as a higher Mg/Ca ratio and a lower SO4 content, can promote dolomite precipitation, these factors exist in Precambrian dolomite (Tucker 1992; Hardie 203).

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Chapter 3

The Cambrian Period

Abstract This chapter informs the reader about the general geologic information about the Cambrian Period, including definitions, classifications, fauna and flora, palaeogeography, and tectonic events that occurred during this period. It describes two rock units in Egypt: the Middle Cambrian Araba Formation, which is visible on the surface, and the Shifa Formation, which is found in the subsurface at the Siwa basin in the northwestern Desert. This chapter describes the Araba Formation in various locations, including the Quseir-Qift road, the Eastern Desert, the Umm Bogma area, the entrance to Wadi Mokattab, El Sheikh Soliman, and Taba in Sinai. The Araba and the Shifa formations have been thoroughly studied, including stratigraphic boundaries, lithological characteristics, thickness and distribution throughout Egypt, and faunal and trace fossils. The above formations are correlated to their equivalents rock units in Libya, Jordan, Saudi Arabia and Iraq. A paleogeographic map has been drawn all over the studied countries to manifest the facies changes and the possible depositional environment. Keywords Araba Formation · Shifa Formation · Siwa · Sinai · Eastern Desert · Libya · Jordan · Saudi Arabia · Iraq

3.1 Introduction 3.1.1 Definition English geologist Adam Sedgwick initially used the term “Cambrian System” in 1835 to refer to a series of slaty rocks found in southern Wales and southwestern England. Wales’s Roman name, Cambria, served as the type locality for the Cambrian period and system names. In this period, animal groups first emerged in the geological record. Because of the short period over which this variety of forms occurs, this phenomenon is commonly referred to as the “Cambrian Explosion.” The oldest and first fossilized organisms, such as trilobites, were initially believed to be found in Cambrian rocks. The Cambrian Period is the earlier geological time of the Paleozoic Era (Howe 1911). The Cambrian lasted 53.4 Ma years from the end of the preceding © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_3

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Ediacaran Period 538.8 Ma to the beginning of the Ordovician Period 485.4 Ma (Stratigraphic chart 2022).

3.1.2 Classification The Cambrian rocks have been carefully studied by eminent geologists and can be classified into three series, each characterized by a distinctive trilobite fossil. Thus, the Lower Cambrian is called Olenellus, the Middle Cambrian is called Paradoxides, and the Upper Cambrian is named Olenus. On the North American continent, as in Europe, the Cambrian system is divisible into three series: (1) the lower or “Georgian,” with Olenellus fauna; (2) the middle or “Acadian,” with Paradoxides or Dikelocephalus fauna and (3) the upper or “Potsdamian,” with Olenus fauna (Fig. 3.1). The lower boundary of the Cambrian period was initially designated to represent the first appearance of trilobites and trace fossil Treptichnus pedum. The Cambrian period was restricted between two ice times; one occurred during the Late Proterozoic and the second during the Ordovician. However, during the Cambrian, there was no significant ice formation.

3.1.3 Fauna and Flora Though there is some scientific debate about what fossil strata should mark the beginning of the period, the International Commission on Stratigraphy places the lower boundary of the period at 541 million years ago, with the first appearance in the fossil record of worms that made horizontal burrows. The end of the Cambrian Period is marked by evidence in the fossil record of a mass extinction event about 485.4 million years ago. The most distinctive fossils in the Cambrian period are: Trilobites first appear about 525 Mya. They are the most common and best known of Cambrian fossils (typically 90% of skeletonized fossils), dominating the seas for most of this period. Next to trilobites, inarticulate brachiopods (brachiopods with untoothed hinges) comprise the most common fossil type, representing 5–7% of skeletonized remains. Echinoderms were primitive and uncommon in the Cambrian period. These unusual organisms have very distinctive skeletons. They were possibly related to the sponges. The archeocyathids were the first reef-building animals, originating in the Cambrian explosion around 525 Ma. Burrowing animal trace fossils mark the existence of digging organisms and the beginning of the Phanerozoic. One type of burrow from worms, the Skolithos burrow, often marks the boundary between Cambrian and Precambrian deposits.

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Fig. 3.1 Geological chart showing the classification of the Cambrian period (after, ICS 2020)

3.1.4 Tectonics and Paleogeography In this period Rodina supercontinent was breaking up early in the Cambrian into Laurentia (North America), Baltica, and Siberia (Scotese 1998). They had been separated from the main supercontinent of Gondwana to form isolated land masses (Mckerrow et al. 1992). Most continental lands were clustered in the Southern Hemisphere at this time but were drifting north (Mckerrow et al. 1992). Gondwana’s

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significant, high-velocity rotational movement appears to have occurred in the Early Cambrian (Mitchell et al. 2010). In Egypt, the Cambrian rocks include two rock units: The exposed Araba Formation and its equivalent Shifa Formation, in the subsurface.

3.2 The Araba Formation 3.2.1 Definition Hasan (1967) described the term Araba Formation in the stratigraphic succession of southern Sinai. This name was formalized later on by Said (1971). Its type locality occurs at Gebel Araba, Wadi Araba between El Tor and Abu Durba southwest of Sinai. Also the second type locality occurs at Umm Bogma, southwest Sinai (Fig. 3.2). In 1969, Soliman and Abu El Fetouh classified the Araba Formation at Um Bogma area, southwestern Sinai into three formations, from base to top as follows: Sarabit El Khadim, Abu Hamata, and Adedia formations. Furthermore, Kora (1991) modified the classification of Soliman and Abu El Fetouh (1969) as follows: Sarabit El Khadim, Abu Hamata (Nasib and Ras Naqab members) and Adedia formations. El Kelani and Said (1990) introduced the term Taba Formation (Infracambrian) to the coarsepebbly clastic of the basal Araba Formation. Other classifications of the Cambrian rocks are illustrated in Table 3.1. The above classifications have not followed the rules of the North American Stratigraphic Code (1983) because these rock units are not mappable in the field, and their ranks are lowered to member status in the Umm Bogma area only. Nevertheless, it takes work to apply in other localities in Sinai. Thus, the classification of the Araba Formation by Soliman and Abu El Fetouh (1969) and Kora (1991) is discarded herein, while the suggested Infracambrian Taba Formation is lowered to member status that is equal to the basal unit of the Araba Formation (El-Araby and Abdel-Motelib 1999; Khalifa et al. 2006) (Table 3.1).

3.2.2 Stratigraphic Contacts The lower contact of the Araba Formation nonconformably overlies the basement rocks at Gebel Araba, Gebel Ekma, Wadi Feiran, Gebel Gunna, and Taba region (Sinai), Marsa Alam-Idfu road, Quseir-Qift Road and Gebel El-Zeit (Eastern Desert) (Fig. 3.3a, b). Its upper contact is unconformable with the overlying Ordovician Naqus Formation, at Gebel Gunna and Gebel Ekma (Fig. 3.3c). At the latter localities, the upper contact lies between the reddish sandy siltstone of the uppermost Araba Formation and the conglomeratic white sandstone of the basal Naqus Formation (Khalifa et al. 2006). In the Taba area, where the Naqus Formation is missed, the top boundary of the Araba Formation is unconformable with the overlying Lower

3.2 The Araba Formation

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Fig. 3.2 Field photograph showing the lithological characteristics of the Araba Formation at Umm Bogma area, southwestern Sinai. Notice the presence of three lithologic units

Cretaceous Malha Formation. In the southeastern Desert near the Sudanese border at Wadi Gabgaba, the Araba Formation nonconformably rests on the basement rocks and unconformably subjacent below the Ordovician–Silurian Gabgaba Formation which is equal to the Naqus Formation (Osman et al. 2002).

3.2.3 Lithology The Araba Formation shows slight facies changes from the Eastern Desert to Sinai. In the Eastern Desert, two informal lithostratigraphic units (lower and upper) make up the Araba Formation (Fig. 3.4a). The lower unit consists of basal conglomerate at the base, followed upward by massive pebbly sandstone with intercalation of reddish, yellow paleosols enriched with plant roots. They form fining-upward cycles (Fig. 3.5a); each cycle begins with pebbly, massive sandstone (1–2 m thick), capped by reddish, yellow, white, and violet sandy clay to claystone paleosols enriched with plant roots (3–10 m thick). The upper unit is made up of coarsening-upward cycles each begins with thin-bedded yellow siltstone laminated fine sandstone to siltstone (Fig. 3.5b), followed by planar cross-bedded convolute and rippled sandstone. At

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Table 3.1 Different classification of the Cambrian Araba Formation by eminent geologists in Sinai

Umm Bogma, this formation includes three lithologic units (Fig. 3.4b), massive, pebbly to coarse-grained sandstone (35 m thick) (lower unit), followed by intercalation of thin-bedded sandstone and sandy claystone (40 m thick) (middle unit). The upper unit comprises cross-bedded, rippled sandstone (50 m thick) (Figs. 3.2 and 3.4b). At the entrance of Wadi Mokattab and At Sheikh Seleem, the Araba Formation is made up of one unit comprising intercalation of coarse-grained cross-bedded, rippled sandstone and thin beds of sandy siltstone (Fig. 3.6a, b). At Taba area, near the tip of Aqaba Gulf, this formation includes two units (Fig. 3.4c), the lower is composed of pebbly sandstone interbeds and matrix-supported conglomerate, followed by intercalation of sandstone and thin laminated siltstone (Fig. 3.7a). The upper unit consists of fine-grained, yellow, and violet intercalated with burrowed sandstones and yellow and violet siltstones enriched with skolithos burrows (Fig. 3.7b).

3.2.4 Distribution and Thickness The Araba Formation is not recorded at Gebel El Uweinat in the southwestern Desert (Klitzsch 1990). It is exposed at Wadi Gabgaba southeastern Desert adjacent to the

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Fig. 3.3 a Field photograph showing the lower non-conformable contact between Precambrian basement rocks and the Cambrian Araba Formation, Quseir-Qift road, Eastern Desert, Egypt. b Field photograph showing the non-conformable contact of the Araba Formation with the underlying basement rocks at Gebel Ekma, southwest Sinai. Notice the presence of white-reddish paleosol that pinched out laterally between them. c Field photograph manifesting the upper boundary of the Araba Formation with the overlying Ordovician Naqus Formation at Gebel Ekma, southwest Sinai

Sudanese borders (Osman et al. 2002), Wadi Araba and along the western coast of Aqaba Gulf in Sinai, the western coast of Suez Gulf (Gebel El Zeit), and in Wadi Qena, north of the Eastern Desert, Marsa Alam-Edfu road and Quseir-Qift road (Fig. 1.1). In the subsurface of northwestern Desert it was encountered in 14 wells, in four wells (Bahariya-1, Ghazalat-1, Gib Afia-1 and Kahraman-1) the Cambrian rocks were proven by paleontological evidence (Hantar 1990). In general, the Araba Formation covers a vast area in the subsurface north of the Western and north of Eastern Deserts and Sinai, except for the uplifted basement rocks, it was eroded, and the younger formation, such as the Naqus Formation nonconformably overlies the basement rocks. The Araba Formation varies in thickness from one locality to another in Sinai. The maximum thickness (130 m) was recorded at Gabal Araba and 123 m at Sarabit El Khadim (El Kelani et al. 1999). In contrast, at Taba, Wadi Feiran, Gabal Dhalal, Gabal El-Zeit and Gabal Gunna, the thickness is 120, 100, 80, 64 and 50 m, respectively.

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Fig. 3.4 Measured lithostratigraphic sections of the Araba Formation at Quseir-Qift road, Eastern Desert (a), at Umm Bogma area, southwest Sinai (b), at Taba, northern Sinai (c) and the Shifa Formation, Siwa basin northwestern Desert (d)

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Fig. 3.5 a Field photograph manifesting the fining-upward cycles of the lower unit of the Araba Formation, which consists of coarse to pebbly sandstone at the base, capped by reddish paleosol at the top, at Quseir-Qift road, central Eastern Desert. b Field photograph manifesting the upper unit of the Araba Formation that consists of coarsening-upward cycles, each begins with thin-bedded siltstone, capped by cross-bedded sandstone, at Quseir-Qift road, central Eastern Desert

3.2.5 Age Assignment and Correlation Paleontological information is rare for the Cambrian rocks of Egypt. Further paleontological information was given by Andrawis et al. (1983) and El Dakkak (1988), who mentioned the occurrence of brachiopods and single trilobites from two core drill holes in the Western Desert that indicate a Cambrian age (possibly MiddleCambrian). The exact age was indicated by palynomorphs recognized in the north Western Desert (Gueinn and Rasll 1986; Keeley 1989). Moreover, Hantar (1990) stated that the Cambrian rocks in Bahariya-1, Ghazalat, Gib Afia, Kahraman, and Yakut wells contain trilobites and brachiopods. The early Cambrian age was attributed to the Araba Formation (Omara 1972; Seilacher 1990), while Issawi and Jux (1982) and Kora (1984, 1991) suggested that the age can be extended to CambroOrdovician. Elicki et al. (2013) and Hofmann et al. (2012) suggested that the available ichnological data in the Araba Formation at Gebel Zeit and in Um Bogma indicate

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Fig. 3.6 a Field photograph manifesting the homogenous composition of the Araba Formation that is difficult to discriminate any independent lithologic unit in this formation at Wadi Mokattab, southwestern Sinai. b Field photograph manifesting the homogenous sequence (mostly reddish sandstone with thin siltstone beds), Sheikh Soliman, northern end of Wadi Mokattab, southwestern Sinai

the Early Middle Cambrian age due to the presence of Crusiana salomonis Seilacher (Fig. 3.8a) and Rusophycus burjenesis Hofmann (Fig. 3.8b). These trace fossils occur in Early Cambrian age for Araba Formation. The Araba Formation can be correlated with the Shifa Formation in the subsurface (Siwa basin) northwestern Desert. Moreover, it can be correlated with the Hasawnah Formation in Libya, the Saq Sandstone in Saudi Arabia (Powers et al. 1966; Khalifa 2017), Saleb, Burj, Ishrin and Disi formations in Jordan (Lloyd 1968; Selley 1972) (Fig. 3.9).

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Fig. 3.7 a Field photograph manifesting the lithology of the lower unit of the Araba Formation at Taba area, northeastern Sinai. b Field photograph manifesting the brown, violet siltstone enriched with vertical burrows (Skolithos Sp), constituting the upper unit of the Araba Formation at Taba area, northeastern Sinai

3.3 The Shifa Formation 3.3.1 Definition Keeley (1989) introduced the name Shifa Formation for the lowermost Paleozoic clastic sequence encountered in wells drilled in the Siwa Basin north of the Western Desert. Its name originated from the spring’Ain esh Shifa, at Siwa. Its type locality lies at Siwa-1 well, while its type interval is between 3058 and 3373 m (Fig. 3.4d).

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Fig. 3.8 a Field photograph showing the trace fossil of Cruziana salomonis (Seilacher 1990) occurs near the Araba Formation’s lower part at Umm Bogma area, southwest Sinai (after Elicki et al. 2013). b Field photograph showing the trace fossil of Rusophycus burjenesis HOFMAN, Which occurs in the lower part of the Araba Formation at Sarabit El Khadim, Umm Bogma area, southwest Sinai (after Elicki et al. 2013)

3.3.2 Stratigraphic Contact The Shifa Formation unconformably rests on the Pre-Cambrian basement rocks. At the same time, its upper contact unconformably underlies the Silurian (Llandoverian to Early Ludlovian) Kohla Formation or underlies the Silurian (Ludlovian) Basur Formation (Keeley 1989). The absence of Late Ordovician rocks at the top of the Shifa Formation may be referred to the severe glacial erosion during this time.

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Fig. 3.9 Correlation of the Araba Formation (b) with their corresponding rock units in Libya (a), Jordan (c) and Saudi Arabia (d)

3.3.3 Lithology The lithology of this formation is a heterogeneous unit involving sandstones with intercalation of conglomerates, claystone, and skeletal dolomitized carbonates (Fig. 3.4d). Glauconite and pyrite are usually associated in the finer-trained rocks. Kaolinite is contaminated in the coarser arkosic rocks. Rare basic tuffaceous beds have been recorded, but no glacial facies are recognized (Keeley 1989).

3.3.4 Distribution and Thickness Keeley (1994) mentioned that the complete sediments of the Shifa Formation (Cambrian-Ordovician) are preserved and can be encountered at localities east of Lat. 29 E. This formation ranges in thickness from about 315 m to more than 1500 m in the

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Ghazalat Basin depocenter. It has a wide distribution in the subsurface northwestern Desert, representing the northern extension of the Araba Formation.

3.3.5 Age Assignment and Correlation Keeley (1989) assigned a Late Cambrian-Early Ordovician age to this unit between 3058 and 3373 m. The Shifa Formation is coeval with the Araba Formation (Fig. 3.4d).

3.4 The Cambrian Rock Units in Adjacent Countries 3.4.1 In Libya The Cambrian rocks are studied under the term The Hasawnah Formation (Fig. 3.9a). The name was introduced by Massa and Collomb (1960) at the Jabal Hasawnah on the A1 Qarqaf Arch. The Hasawnah Formation non-conformably overlies the Precambrian granites on the A1 Qarqaf Arch. It unconformably underlies the Ash Shabiyat Formation. In some localities, it is unconformably overlain by the finegrained Haouaz Formation (Collomb 1962). the formation can be subdivided into three parts (Altumi et al. 2013) (Fig. 3.9a). The lower unit begins with a basal conglomerate of quartz pebbles about 10 m thick but reaching a maximum of 13 m. The conglomerate is overlain by massive banks of cross-bedded quartz sandstones, each up to 10 m thick, with a clay or siltstone matrix. The middle unit is exposed at the Ghat, is more silty and fine-grained than in the A1 Qarqaf area, and shows ripple marks and boudinage structures. The upper unit is dominated by several cycles, each of which begins with massive sandstones, capped by rippled sandstones with abundant Tigillites. No Fossils are recognized in this formation, except the presence of poor tracks, and Tigillites are recorded in this formation. The formation is dated to the Cambrian age (Massa and Collomb 1960).

3.4.2 In Jordan The Cambrian rocks are represented by the Salib, Burj, and Umm Ishrine formations (Fig. 3.9b). The Salib Formation was established by Lloyd (1969) and Selley (1970, 1972) and is derived from Qa Salib, near Quweira village, where the type section is exposed. No macrofossils are found in the Salib Formation, but Skolithos and Cruziana trace-fossil assemblages indicate the early to mid-Cambrian age

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(Selley 1970; Powell 1989; Amireh et al. 1994; Powell et al. 2014). The formation base is at the erosional unconformity above the Neoproterozoic Aqaba or Araba complexes. In the Safi-Wadi Numayri area adjacent to Wadi Araba, the unconformable base of the Salib Formation unconformably rests on the steeply dipping late Neoproterozoic Saramuj Formation (Powell 1988; Jarrar et al. 1991) and locally on the Ediacaran Umm Ghaddah Formation (Amireh et al. 2008). The Salib Formation comprises approximately yellow–brown, red, and purple mediumto very coarse-grained, pebbly cross-bedded arkosic and sub-arkosic sandstone; pebble- to cobble-conglomerates are locally present, and thin beds of planar to ripple cross-laminate. The Burj Formation (120–130 m thick) was initially defined by Quennell (1951) as the ‘Burj Series. The latter definition is adopted by Powell (1988, 1989) and classified into three members, namely, from the base upward, the Tayan Siltstone (20 m of siltstone and fine-grained sandstone), Numayri Dolomite (30–60 m of limestone and dolomite) and Hanneh Siltstone (30 m of siltstone and fine-grained sandstone). This formation conformably overlies the Salib Formation and unconformably underlies the Umm Ishrin Formation (Powell 1988, 1989; Rushton and Powell 1998). Articulate brachiopods and trilobites were first identified from the Burj Formation by Blanckenhorn (1912, 1914). Cooper (1976) proposed a Late Early Cambrian age. However, Elicki and Geyer (2013) identified new genera and species of trilobite (Campbelli and Redlichops faunules) and attributed them to the Middle Cambrian (Paradoxides). The Abu Khusheiba Formation was established by Bender (1974). Its name was taken from Wadi Abu Khusheiba in central Wadi Araba (Powell 1989), and its type section was first defined by Bender (1968, 1974). This formation attains about 110 m and consists of white to pale-grey and pinkish, fine- to medium-grained, micaceous sandstone that is clayey in part as it is correlated with the Burj Formation, an early mid-Cambrian age possible (Elicki and Geyer 2013). Its upper boundary shows a sharp to erosional contact with the overlying Umm Ishrin formation. The lower boundary is marked by sharp contact with the underlying Salib Formation (Bender 1974). Umm Ishrin Formation is taken from Jabal and Gaa Umm Ishrin in the Ram area (Lloyd 1968, 1969). It was called the “Massive Brownish Weathered Sandstone Unit” (Bende 1974). It overlies the Saleb Formation and attains about 300 m thick, consisting of quartz sandstone intercalated with tidal fine- to coarse-grained sandstone. The Umm Ishrin Formation is of late Cambrian (Elicki 2007).

3.4.3 In Saudi Arabia The Cambrian rocks were studied under the term Saq Sandstone (Fig. 3.9c). The Saq Formation was defined formally by Steineke et al. (1958) and described later by Powers et al. (1966). They defined its type section at Gebel Saq, representing the maximum exposed section in the central part of Al Qasim Province, northwest of

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Gebel Isbaa. Vaslet et al. (2005) divided the Saq Formation into two formal members, the Risha Member at the base and the Sajir Member at the top (Fig. 3.9c). The Saq Formation always shows an unconformable relationship with the underlying Precambrian Basement Complex. The upper contact of the Saq Formation with the overlying Ordovician Anz Formation is sharp (Khalifa 2015). It measures 110 m thick and consists of trough cross-bedded sandstone intercalated with medium- to coarse-grained sandstone, planar cross-bedded, horizontal, laminated and burrowed sandstone (Khalifa 2015) (Fig. 3.9c).

3.4.4 In Iraq The Cambrian rocks are not exposed on the surface (Fig. 3.9d). They are not identified in the subsurface in northwest Iraq because the drilling wells were not reached below the Ordovician Khabour quartzite (Buday 1980; Beydon 1988). Based on the data above, some of the Cambrian rocks are partly or missing from the stratigraphic succession in northern Iraq due to non-deposition or it has been eroded in this part of Iraq. The missing Cambrian rocks are due to the effect of tectonic movements (Caledonian event), which happened during the Paleozoic time (Gaddo and Parker 1959; Khalaf et al. 1998).

3.5 Depositional Environments Following the Pan-African orogeny, Northern Gondwana experienced a period of continental-scale uplift, denudation, and erosion (Craig et al. 2008). A broad peneplain that crosses the excavated Precambrian basement and stretches from the Morocco in the west to Oman in the east was created due to this orogeny (Avigad et al. 2003). Throughout much of North Africa, the Pan-African orogeny’s late stages had produced a strong northwest-southeast structural trend (Hallett 2002; Keeley 1994). The subsequent Cambro-Ordovician layers that accumulated on the peneplained “basement” surface during the subsequent stage of tectonic evolution were impacted by this structural tendency (Hallett 2002). The Palaeozoic region resembled Gondwana’s broad, northward-facing passive edge after erosion and peniplaination along northern Africa (Beydoun 1991; Loosveld et al. 1996; Craig et al. 2008). Over millions of years, the granitoid basement of the Arabo-Nubian Shield was uplifted and eroded, creating a peneplain in the northern Gondwana and southern Tethys. During the Cambrian period, the sea transgressed over this peneplain, depositing clastic facies mostly in northern Africa (Libya and Egypt), clastic facies in south Arabia (Saudi Arabia), and clastic facies with thin layers of limestone in north Arabia (in Jordan). There are many Cambrian successions in northern Africa’s subsurface, although they receive little exposure. They are composed primarily of nonmarine deposits with no body fossil material

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over a wide area (Altumi et al. 2013; Elicki and Altumi 2019). Most continental and shallow marine siliciclastics in North Africa are sandstones, with a few intervals of siltstone and shale (Selley 1972; Selley 1996). They exhibit a fine-grained size and an accompanying rise in maturity upward. The North African Sahara basins were covered with thicker strata of finer-grained clastic sediment throughout the Cambrian period. The intervening uplifted region, however, had sequences that were thinner and slightly coarser in grain and had accumulated with numerous local unconformities (Gueinn and Rasll 1986). Deposition occurred in poor accommodation space on the broad shelf with prevailing south-to-north and southeast-to-northwest driven paleocurrents. The vast Gondwana hinterland in the south was the most likely source of sediment of Cambrian facies (Powell et al. 2014). The Cambrian Araba Formation covered a large geographic area in the Western, Eastern Deserts, and Sinai, except for the uplifted areas in northeastern Gebel Uweinat. In the later area, the Ordovician Karkur Talh and Silurian Umm Ras formations nonconformably rest on the basement rocks (Klitzsch and Wycisk 1987; Klitzsch 1990). Furthermore, in the Gunna region of central Sinai, Cambrian Araba Formation was neither eroded nor non-deposited on the basement rocks. In contrast, the Ordovician Naqus Formation rests directly on the basement rocks. Northwestern, Northeastern Desert, and Northern Sinai have subsurface rocks similar to the Araba Formation, named Shifa Formation. At the same time, the Cambrian rocks cover a vast region in Libya represented by the Hasawnah Formation and the Salib, Burj, Abu Khusheiba, and Umm Ishrin formations in Jordan, and the Saq Sandstone in Saudi Arabia are also covered (Powers et al. 1966; Vaselet et al. 1985). According to Gaddo and Parker (1959) and Khalaf et al. (1998), the Caledonian and Hercynian episodes in Iraq did not deposit the Cambrian rocks. Since the shelf in North Africa was generally stable throughout this time, substantially comparable Cambrian successions were also deposited there. Egypt or nearby countries’ Cambrian rocks displayed the typical transgression and regression from base to top as the sea level rose. For instance, the Araba Formation in Egypt exhibits thickness and facies shifts from the southwest to the northeast (Fig. 3.10). The Araba Facies consists primarily of two units. The upper units are composed of shallowingupward cycles, and each one starts with horizontally bedded, laminated siltstone that may include some trace fossils. The lower unit consists of a conglomerate at the bottom and a cycle that exhibit fining-upward cycles. Each cycle starts with large pebbly sandstone, followed by reddish-yellow siltstone and sandy clays supplemented with plant roots. Planar cross-bedded, overturned cross-bedded, and rippling sandstone. While in Sinai at Um Bogma, slight subsidence occurs, resulting in the deposition of thicker facies represented by three units. The lower unit was most probably deposited in a fluvial setting, while the upper unit represents a coastal to a marginal marine setting. The lower unit comprises an oligomictic conglomerate at the base, followed by massive bedded pebbly sandstone, representing fluvial facies. The middle unit consists of fine sandstone intercalated with siltstone that contains Crziana and Skolithos burrows. The upper unit comprises bedded coarse-grained, planar cross-bedded, and rippled sandstone. At the entrance of Wadi Mokattab and Skeikh Soliman, the facies are entirely homogenous, comprising coarse-grained sandstone

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with a thin siltstone bed without paleosols and mudstone. These facies indicate high agitation over structurally high, resulting in winnowing the finer clastic (mudstone) during sedimentation of the Araba Formation (Fig. 3.10). Farther northward and northwestwards, before the Taba area, there was a slight deepening, depositing mostly burrowed siltstone with thin beds of dolomitic limestone beds (El Arabi and Abdel Moteleb 1999). At Taba, the upper two-thirds of the Araba Formation consist of fine sandstone and siltstone enriched with vertical Skolithos burrows indicating coastal and marginal marine settings (Fig. 3.10). In general, four depositional environments were dominated during the sedimentation of the Cambrian rocks in Egypt, Libya, Jordan, Saudi Arabia, and Iraq. These are (1) cratonic or uplifted areas, (2) fluvial environments, (3) coastal marine environments, and (4) marginal marine environments (Fig. 3.11). (1) Cratonic area covers a stretch extending northeast-southwest, covering Tibesti-Sirt Arch and Cyrenaica) and southeastern Libya (Gebel Uweinat) (Hallett 2002). Over these regions, especially in Libya, the Cambrian rocks mainly were not deposited (Hallett 2002). These areas were high during the Cambrian time. Also, the cratonic area covers most of Iraq, where there is no record of the Cambrian rocks which were not deposited or eroded in Iraq by the effect of the Taconic events that culminated during the Ordovician time (Gaddo and Parker 1959; Khalaf et al. 1998) (Fig. 3.11). In Egypt, it is missed in and around Gebel Uweinat (Fig. 3.11). The missing of the Araba Formation around Gebel Uweinat most probably was not deposited, while it is missing in Gebel Gunna, central Sinai may be due to the erosion of the overlying glacial sediments of the Ordovician Naqus Formation, where the Naqus Formation directly rests on the basement. (2) The fluvial environment dominated the basin margins (south, east, western Libya, Egypt, and Saudi Arabia) (Fig. 3.11). Most facies are represented by oligomeric to polymict conglomerate at the base followed by a succession of finingupward cycles; each cycle starts with massive, pebbly sandstone, capped by reddish, yellow, and violet sandy clay and siltstone enriched with plant remains. The conglomerate facies occurs only at the base of the Hasawnah Formation (Libya), Araba Formation (Egypt).

Fig. 3.10 Schematic cross section showing the lateral, vertical facies changes and thickness variation of the Araba Formation along the northeast direction, including the Eastern Desert and Sinai

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Fig. 3.11 Regional distribution map showing the facies types and possible depositional environments of the Cambrian rocks in Libya, Egypt, Jordan and Saudi Arabia

Saq Sandstone (Saudi Arabia), and the Salib Formation (Jordan). It is also recorded in the Shifa Formation at Siwa Basin (in the subsurface, Western Desert). These facies are white, yellow, and dark grey pebbly-sized, mostly of quartz, basement, and metamorphic debris. Other clasts are made up of pink granite, schist, and metasediments. The conglomerates are either clast-supported or are poorly sorted with subrounded to subangular clasts. The thickness of the conglomerate is variable, ranging from 2 to 10 m. The maximum thickness generally occurs in the topographic lows and rifted basins. It decreases on the topographic highs and or misses in uplifted areas. The presence of pink granite, schist, and meta-sediment clasts suggests that the conglomerates were dominantly derived from a proximal source, probably bearing Precambrian rocks. The conglomerate facies were most probably deposited in fluvial fan settings and braided streams (Simpson et al. 2002; Buatios and Mangano 2003). The fining-upward cycles are found in fluvial and meander streams (Fig. 3.12a) (Miall 1977, 1985; Smith and Smith 1980). The basal cycle comprises coarse-grained pebbly sandstone (Fig. 3.12b), while the upper part of cycle consists of reddishviolet paleosol facies enriched with plant roots (Fig. 3.12c). The presence of plant roots (Fig. 3.12c) is one of the best criteria for recognizing paleosols in sedimentary rock (Retallack 2001). The absence or destruction of original sedimentary structures suggests attributed to bioturbation by roots, organisms, and other soil processes (McCarthy et al. 1998; Kraus 1999). The absence of finer-grained interbedded sediments represents alternating sediment fallout and tractive sedimentation in poorly developed floodplains and marshes (Buatios and Mangano 2003). (3) Coastal marine environment: Near the end of the Early Cambrian and at the beginning of the middle Cambrian, the global sea level started to rise (Vail et al. 1977). This rise in sea level resulted in a significant landward transgression, reducing the

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Fig. 3.12 Field photograph showing the fining-upward cycles in the lower unit of the Araba Formation at Quseir-Qift road (a). Notice that each cycle begins with massive pebbly sandstone (b), capped by reddish siltstone enriched with plant roots (c)

area of fluvial deposition. The coastal marine environments occur north of the fluvial environment, covering enormous regions in Libya, Egypt, Jordan, and Saudi Arabia (Fig. 3.11). This environment was responsible for the depositing the upper part of the Arab Formation at both the Quseir-Qift road and at Umm Bogma. The facies sequence includes shallowing-upward cycles; each begins with horizontal laminated yellow siltstone, capped by planar cross-bedded sandstone (Fig. 3.13a), rippled sandstone (Fig. 3.13b), and herringbone sandstone, and recumbent cross-bedded sandstone (Fig. 3.13c). Such sequence was probably deposited in the coastal and tidal zone. The thin, horizontally bedded siltstone strata several centimetres thick indicate tidal flat (Reineck and Singh 1980). Potter et al. (2005) mentioned that the horizontally arranged siltstone indicates slow suspension settling. The horizontal laminations in

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these facies are due to variations in the composition of the layers, suggesting that it was deposited in a tidal zone (Drises et al. 1987). Herringbone structure and convolute cross-bedding may indicate intertidal to coastal marine environments (Drises et al. 1987). Recumbently folded cross-bedding and convolutions in sandstones indicate synsedimentary deformation, characteristic of rapid sedimentation rates in the tidal zone. There is widespread agreement that the vertical passage of water causes folding and convolutions through loosely packed sand (Selley 2000). (4) The inner neritic environment: This environment occurred after a further increase in sea level and was dominated by shallow subtidal settings. This depositional phase is represented by the upper part of the Araba Formation in the northeast Sinai and farther northwest in the northern Western Desert. In the northeast Taba area, the upper two-thirds of the Araba Formation consists of pale brown fine-grained

Fig. 3.13 Field photographs showing the different sandstone types, planar cross-bedded sandstone (a), rippled sandstone (b) and the recumbent and overturned thin-bedded sandstone (c), capping the coarsening-upward cycles in the upper unit of the Araba Formation at Quseir Qift road, central Eastern Desert

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sandstone and silty clay (Fig. 3.4a), which are enriched with vertical burrows formed by Skolithos fauna (Fig. 3.7b). The common occurrence of skolithos vertical burrows indicates intertidal environment. Vertical burrows are commonly formed in the intertidal zone, whereas horizontal burrows are typical in the subtidal zone (Rhoads 1967). The tidal environments are characterized by large populations of restricted organism diversity (Reineck 1972; Kraus 1999). The marginal marine environment covers farther northwards, nearly at latitude 29 N. In such an environment, there was more deepening of the shelf that gave rise to the deposition of marginal marine facies comprised of siltstone, sandy clays, and thin beds of carbonate rocks as appear in northern Libya, Egypt, Saudi Arabia and Jordan (Fig. 3.10). Such facies are encountered in the upper part of the Shifa Formation in Siwa basin and in the upper part of the Araba Formation near Taba (El Arabi and Abdel Motelib 1999). Additionally, the appearance of the limestone and dolostone (Al Burj Formation within the Cambrian sandstone in Jordan) (Fig. 3.10). The carbonate facies increases northward and can cover a vast region in Jordan (Powell et al. 2014), and Syria (Best et al. 1993).

References Altumi, M. M., Elicki, O., Linnemannc, ULF.; Hofmann, M.; Sagawe, A.; Gärtner, A., 2013. U–Pb LA-ICP-MS detrital zircon ages from the Cambrian of Al Qarqaf Arch, central-western Libya: Provenance of the West Gondwanan sand sea at the dawn of the early Palaeozoic. Jour. Afr. Ear. Sciences, 79: 74–97 pp. Amireh, B.S., W. Schneider and A.M. Abed 1994. Evolving fluvial-transitional-marine deposition through the Cambrian sequence of Jordan. Sedimentary Geology, v. 89, p. 65–90 pp. Amireh, B.S.; Amaireh, M. N.; Abed, A. M., 2008. Tectono sedimentary evolution of the Umm Ghaddah Formation (late Ediacaran–early Cambrian) in Jordan. Journal of Asian Earth Sciences 33: 194–218 pp. Andrawis, F.; El Afify, F.; Abd El Hameed., T., 1983. Lower Paleozoic trilobites from the subsurface rocks of the Western Desert, Egypt. Neues 3ahrbuch fur Geologie und Palaontologie. Monatshefie 2 : 65–68 pp. Avigad, D., Kolodner, K., McWilliams, M., Persing, H.; Weissbrod, T., 2003. Blanckenhorn, M. 1912. Naturwissenschaftliche studien am Toten Meer und in Jordantal. Berlin, Friedlander, 478 pp. Blanckenhorn, M. 1914. Syrien, Arabien, Mesopotamien. Handbook Regional Geology, Heidelberg, 159 pp. Bender, F. 1968. Geologie von Jordanien, Beitrage zur Regionalen Geologie der Erde. Band 7, Bornträger, Berlin, 230 pp. Bender, F. 1974. Geology of Jordan. Gebrueder Bornträger, Berlin, 196 pp. Best, J.A.; Barazangi, M.; Al-Saad, D.; Sawaf, T.; Gebran, A., 1993. Continental margin evolution of the Northern Arabia Platform in Syria. American Association of Petroleum Geologists, 77: 173–293 pp. Beydoun ZR (1988) The Middle East: regional geology and petroleum resources. Scientific Press, UK, p 291. Beydoun ZR. 1991. Arabian plate hydrocarbon, geology and potential: a plate tectonic approach. American Association of Petroleum Geologists, Studies in Geology 33: 1–7. Buatios, L.A., Mangano, M.G., 2003. Sedimentary facies, depositional evolution of the Upper Cambrian–Lower Ordovician Santa Rosita Formation in northwest. Journal of South American Earth Sciences. 16 (5), 343–363 pp.

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Buday, T., 1980. The regional geology of Iraq Vol. 1 stratigraphy and paleogeography D.G, geology surv. Min. investigation, Lib, pub., 1, 445 pp. Collomb, G. R., 1962. Etude geologique de Jebel Fezzan et de sa bordure Paleozoiquue. Notes et Mem. Comp. Fr. Petrole, No.1 35 p., 1carte, Eng. sum., Paris. Cooper, G.A. 1976. Lower Cambrian brachiopods from the Rift Valley (Israel and Jordan). Journal of Palaeontology, 50: 269–289 pp. Craig, J.1; Rizzi, C.1; Said, F., Thusu, B.; Luning, S4; Asball, A. L., Keeley, M.L.; Bell, J. F., Durham, M.J., Eales, M.H. Beswetherick, S., Hamblett, C. 2008. https://www.researchgate.net/ publication/238661584. Drises, S.G., Byers, C.W., Dott, R.H., 1987. Tidal deposition in the basal Upper Cambrian Mt. Simon Formation in Wisconsin. Earth Science Reviews, 47: 41–70 pp. El Arabi, A. Abdel Metilib, A., 1999. Depositional facies of the Cambrian Araba Formation in the Taba region, east Sinai, Egypt. Journal African Earth Sciences, 29:429–447 pp. El Dakkak, W., 1988. Geological studies of subsurface Paleozoic strata of northern western Desert, Egypt. J. African. Earth Sci. 7: 103–111 pp. El Kelani. A. Said, M. 1990. Lithostratigraphy of southwestern Sinai. Ann. Geol. Surv. Egypt, 16: 215–235. El Kelani, A.; El Hag, I.; Bakry, H.; Shaira, M., 1999. Type and stratotype section of the Paleozoic in Sinai, Sp. Pub. No. 77, 94 p., EGSMA, Cairo. Elicki, O, 2007. Facies development during late Early–Middle Cambrian (Tayan Member, Burj Formation) transgression in the Dead Sea Rift valley. Carnets de Geologie, Carne ts de Geologie, 1–20 pp. Elicki, O. Altumi, M. 2019. Cambrian trace fossils from North Africa and their contribution to Gondwana’s paleobiogeography and depositional history. Journal of African Earth Sciences, 158, 103556. Elicki, O.; Geyer, G., 2013. The Cambrian trilobites of Jordan – taxonomy, systematic and stratigraphic significance. Acta Geologica Polonica, 63: 1–56 pp. Elicki, O.; Khalifa, M.A.; Farouk, S.M. 2013. Cambrian ichnofossils from northeastern Egypt. N. Jb. Geol. Paläont. Abh. 270:129–149 pp. Gaddo, J.; Parker D.M.T., 1959: Final well report of Well Khleissia -1, M. P.C. Report, N.O.C. Library, Baghdad. Gueinnk, K. J.; Rasll, S. M., 1986. A contribution to the biostratigraphy of the Palaeozoic of the Western Desert, utilizing new pa1ynoogical data from the subsurface. EGPC VIII Exploration Conference, Cairo. Hallett, D. 2002. Petroleum Geology of Libya. Elsevier, 503 pp. Hantar, G., 1990. North Western Desert. In Said, R. (Ed.), The Geology of Egypt. A. A. Balkema/ Rotterdam/Brookfield, 389 293–319 pp. Hasan, A. A., 1967. A new Carboniferous occurrence of Abu Durba, Sinai, Egypt. Six Arab Petrol. Conf. Baghdad, 1–8 pp. Hofmann, R., M.G. Mángano, O. Elicki and R. Shinaq 2012. Paleoecologic and biostratigraphic significance of trace fossils from Middle Cambrian shallow- to marginal-marine environments from the middle Cambrian (Stage 5) of Jordan. Journal of Paleontology, v. 86, p. 931–955 pp. Howe, John Allen (1911). “Cambrian System”. In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 05 (11th ed.). Cambridge University Press. pp. 86–89 Issawi, B.; Jux, U., 1982. Contribution to the stratigraphy of the Paleozoic rocks in Egypt. Geol. Surv. Egypt. Paper no. 64, 24 pp. Jarrar, G.; Wachendorf, H.; Zellmer, H., 1991. The Saramuj Conglomerate: Evolution of a PanAfrican molasses sequence from southwest Jordan. Neus Jahrbuch für Geologie und Paläontologie Monatshefte, 6: 335–356 pp. Keeley M.L. 1989. the Palaeozoic history of the Western Desert of Egypt. Basin Res 2:35–48 pp. Keeley, M. L., 1994. Phanerozoic evolution of the basins of Northern Egypt and adjacent areas. Geol Rundsch, 83: 728–742 pp.

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Khalaf, F. H.; Yonkhanna, A. H.; AL-Rubaii, M. A.; Samurai, A. I. 1998. The Akkas Formation, a new name for Paleozoic (Silurian) Lithostratigraphy unit in Iraq. Iraqi Gel Jour. vol. 30, No.1, (Special issue). Khalifa, M. A., 2015. Glacial and post-glacial deposits of the Unayzah Formation (Carboniferous– Permian), Saudi Arabia: facies analysis and sequence stratigraphy Carbonates Evaporites, 30: 207–227. Khalifa, M.A., 2017. General characteristics of quartz arenite types and their role in the recognition of sequence stratigraphic boundaries in ancient coastal and near-shorements. A case study from Egypt and Saudi Arabia. Journal of African Earth Sciences 130: 274–292 pp. Khalifa, M.A.; Soliman, H.E.; Wanas, H.A., 2006. The Cambrian Araba Formation in northeastern Egypt: Facies and depositional environments. Journal of Asian Earth Sciences 27: 873–884 pp. Klitzsch, E. 1990. Paleozoic. In Said. R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 393–406 pp. Klitzsch E, Wycisk, P. 1987. Geology of the sedimentary basins of northern Sudan and bordering areas. Berliner Geowiss Abh A 75:97–195 pp. Kora, M., 1984. The Paleozoic outcrops of Umm Bogma area. - Ph. D. thesis, Mansoura Univ., 280 pp. Kora, M. 1991. Lithostratigraphy of the Early Paleozoic succession in Ras EI Naqab area, eastcentral Sinai, Egypt. News Stratigr. Berlin. Stuttgart, 24: 45–57 pp. Kraus, M. J., 1999. Paleosols in clastic sedimentary rocks: their geologic applications. Lloyd, J., 1968. The hydrogeology of the southern desert of Jordan. Report, UNDP Mission, Sandstone aquifer of Jordan, 53 p. Lloyd, J. W. 1969. The hydrogeology of the southern desert of Jordan. UNDP/FAO 212, Technical Report No. 1, Rome. Loosveld RJH, Bell A, Terken JJM. 1996. The tectonic evolution of interior Oman. GeoArabia 1: 28–51. Massa, D.; Collomb, G. R, 1960. Observations nouvelles sur la region d’Aouinet Ouenine et du Djebel Fezzan (Libye). 21st Int. Geol. Congr. Report, Pt, 12, 65–73 pp, Copenhagen. McCarthy, P. J., Martini, I. P., Leckie, D. A., 1998. Use of micromorphology for interpretation of complex alluvial paleosols: examples from the Mill Creek Formation (Albian), southwestern Alberta, Canada. Paleogeography, Paleoclimatology, Paleoecology, 143: 87–110 pp. Mckerrow, W. S.; Scotese, C. R.; Brasier, M. D. (1992). “Early Cambrian continental reconstructions”. Journal of the Geological Society. 149 (4): 599–606. Bibcode:1992JGSoc.149..599M. doi:https://doi.org/10.1144/gsjgs.149.4.0599. S2CID 129389099. Miall, A. D., 1977. A review of the braided-river depositional environment. Earth Sci. Rev. 13, 1–62 pp. Miall, A. D., 1985. Architextural element analysis; a new method of facies analysis applied to fluvial deposits. Earth Sci. Rev. 22, 261–308 pp. Mitchell, R. N.; Evans, D. A. D.; Kilian, T. M. (2010). “Rapid Early Cambrian rotation of Gondwana”. Geology. 38 (8): 755. North American Stratigraphic Code 1983, North American commission on stratigraphic Nomenclature. Am. Assoc. Petrol. Geologists. examples from alluvial valleys near Banff, Alberta. Journal of Sedimentary. 45 pp. Omara, S., 1972. An Early Cambrian outcrop in southwestern Sinai, Egypt. N. Jb. Geol. Palaeont. Mh., 5: 306–314 pp. Osman, R.; Ahmed, S.M.; Khater, T., 2002. The stratigraphy and facies of the Wadi Gabgaba and its surroundings with an emphasis on the lower Paleozoic glaciation. Six Inter. Conf. Geol. Arab. World, Cairo Univ. Egypt, 2:469–476 pp. Potter, P. E., Maynard, J. B., Depetris, P. J., 2005. Mud and Mudstones: Introduction and Overview. Springer, Berlin. 297 pp. Powell, J.H. 1988. The geology of Karak; Map Sheet No 3152 III. Hashemite Kingdom of Jordan, Natural Resources Authority, Bulletin 8, p. 1–72 pp.

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Powell, J.H. 1989. Stratigraphy and sedimentation of the Phanerozoic rocks in Central and South Jordan Part A: Ram and Khreim Groups. Hashemite Kingdom of Jordan Natural Resources Authority, Bulletin 11, 72 pp. Powell, J. H., Abed, A. M., Le Nindre, Y.M. 2014. Cambrian stratigraphy of Jordan. GeoArabia, 19: 81–134 pp. Powers, R.W., Ramirez, L.F., Redmond, C.D., Elberg Jr., E.L., 1966. Geology of the Arabian Peninsula: Sedimentary Geology of Saudi Arabia: U.S. Geological Survey Professional Paper, 560-D, 147 pp. Quennell, A.M., 1951. The geology and mineral resources of (former Transjordan. Coln Geol Min Resource London. 2:85–115 pp. Reineck, H.E., 1972. Tidal flats. In: Rigby, J.K., Hamblin, W.K. (Eds.), Recognition of Sedimentary Environments. SEPM. Spec. Publ. 17: 146–159 pp. Reineck, H.E., Singh, I.B., 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin, 439 pp. Retallack, G.J., 2001. Soils of the Past: an introduction to paleopedology, 2nd ed. Wiley. 404 pp. Rhoads, D.C., 1967. Biogenic reworking of intertidal and subtidal sediment In Barnstable Harbor and Buzzards Bay, Massachusetts. The Journal of Geology. 75, (4). Rushton, A.W.A. and J.H. Powell 1998. A review of the stratigraphy and trilobite faunas from the Cambrian Burj Formation in Jordan. Bulletin of the Natural History Museum London (Geology), v. 54, no. 2, p. 131–146 pp. Said, R. 1971. Explanatory notes to accompany the geological map of Egypt. Egypt. Geol. Surv. paper no. 56, 123 pp. Scotese, C.R., 1998. “A tale of two supercontinents: the assembly of Rodinia, its break-up, and the formation of Pannotia during the Pan-African event”. Jour. Afr. Ear. Sci. 27 : 1–227. Sedgwick, A. (1835). “On the classification and nomenclature of the Lower Paleozoic rocks of England and Wales”. Q. J. Geol. Soc. Lond. 8 (1–2): 136–138 pp. Seilacher, A. 1990. Paleozoic trace fossils. In Said, R. (Ed.). The Geology of Egypt, 649–722. Rotterdam and Brookfield. Selley, R.C. 1970. Ichnology of the Palaeozoic sandstones in the Southern Desert of Jordan: A study of trace fossils in their sedimentologic context. In T.P. Crimes and J.C. Harper (Eds.), Trace Fossils, p. 477–488 pp. Selley, R.C. 1972. Diagnosis of marine and non-marine environments from the Cambro-Ordovician sandstones of Jordan. Journal of the Geological Society of London, v. 128, p. 135–150 pp. Selley, R.C., 1996. Ancient Sedimentary Environments and their Subsurface SHRIMP dating: Geology, 31, 227–230 pp. Selley, R. C., 2000. Applied Sedimentology. Florida: Academic Press. Simpson, E.L., Dilliard, K.A., Rowell, B.F., Higgins, D., 2002. The fluvial-to-marine Eastern Pennsylvania, USA. Sed. Geol. 147, 127–142 pp. Smith, D.G., Smith, N. D., 1980. Sedimentation in an astomosed river systems: Stratigraphic Chart 2022”. International Stratigraphic Commission. February 2022. Retrieved 5 April 2022. Soliman, S. M.; M. Abu El-Fetouh, 1969. Lithostratigraphy of the Carboniferous Nubian type sandstone in west-central Sinai. - U. A. R. Jour. Geol. 13: 61–143 pp. Steineke, M., Bramkamp, R.A., Sander, M.J., 1958. Stratigraphic relations of the Arabian Jurassic oil In Weeks, L.G. (Ed.), Habitat of Oil. American Association Petroleum Geologists Symposium, pp. 1294–1329 pp. Stratigraphy and paleogeography of the Hasawnah formation (Cambrian, Al Qarqaf Arch, centralwestern Libya): Data from detrital zircons and trace fossils. Paleopetrol, Turk. Assoc. Petrol. Geol. Spec. Publ., 6, 97–99 pp. Vail, P.R.; Mitchum, R.M.; Thompson, S. 1977. Global cyclist of relative changes in sea-level. In Epoyton, C. (Ed.), Seismic stratigraphy Application to hydrocarbon, A.A.P.G. Mem. 76: 83–97 pp. Vaslet, D., Le Nindre, Y., Vachard, D., Broutin, J., Crasquin-Soleau, S., Berthelin, M., Gaillot, J., Halawani, M., Al-Husseini, M., 2005. The Permian–Triassic Khuff Formation of central Saudi Arabia. GeoArabia 10, 77–134.

Chapter 4

The Ordovician Period

Abstract This chapter provides general geologic information about the Ordovician Period, including definitions, classifications, fauna and flora, palaeogeography, and tectonic events that occurred during this period. The Karkur Talh, Naqus, and Gabgaba formations are three exposed Ordovician rock units in Egypt. In the subsurface, no Ordovician rock units have been discovered. Each of the rock mentioned above units was discussed in terms of definitions, stratigraphic boundaries, lithological components, distribution and thicknesses, and aga assignment. These rock units could be matched with their counterparts in neighbouring countries such as Libya, Jordan, Saudi Arabia, and Iraq. Based on facies types, faunal and floral associations, and trace fossils, the depositional environments of Ordovician rock units have been identified. A palaeogeographic facies map is created, allowing several synchronous environments to be identified, including cratonic and upland areas, coastal and marginal marine, shoal environments, and continental glacial sediments. Keywords Ordovician · Karkur Talh · Naqus · Gabgaba · Glacial sediments · Shoal · Egypt · Marginal marine

4.1 Introduction 4.1.1 Definition Lapworth (1879) coined the “Ordovician” System to define the second period of the Paleozoic Era. The term Ordovician was derived from the Ordovices province in north Wales (England) to describe the transitional period between the Cambrian and Silurian, which is intermediate in position and character. This period survived along 41.6 Ma that occurred between the end of the Cambrian Period (485.4 Mya) and the beginning of the Silurian Period (443.8 Mya) (ISC 2015, Fig. 4.1).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_4

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Fig. 4.1 Geological chart showing the time classification of the Ordovician Period (After ICS 2021). “Chart/Time Scale”. www.stratigra phy.org. International Commission on Stratigraphy

4.1.2 Classification Three epochs make up the Ordovician period: the Early Ordovician (485–470 Mya), Middle Ordovician (470–458.4 Mya), and Late Ordovician (458.4–443.8 Mya) (Fig. 4.1). More subdivision of the Early Ordovician includes In Britain classification; the Ordovician period is divided into: The Early (Tremadocian and Arenig), Middle (Llanvirn, split into Abereiddian and Llandeilian), and Late (Caradoc and Ashgill) epochs (Fig. 4.1).

4.1.3 Fauna and Flora The Ordovician period was characterised by shallow continental seas rich in fauna, such as Trilobites, brachiopods, and reef-forming corals, which first appeared in the

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early Ordovician (Munnecke et al. 2010). Graptolites are common. Green algae were common during the Ordovician period. Terrestrial plants most likely evolved from green algae, which first appeared in the middle to late Ordovician as tiny non-vascular forms resembling liverworts (Borada et al. 2016).

4.1.4 Paleogeography and Tectonics The Panthalassic Ocean, concentrated in the northern hemisphere, covered more than half of the planet (Torsvik et al. 2017). During the Ordovician period, the southern continents merged to form Gondwana, which stretched from north of the equator to the South Pole (Jeffery et al. 2009). Laurentia, which includes North America, Siberia, and Baltica, was separated from Gondwana at the start of the period by more than 5,000 kms (3,100 miles) of the ocean (Nance et al. 2012). This period was marked by widespread tectonic and volcanic activity. However, there was no active mountain-building due to continent–continent collisions. Mountains instead formed along active continental borders as arc terranes or ribbon microcontinents accreted (Glen et al. 2007; Ramos 2018). The Taconic orogeny, which is thought to have been a significant mountain-building phase, began in the late Cambrian and extended into the Ordovician (Van Staal and Hatcher 2010). During this phase, there are two volcanic island arcs collided with Laurentia, forming the Appalachian Mountains. Following that period, Gondwana began to move over the South Pole, resulting in the Hibernian Glacial Period and the extinction catastrophe (Van Staal and Hatcher 2010). The Ordovician–Silurian extinction events have been caused by an ice age that occurred at the upper of the Ordovician Period. The end of the Late Ordovician was one of the coldest periods in Earth’s history over the last 600 million years (Samuel et al. 2001).

4.2 Ordovician Rocks in Egypt In Egypt, the Ordovician rock units include three rock units; Karkur Talh, Naqus, and Gabgaba formations.

4.2.1 The Karkur Talh Formation 4.2.1.1

Definition

Klitzsch and Lejal-Nicol (1984) named the Karkur Talh Formation to describe the fluvial and marine sandstone found at Karkur Talh in the northeastern section of Gebel Uweinat along the Egyptian-Sudanese border (Fig. 4.2).

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Fig. 4.2 Satellite image shows Wadi Karkur Talh, the type locality of Karkur Talh Formation east of Gebel Uweinat, southwestern Desert (After Brugge 2020)

4.2.1.2

Stratigraphic Contact

The Karkur Talh Formation nonconformably overlies the Precambrian metamorphic rocks (Figs. 4.3 and 4.4a) and conformably underlies the Silurian Um Ras Formation (Fig. 4.4b) (Klitzsch and Lejal-Nicol 1984; Klitzsch 1990). The presence of Skolithos sandstone, which forms the top of the Karkur Talh Formation, distinguishes this formation’s upper contact with the overlying Um Ras Formation (Klitzsch and Wycisk 1987).

4.2.1.3

Lithology

The Karkur Talh Formation comprises two lithologic units (Figs. 4.5a and 4.6a). The Fining-upward cycles make up the lower unit. Each cycle begins with intraformational conglomerate, progresses to medium- to coarse-grained, trough and planar cross-bedding, and is capped with fine-grained sandstone and laminated siltstone with wavy lamination and ripple cross-lamination (Klitzsch and Wycisk 1987). Skolithos burrows are abundant in the upper portion of the lower unit (Fig. 4.6b). The upper unit comprises massive cross-bedded reddish sandstone intercalated with fine-grained sandstone to shaly siltstones with some skolithos burrows near the top (Fig. 4.5a).

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Fig. 4.3 Schematic cross-section showing the occurrence of the Karkur Talh and Umm Ras formation at Gilf Kebir, northeast Gebel Uweinat (After Klitzsch and Lejal-Nicol 1984). Notice the nonconformable contact of the Karkur Talh Formation with the underlying basement rocks and unconformably underlies the Umm Ras Formation

a

b

Fig. 4.4 a Field photograph showing the lower contact of the Karkur Talh Formation with the underlying basement rocks, northeast Gebel Uweinat, southwestern Desert, Egypt (After Klitzsch and Lejal-Nicol 1984; Brugge Brugge 2020). b Field photograph showing the upper contact of the Karkur Talh Formation with the overlying Silurian Um Ras Formation, northeast Gebel Uweinat, southwestern Desert, Egypt (After Klitzsch and Wycisk 1987; Brugge 2020)

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Fig. 4.5 Lithostratigraphic section of the Ordovician Karkur Talh Formation (a), northeast Gebel Uweinat, southwestern Desert, Egypt (After Klitzsch and Wycisk 1987; Brugge 2020), Naqus Formation at its type locality, Gebel Naqus, southwest Sinai (b) and the Gabgaba Formation, southeastern Desert (After Osman et al. 2002) (c)

4.2 Ordovician Rocks in Egypt

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a

b

Fig. 4.6 a Field photograph illustrating the two units of the Kakur Talh Formation. The lower unit comprises fine-grained sandstone intercalated with siltstone, while the upper unit consists of massive reddish sandstone with burrowed siltstone (After Klitzsch and Wycisk 1987; Brugge 2020). b Field photograph showing the concentration of Skolithos Sp. in the upper unit of Karkur Talh Formation, Gilf Kebir, northeast Gebel Uweinat, southwestern Desert, Egypt (After Klitzsch and Wycisk 1987; Brugge 2020)

4.2.1.4

Distribution and Thickness

Ordovician rocks have yet to be discovered in Egypt, either on the surface or in the subsurface. The Karkur Talh Formation was encountered at the Karkur Talh locality in the southeastern part of Gebel Uweinat, near the Egyptian-Sudanese border. It assumes ten metres (about thirty metres) in thickness (Klitzsch and Wycisk 1987).

4.2.1.5

Age Assignment and Correlation

Cruziana Sp., Arthrophycus Sp., Cruziana Harlania, and Skolithos Sp. have been discovered in the Karkur Talh Formation on the Egyptian side of Jebel Uweinat (Klitzsch and Lejal-Nicol 1984). The presence of Arthophycus linearis (Fig. 4.7a) and Cruziana goldfussi (Fig. 4.7b) in the present work indicates an Early to Middle Ordovician age (Eliciki Olaf, personal communication). Furthermore, according to

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a

b

Fig. 4.7 a Field photograph showing the Arthophycus linearis trace fossils in the Karkur Talh Formation (After Klitzsch and Wycisk 1987; Brugge 2020). b Field photograph showing the occurrence of the Cruziana goldfussi (Silurian age, Eliciki Olaf, personal communication) in the lower unit of the Karkur Talh Formation (After Klitzsch and Wycisk 1987; Brugge 2020)

Klitzsch and Schandelmeier (1990), the rocks of this formation are heavily burrowed by Skolithos Sp. in its upper part. They contain Cruziana Sp. of Ordovician age in its basal section. This formation can be correlated with the Middle Ordovician Hawaz Formation in Libya, the Hiswa and Dubaydib formations in Jordan and the Khabour Formation in Iraq.

4.2.2 The Naqus Formation 4.2.2.1

Definition

Hassan (1967) established the name Naqus Formation for the first time in southwestern Sinai. This term was later formalised by Said (1971). The term Naqus is an Arabic term that refers to a geomorphologic feature of white sandstone hills that

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Fig. 4.8 Field photograph manifesting the type section of the Naqus Formation at Gebel Naqus, Wadi Araba, southwest of Sinai, Egypt. Notice the geomorphologic feature of the top of the Naqus Formation (look-like bell), which is the conspicuous feature of this formation

resemble a bell, which is a prominent feature of this Formation in most of its occurrences (Fig. 4.8). Gebel Naqus in southwestern Sinai’s Wadi Araba is its type locality (El Kelani et al. 1999).

4.2.2.2

Stratigraphic Contacts

The stratigraphic limits of the Naqus Formation differ depending on where it is found. It unconformably overlies the Cambrian Araba Formation in Gebel Araba, Gebel Abu Durba, Gebel Naqus, and Gebel Ekma in southern Sinai. The contact is found between the top Arab Formation’s reddish siltstones and the uppermost Naqus Formation’s pebbly and conglomeratic, cross-bedded sandstone (Fig. 4.9a). Its upper boundary unconformably underlies the Carboniferous Abu Durba Formation at Gebel Ekma in southwestern Siani (Fig. 4.9b). It non-conformably overlies the Precambrian basement rocks at Gebel Gunna, where the Araba Formation is absent (Fig. 4.9c). At the latter locality. It unconformably underlies the Lower Cretaceous Malha Formation.

4.2.2.3

Lithology

The Naqus Formation is dominated by sandstone, with pebbly sandstone intercalated (Fig. 4.5b). Sandstones are typically massive, with quartz pebbles and granules (Fig. 4.10a) interbedded with light yellow to grey, thick-bedded, and trough crossbedded sandstone (Fig. 4.10b). The thin-bedded, planar cross-bedding (Fig. 4.11a),

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a

b

c

Fig. 4.9 a Field photograph illustrates the Naqus Formation’s lower contact with the underlying Araba Formation. The contact lies between the reddish siltstone of the uppermost Araba Formation and the pebbly and conglomeratic sandstone of the basal Naqus Formation, Gebel Ekma, southwest of Sinai. Notice the angular relation between the pebbly conglomerate (between Araba and Naqus Formations) at the base of Naqus sandstone. b Field photograph illustrates the Naqus Formation’s upper contact and the overlying Upper Carboniferous Abu Durba Formation. The contact is sharp to unconformable and lies between the massive white sandstone of the uppermost Naqus Formation and the reddish brown siltstone of the basal Abu Durba Formation, Gebel Ekma, southwest of Sinai. c Field photograph showing the nonconformable contact between the Precambrian basement below and the Naqus Formation above, Gebel Gunna, central Sinai. Notice the missing Araba Formation at this locality

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a

b

Fig. 4.10 a Field photograph manifesting the massive sandstone with quartz granules and pebbles which build up most of the Naqus Formation, Gebel Gunna, and central Sinai. b Field photograph manifesting the trough cross-bedding sandstone of the Naqus Formation, Wadi Feiran and southwest Sinai

and the presence of recumbent or overturned cross-bedding (Fig. 4.11b) is the most distinguishing feature of this formation. It also has white pebble-sized dropstone (Fig. 4.12a) that is randomly distributed throughout the sandstone. The lower part of this formation at Wadi Feiran includes white, irregular, fractured erratic lithoclasts (Fig. 4.12b) and brownish-reddish pebbly to cobbly-sized erratic lithoclasts.

4.2.2.4

Distribution and Thickness

Most geologists who have studied the Sinai Naqus Formation believe that it has a continuous distribution and a constant stratigraphic position, typically above the Cambrian Araba Formation. Detailed field research shows that it only occurs in a few

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a

b

Fig. 4.11 a Field photograph manifesting the thin-bedded and planar cross-bedding sandstone of the Naqus Formation, Wadi Feiran and southwest Sinai. b Field photograph shows two sets of recumbent and overturned cross-bedding in the sandstone of the Naqus Formation. Notice the presence of two levels of recumbent cross-bedding. Gebel Gunna, Central Sinai

isolated locations known as paleovalleys in the Sinai Peninsula. It is most common in four paleovalleys (Fig. 4.13). The first paleovalley is between Gebel El Zeit and Gebel Ekma, between the latter and before Wadi Feiran; it has been omitted. The second paleovalley formed at Wadi Feiran (the entrance to Wadi Mokttab) and was overlooked until Saint Katherine. It is also ignored to the northeast of Um Bogma. The third paleovalley is located north of Saint Katherine and stretches from Gebel Gunna to the south of Ras El Naqab to the south of Taba (Fig. 4.13). The fourth paleovalley occurs at Ras El Naqab (Fig. 4.14). It is not present north of the latter location until the Taba area. El Araby and Abdel-Motelib noted the absence of this formation from Ras El Naqab to Taba areas in 1998. Similar occurrences are possible in Saudi Arabia’s Sarah and Zarqa formations, which are made up of glacial deposits (Vaselet 1990).

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a

b

Fig. 4.12 a Field photograph showing the random occurrence of rounded, pebble-sized dpopstone in the sandstone of the Naqus Formation, Gebel Gunna, Central Sinai. b Field photograph showing the white, cracked and irregular cobble-sized white lithoclasts randomly scattered in the Naqus Formation. Wadi Feiran, southwest Sinai

Furthermore, Kora (1991) did not mention the Naqus Formation in the Taba area. This observation is consistent with the opinion of Issawi et al. (2009), who stated that the Naqus Formation never crops out north of a line passing through Gebel El NaqabTaba. There are no records of the Naqus Formation in the Eastern Desert, including Wadi Abu Aggag, east of Aswan, at Marsa Alam-Edfu Road, Quseir-Qeft Road, and Wadi Qena. However, in the southeastern Desert, near the Sudanese border, at Wadi Gabgaba, this formation is located above the Araba Formation and below the Lower Carboniferous Wadi Malik Formation (Osman et al. 2002). This formation cannot exist in the southwestern Desert since the Silurian Um Ras Formation occurs over the Ordovician Karkur Talh Formation (Klitzsch 1990). Klitzsch (1990) highlighted that “North Egypt does not include any Ordovician strata, either at the surface or in wells. The maximum thickness occurs at Gebel Gunna, central Sinai (140 m). It measures about 60–120 m at Gebel. Araba, Gebel Naqus, and decreases in thickness northeastwards at Gebel Ekma, measuring only 10 m. It is missed northeast of the latter locality in Um Bogma area.

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4 The Ordovician Period

Fig. 4.13 A Cross-section along the northeast direction in Sinai shows the occurrence of the Naqus Formation in four depressions named paleovalleys in Gebel Ekma, Wadi Feiran, Gebel Gunna and Ras Naqab. Notice that the incised valley removed the Araba Formation and even the upper part of the basement rocks, where the Naqus Formation directly rested on the basement rocks at Gebel Gunna

Fig. 4.14 Field photograph illustrating the paleovalley incised in the top of the Araba Formation and filled by the white sandstone of the Naqus Formation at Ras Naqab, northeast Sinai

4.2.2.5

Age Assignment and Correlation

The Naqus Formation does not include any forms of fossils, fauna, or flora; hence its age was determined based on its stratigraphic position. Since it is found overjacent to the Middle Cambrian Araba Formation and subjacent to the Upper Carboniferous

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Fig. 4.15 Correlated measured lithostratigraphic sections of the Melaz Shuqran and Maumniat formations in Libya (a), Naqus Formation in Egypt (b), Tubeiliyat and Ammar formations in Jordan (c) and Zarqa and Sarah formations in Saudi Arabia (d) and Khabour Formation in Iraq (e)

Abu Durba Formation in most of the examined places in Sinai, it is restricted between the Ordovician and Silurian ages. Furthermore, it comprises glacial sediments, which are assigned Late Ordovician age. It can be correlated with the Ordovician–Silurian Mamuniyat Formation (Massa and Collomb 1960) in Libya, Upper Ordovician Sarah and Zarqa formations in Al Qasim Province, Saudi Arabia (Vaslet 1987, 1990; ClarkLowes 2005), Late Ordovician Ammar Formation in southern Jordan (Abed et al. 1993; Turner et al. 2005) (Fig. 4.15). Based on the correlation described above and the glacial composition of this deposit thus points to Late Ordovician to Early Silurian periods.

4.2.3 The Gabgaba Formation 4.2.3.1

Definition

Issawi (2005) created the term “Gabgaba Formation” to refer to the glacial deposits that fill the Wadi Gabgaba paleovalley in the southeast desert and are represented by diamictite conglomerate (Fig. 4.5c). Its type section is located in Wadi Gabgaba,

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close to the border between Egypt and Sudan (Lat. 22 22 N, Long. 33 24 E) (Issawi 2005; Osman et al. 2002).

4.2.3.2

Stratigraphic Contact

The lower boundary of this formation at Wadi Gabgaba, in the southeast Desert, close to the Sundaes border, is nonconformable with the underlying Cambrian Araba Formation. Red paleosols 8 m thick indicate this contact (Osman et al. 2002). At The above locality, its upper boundary with the overlying Carboniferous Wadi Malik Formation is also unconformable, as demarked by pebbly quartz cemented by coarsegrained sandstone (Osman et al. 2002). In some areas, it unconformably overlies the Precambrian basement rocks.

4.2.3.3

Lithology

Paleosols strata and a small amount of sandstone are intercalated between conglomerate beds that make up the Gabgaba Formation (447 m). It contains four identified glacial phases, each of which is a thick conglomerate rock that alternates with four layers of paleosols (Fig. 4.5c). The aggregates have angular to subangular striated and faceted exterior borders, are white, red to grey, and extremely weakly sorted. The conglomerate is composed chiefly of quartz, kaolinitic sandstone, and other basement pebbles. The thin, coarse-grained, pebbly sandstone intercalated with conglomerate is reddish and ranges in thickness from 0.5 to 5 m. It is stratified with 0.5 to 4 m thick cross-bedded sandstone and breccia (Osman et al. 2002; Issawi et al. 2009).

4.2.3.4

Distribution and Thickness

It only occurs in a small area near the southeast corner of the Eastern Desert, close to the Sudanese border, before it joins Wadi Allaqi (Osman et al. 2002). Typically, this formation occupies the carved-out paleovalleys that stretch in a northwest direction for roughly 30 km (Osman et al. 2002). It assumes a maximum thickness of 447 m (Issawi et al. 2009). It pinches south of Wadi Gabgaba, where the overlying Wadi Malik Formation rests directly on the basement rocks (Osman et al. 2002).

4.2.3.5

Age Assignment and Correlation

Due to its correlation with the Naqus Formation or equal to the lower portion of the Naqus Formation, the Gabgaba Formation is dated to the Late Ordovician-Early Silurian (Osman et al. 2002; Issawi et al. 2009).

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4.2.4 Ordovician Rocks in Adjacent Countries 4.2.4.1

In Libya

Two rock units represent the Upper Ordovician Period: Melaz Shuqran and the Mamuniyat formations (Fig. 4.15a). The Melaz Shuqran formation was named by Massa and Collomb (1960). It unconformably overlies Middle Ordovician Hawaz Formation on the A1 Qarqaf Arch. It also conformably underlies the Mamuniyat Formation. It comprises 60 m of varicoloured green, brown, red, and grey, thinbedded claystone, and siltstone. Collomb (1962) also recorded the occurrence of cobbles of granite, gneiss, and quartzite, which are polished and striated, and which he took to indicate periglacial conditions and iceberg rafting. This formation contains abundant trilobites, bryozoa, brachiopods and graptolites which suggest a Llanvirnian-Llandeilian age for the formation (Collomb 1962). The Mamuniyat Formation was first described by Massa and Collomb (1960) that outcrops on the A1 Qarqaf Arch. The lower contact of the Mamuniyat Formation is unconformable with the underlying Melaz Shuqran Formation. At the same time, its upper boundary is marked by a regional unconformity with the overlying Lower Silurian Tanzuft Formation. It comprises 100–140 m of massive, cross-bedded sandstones. The sandstones are generally medium- to coarse-grained and frequently conglomeratic bands. It is friable, with a high percentage of kaolinitic cement. It contains occasional finegrained sandstone and siltstone stringers (Fig. 4.15a). This formation usually occurs in two deeply incised valleys up to 4 km wide and 150 m deep, which cut the lower Mamuniyat, Melaz Shuqran, and top of the Hawaz Formations, which they attributed to glacial incision (Massa and Collomb 1960). Palynological evidence suggests a Caradocian age for the Mamuniyat Formation, while the brachiopod evidence indicates an Ashgillian age (Ordovician to Early Silurian periods) (Hallett 2002).

4.2.4.2

In Jordan

The Lower–middle Ordovician rocks are represented by Umm Sahm, Hiswa, and Dubaydib formations, while the Upper Ordovician rocks include two rock units, the Tubeiliyat and Ammar formations (Amireh et al. 2001). The Ashgillian Tubeiliyat Formation attains 105 m thick and conformably overlies the Dubaydib Formation (Fig. 4.15c). It comprises greenish, silty shale and hummocky cross-stratified sandstone (Makhlouf 1992). These rocks are organized into coarsening-upward cycles. In the greenish silty shales, trace fossils of the Cruziana Ichnofacies are common (Makhlouf 1992; Makhlouf et al. 2017). The Ammar Formation (Abed et al. 1993; Amireh et al. 2001) incised in and filled the tunnel in the upper part of Tubeiliyat formation and consists of two glacial units, each is underlain by a glacial erosion surface and comprises erosive-based, palaeovalley channel-fill sandstones which is m

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4 The Ordovician Period

ade up of coarse-grained, proximal, braided sandstones containing glacially faceted and striated clasts, typically concentrated in the lower (Powell et al. 1994).

4.2.4.3

In Saudi Arabia

The Ordovician rocks are represented by three rock units (Fig. 4.15d): The Qasim, Zarqa and the Sarah formations. The Qasim Formation (Middle-Upper Ordovician) includes four members, Hanadir Shale, Kahfah, Raan and Quarah Members. These members comprises an intercalation of shale, siltstone and sandstone enriched with graptolites and Cruziana trace fossils and Skolithos (vertical burrows) (Senalp and Al-Duaiji 2001). The upper two rock units represent the Upper Ordovician glacial deposits, the lower is the Zarqa Formation, and the upper is the Sarah Formation. The Zarqa Formation was formally defined and documented by Vaslet et al. (1987) from the Jal Az-Zarqa cuesta near Baq’a town. The type section of the unit is 115 m thick and is located near the Jal Az-Zarqa, about 10 km southwest of Baq’a town (Vaselet 1987; Vaslet et al. 1987). The Zarqa Formation is bounded below and above by two glacially formed unconformity surfaces (Pre-Zarqa and Pre-Sarah unconformities). The Pre-Zarqa unconformity cuts into the underlying Qasim and Saq formations, and its base represents a glacially formed unconformity surface (Vaslet 1990). Its upper part is also profoundly incised by the second glacially formed unconformity surface at the base of the Sarah Formation. This formation consists of repetition and a complex mixture of various types of tillite, boulder-clay, glacial dropstones, and slumped or bulldozed sandstone blocks derived from the older formations (Vaslet 1987, 1989) (Fig. 4.15d). The age of the Zarqa Formation is dated to the Late Ordovician. The Sarah Formation was established by Clark-Lowes (1980) and Williams et al. (1986), while mapping the Al-Qasim area, recognized a distinct unit exposed in the Khanasir Sarah. The Sarah Formation is bounded at the base by another major glacially formed unconformity surface. This unconformity surface cuts deeply into the Zarqa, Qasim, and even the Saq Formation in its proximal parts located at the end of the Hanadir cuesta in central Saudi Arabia. Its upper contact with the overlying hot shale of the Silurian Qalibah Formation. They mentioned that formation comprises conglomerates, conglomeratic sandstone, diamictites, and minor shale horizons. At outcrops of the Sarah Formation, the glacial paleovalleys generally extend in the W-E direction in central Saudi Arabia and the S–N direction in NW Saudi Arabia (Senlap and Tetiker 2020).

4.2.4.4

In Iraq

The Ordovician rocks were named Khabour Formation (Wetzel 1950), located in the Northern Zagros Thrust Zone in northern Iraq close to the Iraqi–Turkish border (Fig. 4.15e). It is encountered in the subsurface and consists of a sequence of shallow marine clastic sediments, including thin-bedded, fine-grained sandstones, calcareous to argillaceous quartzearenite, and silty micaceous olive green to brown shales (about

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87

806 m thick) (Omer 2012). The formation age is based on three Cruziana ichnotaxa, Fucifera isp., Goldfussi isp., and Rugosa sp, considered index fossils for the Middle to Early Upper Ordovician (Omer 2012).

4.2.5 Depositional Environments North African Ordovician sediments are dominated by continental and shallow marine sandstones, with a few siltstone and shale intervals. The deposition occurred on a broad shelf in a low-accommodation environment (Criag et al. 2008). The large Gondwana hinterland to the south, with prevailing south-to-north and southeastto-northwest directed paleocurrents, was the most likely sediment source (Craig et al. 2008). Throughout this time, the general stability of the North African shelf resulted in the sedimentation of broadly similar Ordovician successions throughout the region (Criag et al. 2008). The early Palaeozoic evolution recorded in eastern Algeria, western Libya, and Egypt, on the other hand, was dominated by major NNW-SSE trending structures. This structural trend resulted in low relief of horsts and grabens and regional domal and low depressions, which dominated in the late Cambrian (Klitzsch and Ziegert 2000). This movement could result in the formation of later (“Caledonian”) uplift cores (Criag et al. 2008). The facies in the lower and middle Ordovician are very similar, with cross-bedded sandstone intercalated with sandy clays and siltstone, as found in Libya, Jordan, and Saudi Arabia. Except in Egypt, specifically the Sinai Peninsula, the facies consists solely of a coarse-grained trough and planar cross-bedded sandstone with glacial sediments (erratic boulders and quartz pebbles) (Naqus Formation). These sediments can be broadly classified into four distinct correlatable sequences that reflect second-order eustatic cycles superimposed on a gradual and progressive rise in global sea level over the Ordovician period (Criag et al. 2008). During the Late Ordovician time, there was uplifting due to the effect of the Taconic and Caledonian movements (Criag et al. 2008). This made structural high in certain regions, e.g., Libya, Egypt, Jordan, and Saudi Arabia. In northeast Africa, Caledonian (Ordovician to Early Devonian) tectonic activity was characterized by general northwest-southeast and east–west trending folding and faulting, which further consolidated the pattern of earlier platform basins and uplifts (Klitsch 1968; Bishop 1975). At this time, Paleozoic basins and uplifts were delineated, such as the Ghadames, Murzuk, and Kufra basins, the Gargaf arch in Libya, the Illizi, Erg Oriental, and Erg Occidental basins, and the Aniguid spur in Algeria, elements of the Western Desert basin, as well as numerous smaller trough and high trends extending southeast from the Mediterranean in Egypt. It is possible to define four depositional settings based on the lithofacies types, their distribution, faunal association, and dominated tectonics during the sedimentation of Ordovician rocks in Egypt and neighbouring countries (Fig. 4.16), (1) cratonic and upland areas, (2) coastal and marginal marine, (3) shoal environment, and (4) continental glacial sediments (Fig. 4.16).

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Fig. 4.16 Schematic paleogeographic map illustrating the distribution and depositional environments of the Ordovician rocks in Egypt and their equivalent rock units in Libya, Jordan, Saudi Arabia, and Iraq

1. The upland areas cover most of Egypt, except for a narrow zone northwest of Gebel Uweinat parallel to the Libyan borders. The Karkur Talh Formation filled this zone (Fig. 4.16). The missing Ordovician rocks found throughout Egypt either on the surface or in the subsurface (Western, Eastern Deserts, and Sinai) refers to the tectonic uplift). This viewpoint is consistent with the theories of Gvirtzman and Weissbrod (1984). They claimed that Ordovician sediments were deposited over the studied area (Egypt) but were later removed by local preCarboniferous erosion. Furthermore, Klitzsch (1990) believed that most of Egypt had been uplifted during the Ordovician period. However, some authors identified a cyclic sequence of fine- to coarse-grained fluvial to deltaic white sandstone and mudstone with Skolithos burrows overlying the Cambrian Araba Formation on the western side of the Gulf of Suez between northern Wadi Qena and Wadi ElDakhal. They linked this sequence to the Ordovician Naqus Formation. Unlike the previous authors, Klitzsch (1990) and Klitzsch et al. (1990) did not find any Naqus Formation or Ordovician strata on the western side of the Gulf, and they named this sequence the Somr EI Qaa Formation that belong to the Carboniferous period. The missing of the Ordovician sediments in the above mentioned localities is probably due to the effect of the Taconic and Caledonian movements (Criag et al. 2008). 2. The marginal marine environment covers a limited area in Egypt, most of Libya Libya, Saudi Arabia and Jordan (Fig. 4.16). The thin cross-stratified sandstone, olive-grey claystone associated with vertical burrows, and trace fossils distinguish the marginal marine environment (Martino 1989). The marginal marine

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occurs at the interface of the continental and marine depositional realms. Wave, river, and tidal processes, as well as high-energy waves and currents, dominate such an environment, though some lagoonal and estuarine environments are dominated by quiet-water conditions (Selley 2000; Nichol 2009). Furthermore, delta, beach, barrier island, estuarine, lagoonal, and tidal flat are depositional settings in marginal marine sediment (Selley 2000; Boggs 2009; Nichol 2009). The marginal marine facies in the studied countries include planar crossbedded, overturned cross-bedding, trough cross-bedded sandstone, thin bands of conglomerate, and bioturbated sandstone with sandy clay interbed. Trace fossils such as Cruziana ichnotaxa, Fucifera Sp., Goldfussi Sp., Rugosa Sp., and Skolithos SP. are common. In Egypt, this environment covers a narrow stretch extending from northwest Gebel Uweinat and parallel to the Libyan border. Karkur Talh Formation represents this facies. The marginal marine covers a large portion of Libya (Melaz Shukan and the Mamuniyat formations). The Melaz Shuqran Formation was not found in eastern and central Libya (Hallett 2002). In contrast, the Mamuniyate Formation covered most of Libya due to sea level rise caused by glacier melting. The Ashgillian Tubeiliyat Formation in Jordan is 105 m thick and consists of greenish, silty shale and hummocky cross-stratified sandstone (Makhlouf 1992). These rocks are classified as coarsening-upward cycles. Trace fossils of the Cruziana Ichnofacies are common in the greenish silty shales (Makhlouf 1992; Makhlouf et al. 2017). In addition, the Qasim Formation (Middle-Upper Ordovician) represents the marginal marine environment that covers Saudi Araba. This formation comprises shale, siltstone, and sandstone intercalations rich in graptolites, Cruziana trace fossils, and Skolithos (vertical burrows) (Senalp and Al-Duaiji 2001). 3. The shoal environment (represented by the Khabour Formation) is found only in northern Iraq (Fig. 4.16). This formation is entirely composed of quartzarenite, with only a few thin beds of siltstone facies. This type of quartzarenite is known as depositional quartzarenite and was most likely deposited in fluvialdominated proximal shelf facies (Khalifa 2017). quartzarenite has been discovered near shallow burial in St. Peter Sandstone (Cook et al. 2011). Furthermore, quartzarenite can be found in coastal and near-shore shelf facies (Khalifa 2015). Highly agitated water in such environments can winnow the finer grains away, leaving the detrital quartz grains in place. Pure quartz arenites are particularly common in Lower Paleozoic and Proterozoic strata deposited in non-orogenic environments (Dott 2003). This type of quartzarenite is visible at the tops of the first-order Ordovician–Silurian Naqus sequence, where there was a long (199 my) hiatus (Khalifa 2017). (4) Glacial environment: the glaciation time scale appears to have happened in less than 1 million years. However, the precise time of glaciation varies from less than 1 million years to 35 million years (Herrmann et al. 2004; Delabroye and Vecoli 2010). The Hirnantian stage occurred during the upper Ordovician Period and lasted approximately 1.4 million years, from 445.2 to 443.8 Ma (million years ago) (Herrmann et al. 2004). There is considerable evidence of the glacial environment’s initiation and development. The first was derived from isotopic data that tropical ocean temperatures were about

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five degrees Celsius cooler than they are today during the Late Ordovician; this would have been a significant factor that aided in glaciation (Finnegan 2011). The second piece of evidence is the decrease in sea level during the Late Ordovician period. There is considerable disagreement about the timing of sea level change, but there is some evidence that it began before the Ashgillian, making it a contributing factor to glaciation (Herrmann et al. 2004). A decrease in sea level makes more land available for ice sheet growth (Herrmann et al. 2004). The sea level generally fell by at least 50–100 m during the Late Ordovician continental glaciation, which was centred on the South Pole (Berry and Boucot 1973). The extinction of graptolites is the third point of evidence. A stratigraphic study of the Ordovician–Silurian contact shows that graptolites were significantly reduced during the glacial maximum (Cocks and Rickards 1988). Graptolite mass mortality occurred at the end of the Ordovician period when nearly all Ordovician–Silurian boundary sequences vanished (Koren 1991). Furthermore, in the Late Ordovician, graptolites were nearly wiped out (Melchin and Mitchell 1988). The fourth piece of evidence is that it coincided with a significant mass extinction of nearly 61% of marine life or fauna (e.g., graptolites, Brachiopods, and trilobites) (Sheehan 2001). The fifth indicator is tectonic uplift: Tectonic movement is the primary cause of the glacial episode. Tectonics may be responsible for both increased cooling and decreased temperature. This tectonic movement may be related to the Taconic movement that occurred at the end of the Ordovician Period. This movement caused a hiatus between the Ordovician and Silurian periods. This hiatus can be seen in Siani between the top of the Ordovician Naqus Formation and the overlying Lower Cretaceous Malha Formation. Furthermore, there was a hiatus in Saudi Arabia between the top of the Middle Ordovician. 4. Continental glacial environment: During the Ordovician, Gondwana drifted so far south that by the end of the period, the continent was close to the South Pole (Bandel and Salmeh 2013). Late Ordovician glaciation was first described in north Africa, for example, in the Hoggar Mountains of southern Algeria (Buef et al. 1971). Many other studies on glaciation in northern and western Africa were recognized (Craig et al. 2008). The modes of origin of the palaeovalley are notable features of the Ordovician glaciation. These palaeovalleys have been recorded in Mauritania, Algeria, Libya, Saudi Arabia, and Jordan (Buef et al. 1971; Deynoux 1985; Vaslet 1990; Abed et al. 1993; Powell et al. 1994; Ghienne and Deynoux 1998; Hirst et al. 2002; Le Heron et al. 2004). In Sadi Arabia, such paleovalleys were recognized, in which the Late Ordovician Zarqa and Sarah formations were deposited (Vaslet 1990). Furthermore, glacial sediments of the Ammar Formation were deposited in paleovalleys (Abed et al. 1993). In Egypt, four paleovalleys were recognized as filled with the glacial sediments of the Naqus Formation in Siani (Fig. 4.13). The first paleovalley is between Gebel El Zeit and Gebel Ekma, between the latter and before Wadi Feiran; it has been omitted. The second paleovalley formed at Wadi Feiran (the entrance to Wadi Mokttab) and was overlooked until Saint Katherine. It is also ignored to the northeast of Um Bogma. The third paleovalley is north of Saint Katherine and stretches from Gebel Gunna to Ras El Naqab to the south of Taba (Fig. 4.13). The fourth paleovalley

References

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occurs at Ras El Naqab (Fig. 4.14). It is not present north of the last location in the Taba area. These paleovalleys explain the nature of the occurrence of the glacial sediments of the Naqus Formation in Sinai. This presence of the Naqus Formation, filling the paleovalleys mentioned above, will change geologists’ thinking about the existence of the Naqus Formation in Sinai. Because most geologists, if not all, believed that the Naqus Formation usually occurs as bedded strata conformable above the Cambrian Araba Formation. Another lithological characteristic of the glacial sediments is the presence of diamictites and tillites, known from Saudi Arabia. It may have partly been derived from central African glaciers and transported by a fluvial drainage system. Scratch marks and grooves on the bedrock were formed when ice with rocks frozen into it migrated away from the area where the glaciers grew in thickness, towards lower land, and scraped the ground on their way. Diamictites are recognized in the Naqus Formation at Wadi Feiran (Fig. 4.12a, b). Glaciations and deposition of much ice on the continent were connected to a substantial fall in sea level because the water forming the ice had been part of the ocean water. Qasim Formation and the overlying Upper Ordovician Zarqa and Sarah formations.

References Abed, A. M.; Makhouf, I. M.; Amireh, B. S.; Khalil, B., 1993. Upper Ordovician glacial deposits in southern Jordan. Episodes, 16, p. 316–327. Amireh, B. S.; Chneiderb. W.S.; Abed, A. M., 2001. Fluvial-shallow marine-glaciofluvial depositional environments of the Ordovician System in Jordan. Jour. As. Ear. Sci., 19: 45–60. Bandel. K., Salameh, E., 2013. Geologic Development of Jordan. Evolution of its Rocks and Life. The Hashemite Kingdom of Jordan. The deposit Number at the National history, 960/3/2013. Berry, W. B. N.; A. J. Boucot, A., 1973. Glacio-eustatic control of Late Ordovician-Early Silurian platform sedimentation and faunal change, Geol. Soc. Am. Bull. 84, 275–284. Beuf, S.; Biju-Duval, B.; de Charpal, O.; Rognon, P.; Gariel, O. Bennacef, A., 1971. Les Grès du Palaéozoique inferiéur au Sahara. Editions Technip, Paris, 464 pp. Bishop, W. F., 1975. Geology of Tunisia and adjacent parts of Algeria and Libya: Am. Assoc. Petr. Geol. Bulletin, 59: 413–450 pp. Boggs, S., Jr,. 2009, Principles of Sedimentology and Stratigraphy Fourth Edition. New Jersey: Pearson Prentice Hall. 676 pp. Brugge, N. 2020. Structure and Geology of Jebel Uweinat in the three-country triangle EgyptSudan-Libya, internet report. Carbo. Evap. 30, 207–227 pp. “Chart/Time Scale”. International Commission on Stratigraphy (ICS, 2021). Clark-Lowes, D. D., 1980. Sedimentology and mineralization potential of Saq and Tabouk formations. Imperial Coll. Sc. Tech. Open-File Report CRC/IC7, 88 P. Clark-Lowes, D.D., 2005. Arabian glacial deposits: recognition of palaeovalleys within the Upper Ordovician Sarah Formation, Al Qasim district, Saudi Arabia. Proceedings of the Geologists’ Association 116: 331–347. Cocks, L. R. M.; Rickards, R. B., 1988. A Global Analysis of the Ordovician-Silurian Boundary, British Museum (Natural History) Bulletin 43 (Geology Series), 394 pp. Collomb, G. R., 1962. Etude geologique de Jebel Fezzan et de sa bordure Paleozoiquue. Notes et Mem. Comp. Fr. Petrole, No. 1 35 p., 1carte, Eng. sum., Paris.

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Cook, J. E.; Goodwin, L. B.; Boutt, D. F., 2011. Systematic diagenetic changes in grain scale morphology and permeability of a quartz-cemented quartz arenite. Am. Assoc. Petro. Geol. 95: 1067–1088 pp. Craig, J.1; Rizzi, C.1; Said, F., Thusu, B.; Luning, S4; Asball, A. L., Keeley, M.L.; Bell, J. F., Durham, M.J., Eales, M.H. Beswetherick, S., Hamblett, C. 2008. https://www.researchgate.net/ publication/238661584. Delabroye, A.; Vecoli, M., 2010. The end-Ordovician glaciation and the Hirnantian Stage: A global review and questions about the Late Ordovician event stratigraphy. Earth-Science Reviews. 98: 269–282 pp. Deynoux, M., 1985. Terrestrial or waterlain glacial diamictites? Three case studies from the late Precambrian and late Ordovician glacial drifts in West Africa. Palaeoge, Palaeocl., Palaeoec., Volume 51: 97–141. Dott, R.H., 2003. The importance of eolian abrasion is supermature quartz sandstones and the paradox of weathering on vegetation-free landscapes. J. Geo. 111: 387–405. El Kelani, A.; El Hag, I.; Bakry, H.; Shaira, M., 1999. Type and stratotype section of the Paleozoic in Sinai, Sp. Pub. No. 77, 94 p. EGSMA, Cairo. Finnegan, S., 2011. The Magnitude and Duration of the Late Ordovician-Early Silurian Glaciation. Science. 331: 903–906 pp. Ghienne, J. F.; Deynoux, M., 1998. Large-scale channel fill structures in Late Ordovician glacial deposits in Mauritania, western Sahara. Sed. Geol., 119, p. 141–159. Glen, R. A.; Meffre, S.; Scott, R. J., 2007. Benambran Orogeny in the Eastern Lachlan Orogen, Australia. Aust. Jour. Ear. Sci. 54: 385–415. Gvirtzman, G.; Weissbrod, 1984. The Hercynian giant line of Helez and the Late Paleozoic history of the Levant. In Dixon, J. E; Robertson (Eds.). The geologic evolution of the Eastern Mediterranean Geol. Soc. London, Spec. Pub. 17, 117 pp. Hallett, D. 2002. Petroleum Geology of Libya, Second Edition. PP. 427. Hasan, A.A., 1967. A new Carboniferous occurrence of Abu Durba, Sinai, Egypt. Six Arab Petrol. Conf. Baghdad, 1–8 pp. Herrmann, A. D.; Patzkowsky, M. E.; Pollard, D., 2004. The impact of paleogeography, pCO2, poleward ocean heat transport, and sea level change on global cooling during the Late Ordovician. Palaeogeo., Palaeoclim., Palaeoeco. 206: 59–74 pp. Hirst, J. P. P.; Benbakir, A.; Payne, D. F.; Westlake, I. R., 2002. Tunnel Valleys and Density Flow Processes in the upper Ordovician glacial succession, Illizi Basin, Algeria: influence on reservoir quality, Jour. Petr. Geol., 25: 297–324. International Chronostratigraphic Chart v.2015/01. International Commission on Stratigraphy. January 2015. Issawi, B. 2005. Archean-Panerozoic birth and development of the Egyptian land. Fir. Inter. Geol. Tethys, Cairo Univ. 339–358 pp. Issawi, B.; Francis, M. H.; Youssef, A.A.A.; Osaman, R., 2009. The Phanerozoic Geology of Egypt: A Geodynamic Approach. Egypt. Geol. Surv. Paper No. 81, 589 pp. Jeffrey, P. C.; Hibbard, J. P.; Paul, S. J., 2009. “Early Ordovician rifting of Avalonia and birth of the Rheic Ocean: U–Pb detrital zircon constraints from Newfoundland”. Jour. Geol. Soc., 166 (3): 501–515. Khalifa, M. A., 2015. Glacial and post-glacial deposits of the Unayzah Formation. Carbon. Evap., 30:207–227. Khalifa, M. A., 2017. General characteristics of quartz arenite types and their role in the recognition of sequence stratigraphic boundaries in ancient coastal and near shore sediments. A case study from Egypt and Saudi Arabia. Jour. Afr. Ear. Sciences 130: 274–292. Klitzsch, E., 1968. Outline of the geology of Libya, in Geology and archaeology of northern Cyrenaica, Libya: Petroleum Exploration Society of Libya, 10th Annual Field Conference, 71–78 pp. Koop, W. J., and Stoneley, R., Subsidence history. Klitzsch, E. 1990. Paleozoic. In Said. R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 393–406.

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Klitzsch, E.; Lejal-Nicol, A., 1984. Flora and fauna from strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Berl. Geowiss. Abh. 50 (A):47–79. Klitzsch, E.; Schandelmeier, H., 1990. Southwestern desert. In Said, R. (Ed.): The Geology of Egypt. Balkema, Rotterdam, Brookfield: 249–257. Klitzsch, E.; Wycisk, P., 1987. Geology of sedimentary basins of northern Sudan and bordering areas. Berl. Geowiss. Abh. 75 (A)1: 97–136. Klitzsch, E. and Ziegert, H., (2000). Short nortes and guidebook on the Geology of the Dor el Gussa-Jabal Bin Ghanimah area. Sedimentary Basins of Libya, Second Symposium, Geology of Northwest Libya Fieldtrip, November 9–13, 2000, 52 pp. Earth Science Society of Libya. Kora, M., 1991. Lithostratigraphy of the Early Paleozoic succession in Ras EI Naqab area, eastcentral Sinai, Egypt. News. Stratigr. Berlin. Stuttgart, 24: 45–57. Koren, T. N., 1991. Evolutionary crisis of the Ashgill graptolites, in Advances in Ordovician Geology. In Barnes, C.R.; Williams, S. H. (EdS.), Geological Survey of Canada Paper 90-9, 157–164. Lapworth, C., 1879. “On the Tripartite Classification of the Lower Palaeozoic Rocks,” Geological Magazine, new series, 6: 1–15 pp. Le Heron, D.; Sutcliffe, O.; Bourgig, K.; Craig, J. Visentin, C.; Whington, R. 2004. Sedimentary architecture of Upper Ordovician tunnel valleys Gargaf Arch, Libya: Implications for the genesis of a hydrocarbon reservoir. GeoArabia, Vol. 9, No. 2, Gulf Petrolink, Bahrain. Makhlouf, I.M., 1992. Depositional environments and facies in the Dubaydib and Tubeiliyat sandstones, Southern Desert, Jordan. Subsurface Geology Bulletin 3 (Natural Resources Authority). Makhlouf, I, Abu Hamad, A., Basem, B., 2017. Sedimentology and depositional environments of the Ordovician Umm Sahm Sandstone Formation in southern Jordan. Arab J. Geosci., 10:178 pp. Martino, R. L., 1989. Trace fossils from marginal marine facies of the Kanawha Formation (Middle Pennsylvanian), west Virginia. J. Paleont., 63: 389–403 pp. Massa, D.; Collomb, G. R, 1960. Observations nouvelles sur la region d’Aouinet Ouenine et d u Djebel Fezzan (Libye). 21st Int. Geol. Congr. Report, Pt, 12, pp. 65–73, Copenhagen. Melchin, M.J.; Mitchell, C.E., 1988. Late Ordovician mass extinction among the Graptoloidea, in Abstracts of the Fifth International Symposium on the Ordovician System. In Williams, H. S.; Barnes, C.R. (Eds.), St. John’s, Newfoundland, p. 58. Munnecke, A.; Calner, M.; Harper, D. A. T.; Servais, T., 2010. Ordovician and Silurian sea-water chemistry, sea level, and climate: A synopsis. Paleogeography, Paleoclimatology, Paleoecology. 296 (3–4): 389–413 pp. Nance, R. D.; Gutiérrez-Alonso, G.; Keppie, J. D.; Linnemann, U.; Murphy, J. B.; Quesada, C.; Strachan, R. A.; Woodcock, N. H., 2012. A brief history of the Rheic Ocean. Geoscience Frontiers. 3 (2): 125–135. Nichols, G., 2009. Sedimentology and Stratigraphy, Second Edition. West Sussex: John Wiley & Sons Ltd. Omer, M. F., 2012. The sedimentology and geochemistry of the Khabour Formation Northern Iraq, Unpublisher Ph.D. thesis, 201 pp. University of Baghdad, Baghdad, Iraq. Osman, R., Ahmed, S.M., Khater, T., 2002. The stratigraphy and facies of Wadi Gabgaba and its surroundings with an emphases on the Lower Paleozoic glaciation. Sixth Inter. Conf. Arab World, Cairo Univ. Egypt, 2:469–482. Porada, P.; Lenton, T. M.; Pohl, A.; Weber, B.; Mander, L.; Donnadieu, Y.; Beer, C.; Pöschl, U.; Kleidon, A., 2016. “High potential for weathering and climate effects of non-vascular vegetation in the Late Ordovician”. Nature Communications. 7 (1): 12113. Powell, J.H., Moh’d, B.K. & Masri, A. 1994. Late Ordovician–Early Silurian glaciofluvial deposits preserved in palaeovalleys in South Jordan. - Sedimentary Geology 89, 303–314 pp. Ramos, V. A., 2018. “The Famatinian Orogen Along the Protomargin of Western Gondwana: Evidence for a Nearly Continuous Ordovician Magmatic Arc Between Venezuela and Argentina”. The Evolution of the Chilean-Argentinean Andes. Springer Earth System. Sciences: 133–161 pp.

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Said, R., 1971. Explanatory notes to accompany the geological map of Egypt. Geol. Surv., paper 56, 123 pp. Samuel MD, Moussa HE, Azer MK, 2001. Geochemistry and petrogenesis of Iqna Shar, a volcanic rocks Central Sinai Egypt. Egypt J Geol 45:921–940. Selley, R. C., 2000. Applied Sedimentology. Florida: Academic Press. Senalp, M.; Al-Duaiji, A. A., 2001. Qasim Formation: Ordovician Storm- and Tide-Dominated Shallow-Marine Siliciclastic Sequences, Central Saudi Arabia, GeoArabia, 6: 233–268. Senlap, P. Tetiker, S. 2020. Sedimentology and hydrocarbon potential of the Late Ordovician glacial deposits on the Arabian Platform and southeastern Turkey. Turk. J Ear. Sci., 29: 1–46. Sheehan, P. M., 2001. The Late Ordovician Mass Extinction. Annual Review of Earth and Planetary Sciences. 29: 331–364 pp. Torsvik, T. H.; Cocks, L.; Robin, M., 2017. Earth history and paleogeography. Cambridge, United Kingdom: Cambridge University Press. p. 102. Turner, B. R.; Makhlouf, I. M.; Armstrong, H. A., 2005. Late Ordovician (Ashgillian) glacial deposits in southern Jordan. Sed. Geol. 181: 73–91. Van Staal, C. R.; Hatcher, R.D., Jr., 2010. “Global setting of Ordovician orogenesis”. Geol Soc. Am. Spec. Pap. 466: 1–11. Vaslet, D., 1987. Early Paleozoic Glacial Deposits of Saudi Arabia; A Lithostratigraphic Revision: Saudi Arabian Directorate General for Mineral Resources. Technical Record BRGM-TR-07-1, 24 p. Vaslet, D., 1989. Late Ordovician Glacial Deposits in Saudi Arabia: A Lithostratigraphic Revision of the Early Paleozoic Succession. Jeddah, Saudi Arabia: Saudi Arabian Deputy Ministry for Mineral Resources Professional Papers. Vaslet, D., 1990. Upper glacial deposits in Saudi Arabia. Episodes, 13: 147–161. Vaslet, D.; Berthiaus, A.; Le Start, P.; Kollogg, K.S.; Vincent, P.L., 1987. Geologic map of Baqa quadrangle, sheet 27F, Kindom of Saudi Arabia, Saudi Arabian Ministry for Mineral Resources Geoscience Map GM-116 A, scale 1: 250,000. Wetzel, R., 1950. Khabour Quartzite Formation. In Bellen, R.C.; Van Dunnington, H.V.; Wetzel, R.; Morten, D. (Eds.), Lexique stratigraphique (Vol. 3). Paris, France: International Asia. Williams, P. L.; Vaslet, D.; Johnson, R. P.; Berthiaux, A.; Le Strat, P., 1986. Geologic Map of the Jabal Habashi Quadrangle, Sheet 26F, Kingdom of Saudi Arabia. Jeddah, Saudi Arabia: South Arabian Deputy Ministry for Mineral Resources Geoscience Map Series.

Chapter 5

The Silurian Period

Abstract This chapter describes three Silurian rock units in Egypt: the Um Ras Formation, which is visible on the surface, and the Kohla and Basour formations, which are found in the subsurface in the Siwa basin in the northwestern Desert. The Um Ras formation is found in the Um Ras Plateau, northeast of Gebel Uweinat. It comprises a non-cyclic sequence of pale reddish massive sandstone with thin intercalations of horizontally bedded sandstone enriched with vertical burrows (Skolithos Sp.). Harlania harlania and Cruziana acacensis are Late Silurian fossils found in the Um Ras Formation. The Kohla and Basour formations were discovered in the subsurface of the Siwa basin in the northwestern Desert. They are composed of kaolinitic sandstone with thin siltstone and conglomerate beds. They range in age from the Early Silurian to the Late Silurian. These rocks are linked to their counterparts in Libya, Jordan, Saudi Arabia, and Iraq. A paleo-environmental map is created to depict the various depositional environments. Keywords Um Ras · Kohla · Basur · Gebel Uweinat · Egypt · Silurian · Skolithos · Libya · Saudi Arabia · Jordan · Iraq

5.1 Introduction 5.1.1 Definition The Silurian is the geologic period and system spanning 24.6 million years, starting from the advent of the Ordovician Period (443.8 Mya) to the beginni ng of the Devonian Period (419.2 Mya) (ICC, 2015). It is considered the shortest period of the Paleozoic Era. The Silurian period was first identified by British geologist Murchison (1835), who examined fossil-bearing sedimentary rock strata in south Wales.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_5

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5.1.2 Classification This period is subdivided into four epochs, from base to top are: Pˇrídolí, Ludlow (Gorstian and Ludfordian),Wenlock ( Homerian and Sheinwoodian), and Llandovery (Telychian, Aeronian and (Rhuddanian) (Fig. 5.1).

5.1.3 Fauna and Flora The Silurian was the first period to see megafossils of extensive terrestrial biota in moss-like miniature forests along lakes and streams (Axel et al. 2010). The first bony fish, represented by the Acanthodians covered with bony scales. Fish reached considerable diversity and developed movable jaws. A diverse fauna of eurypterids (sea scorpions), some of them reach several meters in length and survive in the shallow Silurian seas of North America and New York state. Furthermore, brachiopods, bryozoa, molluscs, hederelloids, tentaculitoids, crinoids, and trilobites were abundant and diverse (Vinn and Motus 2008; Vinn et al. 2014). Reef abundance was patchy, sometimes, fossils are frequent, but at other points, they are virtually absent from the rock record (Axel et al. 2010). The earliest-known animals fully adapted to terrestrial conditions appeared during the Mid-Silurian, including the millipede Pneumodesmus (Selden and Read 2008).

5.1.4 Tectonics and Paleogeography At this time, the supercontinent Gondwana covered the equator and most of the southern hemisphere. Also, a large ocean occupied most of the northern half of the globe (Axel et al. 2010). The high sea levels of the Silurian and the relatively flat land (with few significant mountain belts) resulted in several island chains and, thus, a rich diversity of environmental settings (Axel et al. 2010). During the Silurian, Gondwana continued a slow southward drift to high southern latitudes. However, there is evidence that the Silurian icecaps were less extensive than those of the lateOrdovician glaciation (Gambacorta et al. 2019). The southern continents remained united during this period. The melting of icecaps and glaciers contributed to a rise in sea level, recognizable from the fact that Silurian sediments overlie eroded Ordovician sediments, forming an unconformity. The continents of Avalonia, Baltica, and Laurentia drifted together near the equator, starting the formation of a second supercontinent known as Euramerica.

5.1 Introduction Fig. 5.1 Time chart showing the classification of the Silurian period (After International Chronostratigraphic Chart v.2015/01)

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5.2 The Silurian Rocks in Egypt The Silurian rock units in Egypt include the Um Ras Formation (exposed), the Kohla, and the Basur formations (in the northwestern Desert subsurface).

5.2.1 The Um Ras Formation 5.2.1.1

Definition

The term Um Ras Formation was established by Klitzsch and Lejal-Nicol (1984) to describe the Silurian thick fluviatile and marine sandstone between Gebel Uweinat and the Abu Ras plateau, west of Gilf Kebir plateau, southwestern Desert (Fig. 5.2). Gilf al-Kebir is a plateau in the New Valley Governorate in the southwest corner of Egypt, and southeast Libya. Its name translates as “the Great Barrier, covering an area of about 7,770 km2 (3,000 miles2 ). It rises 300 m (980 ft) from the Libyan Desert (Fig. 5.2). The name Gilf Kebir was given to the plateau by Prince Kamal el Dine Hussein in 1925, the Ancestors of Muhamed Ali Basha. Due to the massive nature of Um Ras Formation, early hunter-gatherers who lived in this remote area, record their daily lives on the rocks, such as drawing of the cattels (Fig. 5.3a, b).

5.2.1.2

Stratigraphic Contact

In general, this formation occurs above the Ordovician Karkur Talh Formation and underlies the Devonian Tadrart Formation (Fig. 5.4). However, it nonconformably rests above the basement rocks at approximately 180 km south of the type locality, northeastern Gebel Uweinat, near the Libyan border (Fig. 5.5a) (Klitzsch and LejalNicol 1984; Klitzsch 1990). In the same latter locality, it unconformably underlies the fluvial sandstone of the probably DevonianTadrart Formation (Fig. 5.5b) (Klitzsch 1990). It has a thickness of approximately 75–80 m.

5.2.1.3

Lithology

The rocks of the Um-Ras Formation are comprised of non-cyclic, pale reddish massive sandstone (Klitzsch and Lejal-Nichol 1984) (Figs. 5.6, 5.7). The sandstones are medium- to coarse-grained sandstone is moderately sorted and exhibits smallto large-scale tabular to planar cross-stratification (Fig. 5.8a). Few beds of horizontal stratification, and low-angle cross-bedding alternate with the massive sandstone (Fig. 5.8b). Several siltstone beds are intensively burrowed by Skolithos sp (Fig. 5.9a). Others contain Harlania Harlania Desio and Cruziana acacensis Seilacher (Klitzsch 1990). Deformed cross-bedding is frequent and may occur in successively

5.2 The Silurian Rocks in Egypt

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Fig. 5.2 Satellite image showing the Um Ras plateau, the type locality of Um Ras Formation, Gilf Kebir, northeast Gebel Uweinat, southwestern Desert

superimposed sets (Klitzsch and Lejal Nichol 1984). The style of deformation ranges from buckled to overturned and convolute forests (Fig. 5.9b). In the Subsurface at Sheiba-1 well, the Silurian rocks comprise an intercalation of shale, siltstone, and thin limestone (Hantar 1990).

5.2.1.4

Thickness and Distribution

This formation covers a broad surface exposure in the southwestern Desert (Klitzsch and Wycisk 1987). The total thickness of the Umm Ras Formation in northwestern Egypt is still being determined because the available data needs to be more comprehensive. However, in the southwestern Desert between Gebel Uweinat and the Abu Ras Plateau, west of the Gilf Kebir, this formation attains about 400 m in thickness (Klitzsch 1990). The minimum thickness ranges from 200 to 300 m. This formation assumes to be 70 m thick within the Great Sand Sea (Ouda 2021). This formation is also encountered in the subsurface in two wells (Foram-1 and Sheiba1), the northwestern Desert (Shrank 1984, 1987). In the subsurface (northwestern

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Fig. 5.3 a and b Field photographs showing the drawing of cattle on the massive sandstone of the Silurian Um Ras Formation, Gilf Kebir Plateau, northeast Gebel Uweinat, southwestern Desert (After Brugge 2020)

Desert), Silurian sediments were encountered in Sheiba 0.1 well on the Sharib-Sheiba basement high (Hantar 1990).

5.2.1.5

Age Assignment and Correlation

The age of this formation has been given Silurian age by Klitzsch and LejalNicol (1984), based on the presence of Harlania harlania (Fig. 5.10a) and Cruziana acacensis (Fig. 5.10b). Moreover, ichnofossils association and sedimentological characteristics indicate probably Ludiow age (Late Silurian) (Klitzsch 1978, 1979, 1981]. This formation can be correlated with the Silurian Akakus Formation in the Kufra Basin in Libya (Klitzsch 1990), Khishsha Formation in Jordan, Sharawra Formation in Saudi Arabia and with the upper part of the Akkas Formation in Iraq (Fig. 5.11).

5.3 The Kohla Formation

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Fig. 5.4 East–west profile showing the stratigraphic position of the Ordovician Karkur Talh, Silurian Um Ras, and Devonian Tadrart formation, northeast Gebel Uweinat southwestern Desert, Egypt (after Klitzsch and Lejal Nicol 1984)

5.3 The Kohla Formation 5.3.1 Definition The Kohla Formation was named by Keeley (1989) to describe the clastic sequence occurring in the subsurface in the Kohla area, north of Siwa. The type well is Zeitoun1 (interval: 2616–3242 m) (Fig. 5.4).

5.3.2 Stratigraphic Contact The Kohla Formation is believed to lie unconformably over a glaciated surface, forming the top of the Shifa Formation. The glacial tillite recorded by Beall and Squyres (1980) beneath Silurian elastics in the southern Western Desert may conform to the Silurian sequence above. The upper junction with the Basur Formation is everywhere conformable, marked by an abrupt upward increase in clastic grain size.

5.3.3 Lithology This formation consists of a few tillite glacial sediments at the base, which may be derived from the top of the underlying Shifts Formation (Keeley 1989). In this

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Fig. 5.5 a Field photograph manifesting the lower nonconformable contact of the Silurian Um Ras Formation with the underlying Precambrian basement rocks, Um Ras plateau, west of Gilf Kebir, southwestern Desert (after Klitzsch and Lejal Nicol 1984; Brugge 2020). b Field photograph manifesting the upper unconformable contact of the Silurian Um Ras Formation with the overlying Devonian Tadrart Formation, Um Ras plateau, west of Gilf Kebir, southwestern Desert (after Klitzsch and Lejal Nicol 1984; Brugge 2020)

formation, the siltstone is the dominant lithology, with only minor interbeds of sandstone and mudstone. Such lithofacies were arranged vertically into fining-upward cycles (Fig. 5.4b). Each cycle begins with thin sandstone beds, followed upward by thick-bedded siltstone, and is capped by mudstone (Fig. 5.4b). The sandstones are unfossiliferous, medium- to coarse-grained, rarely brick red, partly friable, porous, kaolinitic, and partly micaceous. Grey marine claystone is known only from the east, within the centre of the Ghazalat Basin (Keeley 1989).

5.3 The Kohla Formation

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Fig. 5.6 Lithostratigraphic sections of the Silurian Um Ras Formation at Um Ras plateau, west of Gilf Kebir, southwestern Desert (after Klitzsch and Lejal Nicol 1984) (a). The Silurian Kohla Formation in subsurface, Siwa basin, northwestern Desert (after Keeley 1989) (b), the Silurian Basur Formation, Siwa Basin, northwestern Desert (after Keeley 1989) (c)

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Fig. 5.7 Field photograph showing the general view of the Silurian Um Ras Formation, Abu Ras Plateau, west of Gilf Kebir plateau, southwestern Desert (after Klitzsch and Wycisk 1987; Brugge 2020). Notice the massive non-cyclic feature, pale reddish to brown coarse-grained sandstone

5.3.4 Thickness and Distribution The Kohla Formation has been identified in many wells drilled in the Siwa Basin. It has a thickness ranging from 80 to 600 m (Keeley 1989) and occurs between depth intervals of 2616 to 3242 m.

5.3.5 Age Assignment and Correlation This formation assigned a Late Silurian (Early Ludlovian, Keeley 1989). The glacial sediments at the base of the Silurian Kohla Formation can also be correlated with the Upper Ordovician- Early Silurian Gabgaba Formation at Wadi Gabgaba area, south Eastern Desert) (Issawi and Osman 2000, Issawi 2005, Osman et al. 2002). Keeley (1989) also attributed the glacial sediments of the Shifa Formation can be correlated with the Ordovician Silurian glacial tillite recorded in the south Western

5.4 The Basur Formation

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Fig. 5.8 a Field photograph showing Planar cross-bedded, brown sandstone of the Silurian Um Ras Formation, Abu Ras Plateau, west of Gilf Kebir plateau, southwestern Desert (after Klitzsch and Wycisk 1987; Brugge 2020). b Field photograph illustrating the thin horizontal stratification of the Um Ras Formation, Abu Ras Plateau, west of Gilf Kebir plateau, southwestern Desert (after Klitzsch and Wycisk 1987; Brugge 2020)

Desert (Beall and Squyres 1980) and with the Naqus Formation in Sinai [38]. It also correlated with the Llandovery (Early Silurian) Tanezzuft Formation in western Libya (Issawi and Jux 1982), with the Mudawwara Formation In Jordan, the Qusaiba Formation in Saudi Arabia and with the Akkas Formation in Iraq (Fig. 5.11).

5.4 The Basur Formation 5.4.1 Definition The Basur Formation was named by Keeley (1989) to describe the sandstone with an extra-formational conglomerate. Its type well occurs at El Basur-1 well, between intervals 2549 and 3165 m (Fig. 5.4c).

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Fig. 5.9 a Field photograph unravel the bioturbated sandstone of the Um Ras Formation, Abu Ras Plateau, west of Gilf Kebir plateau, southwestern Desert (after Klitzsch and Wycisk 1987; Brugge 2020). b Field photograph unravel the voluminous recumbent cross-bedded or syndepositional deformed sandstone of the Um Ras Formation, Abu Ras Plateau, west of Gilf Kebir plateau, southwestern Desert (after Klitzsch and Wycisk 1987; Brugge 2020)

5.4.2 Stratigraphic Contact The lower boundary of the Basur Formation conformably overlies the Kohla Formation. At the same time, the nature of the upper boundary is somewhat more problematic (Keeley 1989). Its upper boundary was eroded, probably showing an unconformable relation with the overlying Devonian Zeitoun Formation (Keeley 1989). Therefore, a sharp change in lithofacies occurs across the Basur—Zeitoun formations boundary, marking the boundary between two major regressive cycles. Throughout the area, the character of this boundary remains essentially constant (Keeley 1989).

5.4.3 Lithology This formation comprises a sequence of primarily sandstones, with minor interbeds of siltstone and extra-formational (Fig. 5.4c). Alluvial fan and braided stream deposits

5.4 The Basur Formation

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Fig. 5.10 a Field photograph illustrating the Harlania harlania trace fossil in the Um Ras Formation, Um Ras plateau, west of Gilf Kebir plateau, southwestern Desert (after Seilacher 1990). b Field photograph illustrating the Cruziana acacensis trace fossil in the Um Ras Formation, Um Ras plateau, west of Gilf Kebir plateau, southwestern Desert (after Seilacher 1990)

are interpreted as well represented, spreading out from the confining basement arches (Keeley 1989). Thin marginal marine siltstones are uncommon, even within the depocentre of the Ghazalat Basin, but are regionally widespread (Gueinn and Rasll 1986).

5.4.4 Thickness and Distribution The formation ranged in thickness from about 400 m to more than 700 m and was unaffected by subsequent erosion (Keeley 1989).

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Fig. 5.11 Correlation of the Um Ras Formation with corresponding rock units in Libya (Tanzuft and Akakus formations), in Jordan (Mudawwara and Khishshba formations), in Saudi Arabia (Qusaiba and Sharawra formations) and in Iraq (Akkas Formation)

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5.4.5 Age Assignment and Correlation A palynological investigation was performed within the upper part of the Basur Formation led to identification of floral assemblage, indicating Early Gedinnain to Ludlovian (Gueinn and Rasll 1986). This formationcanbe correlated with the Akakus Formation in Libya, Khishsha Formation in Jordan, Shrawra Formation in Saudi Arabia and with the Akkas Formation in Irqa (Fig. 5.11).

5.5 Silurain Rocks in Adjacent Countries 5.5.1 In Libya The Silurian rocks include two rock units, the Tanzuft and Akakus formations (Fig. 5.11a). The Tanzuft Formation was first defined by Desio (1936a) from 65 km north of Ghat on the western margin of the Murz uq Basin. The base of this formation is not exposed at this location, and its top is not defined. Therefore Klitzsch (1965) established a type section of the Tanzuft Formation 35 km south of Ghat in the Wadi Tanzuft at Takarkhouri, where a complete sequence is present. This formation shows unconformable relation with the underlying Mamuniyat Formation (Bellini and Massa 1980; Banerjee 1980). Its upper boundary is gradational and conformable with the overlying Akakus formation (Banerjee 1980). This formation comprises 370 m of dark-grey, marine graptolitic shales with thin siltstone and sandstone stringers. It has a wide distribution throughout North Africa and was deposited on a very irregular surface. Further east, the Tanzuft Formation is missed. The age of the Tanzuft Formation in this area is mid-Llandoverian, based on graptolites (Desio 1936a, b]. Akakus Formation: The term Akakus Formation was introduced by Desio (1936a) in Jabal Akakus in the Ghat. The lower contact is conformable with the underlying Tanzuft Formation, but the upper contact with the Devonian Tadrart Formation is distinctly unconformable. At the type locality, the Akakus Formation comprises 240 m of fine to medium-grained silty sandstone, thinly bedded. It frequently shows cross-bedded, with ripple and flute marks. A conspicuous horizon of ferruginous sandstone marks the top with convolute bedding. It contains the trace fossil Arthrophycus alleghaniensis, Cruziana, Sp. and Tigillites dufrenoyi. The Akakus Formation provides an excellent example of ichnostratigraphy and is characterized by the presence of Cruziana acacensis, indicating mid to late Silurian (Desio 1936a).

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5.5.2 In Jordan The Silurian rocks are represented by two rock units: the Mudawwara and the Khushsha formations (Fig. 5.11c). The Mudawwara Formation (Early Silurian) (Andrews 1991) assumes 220 m thick and conformably overlies the Upper Ordovician. This formation consists of offshore marine shale with graptolite and includes two horizons of hot shale, one of them occur in the basal part, while the second occurs in the upper part (Luning et al. 2000). The Khushsha Formation conformably overlies the Mudawwara Formation and is overlain by the Dubaydib Formation. It is made of red-brown argillaceous sandstone overlain by about 200 m of well-stratified, partly cross-bedded, dominantly medium- and coarse-grey and light-brown sandstone. Many of these strata are full of worm burrows and tracks of arthropods; some Onchus sp., which is a common fossil in the Upper Silurian, have been determined (Bender 1968; Andrews1991]. The Khushsha Formation was assigned Late Silurian (Luning et al. 2000).

5.5.3 In Saudi Arabia The Silurian rocks are studied under the term Qaliba Group (Janjou et al. 1996a). Its name is derived from Qaliba Town in the northwest of Saudi Arabia. This group includes three rock units from base to top: the Uqlah, Qusiaba, and Sharawra formations (Fig. 5.11d). The Uqla Formation was established by Janjou et al. (1996a) to describe Lower Silurian rocks in Wadi Uqlah, Qaliba region, northwest of Saudi Arabia. This formation unconformably overlies and underlies the Ordovician Habwan or Zarqa formation and the Qusaiba Formation, respectively (Fig. 5.9). Its thickness is reduced and ranges from 6 to 10 m and consists of two lithologic units. The lower is yellow fine- to medium-grained with faint cross-bedding to horizontal bedding, while the upper part is made up of pink fine-grained sandstone that usually contains vertical burrows (Janjou et al. 1996b). There are no fossils in this formation; it only contains trace fossils. However, Janjou et al. (1996b) assigned the Uqlah Formation to the Early Silurian (Early Llandoverian). The Qusaiba Formation was attributed to the Qusayba village in the Al Qasim region, central Saudi Arabia (Powers et al. 1966). This formation was named “Qusaiba shale member (Powers 1968; Clark-Lowes 1980; Al-Laboun 1982; Mahmoud et al. 1992). Recently, extensive studies in northwestern Saudi Arabia (Janjou et al. 1996c) gave rise to raising this member to formational status in the Qalibah Group and its subdivision into five lithologic units (Janjou et al. 1996b). The lower contact is unconformable with the underlying Sarah Formation, while its upper contact is also unconformable with the overlying Sharawra Formation. This formation assumes about 482 m and consists of five sedimentary cycles, each of which begins with black, green clayey, silty claystone with thin intercalation with micaceous siltstone. This sequence is followed by fine-grained sandstone (Fig. 5.9). In central and northwestern Saudi Arabia, Qusaiba

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Formation was assigned to the Llandoverian (Early Silurian) based on trilobites, graptolites, and chitinozoans (Clark-Lowes 1980; El-Khayal 1985, 1987; Mahmoud et al. 1992; Aoudah and Al Hajri 1994; Janjou et al. 1996b). The Sharawra Formation was derived from Jabal Sharawra in the Tabuk area, northwest of Saudi Arabia (Roach 1954). Previous studies named it Sharawra Member of the Tabuk Formation (Roach 1954; Steineke et al. 1958; Powers et al. 1966; Clark-Lowes 1980; Al-Laboun 1982, 1986; Bahafzallah et al. 1981a; Vaslet et al. 1987). Its lower boundary unconformably overlies the Qusaiba Formation, while its upper boundary disconformably underlies the Devonian Tawil Formation of the Huj Group. It assumes 350 m thick at its type locality and comprises an interaction of claystone, siltstone, and fine-grained sandstone. The siltstone and sandstone are enriched with skolithos burrows and Cruziana trace fossils (Fig. 5.9). This formation was assigned Middle to Late Silurian (Aoudah and Al Hajri 1994; Janjou et al. 1996b).

5.5.4 In Iraq The Silurian rocks were named Akkas Formation by Al-Jubouri et al. (1997) in the subsurface in western Iraq in the Akkas-1 well, which is considered a type section of this formation (Fig. 5.11e). The Akkas Formation conformably overlies the Ordovician Khabour Formation and is overlain across a regional unconformity by the late Devonian Pirispiki Formation (Aqrawi 1998; Al-Juboury et al. 2021]. This formation comprises interbedded shales, siltstones, sandstones, and marls. It ranges in thickness from 340 to 2000 m. In general, it decreases in thickness northwards and eastwards and is locally absent across the Salman High by late Devonian unconformity and is absent in Palaeozoic outcrops in Northern Iraq (AL-Juboury 1997; Aqrawi et al. 2010).

5.6 Depositional Environments The Gondwanan passive margin was marked by continued subsidence during the Silurian period, reflecting the development of the proto-Tethyan ocean between Gondwana, Armorica, and Avalonia (Selley 1997; Craig et al. 2008). During this time, the North African region subsided significantly, resulting in a northerly dipping passive ramp margin with dominant structural axes oriented at a high angle to the plate margin (Schandelmeier and Reynolds 1997). The Cambro-Ordovician tectonic movements, in conjunction with Late Ordovician glacial and post-glacial processes, may have influenced the earliest Silurian relief, at least in part (Craig et al. 2008). Based on vertical lithological changes, faunal association, distribution, nondeposition or erosion, and thicknesses of Silurian rocks in Libya, Egypt, Jordan, Saudi Arabia, and Iraq, synchronous depositional environments in the countries as mentioned earlier,

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could be suggested, as illustrated in the proposed depositional map (Fig. 5.12). In the studied countries, two depositional phases can be deduced during the Silurian period. During the Early Silurian, the first or earlier phase included synchronous depositional environments such as (1) upland area and (2) outer neritic. (1) The uplifted region and cratonic areas cover the majority of the eastern part of the Western Desert (east of longitude 27 E), the Eastern Desert, Sinai, and western Jordan (Fig. 5.12). There is no record of Silurian rocks in these areas, either on the surface or in the subsurface. The missing Silurian rocks were most likely eroded due to the Caledonian movement, which culminated at the Silurian’s end and the Devonian’s beginning (Craig et al. 2008). (2). The Silurian strata in Jordan are restricted to a belt in eastern Jordan because the unit was removed in western Jordan by erosion following the Hercynian orogeny’s uplift (Luning et al. 2000). Nonetheless, facies and paleogeographic considerations indicate that marine Silurian strata were deposited much further west than the current eastern Jordanian sub-crop termination [Schandelmeier and Reynolds 1997; Luning et al. 2000). (2) The lower Silurian period is defined by deep subtidal or outer neritic environments, which resulted in the deposition of the Tanzuft Formation in Libya, Mudawara Formation in Jordan, Qusaiba Formation in Saudi Arabia, and the lower part of the Akkas Formation in Iraq (Fig. 5.10). The majority of the facies in this environment are very similar, consisting entirely of dark green to almost black shale with thin sandstone layers. Graptolites, trilobites, and chitinozoans abound. This facies type (outer neritic) was primarily caused by the melting of the glacial ice cap that formed in the Late Ordovician. This glacial melting resulted in a significant transgression during the Early Silurian period (Loydell 1998). The highest sea level recorded during the Silurian period was caused by a 100-m rise in sea level (Craig et al. 2008; Luning et al. 2000). This increase in sea level resulted in the deposition of massive and thick shales across much of northern Gondwana. Hot shale refers to green to black shale

Fig. 5.12 Paleogeographic map illustrating the possible depositional environments of the Lower and Upper Silurian rocks in Egypt, Libya, Jordan, Saudi Arabia and Iraq

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rocks enriched with graptolite (Davidson et al. 2000; Lüning et al. 2000, 2003a, b]. It can be found in many regions of North Africa and Arabia (the Tanzuft Formation in Libya, the Mudawara Formation in Jordan and the Qusaiba Formation in Saudi Arabia). The organic-rich shale can be found near or at the base of the Silurian shale unit (Lüning et al. 2000). This carbonaceous shale is known as the “lower hot shale unit” in Jordan and is located at the base of the Mudawwara shale (Andrews 1991). The Lower Silurian Tanzuft Formation is an essential stratigraphic unit in Libya for petroleum exploration (Hallett 2002). It has been established that it is one of the significant source rocks of North Africa, so its distribution and extent are critical. The black shales are typically composed of parallel lamination, implying the deposition of bed load or traction carpet (Allen 1982; Best and Bridge 1992). Because of their high organic matter content concentration, black shales are commonly used as valuable oil and gas resources (Uffmann et al. 2012; Zou 2013). In the Lower Paleozoic, hot black shales are considered hydrocarbon source rocks (Boote et al. 1998). The black shales, most likely associated with a large-scale anoxic event, are limited to paleo-depressions with pelitic sedimentation (Luning et al. 2005). These rocks are missing from paleohighs dominated by higher energy and marine to terrestrial sandstone–siltstone (Luning et al. 2005). This explains the absence of hot shale in Egypt because the Kohla sediments (Siwa Basin, northwestern Desert) consist of green-grey sandy clays with intercalation of the kaolinitic sandstone formation. It was formed on the flanks of paleohighs in Saudi Arabia’s Siluain Qusaiba Formation (Janjou et al. 1996b). In Jordan, the Silurian shale unit is known as the Mudawwara Formation and the Batra Formation (Powell 1989; Andrews 1991), and in western Iraq, the Silurian Akkas Formation (Al-Jubouri 1997). Graptolites are Silurian period index fossils that are found all over the world. They are most frequently found in shales and sandy clay rocks. Thus, graptolites are planktonic fossils in sediments deposited in relatively deep water with poor bottom circulation and low oxygen levels. The second depositional phase occurred during the Late Silurian or Late SilurianEarly Devonian period. The second depositional phase saw the formation of the one dominant depositional environment known as coastal marine (Fig. 5.12). It includes the Akakus Formation in Libya, the Um Ras Formation in northeast Gebel Uweinat, and the Basure Formation in Siwa Basin, northwestern Desert, the Khushsha Formation in Jordan, the Shawara Formation in Saudi Arabia, and the upper part of the Akkas Formation in Iraq. This uplift caused sea-level shallowing, resulting in a significant eustatic sea-level fall. This shallowing resulted in a shift in the depositional environment from deep subtidal marine to continental and coastal marine and nearshore facies in eastern and central North Africa from the Early Silurian (Craig et al. 2008). This regressive phase caused more interruptions in sedimentation, resulting in the formation of several erosional unconformities of varying importance across the region. The most significant of these unconformities are associated with Devonian (“Caledonian”) events in the base Devonian (Luning et al. 2003a, b). This hiatus was discovered in the Siwa Basin, northwestern Desert, between the Silurian Basur Formation and the Devonian Zeitoun Formation (Keeley 1989). In addition, an unconformity surface and a hiatus are observed in Saudi Arabia between the Upper

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Silurian Sharawra Formation and the Lower Devonia Tawil Formation. Most facies are nearshore clastic, with planar cross-bedded and recumbent sandstone, massive pebbly sandstone, and bioturbated sandstone (skolithos burrows) with thin conglomerate bends. This is seen in Egypt’s Um Ras Formation. The Um-Ras Formation deposits are described as non-cyclic, braided fluvial systems (Klitzsch andWycisk 1987). Cross-bedding with deformed edges is common and can occur in successively superimposed sets. Deformation styles range from buckled to overturned and convoluted forests. The planar stacked cross-bedded sandstone is attributed to high-stage deposition within transverse bars by straight-crested mega ripples. The facies association corresponds to shallow-water marine environments, comprised of upper and lower Shoreface marine depositional environments (Davis 2012; Siddiqui et al. 2017; Li et al. 2020). The abundant overturned forests or recumbent cross-bedding within these facies are thought to be caused by the current drag deformation of liquefied (or possibly fluidized) sand following an earthquake shock (Allen 2006). Skolihos burrows are commonly vertical, and Cruziana ichnofossils burrows are horizontal. Skolithos burrows date from the early Cambrian period (Desjardins et al. 2010) to the present (Gingras et al. 1999). They are found in sediments and sedimentary rocks primarily composed of sands and sandstones. They are usually of marine origin (Trewin and McNamara 1995) and are frequently associated with high-energy environments near the shoreline (Desjardins et al. 2010). Vertical Skolithos burrows can also be found in fluvial sediments (e.g., braided river deposits), where the periodic fluctuation of the river is observed. This periodic water fluctuation corresponds to tidal activity in shallow marine environments but also occurs in alluvial deposits over longer time intervals (Fitzgerald et al. 1986). Skolithos occurrences are common in nearshore to shoreface sandstone, a common association in high-energy and shallow marine environments in the lower Paleozoic (DeGiberta et al. 2011). This Skolithos ichnofacies is associated with prograding regressive sand belts during high-stand sea level conditions. Cruziana ichnofacies dominated by horizontal burrows and trails, on the other hand, are most abundant in transgressive intervals (DeGiberta et al. 2011). Two extinction pulses were observed, one at the beginning of the glaciation when the sea level was lower and the second when the glaciation abruptly ended, and the sea level rose. Graptolite preservation is three-dimensional in some layers of Jordan’s hot shale. The regionally widespread nature of early Silurian black graptolitic shale facies suggests that the sea was less well-oxygenated than was typically the case at other times. This primarily sandy facies persists in Saudi Arabia, reaching greater thickness here, and it has also been traced in the subsurface of the Jafr Basin.

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Keeley, M. L., 1994. Phanerozoic evolution of the basins of Northern Egypt and adjacent areas. Geol Rundsch (1994) 83: 728–742. Klitzsch, E. 1965. Ein profil aus dem typusgehebiet gotlandischer (westrand Murzuk becken, Libyen). Erdol u. Kohle. Deut, 18 : 605–607 pp. Klitzsch, E., 1978. Geologische Bearbeitung Sudwest Agyptens. Geol. Rundschau 67: 509–520 pp. Klitzsch, E., 1979. Zur Geologie des Gilf Kebir Gebietes in der Ostsahara. Clausthaler Geol. Abh. 30: 113–132 pp. Klitzsch, E., 1981. L ower Palaeozoic Rocks of Libya, Egypt and Sudan. In: Holland, C.H. (Ed.) Lower Palaeozoic of the Middle East and Southern Africa and Antarctica, 13 :1–164 pp. Wiley, Chichester. Klitzsch, E. 1990. Paleozoic. In Said. R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 393–406 pp. Klitzsch, E.; Lejal Nicol, A., 1984. Flora and fauna from a strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Berl. Geowiss. Abh. 50 (A):47–79. Klitzsch, E.; Wycisk, P., 1987. Geology of sedimentary basins of northern Sudan and bordering areas. Berl. Geowiss. Abh. 75 (A)1: 97–136. Li, C.; Hu, X.; Wang, J.; Vermeesch, P.; Garzanti, E., 2020. Sandstone provenance analysis in Longyan supports the existence of a Late Paleozoic continental arc in South China. Tectonophysics, 780, 228400. Loydell, D. K., 1998, Early Silurian sea-level changes: Geological Magazine, 135: 447–471 pp. Luning, S.; Craig, J.; Loydell, D. K.; Štorch, P.; Fitches, B., 2000. Lowermost Silurian ‘hot shales’ in North Africa and Arabia: regional distribution and depositional model. Earth-Science Reviews, 49:121–200 pp. Lüning, S., R. Archer, J. Craig and D.K. Loydell 2003a. The Lower Silurian ‘Hot Shales’ and ‘Double Hot Shales’ in North Africa and Arabia. In, M.J. Salem, K.M. Oun and H.M. Seddiq (Eds.), The Geology of Northwest Libya (Ghadamis, Jifarah, Tarabulus and Sabratah Basins), Vol. 3. Earth Science Society of Libya, Tripoli, p. 91–105 pp. Lüning, S., S. Kolonic, D. Loydell and J. Craig 2003b. Reconstruction of the original organic richness in weathered Silurian shale outcrops (Murzuq and Kufra basins, southern Libya). GeoArabia, v. 8, p. 299–308 pp. Luning, S.; Shahin, Y. M.; Loydell, D.; Al-Rabi, H.T.; Masri, A.; Tarawneh, B.; Kolonic, S., 2005. Anatomy of a world-class source rock: Distribution and depositional model of Silurian organicrich shales in Jordan and implications for hydrocarbon potential. Am. Assoc. Pet. Geologists. AAPG Bulletin. 89(10): 1397–1427 pp. Mahmoud, M. D.; Vaslet, D.; Husseini, M. I., 1992. The Lower Silurian Qalibah Formation of Saudi Arabia: An important hydrocarbon source rock: Am. Assoc. Petrol. Geolo. Bull., 76: 1491–1506 pp. Murchison, R. I., 1835. “On the Silurian system of rocks”. Philosophical Magazine. 3rd series. 7: 46–52. Osman, R., Ahmed, S.M., Khater, T., 2002. The stratigraphy and facies of Wadi Gabgaba and its surroundings with an emphasis on the Lower Paleozoic glaciation. Sixth Inter. Conf. Arab World, Cairo Univ. Egypt, 2:469–482 pp. Ouda, K., 2021. The Nubia Sandstone (Nubia Group), Western Desert, Egypt: An Overview. International Journal of Trend in Scientific Research and Development (IJTSRD), 5: 2456–6470 pp. Powell, J., 1989. Stratigraphy and sedimentation of the Phanerozoic rocks in central and south Jordan, Part A: Ram and Khreim Groups. Geol. Map. Div. Bull. 11. NRA, Amman, 92 pp. Powers, R.W., 1968, Lexique stratigraphique international: Saudi Arabia: v. III, Asie, fa sc. 10 b 1: Centre National de la Recherche Scientifique, Paris, 177 pp. Powers, R.W., Ramirez, L.F., Redmond, C.D., and Elberg, E.L., Jr., 1966, Geology of the Arabian Peninsula: Sedimentary Geology of Saudi Arabia: U.S. Geological Survey Professional Paper, 560–D, 147 pp.

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Roach, S. J., 1954. Unpublished report in Powers, R.W., 1968, Lexique stratigraphique international: Saudi Arabia: v. III, Asie, fasc. 10 b 1: Centre National de la Recherche Scientifique, Paris, 177 pp. Schandelmeier, H.; Reynolds, P. O., 1997. Palaeogeographic-palaeotectonic atlas of northeastern Africa, Arabia and adjacent areas. 180 p. Schrank, E., 1984. Paleozoic and Mesozoic planomorphs from the Foram-1 well (Western Desert, Egypt). N. Jb. Geol. Palanot. MH. 2:95–11 pp. Schrank, E., 1987. Palaeozoic and Mesozoic palynomorphs from northeast Africa (Egypt and Sudan) with special reference to Late Cretaceous pollen and dinoflagellates. Berliner Geowissenschaftliche Abhandlungen (A), 75: 249–310 pp. Seilacher, A., 1990. Paleozoic trace fossils. In Said, R. (Ed.). The Geology of Egypt. A. A. Balkema/Rotterdam/ Brookfield. Selden, P.; Read, H., 2008. The oldest land animals: Silurian millipedes from Scotland. Bulletin of the British Myriapod & Isopod Group. 23: 36–37 pp. Selley, R.C., 1997. The basins of Northwest Africa: Structural evolution. Sedimentary Basins of the World. 3: 17–26 pp. Siddiqui, N. A., Rahman, A. H. A., Sum, C. W., Yusoff, W. I. W., & bin Ismail, M. S. (2017). Shallowmarine sandstone reservoirs, depositional environments, stratigraphic characteristics and facies model: A review. Journal of Applied Sciences, 17(17), 212–237. Steineke, M.; Bramkamp, R. A.; Sander, N. J., 1958. Stratigraphic relations of Arabian Jurassic oil: American Assoc. Petr. Geol. Symp., Tulsa, U.S.A., pp. 1294–1329. Trewin, N. H.; McNamara, K. J., 1995. “Arthropods invade the land: trace fossils and palaeoenvironments of the Tumblagooda Sandstone (? late Silurian) of Kalbarri, Western Australia”. Transactions of the Royal Society of Edinburgh: Earth Sciences. 85: 177–210 pp. Uffmann, A. K.; Littke, R.; Rippen, D., 2012. Mineralogy and geochemistry of Mississippian and Lower Pennsylvanian Black Shales at the Northern Margin of the Variscan Mountain Belt (Germany and Belgium). International Journal of Coal Geology 103: 92–108 pp. Vaslet, D.; Berthiaus, A.; Le Start, P.; Kollogg, K.S.; Vincent, P.L., 1987. Geologic map of Baqa quadrangle, sheet 27F, Kindom of Saudi Arabia, Saudi Arabian Ministry for Mineral Rsurces Geoscience Map GM-116 A, scale 1: 250,000. Vinn, O.; Mõtus, M. A., 2008. “The earliest endosymbiotic mineralized tube worms from the Silurian of Podolia, Ukraine”. Jour. Paleonto, 82: 409–414 pp. Vinn, O.; wilson, M. A.; Mõtus, M. A., 2014. “Symbiotic endobiont biofacies in the Silurian of Baltica”. Palaeog., Palaeoclim., Palaeoeco. 404: 24–29 pp. Zou, C., 2013. Chapter 5 – Shale Gas. Unconventional Petroleum Geology: 149–190 pp.

Chapter 6

The Devonian Period

Abstract The reader is provided with geological details about the Devonian period in this chapter, including its definition, classification, associations of animals and plants, as well as paleogeography and tectonic movements that peaked during this time. It gives a description of the Devonian rock unit found in Egypt and nearby countries, like Libya, Jordan, Saudi Arabia, and Iraq. The Tadrart Formation, which is exposed in the southwest Desert, and the Zeitoun Formation, which is encountered in the subsurface in the Siwa basin, northwest Desert, are the two Devonian rock units that have been discussed. Each rock unit has been described in terms of its definition, stratigraphic limits, lithology, distribution, thickness, and age and correlation. To show the potential depositional environments of the studied rock units in Egypt and the surrounding nations, a paleogeographic map is created. Keywords Devonian · Tadrart formation · Zeitoun formation · Western desert · Siwa basin · Egypt · Libya · Jordan · Saudi Arabia · Iraq

6.1 Introduction 6.1.1 Definition The Devonian epoch was named to describe the fossiliferous rocks discovered in the Devonshire region of southwest England in 1840 by Sedgewick and Murchison. It is the 63 Mya-long Paleozoic Era, which begins from the end of the Silurian (419.2 Mya) to the base of the Carboniferous (358.9 Mya) (Gradsein et al. 2004). The Old Red Sandstone was the non-marine facies in Scotland and Wales that corresponded to the Devonian marine layers. The Devonian period is considered one of life’s Big Five mass extinctions. This period was known among geologists as “the Age of Fishes” due to the high diversity of fish (Michael 2006). The diversification of vertebrate animals characterizes the Devonian Period (new fish species that proliferated occurred in marine and freshwater environments), including the evolution of the first terrestrial vertebrates, the amphibians (Michael 2006).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_6

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6.1.2 Calssification The Devonian Period is divided into three epochs, from oldest to youngest, the lower, middle and upper. The lower epoch includes Lochkovian, Pragian and Emsian (419.2–393.3 Mya), the Middle epoch includes Eifelian and Givetian (393.3–382.7 Mya), the upper epoch includes Frasnian and Famennian (382.7–358.9 Mya) (Cohen et al. 2013, Fig. 6.1). The International Commission approved such classification on Stratigraphy (ICS).

6.1.3 Fauna and Flora In the Devonian time, it illustrates the peak of marine faunal diversity during the Paleozoic Era. New predators such as sharks, bony fishes and ammonoids ruled the oceans. Trilobites continued their decline, while brachiopods became the most abundant marine organism. Also, Ammonoids, coiled cephalopods, and Nautilus disappeared, with an estimated 88% species extinction. The flora is represented by free-sporing vascular plants, which cover the continents. They began to spread across dry land, forming extensive forests. During the middle Devonian, numerous groups of plants had evolved leaves and true roots. The first seed-bearing plants appeared at the end of the Devonian period.

6.1.4 Tectonics and Paleogeography The Caledonian Mountains were formed due to tectonic action during the Devonian Period (Cocks and Torsvik 2016). Such mountains underwent severe erosion, resulting in the deposition of reddish sandstone known as the Old Red Sandstone. The European Lower Devonian was dominated by the Old Red Sandstone from the belt, but it was confined and scarce. Similar activity was followed in eastern North America by renewed activity during the Middle Devonian, connected to the Acadian orogeny and the start of the Catskill Delta. During the Devonian, there were geographic changes all over the Globe, where the Globe collected into two supercontinents, the Gondwana in the southern hemisphere and the Euramerica in the northern hemisphere. The Gondwana supercontinent is a composite continent, including South America, Africa, Antarctica, and India (Cocks et al. 2016). In contrast, the Eurasia supercontinent includes North America, Europe and Asia. Significant landmasses were relatively near each other in a single hemisphere, while a vast ocean covered the rest of the Globe (Jan 2020). The Devonian Period ended with one of the five great mass extinctions of the Phanerozoic Era. However, unlike the four other significant extinction events, the Devonian extinction appears to have been a prolonged crisis composed of multiple

6.1 Introduction Fig. 6.1 Time chart of the Devonian Period (After CIS 2015)

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events over the last 20 million years of the Period. About 20% of all animal families and three-quarters of all animal species died out.

6.2 The Devonian Rock Units in Egypt Two Devonian rock units are encountered in Egypt: The Tadrart Formation is exposed at northeast Gebel Uweinat in the southwestern Desert and the Zeitoun Formation in the subsurface at Siwa basin, northwestern Desert.

6.2.1 The Tadrart Formation Issawi and Jux (1982) named the Devonian rocks in Gebel Abu Drba, southwest Sinai, the Wadi Malik Formation. It lies unconformably on top of the Naqus Formation. They also claimed that this formation could be found in Wadi Dakhel, Wadi Qena, Aswan, Abu Ballas, Aqaba, and Abu Ras. Issawi et al. (2009) revised the previously mentioned geologic data on Devonian rock distribution, stating that the Devonian Wadi Malik Formation occurs in the southwestern Desert but lacks information on its type locality, boundaries, lithological characteristics, and faunal association. The above mentioned work is unprofessional, unsatisfactory, and deceptive for the following reasons: (1) No geologists have recognised or identified this formation in Gebel Abu Durba, southwest Sinai, from 1982 to the present; (2) they attributed the type locality of the Devonian Wadi Malik Formation in Wadi Abu Durba even though there is no place in Sinai called Wadi Malik. (3) When assigning the Wadi Malik Formation to the Wadi Abdel Malik in the southwest Desert, Issawi et al. (2009) could not have described the type locality, lithological characteristics, and faunal index association, nor could they have identified the lower and upper boundaries. (4) The Wadi Malik Formation was incorrectly named by the North American Stratigraphic Nomenclature Code (1983) due to the lack of a type section, definite boundaries, and index fossils. For the reasons listed above, the name Wadi Malik Formation of Issawi and Jux (1982), Issawi et al. (2009) are rejected here to describe the Devonian rocks. We instead used the term Tadrart Formation used by Klitzsch and Lejal-Nicol (1984), who encountered this formation in the western Abu Ras plateau, northeast Gebel Uweinat. They defined the type locality, its lower and upper boundaries, and its age based on the presence index of trace fossils. They mentioned that this rock unit is identical in lithological characteristics to Libya’s Middle Devonian Tadrart Formation. In the subsurface, the Devonian rocks are encountered in ten wells, questionably in two wells (Hantar 1990). In Siwa Basin, the Devonian rocks are named Zeitoun Formation (Keeley 1989).

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Fig. 6.2 Field photograph showing the general view of the Devonian Tadrart Formation that unconformably underlies the Lower Carboniferous Wadi Malik Formation at Um Ras plateau northeast of Gebel Uweinat (after Klitzsch and Lejal-Nicol 1984; Brugge 2020)

6.2.1.1

Definition

The Devonian rocks in the western Abu Ras plateau northeast of Gebel Uweinat were described as the Tadrart Formation by Klitzsch and Lejal-Nicol (1984). This name is derived from the Devonian Tadrart Formation, which is common in Libya. The type locality is located on the western Abu Ras plateau, northeast of Gebel Uweinat (Klitzsch and Lejal-Nicol 1984) (Fig. 6.2).

6.2.1.2

Stratigraphic Contact

The upper boundary of the Tadrart Formation is roughly parallel to that of the overlying Carboniferous Wadi Malik Formation (Klitzsch and Wyicsk 1987) (Fig. 6.2). The lower boundary of this formation unconformably overlies the Silurian Um Ras Formation in the Gilf Kebir area (Fig. 6.3a). The stratigraphic boundary is between the uppermost Silurian Um Ras Formation’s exfoliation sandstone and the basal Tadrart Formation’s brown-reddish sandstone (Klitzsch and Wyicsk 1987).

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Fig. 6.3 a Field photograph showing the unconformable lower boundary of the Tadrart Formation with the underlying Silurian Um Ras Formation, Um Ras Plateau, northeast Gebel Uweinat (After Klitzsch and Wycsik 1987; Brugge 2020). b Field photograph showing the presence of an iron-rich crust that documented a time gap between Silurian and Devonian, Um Ras Plateau, northeast Gebel Uweinat (After Klitzsch and Wycsik 1987; Brugge 2020)

An iron-rich crust marks the contact between Silurian and Devonian rocks in some areas, indicating a time gap between the Silurian and Devonian (Klitzsch and Wyicsk 1987) (Figs. 6.3b, 6.6).

6.2.1.3

Lithology

This formation is composed primarily of two units (Fig. 6.4a), the lower of which is massive sandstone with intercalation of planar cross-bedded sandstone. Near the top of this unit are a few thin conglomerates (Fig. 6.5a). The upper units are made up of planar cross-bedded and recumbent cross-bedded sandstoneswhich interbedded with thin siltstone beds (Fig. 6.5b). The thin-bedded pebble-bearing sandstone layers

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formed by cross-bedding are medium- to coarse-grained, subangular to subrounded, and moderately sorted. The most common bedding type is small-scale to large-scale stacked tabular cross-bedding. Horizontal bedding and thin lamination characterise the siltstones. In contrast to the Silurian strata, these have an increasing pebble content. Deposits of pebbly sandstone can be seen (Klitzsch and Wycsik 1987).

6.2.1.4

Distribution and Thickness

According to Klitzsch (1990), the Devonian rocks known as the Tadrart Formation are exposed along the northwestern and western edge of the Abu Ras plateau near the Libyan border. Italso occus in the northeastern part of Gebel Uweinat (Klitzsch and Wycisk 1987; Klitzsch 1990). Devonian rocks with thicknesses ranging from 50 to 70 m These are Devonian blanket rocks that extend south toward the Ennedi Mountains in northeast Chad (Klitzsch 1979; Klitzsch 1990).

6.2.1.5

Age Assignment and Correlation

There is no paleontological evidence in the Devonian rocks of southwest Egypt, but its age is determined by its stratigraphic position. The Devonian age is assigned because it overlies the Silurian Umm Ras Formation and conformably underlies the Carboniferous Wadi Malik Formation. Klitzsch (1990) assigned this formation to the Middle Devonian. Furthermore, it has a strong correlation with Libya’s EarlyMiddle Devonian Tadrart and Van Kassa formations (Klitzsch and Lejal-Nicol 1984) (Fig. 6.6a) and Saudi Arabia’s Jauf Formation and the Kasita Formation in Iraq (Fig. 6.6).

6.2.2 The Zeitoun Formation 6.2.2.1

Definition

Zeitoun Formation was coined by Keeley (1989) to describe the Devonian fine clastic rocks found in the subsurface of the Siwa Basin in the northwestern Desert. At Zeitoun well-1, the intervals between 1670 and 1938 m are its type location. (Fig. 6.4b).

6.2.2.2

Stratigraphic Contact

The Zeitoun Formation unconformably overlies the Silurian Basur Formation in the Siwa Basin (Keeley 1989). The erosional unconformable contact is thought to be a hiatus zone (Keeley 1989). On the other hand, this hiatus can be seen in the

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Fig. 6.4 Measured lithostratigraphic sections of the Devonian Tadrart Formation at Um Ras Plateau, northeast Gebel Uweinat (After Klitzsch and Wycsik 1987), a the Zeitoun Formation at Siwa Basin (after Keeley 1989), b the Zeitoun Formation at Gib Afia-well (After, Marzouk et al. 2016), c the Zeitoun Formation at Faghour–IX well (After Makled et al. 2018, c)

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Fig. 6.5 a Field photograph showing the lithology of the Lower unit of the Tadrart Formation in the western Abu Ras plateau, northeast of Gebel Uweinat (After Klitzsch and Wycsik 1987; Brugge 2020). b Field photograph showing the lithology of the upper Tadrart Formation in the western Abu Ras plateau, northeast of Gebel Uweinat (After Klitzsch and Wycsik 1987; Brugge 2020)

palynological assemblages of the upper Basur and lower Zeitoun Formations (Ludlovian—Early Gedinnian) (Gueinn and Rasulls 1986). Its upper boundary in Faghur FRX-1 is conformable with the overlying Desouqy Formation. The Desouqy Formation lies unconformably on the progressively older and thinner Zeitoun Formation to the south and east. However, Hantar (1990) stated that the upper and lower Devonian rock boundaries are poorly defined and are usually arbitrarily marked. The Devonian Zeitoun Formation unconformably underlies and overlies Lower Cretaceous and Silurian rocks at the Gib Afia-2 well (Marzouk et al. 2016).

6.2.2.3

Lithology

The Zeitoun Formation at Siwa Basin consists of two lithologic units. The basal unit accounts for approximately two-thirds of the formation and comprises thick-bedded

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Fig. 6.6 Lithostratigraphic correlation of measured sections of the Devonian rocks in Egypt with their corresponding Devonian rock units in Libya (A), Saudi Arabia (D) and Iraq (E)

claystone with a thin pebbly conglomerate (Keeley 1989). The thickness of each claystone bed ranges from 80 to 120 m. In comparison, the pebbly conglomerate ranges in thickness from 7 to 10 m (Fig. 6.4b). The Devonian rocks, according to Marzouk et al. (2016), are divided into three lithologic units at Gib Afia-2 in the northern Arabian Peninsula (Fig. 6.4c). The lower Devonian is composed of sandstone intercalation with shale and siltstone interbeds (2089–2312 m depth). The Middle Devonian lies at a depth of 1766–2098 m and contains white to brick-red, micaceous to kaolinite sandstone. The Upper Devonian (1295–1760 m depth) is made up of intercalations of fine sandstone to siltstone, claystone, and thin strata of dolostone (Fig. 6.4c). Further north, the Devonian Zeitoun Formation is encountered between depths 7700 and 10,000 m at the Faghour 1X well (Fig. 6.4d), which is located near the Egyptian-Libyan border in the Faghur basin (Maklad et al. 2018). It is primarily composed of two units: the lower is claystone to silty clay with thin, finegrained sandstone interbeds, and the upper is primarily sandstone with thin claystone to sandy clay interbeds (Fig. 6.4d), (Abd El Gawad et al. 2019; Maklad et al. 2018; Hallett and Clark-Lowes 2012).

6.2.2.4

Distribution and Thickness

Lower Devonian rocks were discovered in the subsurface at Gib Afia, northwestern Desert, at depths ranging from 2098 to 2312 m (thickness 214 m) (Marzouk et al.

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2016). The Zeitoun Formation is approximately 288 m thick in the Siwa basin (Keeley 1989). It is also found in ten wells, except Yakout-1, which are located east of Longitude 27 E and have an average thickness of 950 m. Hantar (1990). Furthermore, the Devonian strata have been identified and studied in the Faghour-1X borehole near the Egyptian-Libyan border. The total thickness in this well reaches 1200 between 2400 and 3600 m (El Shamma et al. 2018). According to the previously mentioned data, the thickness of Devonian rocks increases northwestwards towards the Libyan border.

6.2.2.5

Age Assignment and Correlation

Schrank (1984) was the first to identify numerous Early to Middle Devonian palynomorphs from the foram-1 well in northwest Egypt. The Zeitoun Formation is most likely Devonian (Gedinnian to Strunian) (Keeley 1989). Some Devonian fossils, such as Hyperammina sp., Oxinoxis ligula, Protennina cumberlandiae, Psammosphaera gracilis, Thurammina deformens, T. elliptica, T. tabulate, Thuramminoides sphaeroidalis, and Tolypammina bulbosa (Marzouk et al. 2016). The Faghuor-1X well is located on the eastern rim of the Ghazalat basin, near the Egyptian-Libyan border. For the first time, El Shamma et al. (2018) discovered an association of scolecodonts indicating the Early to Middle Devonian age. Foraminifera, ostracods, conodonts, brachiopods, bryozoans, and echinoderms were discovered in the upper part of this formation (shale unit) (Hantar 1990). Mostafa (1997) discovered plant spores indicating the Early and Middle Devonian age in the Ghazalat basin northwest of the Qattara Depression at the le-11-2 well. This formation can be correlated with the Tadrart and Wan Kasa formations in Libya (Burollet 1960; Banerjee 1980), with the Jauf Formation in Saudi Arabia (Vaslet et al. 1987; Janjou et al. 1996) and with the Kasita Formation in Iraq (Buday 1980) (Fig. 6.6).

6.2.3 Devonian Rocks in Adjacent Countries 6.2.3.1

In Libya

Devonian rocks are represented in Libya by three rock units, from bottom to top: Tadrart, Van Kasa, and Awaynat Winin formations (Fig. 6.6a). The Tadrart Formation (Burollet 1960) is unconformable with the Upper Silurian Akakus Formation beneath it. At the same time, the Wan Kasa Formation is underlain by its upper boundary conformable (Banerjee 1980). Its thickness ranges from 150 to 300 m. This formation is made up of massive, cross-bedded sandstone. Tidal channels and herringbone structures are common (Hallett 2002; Hallett and Clark-Lowes 2016). The Tadrart Formation in this area has been dated as Pragian to Early Emsian based on numerous plant remains and microspores. However, palynological analysis in the Ghadamis Basin’s centre revealed that Tadrart deposition began in the Lochkovian. Sparse fossil

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evidence and distinctive trace fossils point to an early Devonian (Banerjee 1980). The Wan Kasa Formation (Borghi 1939) has conformable contact with the Lower Devonian Tadrart Formation and is unconformably overlain by Awaynat Wanin Formation sandstones (Klitzsch 1970). The Wan Kasa Formation comprises grey to reddish ferruginous siltstones and shales interspersed with thin layers of gypsum containing brachiopods and trace fossils. The siltstones coarsen upwards, displaying wavy and flaser-bedded bedding before grading into more massive cross-bedded sandstones at the top (Hallett 2002). It has a thickness of 55 to 137 m and a depth of 365 m in the subsurface (Belhaj 1996). Klitzsch (1970) proposed that the Wan Kasa Formation is mid-Devonian in age. Lelubre (1946) was the first to establish the Awaynat Winin Formation. Its upper boundary is deformable primarily with the lower Carboniferous Marar Formation overlying it (Banerjee 1980). This formation’s lower boundary is erosive to transgressive with the underlying Wan Kasa Formation. It is about 188 m long and made up of several shallowing-upward cycles of thin claystone followed by thick massive sandstone. Brachiopods and the trace fossil Bifungites fezzanensis can be found in the claystone. Following the claystone are massive ferruginous sandstones with a conglomeratic at the base. The sandstone is typically quartzitic with abundant pelecypods and brachiopods, giving it a Frasnian age (Klitzsch 1970; Hallett 2002). Klitzsch (1970) suggested a Mid-Devonian age for the Awaynat Winin Formation. However, it was dated based on its brachiopod fauna and abundant microplanktons and spores in south Taroot to the Upper Devonian age (Banerjee 1980).

6.2.3.2

In Jordan

The Devonian rocks are not exposed (Fig. 6.6c), but they may be in the subsurface of the AI Azraq-Wadi as Sirban and AI Jafr Basins. Approximately 80 to 120 km southeast of the southeastern corner of Jordan (Bender 1975).

6.2.3.3

In Saudi Arabia

Saudi Arabia’s Devonian rocks are divided into two geological units: the Jauf and Jubah Formations (Fig. 6.6d). The Jauf Formation was named by Berg et al. (1944). Steineke et al. (1958) later designed its type section in Al Jawf town. It is distinct from the Tawil Formation and the Jubah Formation. It is approximately 300 m thick and composed of green and brown claystone intercalation and planar cross-bedded sandstone. The upper section contains limestone and dolostone beds (Powers et al. 1966). There are fossilised corals, bryozoa, pelecypods, brachiopods, and fish remnants. It is thought to be between the lower and middle Devonian (Powers 1968). Vaslet et al. (1987), on the other hand, and Janjou et al. (1996) attributed the Jauf Formation in central Arabia to the Early Devonian (Pragian–Emsian). The Jubah Formation was named after Jawbah, a town in northeastern Saudi Arabia (near the Sakaka region) (Meissner et al. 1989). It overlies the Jauf Formation unconformably and underlies

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the Cretaceous Wasia Sandstone unconformably. It has a thickness of about 220 m and is made up of fine to medium-grained, well-sorted, thin- to medium-bedded sandstone intercalated with white, pale brown, or pale grey to greenish-grey sandstone. This formation ranges in age from the Middle to Upper Devonian (Givetian to Frasnian) (Meissner et al. 1989; Wallace et al. 1997).

6.2.3.4

In Iraq

Devonian rocks are divided into two geological units: the Kaista Formation at the bottom and the Ora Shale at the top (Fig. 6.6e). The Kaista Formation is described by Morton (1950–1951) and Wetzel (1952). The lower section consists of siltstones, silty shales with quartzites, and marly limestones intercalated with claystone. The Kaista Formation is Late Devonian (Famennian) in age (Buday 1980). In the northern outcrop area, the thickness of the Kaista Formation exceeds 70 m (Buday 1980). Northern Iraq is home to the Ora Shale (Wetzel 1952). It has a thickness of up to 220 m and is composed of dark calcareous shales interbedded with silty marls, lenticular organic limestones, and fine-grained limestones (Wetzel 1952). Buday (1980) found that it was deposited on a shallow sea shelf and was common in northern Iraq, although it may not be present in the southern half of Iraq. The Ora Shale is assigned as the Late Devonian (Wetzel 1952).

6.2.4 Depositional Environments In northeast Africa, Caledonian tectonic activity (Ordovician to Early Devonian) was characterized by general northwest-southeast and east–west trending folding and faulting, which further produced basins and uplifts (Klitsch 1968; Bishop 1975). Palaeozoic basins were filled with Devonian clastic sediments, no deposition or intensive erosion had been active in the uplifted areas. It has long been believed that the Silurian-Devonian boundary in Libya is almost everywhere unconformable, and the presence of hiatus between them (Hallett 2002). Also, these hiatus occur in Iraq, where the Upper Devonian Kasita Formation unconformably overlies the Silurian Akkas Formation (Al-Juboury et al. 1997). This hiatus was believed to represent a significant episode of uplift, folding and erosion reflecting major tectonic events on the northern margin of west Gondwana (Craig et al. 2008). These events significantly impacted the configuration of the pre-Devonian topography, resulting in the creation of basins and structural high or uplift. In the Devonian time, two paleogeographic maps have been suggested to manifest the depositional environments during the Early-Middle and the Late Devonian, based on the facies occurrence, lithological character, and missed rocks. During the Early-Middle Devonian, two primary depositional environments were dominated in Libya, Egypt, Jordan, Saudi Arabia and Iraq: (1) cratonic or continental setting and (2) coastal marine environments (Fig. 6.7). Also, these depositional setting is

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illustrated in east–west sechematic profile (Fig. 6.8). (1) Over the cratonic area, the Devonian rocks were not deposited. In Egypt, the high structural areas cover a vast region, creating cratonic areas where most of the Western and Eastern Deserts and the Sinai Peninsula were left emergent during the deposition of the Devonian sediments (Figs. 6.7, 6.8). Except for a narrow stretch extending from the north and northeast Gebel Uweinat parallel to the Libyan borders is filled with the Tadrart formation in the south and the Zeitoun Formation in the north (Figs. 6.7, 6.8). Also, cratonic setting covers most of the Jordanian territory. In Libya, it covers northeast Libya including the Sirt basin, Al Qaqaf high and Cyrenaica adjacent to the Egyptian borders, where the Tadradrt and Wan Kasa were not detected (Hallett 2002) (Fig. 6.7). In Iraq, the cratonic area covers most of this country, where the there is an extended hiatus between the Silurian Akkas Formation and upper Devonian Kasita Formation (AlHadidy 2001). This cratonic area was probably formed due to the continuation of the Taconic movement that reached the Caledonian movement at the end of Devonian. The cratonic regions were considered the primary source for supplying the clastic sediment to the coastal and fluviomarine surrounding the deeper basin in Iraq, Saudi Arabia and further northeast. The margins of the Arabian-African craton constituted a shelf environment with significant uplift during Famennian (late Devonian) to Early Tournaisian (early Carboniferous) times. During these times, severe erosion removed most of the Devonian, Silurian and Ordovician sediments from Jordan, Palestine and Egypt, including Sinai (Bandel and Salameh 2013). (1) Fluvio-marine environment: This habitat encompasses a variety of subenvironments, such as estuaries, tidal zones, coastal marshes, and the inner parts of the continental shelf (Flügel 2004). This environment caused the deposition of the Tadrart and Wan Kasa formations in Libya and the Zeitoun Formation in Egypt and the Jauf Formation in Saudi Arabia (Fig. 6.7). These formations’ sediment is composed of horizontally bedded fine-grained sandstone with intercalation of

Fig. 6.7 Regional map showing the distribution and possible depositional environments of the Lower-Middle Devonian rocks in Libya, Egypt, Jordan, Saudi Arabia and Iraq

6.2 The Devonian Rock Units in Egypt

133

Fig. 6.8 East–West schematic profile showing the lateral relationships of the Lower-Middle Devonian rock unit in Libya, Egypt, Jordan, Saudi Arabia and Iraq

siltstone and claystone and is abundant in corals, bryozoa, brachiopods, and pelecypods, indicating a shallow marine nearshore context (Flügel 2004; Nichols 2009). The presence of cross-bedding sandstone and fish bones in the Jubah Formation suggests brackish water in delta channels. Such settings are covered in Eastern Libya, where the Tadrart and Van Kasa facies consist of intercalating claystone and sandy clay with a thin pebbly conglomerate. These facies imply mixing fluvial, coastal, or marginal marine with estuarine phases. In addition the presence of fish remains in theJauf Formation in Saudi Arabia suggests brakish water and esturine conditions (Janjou et al. (1996). During the Upper Devonian, there were deepening-upward and increase in sea-level on the western and eastern Africa and Arabia. This gave rise decrease in the cratonic regions in Libya and Iraq, as illustrated in the plaeogegraphic map (Fig. 6.9) and the east–west schematic profile (Fig. 6.10). In general, three synchronous depositional environments have been proposed: (1) cratonic region, (2) deltaic environment and (3) inner neritic environments. (I) cratonic setting was domination in Egypt and Joran. The missing of Upper Devonian rocks in both Egypt and Jordan may be due to the Caledonian movement (Craij et al. 2008) (Fig. 6.10). (2) Deltica facies are found in the facies of the Awaynat Winin Formation in Libya and the Jubah Formation in Saudi Arabia (Fig. 6.9). The deltic facies in the Awynat Winin Formation comprises shallowing-upward cycles, each cycle begins with claystone containg pelcypods, followed by siltstone, which pass upward to 4 m thick of oolitic ironstone (Hallet 2002).The above sequence, represents a deltaic environment ranging from delta front to fluvial-distributary channels, all reworked by tides and storm waves (Hallett 2002). The Primary oxidized ironstone minerals were formed in nearshore fluviatile environment (Umeorah 1983). In addition, geochemical studies were carried on the the Devonian oolitic ironstones in Libya are commonly interpreted to have been deposited in a narrow coastal zone or inland restricted bays and lagoons with clastic and carbonate sedimentary sequences (Liao et al. 1993; Zhao and Bi 2000).

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Fig. 6.9 Regional map showing the distribution and possible depositional environments of the Upper Devonian rocks in Libya, Egypt, Jordan, Saudi Arabia and Iraq

Fig. 6.10 East–West schematic profile showing the lateral relationships of the Upper Devonian rock unit in Libya, Egypt, Jordan, Saudi Arabia and Iraq

(2) Inner neritic or deep subtidal marine shelves only occur eastward in Iraq, represented by the Kaista Formation in the lower part and the Ora Shale in the top part (Fig. 6.7). Dark calcareous shales are interbedded with silty marls, lenticular organic limestones, and fine-grained limestones. These facies have primarily clastic and contains corals, pelecypods, brachiopods, and fishes that remain similar to those found in Saudi Arabia. The crinoids, brachiopods, and dolomite, these facies may be deposited in the mid-ramp to outer ramp environment (Al-Juboury and Al-Hadidy 2008). Near the end of the Devonian, there was shallowing and a drop in sea level, resulting in unconformable contact with the overlaying Carboniferous rocks. This unconformable contact can be found in Iraq, where the Devonian Ora Shale unconformably underlies the Carboniferous strata (Al-Juboury and Al-Hadidy 2008). Furthermore, there was a significant gap between the Upper Devonian Jubah Formation and the Carboniferous

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Unayzah Formation (Al Laboun 1986, 1988). The caledonian event most likely caused this drop in sea level and unc onformity with the Carboniferous at the end of the Devonian.

References Abd El Gawad, E. A.; Ghanem, M. F.; Makled, W. A.; Mousa, D. A.; Lotfy, M. M.; Temraz, M.G., Shehata, A.M., 2019. Source rock evaluation of subsurface Devonian–Carboniferous succession based on palyno-organic facies analysis in Faghur Basin, north Western Desert of Egypt: a division of the north Africa Paleozoic basins. Arab. Jour. Geosc. 12, 655. Al-Hadidy, A. H., 2001. Facies and sedimentary environment of Late Paleozoic successions (Devonian–Permain) of Iraq. Ph.D Thesis, Mosul University, Iraq. Al Joubory, A. A.; Al-Hadidy, A., 2008. Facies and depositional environments of the Devonian– Carboniferous succession of Iraq. Geological Journal 43:383–396. Al Laboun A. A., 1988. The distribution of Carboniferous–Permian siliciclastic rocks in the greater Arabian basin. Geol Soc Am Bull, 100:362–373 Al Laboun, A. A., 1986. Stratigraphy and hydrocarbon potential of the Palaeozoic succession in both Tabuk and Widyan basins, Arabia.In: Halbouty, M.T. (Ed.), Future Petroleum Provinces of the World.Am. Asso. Pet. Geol. Mem, 40, pp. 373–393. Al-Jubuory, F. H. K.; Youkhanna, A. K.; Al-Rubai, M. A.; Samarrai A. I., 1997. The Akkas Formation: a new name for a Paleozoic (Silurian) lithostratigraphic unit in Iraq. Iraqi Geological Journal 30: 1–3. Bandel, K.; Salameh, E., 2013. Geologic development in Jordan: Evolution of its rock and life. The Hashemite Kingdom of Jordan. The deposit Number at the National Library, 690/3/2013. Banerjee, S., 1980. Stratigraphic Lexicon of Libya. Department of Geological Researches and Mining Bulletin, No.13.Socialist People’s Libyan Arab Jamahiriyah Industrial Research Centre, Tripoli, 300pp. Belhaj, F., 1996. Palaeozoic and Mesozoic Stratigraphy of Eastern Ghadamis and Western Sirt Basins. In: Salem, M. J.; A.J. Mouzughi, A. J.; O.S. Hammuda, O.S. (Eds.). the Geology of Sirt Basin, Elsevier, Amsterdam, I:57–96 Bender, F., 1975. Geology of Arabian Peninsula, Jordan. Geological Survey, Professional Paper 560-I. United States Government Printing Office, Washington. Berg and others, 1944, unpublished report in Powers, R.W., 1968, Lexique stratigraphique international: Saudi Arabia: v. III, Asie, fasc.10b1: Centre National de la Recherche Scientifique, Paris, 177 p. Bishop, W. F., 1975. Geology of Tunisia and adjacent parts of Algeria and Libya: Amer. Assoc. Petr. Geol. Bull., 59: 413–450. Borghi, P. 1939. Fossili devonici del Fezzan. Bull. Soc. Geol. Ital, 58: 186–188, Roma. Brugge, N., 2020. Structure and Geology of Jebel Uweinat in the three country triangle EgyptSudan-Libya, internet report. Buday, T. 1980. The Regional Geology of Iraq. Stratigraphy and Palaeogeography. Dar Al-Kutub Publishing House, University of Mosul, Iraq. v. 1. Burollet, P. F. 1960. Lexique Stratigraphique Ineternational, Vol.4, Afrique, No. 4a, Libye, 62p. Cocks, L. R. M.; Torsvik, T. H., 2016. Devonian, Earth History and Palaeogeography, Cambridge: Cambridge University Press, pp. 138–158. Cohen, K. M.; Finney, S. C.; Gibbard, P.L.; Fan, J. X., 2013. The ICS International Chronostratigraphic Chart. Episodes 36: 199–204.

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Craig J, Rizzi C, Said F et al (2008) Structural styles and prospectivityin the Precambrian and Palaeozoic hydrocarbon systems. In Conference proceedings, geology of east Libya symposium 2004, Binghasi, 52 pp (preprint). El Shamma, A. A.; Mostafa, T. F.; Abdel Malik, W. M. 2018. Devonian spores from subsurface rocks in the Western Desert,Egypt. Proceeding of 14th Petroleum Conference, Cairo, Egypt.Egyptian General Petroleum Company, 1: 451–455. Flügel, E., 2004, Microfacies of carbonate rocks, Analysis, Interpretation and application: Berlin– Heidelberg, Springer–Verlag, 976 pp. Gradstein, F. M.; Ogg, J. G.; Smith, A. G., 2004. A Geologic Time Scale. Cambridge University Press. ISBN 978-0521786737. Gueinn, K. J.; Rasll, S. M., 1986. A contribution to the biostratigraphy of tne Palaeozoic of the Wcstcrn Dcscrt.utilising new pa1yno’:ogical data from the subsurface. EGPC Hallett, D. 2002. Petroleum Geology of Libya. Elsevier, 503 p. Hallett, D., Clark-Lowes, D., 2016. Petroleum Geology of Libya, p. 391. Hantar, G., 1990. North Western Desert. In Said, R. ( Ed.), the Geology of Egypt. A. A. Balkema/ Rotterdam/Brookfield, 389 pp. 293–319. Issawi, B; Francis, M. H.; Yossef, E. A. A.; Osman, R. A., 2009. The Phanerozoic Geology of Egypt. A Geodynamic Approach. Sepc. Public. No.81. Ministry of Petroleum. The Egyptian Mineral Resources Authority, 589 pp. Issawi, B.; Jux, U., 1982. Contributions to the stratigraphy of the Paleozoic rocks in Egypt. Geol. Surv. Egypt, Paper 64, 28 pp. Jan, G., 2020. “Late Devonian paleogeography in the framework of global plate tectonics”. Global and Planetary Change. 186: 103129. Janjou, D. Halawani, M. A., Brosse, J. M., Al-Muallem, M.S., Becq-Giraudon, J.F., Dagain, J., Genna. A., Razin, Ph., Roobol, M.J., Shorbaji, H. and Wyns, R., 1997. Geologic map of the Tabuk quadrangle, sheet 28B, Kingdom of Saudi Arabia: Saudi Arabian Deputy Ministry for Mineral Resource Map GM-137, scale 1:250,000. Keeley, M. L., 1989, The Paleozoic history of the Western Desert of Egyp. Basin Research, 2: 35–48. Klitzsch E (1970) Problem of continental Mesozoic strata of Southwestern Libya (with discussion). In: Proceedings of the Conference African Geology. Regional Geology. University of Abadan, Department of Geology, Ibadan Nigeria, pp 483–494 Klitzsch, E. 1990. Paleozoic. In Said, R. (Ed.). The Geology of Egypt. Balkema, Rotterdam, Brookfield: 393–406. Klitzsch, E., 1968. Outline of the geology of Libya, in Geology and archaeology of northern Cyrenaica, Libya: Petroleum Exploration Society of Libya, 10th Annual Field Conference, p. 71–78. Klitzsch, E.; Harms J. C.; Lejal-Nicol A.; List, F. F., 1979. Major subdivisions and depositional environments of Nubia strata, southwestern Egypt. Bull. Am. Assoc.Petrol. Geol. 63: 974–976. Klitzsch, E.; Lejal-Nicol, A., 1984. Flora and fauna from a strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Berl. Geowiss. Abh. 50 (A):47–79 Klitzsch, E.; Wycisk, P., 1987. Geology of sedimentary basins of northern Sudan and bordering areas. Berl. Geowiss. Abh. 75 (A)1: 97–136 Lelubre, M., 1946. Sur la Paleozoique du Fezzan. C. R. Hebd. Seanc. Accad. Sci. Vol. 223, No.11. pp. 359–361. Liao, S. F., Wei, L. H., Liu, C. D., Zhang, X. S., Ran, C.Y., 1993. Sedimentary environments and origin of the Devonian oolitie ironstones in China. Acta Sedimentol. Sin. 11: 93–102. Makled, W.A.; Mostafa, T. F.; Mousa, D. A.; Abdou, A. A., 2018. Source rock evaluation and sequence stratigraphic model based on the palynofacies and geochemical analysis of the subsurface Devonian rocks in the Western Desert, Egypt. J. Mar. Pet. Geol. 89: Marzouk, A. K.; Obeid, F. L.; Abd El-Aziz, A.; Mahmoud, A. A.; Edress, N.A.; Allam, A. A., 2016. Geological and stratigraphical studies on the subsurface sequence in Gib Afia-2 well, Northern Western Desert, Egypt. Delta J. Sci. 37; 128–135.

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Meissner, C. R.; Dini, S. M.; Farasani, A. M.; Riddler, G. P. Van Eck, M.,; Aspinall, N. C., 1989. Preliminary geologic map of the Al Jawf quadrangle, sheet 29D, Kingdom of Saudi Arabia: Ministry of Petroleum and Mineral Resources, Kingdom of Saudi Arabia, 42p. Michael, J. F., 2006. “Paleobiology: The Late Paleozoic: Devonian”. The Online Biology Book. Estrella Mountain Community College. Morton, D.M. 1950–51. Stratigraphic Sections in Kurdistan. IPC report, INOC Library, No IR/DM 3-20, Baghdad. Mostafa, T. F., 1997. Palynostratigraphic studies of Devonian of the Western Desert, Egypt. Ph. Thesis. Ain Shams Univ. Egypt. Murchison, R. I. (1840). “On the physical structure of Devonshire, and on the subdivisions and geological relations of its older stratified deposits, etc. Part I and Part II”. Transactions of the Geological Society of London. Second series. Vol. 5 part II. p. 701 Nichols, G. (2009). Sedimentology and stratigraphy (2 ed.). John Wiley and Sons. p. 168. North American Stratigraphic Code 1983, North American commission on stratigraphic Nomenclature. Am. Assoc.. Petrol. Geologists. Powers, R. W., 1968, Lexique stratigraphique international: Saudi Arabia: v. III, Asie, fasc. 10 b 1: Centre National de la Recherche Scientifique, Paris, 177 p. Powers, R.W., Ramirez, L.F.; Redmond, C. D.; Elberg, Jr. E. L., 1966. Geology of the Arabian Peninsula: Sedimentary Geology of Saudi Arabia: U.S. Geological Survey Professional Paper, 560-D, 147 Schrank, E., 1984. Paleozoic and Mesozoic planomorphs from the Foram-1 well (Western Desert, Egypt).N. Jb. Geol. Palanot. MH.2: 95–11. Steineke, M.; Bramkamp, R. A.; Sanders, N. J., 1958. Stratigraphic relations of Arabian Jurassic oil. In: Weeks, L. G. (Ed.), Habitat of Oil, Am. Association Pet. Geol., Tulsa, Oklahoma, USA, pp. 1294–1329. Umeorah, E. M., 1983. Depositional environment and facies relationships of the Cretaceous ironstone of the Agbaja Plateau, Nigeria. Jour. Afr. Earh. Scie. 8: 385–390. Vaslet, D.; Berthiaus, A.; Le Start, P.; Kollogg, K.S.; Vincent, P.L., 1987. Geologic map of Baqa quadrangle, sheet 27F, Kindom of Saudi Arabia, Saudi Arabian Ministry for Mineral Rsurces Geoscience Map GM-116 A, scale 1: 250,000. Wallace, C. A., Dini, S. M.,; Al-Farasani, A. A., 1997. Geologic map of the Al Jawf quadrangle, sheet 29 D, Kingdom of Saudi Arabia: Saudi Arabian Deputy Ministry for Mineral Resources Geoscience Map GM-128C, scale 1:250,000. Wetzel, R. 1952. Stratigraphic Survey in Northern Iraq. MPC Report, NIMCO Library, No. 139, Baghdad. (Internal Report) Zhao, Y.M., Bi, C.S., 2000. Time-space distribution and evolution of the Ningxiang type sedimentary iron deposits. Miner. Deposits 19: 350–362.

Chapter 7

The Carboniferous Period

Abstract This chapter informs the reader about the geology of the Carboniferous period. This geological background includes definitions, classifications, faunal and floral associations, and other information. It is concerned with the Carboniferous rock units of Egypt and neighbouring countries. Lower Carboniferous rock units include the Umm Bogma and Abu Thora formations in southwest Sinai and the Wadi Malik Formation in the Gilf plateau in the southwestern Desert. Desouky and Diffah formations are also found in the subsurface at the Siwa basin in the northwest desert. Upper Carboniferous rock units include the Abu Durba Formation in Sinai, the Rod El Hamal, Abu Darag, and Aheimer formations west of the Suez Gulf, and the North Wadi Malik and Safi Formations in the Western Desert. A paleogeographic map is used to discuss their depositional environments. The abovementioned rock units will be correlated with equivalent rock units in Libya, Jordan, Saudi Arabia, and Iraq. Keywords Carboniferous · Umm Bogma · Abu Thora · Abu Durba · Wadi Malik · North Wadi Malik · Desouqy · Dhiffah · Safi

7.1 Introduction 7.1.1 Definition Conybeare and William (1822) coined the Carboniferous Period. During their investigation of the British rock succession. Carboniferous means rocks containing coal beds (Cossey et al. 2004). It is the geologic time that spans 60 million years from the last of the Devonian Period (358.9 Mya) to the start of the Permian Period (298.9 Mya) (Fig. 7.1). It is the most prolonged period of the Paleozoic Era and the second most extended period of the Phanerozoic Eon. The first attempt to establish an international time scale for the Carboniferous was during the Eighth International Congress on Carboniferous Stratigraphy and Geology in Moscow in 1975, when all modern ICS stages were proposed (Davydov et al. 2012).

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_7

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Fig. 7.1 Time chart showing the classification of the Carboniferous period (After, CIS, 2015)

7.1.2 Classification The Carboniferous period is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Alexander Winchell first proposed the Mississippian, and Stevenson proposed the Pennsylvanian in 1888, and both were proposed as distinct and independent systems by Davydov et al. (2012). The Mississippian Epock was subdivided into three ages (Tournaisian, Viséan

7.2 Lower Carboniferous Rock Units in Egypt

141

and Serpukhovian while the Pennsylvanian was also subdivided into Bashkirian, Moscovian, Kasimovian and Gzhelian (Davydov et al. 2012) (Fig. 7.1).

7.1.3 Fauna and Flora The Carboniferous period is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Alexander Winchell first proposed the Mississippian, and Stevenson proposed the Pennsylvanian in 1888, and both were proposed as distinct and independent systems by Williams in 1881 (Davydov et al. 2012). The Mississippian Epock was subdivided into three ages (Tournaisian, Viséan and Serpukhovian while the Pennsylvanian was also subdivided into Bashkirian, Moscovian, Kasimovian and Gzhelian (Davydov et al. 2012) (Fig. 7.1).

7.1.4 Tectonic and Paleogeography During the Carboniferous period, the supercontinent Pangaea was forming, and active mountain-building occurred. The southern continents remained linked in the supercontinent Gondwana, which collided with North America-Europe (Laurussia) along the current eastern North American line. The Hercynian orogeny in Europe resulted from this continental collision (Stanley 1999). During the Carboniferous Period, there were two significant oceans, Panthalassa and Paleo-Tethys, located within the Carboniferous Pangaea. An increase in global sea level in the early Carboniferous caused an increase in thickness of deposited rocks. In this work we classify the Carboniferous rock units in Egypt into Lower Carboniferous and Upper Carboniferous rock units.

7.2 Lower Carboniferous Rock Units in Egypt The Lower Carboniferous rock units include the Umm Bogma and Abu Thora formations (Umm Bogma area, southwestern Sinai), Wadi Malik Formation (Gilf plateau, northeast Gebel Uweinat), Desouqy and Dhiffah formations (in the subsurface, Siwa basin, northwestern Desert) (Table 7.1).

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Table 7.1 Correlation of the exposed Lower and Upper Carboniferous rock units in Sinai, Eastern Desert and Western Desert with their equivalent rock units in the subsurface in northwestern Desert

7.2.1 The Umm Bogma Formation 7.2.1.1

Definition

The Umm Bogma Formation was established by Kostandi (1959) in Um Bogma area of west-central Sinai. Different names were previously attributed to this formation, e.g. Limestone Series Ball (1916), dolomitic formation (Omara 1965), Khaboba Formation (Soliman and El Fetouh 1969) and Umm Bogma Series (Weissbord 1969; Omara 1971). The above names do not follow the rules of the North American Stratigraphic Code (1983). Hence, we use the term Umm Bogma Formation (Fig. 7.2).

7.2.1.2

Stratigraphic Contact

Kora (1992) mentioned that the lower boundary of the Umm Bogma Formation unconformably overlies the Sarabit El Khadim Member (the lower member of the Araba Formation). Later on, Kora et al. changed their opinion and stated that this lower contact unconformably overlies the pebbly sandstones of the Adeidia Member

7.2 Lower Carboniferous Rock Units in Egypt

143

Fig. 7.2 Field photograph showing the general view and the lithological characteristics of Umm Bogma Formation, Umm Bogma area, southwestern Sinai

(the uppermost Cambrian Araba Formation) at Wadi Khaboba, Gebel Nukhul and Wadi Shallal (Fig. 7.3a). Its upper boundary is overlain conformably by fine-grained sandstones with kaolinitic clays of the Carboniferous Abu Thora Formation [63] (Fig. 7.3a).

7.2.1.3

Lithology

The Umm Bogma Formation was divided into three informal members: Lower dolostone member, middle marly dolostone-siltstone member and upper dolostone member (Kora 1986). Later, Kora et al. formalized the above mentioned members, from base to top as follows: the Ras Samra, El Qor and Um Shebba members (Fig. 7.4a). The Ras Samra Member consists of pink-brown, hard, thickly bedded, coarsely crystalline dolostones (Fig. 7.5a). It contains vugs and cavities filled with calcite. In its type locality, it assumes 17 m in thickness in the western part of the Urn Bogma area and generally decreases towards the east. This member was eroded completely from Gabal Moneiga in the south and from Wadi Budra in the southwest. The main manganese-iron horizon is recorded in this member (Fig. 7.5a). El Qor Member comprises of alternations of yellow, moderately hard, thinly bedded marly

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Fig. 7.3 a Field photograph showing the lower boundary of Umm Bogma Formation with the underlying Araba Formation at Sarabit El Khadim, Umm Bogma area, southwest Sinai. b Field photograph manifesting the upper boundary of Umm Bogma Formation with the overlying Abu Thora Formation at Umm Bogma area, southwest Sinai

dolostones and dolomitic limestones with soft siltstones and shaly beds (Fig. 7.5b). The member is best developed underground in EI Qor area, where a maximum thickness of 17–24 m is recorded. The uppermost Um Shebba Member is brown and grey, very hard, thickly bedded and is crystalline dolostones, containing variable amounts of coarse sand grains and quartz pebbles (Fig. 7.5b). At its type locality it reaches up to 17 m thick. The economic development of the Um Bogma area is concerned mainly with the mining of the ferromanganese ores associated with the dolostone boundaries in the Um Bogma Formation.

7.2.1.4

Distribution and Thickness

It is encountered on the surface and in the subsurface. In west-central Sinai, the exposed Um Bogma Formation varies in thickness from 0 to 10 m in the southeastern and northeastern parts and reaches a maximum thickness of 30–40 m in the

7.2 Lower Carboniferous Rock Units in Egypt

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Fig. 7.4 Lithostratigraphic section illustrating the lithological characteristics of the Umm Bogma Formation at Umm Bogma, southwest Sinai (a), the Abu Thora Formation at El Hashash area, at Umm Bogma, southwest Sinai (b), Wadi Malik Formation, at Wadi Abdel Malik, Gilf plateau, northeast Gebel Uweinat, southwestern Desert (c)

northwestern part between Gabal Nukhul and Wadi Khaboba. It shows a gradual decrease in thickness towards the southeast. In the subsurface, it is encountered in the drilled wells in the El Qor area, Abu Thora and Um Rinna. It ranges in thickness from 22 to 18 m.

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Fig. 7.5 a Field photograph illustrates the lower member (Ras Samra) of the Umm Bogma Formation, which contains a manganese bed in the lower part of the Umm Bogma area, southwest Sinai. b Field photograph illustrating the middle (El Qor) and the upper (Um Shebba) members of Umm Bogma Formation, umm Bogma area, southwest Sinai

7.2.1.5

Age Assignment and Correlation

An Early Carboniferous (Viséan) age was attributed to the Um Bogma Formation, which is accepted by most workers, based on micro- and macrofossil contents (Mamet and Omara 1969; Brenckle and Marchant 1987; Kora 1989). The Late Visean coral/brachiopod assemblage restricted to the carbonates of EI-Qor Member in the middle of the Umm Bogma Formation Also, a brachiopod/trace fossil assemblage of Serpukhovian age were recognized. The Umm Bogma Formation can be correlated with the Lower Carboniferous Marar in Libya (Fig. 7.6a) and the lower part of the Bewarth Formation in Saudi Arabia (Fig. 7.6d), and with the Ora Shale in Iraq (Fig. 7.6e) (Table 7.2).

7.2.2 The Abu Thora Formation 7.2.2.1

Definition

The Abu Thora Formation was first named by Weissbrod (1980). This formation was formerly named Ataqa Series (Kostandi 1959), Upper Sandstone Series (Barron 1907), upper sandstone Formation (Omara and Schultz 1965), Ataqa Formation (Weissbrod 1969; Said 1971; Klitzsch 1990), the lower part of El Tih Sandstone

7.2 Lower Carboniferous Rock Units in Egypt

147

Fig. 7.6 Correlation of the Carboniferous rock units in Libya (a), Egypt (b), Jordan (c), Saudi Arabia (d) and Iraq (e)

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7 The Carboniferous Period

Table 7.2 Correlation of the Carboniferous rock units in Egypt with their equivalent rock units in Libya, Jordan, Saudi Arabia and Iraq

(Omara 1971). The nomenclatures, as mentioned earlier, do not follow the rules of the North American Stratigraphic Code (1983), therefore, we omitted the terms mentioned above herein. Soliman and Abu El Fetouh (1969) classified the rock mentioned above that restricted between Umm Bogma below and the Permo-Triassic sequence above into three formations from base to top: El-Hashash, Magharet El Maiah and Abu Zarab formations. Concerning the above classification of Soliman and Abu El Fetouh (1969), these formations cannot be mapped on aerial photographs or geologic maps. Thus such classification is obsolete herein, and we used the term Abu Thora Formation (Weissbrod 1980), referring to its extensive and common usage among geologists. The type section of this formation lies at Wadi Abu Thora, near Umm Bogma (Fig. 7.7).

7.2.2.2

Stratigraphic Contact

At the Umm Bogma area, the lower boundary of this formation is unconformably underlain by the Lower Carboniferous Um Bogma Formation (Fig. 7.3b). In Abu Durba, Wadi Feiran and Nadia El Samra, it unconformably overlies the Araba Formation (Fig. 7.8a). Its upper boundary is variable from one area to another, (1) it nonconformably underlies the basaltic flows at Wadi Abu Thora (El Kelani et al. 1999), (2) in Abu Durba area, it is overlain by the Upper Carboniferous Abu Durba Formation (Klitzsch 1990). In the northwest of Umm Bogma, it unconformably underlies the Lower Triassic Qiseib Formation (Fig. 7.8b). At Wadi El Dakhel, it unconformably lies below the Lower Cretaceous Malha Formation (Kora 1998).

7.2 Lower Carboniferous Rock Units in Egypt

149

Fig. 7.7 Field photograph illustrating the general lithological features and the three lithologic members of the Abu Thora Formation, El Hashash area, Umm Bogma area, southwest Sinai

7.2.2.3

Lithology

Lithologically, the Abu Thora Formation is light-coloured sandstone with subordinate claystone, green to grey shale; carbonaceous shale, coal seams and siltstones are the most abundant lithotypes (Fig. 7.4b). Weissbrod (1969) recognized two members of this formation: a sandy-clayey member at the base and a sandyquartzitic member at the top. Also, Kora (1998) divided this formation into two units, lower is the kaoline/coal member, while the upper consists of a glass-sand member. This formation is currently subdivided into three units (Fig. 7.4b). The lower unit consists of sandstone and thin beds of siltstone. The siltstone is white and thin-bedded look-like varves (Fig. 7.9a). The middle unit consists entirely of grey, pale green, and sometimes black laminated claystone with plant remains. Thin coal seams and sulfur pockets were recorded through the shale beds, especially in the middle part of the sequence. This unit exhibits sharp contact with the lower and upper members (Fig. 7.9b). The upper unit comprises the intercalation of sandstone and siltstone. Such succession shows two types of cycles. The first type occurs in the lower part of this member, comprising thin siltstone capped by thick massive sandstone (Fig. 7.10a). Another type of cycle constitutes two-thirds of the upper member and comprises thick, thin-bedded siltstone capped by thick bioturbated sandstone

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Fig. 7.8 a Field photograph illustrating the lower unconformable contact of the Abu Thora Formation with the underlying Cambrian Araba Formation, at Abu Durba, Wadi Feiran and the Nadia El Samra, southwestern Sinai. b. Field photograph illustrating the upper unconformable contact of the Abu Thora Formation with the overlying Lower Triassic Qiseib Formation, at Bedaa area, southwestern Sinai

(Fig. 7.10b). Some cycles consist of reddish, yellow claystone or paleosols enriched with plant roots and wood trunks (Fig. 7.11a). These wood trunks are usually fragmented and parallel to bedding plane (Fig. 7.11b). The sequence of Abu Thora Formation is intruded by basalt and dolerite dykes and sills in Um Bogma area and at Wadi Budra (El Kelani et al. 1999).

7.2 Lower Carboniferous Rock Units in Egypt

151

Fig. 7.9 a Field photograph illustrating the lithological features of the lower member at El Hashash area, Umm Bogma, southwest Sinai. b Field photograph illustrating the lithological features of the middle member (dark-grey claystone) and the massive sandstone of the upper member of Abu Thora Formation at El Hashash area, Umm Bogma, southwest Sinai

7.2.2.4

Distribution and Thickness

The Abu Thora Formation is widely distributed in the Um Bogma area extending eastwards to Wadi Mukattab and Wadi Feiran. It extends northwards, covering a wide area (at Bedaa and Thora) where it underlies the Permo-Triassic Qiseib Formation. The Abu Thora Formation measured 242 m at Wadi Abu Thora (the type section), 102 m at Wadi Mukattab, 60 m at Wadi Feiran and 66 m at Wadi Araba (El Kelani et al. 1999). It is well developed and best exposed at Wadi Abu Thora, Um Bogma, Wadi El Mukattab and Wadi El Shallal. The upper part of the section contains fossil plants.

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Fig. 7.10 a Field photograph manifesting the first type of cycle in the lower part of the upper unit and comprises thin siltstone at the base, capped by thick massive sandstone at the top, Abu Thora Formation, Gebel E l Marahil, Umm Bogma area, southwest Sinai. b Field photograph manifesting the second type of cycle that constitutes two-thirds of the upper unit. It consists of thick, thin laminated siltstone at the base, capped by thick massive sandstone, Abu Thora Formation, Gebel El Marahil, Umm Bogma area, southwest Sinai

7.2.2.5

Age Assignment and Correlation

Several workers recorded some plant remains in Abu Thora Formation (e.g. Ornara and Schultz 1965; Horowitz 1973; Kora 1984). These plants consist predominantly of poorly preserved stems and roots of Lepidodendron, Lepidodendropsis, Lepidophloios, Knorria, Sigillaria, Calamités, Bathrodendron, Noeggeratbia. The Abu Thora Formation is of Early Carboniferous (Visean) age as it contains Lepidodendron Sternberg, Lepidodendron veltheimii (El Kelani et al. 1999; Darwish and El Kelani 2001; El Kelani and Darwish 2001). An age ranging from the Late Viséan to the Early Namurian was suggested for the Abu Thora Formation, based on microfloral (Synelnikov and Kollerov 1959; Kora and Schultz 1987). In the Northern Wadi QenaWadi El-Dakhel, équivalent deposits were named Somr El Qaa Formation (Klitzsch 1990). This formation can be correlated with the Wadi Malik Formation in Gilf Kebir plateau and with the Desouqy Formation in the Siwa basin. In addition, it can be correlated with the Marar Formation in Lybia, Lower part of the Bewarth Formation in Saudi Araia and with the Ora Shale in Iraq (Fig. 7.6, Table 2.7).

7.2 Lower Carboniferous Rock Units in Egypt

153

Fig. 7.11 a Field photograph manifesting the occurrence of wood trunks in the upper member of Abu Thora Formation, Nadia Samra, east of Wadi Feiran, southwest Sinai. b Field photograph manifesting the occurrence of fragmented and broken wood trunks that usually parallel to the bedding plane in the upper member of Abu Thora Formation, Nadia Samra, east of Wadi Feiran, southwest Sinai

7.2.3 The Wadi Malik Formation 7.2.3.1

Definition

The Wadi Malik Formation was first coined by Klitzsch and Wycisk (1987) to describe the Lower Carboniferous rocks in Wadi Abdel Malik northeast of the Gilf Kebir plateau, northeast Gebel Uweinat. Before this date, Issawi and Jux (1982) and Issawi et al. (2009) proposed the term Gilf Formation to describe the Carboniferous sediments in the Gilf Kiber plateau. They mentioned that this formation occurs in Sinai, overlying the Ordovician Naqus Formation and underlying Permo-Triassic rocks. We disagree with the opinion mentioned earlier for the following reasons. (1) they did not manifest the definite type section of this formation in the Gilf Kiber plateau because this area includes Ordovician, Silurian, Carboniferous, Lower Cretaceous and Upper Cretaceous rocks. (2) they do not define the lower and upper boundaries of this formation at Gilf Kebir, (3) they stated that the Gilf Formation occurs

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in southwest Sian, overlying the Ordovician Naqus Formation and underlying the Permo-Triassic rocks, knowing that there was previous Upper Carboniferous Abu Durba Formation (Hasan 1967; Said 1971) overlying the Naqus Formation. (4) Many geologists studied this area (southwest Sinai) and did not observe and use the term Carboniferous Gilf Formation. For the reasons mentioned earlier, we rejected the name Gilf Formation for describing the Carboniferous rocks, and instead, we use the term Wadi Malik Formation proposed by Klitzsch and Wycisk (1987), Klitzsch (1990).

7.2.3.2

Stratigraphic Contact

In the southwestern Desert, at Karkur Murr, this formation nonconformably overlies the Precambrian basement rocks, while at Karkur Talh and east of Gebel Uweinat, it overlies the older Paleozoic rocks (Klitzsch et al. 1979; Said 1990). In most places, it conformably overlies the Devonian Tadrart Formation (Klitzsch and Schandelmeier 1990). Its upper boundary underlies the Upper Carboniferous North Wadi Malik Formation.

7.2.3.3

Lithology

The Wadi Malik Formation consists of marine sandstone, siltstone and shale interbedded with fluvial, deltaic and tidal sandstone (Fig. 7.12a). The formation comprises three lithologic units (Klitzsch and Wycisk 1987) (Fig. 7.4c). The lowermost unit consists of medium- to coarse-grained sandstone with grouped sets of smallto large-scale planar cross-bedding alternating with horizontally bedded mediumgrained sandstone (Fig. 7.12b). The middle unit includes fining-upward cycles; each begins with medium- to fine-grained sandstone, capped by thin laminated clayey, rippled siltstone and partly even laminated overbank deposits, which locally display pedogenetic features (Fig. 7.13a). This unit contains Lepidodendron Sp and Sigillaria sp. plant remains (Klitzsch and Wycisk 1987). The upper unit consists of largescale rippled fine-grained sandstone with shaly siltstone intercalations and horizontal strata. The main primary structures are ripple cross-lamination and ripple marks (Fig. 7.13b), even and wavy lamination and flaser-bedding (Klitzsch and Wycisk 1987). The upper part contains intensive bioturbation, trace fossils such as Bifungites and remains of brachiopods confirm the marine origin (Klitzsch and Wycisk 1987).

7.2.3.4

Distribution and Thickness

It is best exposed along the Wadi Abdel Malik and its side wadis in the Wadi Talh area, which reach from the southern and southwestern part of the immense plateau towards its relatively flat northern. Also, it occurs northeast of Gebel Uweinat at Karkur Mrr

7.2 Lower Carboniferous Rock Units in Egypt

155

Fig. 7.12 a Field photograph illustrating the lithological features of Wadi Malik Formation, Wadi Abel Malik, northeast Gebel Uweinat, southwestern Desert (after (Klitzsch and Wycisk 1987), Brugge 2020). b Field photograph illustrating the coarse-grained, massive sandstone of the lower unit of Wadi Malik Formation, Wadi Abel Malik, northeast Gebel Uweinat, southwestern Desert (after (Klitzsch and Wycisk 1987), Brugge 2020)

and northeast of Karkur Talh (Klitzsch and schandelmier 1990). Its thickness varies from 50 to 120 m.

7.2.3.5

Age Assignment and Correlation

This unit was assigned as Early Carboniferous age (Tournaisian to Visean) by Klitzsch et al. (1979), Klitzsch and Wycisk (1987), and Klitzsch and Squyres (1990). In marine beds are frequent brachiopods (Camerotoechia sp.), Sigillaria imprint on fine-grained sandstone (Fig. 7.14a), Lepidodendron sp. (Fig. 7.14b), Lepidofloyos SP., Heleniella eostulata, Lepidodendron veltheimii (Fig. 7.15a) and calamite Sp. (Fig. 7.15b) indication Visean (Early Carboniferous). This formation can be correlated with the Umm Bogma and Abu Thora formations in Sinai. Also, it can be correlated with the Desouqy and the Dhiffah formations in the Siwa basin, northwestern Desert. In addition, it is possible to correlate it with the Marar Formation in

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Fig. 7.13 a Field photograph illustrating the ripple marks of the middle unit of Wadi Malik Formation, Wadi Abel Malik, northeast Gebel Uweinat, southwestern Desert (after (Klitzsch and Wycisk 1987), Brugge 2020). b Field photograph illustrating the large-scale ripple marks of the upper unit of Wadi Malik Formation, Wadi Abel Malik, northeast Gebel Uweinat, southwestern Desert (after (Klitzsch and Wycisk 1987), Brugge 2020)

Libya, lower part of the Berwath Formation in Saudi Arabia and with the Ora Shale in Iraq (Fig. 7.6, Table 2.7).

7.2.4 The Desouqy Formation 7.2.4.1

Definition

This formation was named by Keeley (1989), describing the Lower Carboniferous rock in the subsurface in the northern Western Desert. Its type locality occurs at El Desouqy well-1, between interval 1933–2295 m (Fig. 7.16a).

7.2 Lower Carboniferous Rock Units in Egypt

157

Fig. 7.14 a Field photograph showing the wood fossil of Sigillaria imprint on fine-grained sandstone, Wadi Malik Formation, northeast Gebel Uweinat, southwestern Desert (after Lejal-Nicol, Brugge 2020). b Field photograph showing the wood fossil of Lepidodendron SP. imprint on finegrained sandstone, Wadi Malik Formation, northeast Gebel Uweinat, southwestern Desert (after Lejal-Nicol, Brugge 2020)

7.2.4.2

Stratigraphic Contact

The Desouqy Formation rests unconformably upon the progressively older, more argillaceous and thinner Zeitoun Formation (Keeley 1989). This formation lies disconformably over the inverted Ghazalat Basin. The upper boundary is usually sharp, sometimes complete, and conformable with the overlying Dhiffah Formation (Keeley 1989). In the northwest Faghur FRX-1 well, its lower contact is conformable to the older rocks (Keeley 1989).

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Fig. 7.15 a Field photograph showing the wood fossil of Lepidodendron aff. veltheimi imprint on fine-grained sandstone, Wadi Malik Formation, northeast Gebel Uweinat, southwestern Desert (after Lejal-Nicol, Brugge 2020). b Field photograph showing the wood fossil of calamite imprint on fine-grained sandstone, Wadi Malik Formation, northeast Gebel Uweinat, southwestern Desert (after Lejal-Nicol, Brugge 2020)

7.2.4.3

Lithology

This formation consists of kaolinitic sandstones, considered the dominant lithological constituent, with intercalation of minor layers of carbonaceous siltstones and mudstone (Fig. 7.16a) (Keeley 1989). Mudrocks are more abundant towards the top of the formation, indicating the retreat of continental facies belts, most probably in response to a regional rise in sea level (Keeley 1989). A suite of continental to shallow marine palaeo-environments is represented, from high—energy fluvial sandstones.

7.2.4.4

Distribution and Thickness

The formation ranges from about 100 m to more than 300 m in thickness. However, unlike all preceding facies patterns in the Western Desert, marine influences increase

7.2 Lower Carboniferous Rock Units in Egypt

159

Fig. 7.16 Lithologic log for the Desouqy Formation (a) and the Dhiffah Formation (b), Siwa Basin, northwestern Desert (after, Keeley 1989 with modification)

toward the west, as they do in all succeeding Palaeozoic formations. After the inversion of the Ghazalat Basin during Strunian times, a new depositional regime began, resulting in regional downwarp striking north—northwest along the present day Libyan border (where the Calanshiyu—Awaynat Arch was previously sited): the Tehenu Basin. Also active in this new regime was the Awaynat—Bahariyah Arch and a series of parallel high and low depositional axes (striking east—northeast).

160

7.2.4.5

7 The Carboniferous Period

Age Assignment and Correlation

Early Dinantian (Tournaisian to Early Viséan) (Keeley 1989). This formation can be correlated with the Umm Bogma and Abu Thora formations in Sinai, with the Wadi Malik Formation in Gilf Kebir plateau, southwestern Desert. In addition, it can be correlated with the lower Carboniferous rock units in Libya, Saudi Arabia and Iraq (Fig. 7.6, Table 2.7).

7.2.5 The Dhiffah Formation 7.2.5.1

Definition

This formation was established by Keeley (1989) to describe the Lower Carboniferous rocks in the Siwa Basin in the northwestern Desert. Its name was derived from the Dhiffah plateau adjacent to the Libyan border. Its type section occurs West of Faghur-lx between intervals: 2245–2641 m (Fig. 7.16b).

7.2.5.2

Stratigraphic Contact

The lower boundary of Dhiffah Formationis probably unconformable with the underlying Desouqy Formation, while its upper boundary is also unconformable with the overlying Upper Carboniferous Safi Formation. The unconformable relation with the subjacent and overjacent formation most probably referred to radical changes from mud to coarse clastic rocks. Keely (1989) stated that sharp changes in bulk lithology mark both boundaries.

7.2.5.3

Lithology

Calcareous, carbonaceous mud rocks dominate this formation with intercalation of sandstone and oolitic and bioclastic limestones (Keeley 1989) (Fig. 7.16b). The sandstone becomes more familiar towards the top. Also, the oolitic and bioclastic limestones are important as interbeds throughout the formation. The limestones are thick and prominent marker beds, one of which occurs close to the base and is named Lower Limestone, while the second occurs near the top and calls Upper Limestone (Keeley 1989). The claystone and sandstone are arranged vertically into fining-upward cycles, each of which comprises sandstone at the base and calcareous sandstone at the top (Fig. 7.16b). The thickness of carbonates and even the formation increase significantly westwards into the axis of the Tehenu Basin adjacent to Libyan borders and northwards into the site of Palaeotethys (Keeley 1989).

7.3 Upper Carboniferous Rock Units

7.2.5.4

161

Distribution and Thickness

Only in a few wells is the formation not truncated by ‘Variscan’ erosion; in these, the formation ranges between 300 and 450 m in thickness.

7.2.5.5

Age Assignment and Correlation

This formation was dated back to the Mid Dinantian (Early viséan) to Late Namurian based on the foraminiferal faunas and Palynological that examined from carbonates rocks (Keeley 1989, 1994). This formation was probably equivalent to the Assedjefar and Marar formations (Lelubre 1952) in Libya, with the lower part of the Berwath Formation (Hemer and Powers 1986) in Saudi Arabia with the Ora Shale in Iraq (Fig. 7.6, Table 2.7).

7.3 Upper Carboniferous Rock Units The Upper Carboniferous rock units include the Abu Durba Formation (sothwest Sinai), Rod El Hamal, Abu Darag and Aheimer formations (west of Suez Gulf, Eastern Desert), North Wadi Malik Formation (southwestern Desert) and Safi Formation (in subsurface, Siwa basin, northwestern Desert) (Table 7.1).

7.3.1 The Abu Durba Formation 7.3.1.1

Definition

The Abu Durba Formation was first established by Hassan (1967) and then formalized by Said (1971). Its type section occurs at Gebel Abu Durba, east of Belayim bay, on the eastern coast of the Gulf of Suez, southwest Sinai.

7.3.1.2

Stratigraphic Contact

The Abu Durba Formation unconformably overlies the Ordovician–Silurian Naqus Formation at Gabal Ekma (Fig. 7.17a). At the latter locality, the basal unconformable contact is characterized by sharp and uneven nature. It is represented by an about 40 cm-thick conglomerate bed consisting of quartz pebbles and granules embedded in coarse- and fine-grained sand and of lithoclasts from the underlying rocks at the basal part of the Abu Durba Formation (Soliman 2009). At Wadi Feiran and

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Fig. 7.17 a Field photograph manifesting the lower boundary of the Abu Durba Formation with the underlying Naqus Formation, Gebel. Emma, southwestern Sinai. b Field photograph manifesting the upper boundary of the Abu Durba Formation with the overlying Lower Cretaceous Malha Formation, Gebel. Ekma, southwestern Sinai

Umm Bogma areas, it unconformably overlies the Abu Thora Formation and unconformably underlies the Lower Cretaceous Malha Formation (El Kelani et al. 1999; Soliman 2009) (Fig. 7.17).

7.3.1.3

Lithology

In the Abu Durba area, the formation comprises claystone with intercalation of siltstone and sandstone (Fig. 7.18a). Three dolostone beds occur in the upper of the formation. This formation is made up of shallowing-upward cycle; each cycle begins with dark green to dark grey siltstone, capped by planar cross-bedded sandstone (Fig. 7.18). In the upper part, some cycle comprises green to yellow claystone, followed by dark-grey hard dolostone (Fig. 7.19). The middle comprises white or multi-coloured medium to coarse-grained sandstones ranging from thin-bedded to tabulate-planar cross-bedded. The upper part of the formation is characterized by

7.3 Upper Carboniferous Rock Units

163

the occurrence of a dark grey to green fossiliferous shale horizon with two sandy dolostones to dolomitic sandstone interbeds.

Fig. 7.18 Measured lithostratigraphic section of the Abu Durba Formation (a), Rod El Hamal Formation (b), Abu Darag Formation (c) and Aheimer Formation (d)

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Fig. 7.19 Field photograph illustrating measured lithostratigraphic section of the Abu Durba Formation, which comprises the cyclic sequence. Each cycle begins with dark green claystone, capped by a thin dolostone bed, at its type locality (Gebel Abu Durba), southwestern Sinai (after Kora 1992)

7.3.1.4

Distribution and Thickness

This formation is exposed at Wadi Feiran and Wadi Budra along the eastern coast of the Suez Gulf (El Kelani et al. 1999). It measures about 120 m at east El-Belayim Bay (Kora 1995). It occurs in southeast Abu Durba (60–180 m thick, Issawi et al. 2009) and south of Umm Bogma and Gebel Ekma (120 m, Soliman 2009).

7.3.1.5

Age Assignment and Correlation

The possible age of this formation is Moscovian (Issawi et al. 2009). In Sinai, this formation includes (1) three corals, Clisiophyllum ganooodi (Salée), Palaeacis sp. and Michelinia macerimuris Webb, (2) two bryozoans; Ascopora sp., and Stenophragmidium sp., and (3) five brachiopods; Reticulatia sp., Rhynchopora sp., Margincmatia moitordeiisis Gordon and Henry, Composita cf. ambigua (Sowerby) and Frechella sp. (Legrand-Blain) (Kora 1992, 1995). These fossils indicate Early Moscovian (Late Carboniferous) (Kora 1995). This formation can be correlated with

7.3 Upper Carboniferous Rock Units

165

the Rod El Hamal, Abu Darag and Aheimer formations in the western side of Suez Gulf, and with the Safi Formation in Siwa basin in Egypt. It is also correlated with the Dimbaba Formation in Lybia, Unayzah Formation in Saudi Arabia and the Qaraa Formation in Iraq (Fig. 6.7, Table 2.7). According to Kora (1992), the Abu Durba Formation is to be better correlated with the upper part of the Abu Darag Formation exposed on the western side of the Gulf of Suez.

7.3.2 The Rod El Hamal Formation 7.3.2.1

Definition

The term Rod El Hamal Formation was first introduced by Abdallah and El-Adindani (1963) for the Carboniferous strata at the southern footslope of the northern Galala Plateau. Its type locality occurs at the junction of Wadi Araba and Wadi Rod El Hamal and is represented in one composite stratigraphic section as shown in (Fig. 7.20). The Rod El-Hamal Formation occurs as small hills scattered at Wadi Araba (Fig. 7.20).

Fig. 7.20 Field photograph illustrating measured lithostratigraphic section of the Rod El Hamal Formation, Wadi Araba, southern northern Galala, Eastern Desert (after El Feky 2018)

166

7.3.2.2

7 The Carboniferous Period

Stratigraphic Contacts

The lower and upper contacts of the Rod El-Hamal Formation are challenging to distinguish. Meanwhile, Wadi Araba borehole No.1 overlies a fossiliferous black shale unit (“B member”) of the oil company geologists’ classification; Said 1971; Kora et al. 2019). Its lowermost bed is distinguished by highly ferruginous sandstone (El Feky 2018). On the other hand, its uppermost bed is a pebbly to cobbly-sized conglomerate. In the Wadi Araba area, the Rod El Hamal Formation unconformably underlies the lower Triassic red beds of the Qiseib Formation (Abdallah and El Adindani 1963; Darwish 1992; Issawi et al. 2009).

7.3.2.3

Lithology

According to Abdallah and Adindani (1963), the Rod El-Hamal Formation includes four lithologic units from base to top as follows (Fig. 7.18b), (1) sandstone and shale, (2) crinoidal dolomitic limestone with intercalation of claystone; (3) fossiliferous shale with intercalation of thin fossiliferous sandy limestone and Sandstone; (4) interaction of Sandstone, siltstone, fossiliferous marl and thin limestone bands. These siliciclastic rocks are sandstone, sandy claystone, shale, siltstone and claystone. Kora et al. (2019) recognized only three units. They combined the previously defined units 2–3 into a single variegated unit 2 composed of greenish fossiliferous marls and interbedded crinoidal dolomitic limestone beds, multicoloured shales and intercalated sandy limestone ledges, and thick, cross-bedded sandstone horizon capping the unit. The sandstone grades from very fine, fine, medium, to coarse-grained and pebbly Sandstone and is multicoloured (greenish white, red, yellow, grey, brown, yellowish white and yellowish brown). It characterizes by primary structures such as planar cross-bedding, flat bedding and herringbone cross-bedding. This Sandstone has fractures that are filled with iron oxides. Shale has different colours (reddish grey, reddish brown, grey) and fissile. Siltstone and claystone are multicoloured (brown, grey, violet, yellow and white) and contain plant roots. They also have nodules of ferruginous Sandstone. They are intercalated with sandstones and shale. The uppermost part of the Rod El-Hamal Formation is characterized by an occurrence of a thick (2 m) conglomerate bed (El Feky 2018).

7.3.2.4

Distribution and Thickness

Rod El-Hamal Formation occurs as small hills scattered at Wadi Araba (Fig. 7.20) At the junction of Wadi Rod El Hamal and Wadi Araba. the Rod El-Hamal Formation attains a thickness of 67.7 m (El Feky 2018).

7.3 Upper Carboniferous Rock Units

7.3.2.5

167

Age Assignment and Correlation

This formation contains corals and pelecypods in the upper member, which indicates Late Pennsylvanian (Early Carboniferous) (Abdallah and Adindani 1963). Kora (1995) dated this formation back to the Visean-Namurian age (Abdallah and Adindani 1963; Said and Eissa 1969; Said 1971; El Feky 2018). On the other hand, Darwish (1992) gave Rod El-Hamal Formation Carboniferous/Permian age. Ernst et al. (2020) identified well-preserved Bryozoans from Rod El Hamal Formation, indicating Upper Moscovian. The Late Carboniferous flora recorded from Rod El-Hamal Formation is represented by Lycophyta, Sphenophyta, Pterophyta and Cordaitophyta, similar to that recorded by Lejal-Nicol (1990) from the uppermost Carboniferous flora from Wadi Qaseib, 30 km to the north of Wadi Araba (Darwish and El Safori 2016).

7.3.3 The Abu Darag Formation 7.3.3.1

Definition

Abdallah and Adindani (1963) were the first to coin the term “Abu Darag Formation” for Carboniferous rocks which occur in the Abu Darag area to the north of Wadi Araba, along the Gulf of Suez coast (Fig. 7.21). Darwish (1992) considered that the Abu Darag Formation as a member or unit of the Rod El Hamal Formation. The type section of this formation is exposed at the core and southern flank of the Abu Darag anticline between Wadi Malha and 6 km south of Abu Darag Lighthouse with a maximum thickness of 175 m (Kora and Mansour 1992).

7.3.3.2

Stratigraphic Contacts

The base of the Abu Darag Formation is not exposed, while its upper contact is unconformably overlain by red and brown sandstones of the Lower Triassic Qiseib Formation (Kora and Mansour 1992; El Feky 2018). This unconformable contact is marked by a change in colour and lithology from yellowish-white, cross-bedded, medium-grained sandstone of the uppermost Abu Darag Formation and the red, brown, massive fine-grained sandstone and siltstone of the basal Qiseib Formation (El Feky 2018).

7.3.3.3

Lithology

The Abu Darag Formation consists mainly of sandstone, shale and siltstone intercalation. The Abu Darag Formation exhibits vertical change in lithology and can

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Fig. 7.21 Field photograph showing a general view of the Abu Darag Formation (AH). Western Northern Galala Plateau (El Feky 2018)

be subdivided into three units (Fig. 7.18c). The lower unit mainly consists of varicoloured claystone and siltstone intercalated with a few fine- to medium-grained sandstones. Each claystone bed is dark grey, with a thickness of 5–10 cm. The siltstone is reddish brown and attains a thickness ranging from 10 to 20 cm. the sandstone is white, fine- to medium-grained and massive with vertical burrows. The middle unit consists mainly of shale and claystone with two thin limestone beds in the upper part. The upper unit includes several shallowing-upward cycles; each comprises claystone at the base, followed by siltstone in the middle and limestone in the upper part (Fig. 7.17c) (Abdallah and Adindani 1963).

7.3.3.4

Distribution and Thickness

This formation occurs north of Wadi Araba along the western coast of the Suez Gulf. It attains a thickness of 175 m at its type locality (Abdallah and Adindani 1963). In south Ain Sukhna, it measures 148.5 m (El Feky 2018).

7.3 Upper Carboniferous Rock Units

7.3.3.5

169

Age Assignment and Correlation

Abdallah and Adindani (1963) identified gastropods, bivalves and bryozoans that suggest the Carboniferous/Permian age of the Abu Darag Formation. However, microfossils recorded in this formation indicate Carboniferous age (Said and Eissa 1969; Omara 1971; Abd El-Shafy 1988; El Feky 2018). This formation can be correlated with the Abu Durba Formation, Wadi Malik Formation at Gilf Kebir platea, and Northwadi Malik Formation. In addition, it is possible to correlate it with the Assedjefar and Dimbaba formations in Libya, Unayzah Formation in Saudi Arabia and with the Qaara Formation in Iraq (Fig. 7.6, Table 2.7).

7.3.4 The Aheimer Formation 7.3.4.1

Definition

The term “Aheimer Formation” was first introduced by Abdallah and Adindani (1963) for the Upper Carboniferous rocks that extend along the western side of the Gulf of Suez at the eastern side of the northern Galala Plateau (Fig. 7.22). Its type locality is at Wadi Aheimer, about 10 km southeast of Ain Sukhna (Lat. 29 31 N, Long. 32 28 E). Darwish (1992) considered the Aheimer Formation as a Rod El Hamal Formation unit.

7.3.4.2

Stratigraphic Contacts

The lower contact of the Aheimer Formation is unexposed (Kora 1998; El Feky 2018), while its upper contact is variable. This upper contact is unconformable in some places with the overlying Lower Triassic Qiseib Formation. The contact is between the yellowish-white, cross-bedded sandstones of the uppermost Aheimer Formation and the red, massive, fine-grained, non-fossiliferous sandstone beds of the overlying Qiseib Formation. In some places where the red beds were removed, e.g. on the northern footwalls of Wadi Aheimer and the northern face of Northern Galala, the upper contact is unconformable with the overlying Lower Cretaceous Malha formation (Swedan and Kandil 1990; Darwish 1992; Kora 1998; El Feky 2018). The contact is between the yellowish-white sandstones of the uppermost Aheimer Formation and the purple cross-bedded sandstone of the overlying Malha Formation (El Feky 2018).

7.3.4.3

Lithology

The Aheimer Formation is made up mainly of intercalations of clastic rocks (sandstone and shale) with some fossiliferous limestone and dolostone (Fig. 7.18d). It is

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Fig. 7.22 Field photograph showing a general view of the Aheimer Formation at the western side of the Northern Galala Plateau (El Feky 2018)

subdivided into three informal lithologic units from base to top as follows (Abdallah and Adindani 1963; Kora and Mansour 1992). The lower unit (shale series) is exposed 1.5 km south of Bir Abu Darag along Suez-Ras Gharib asphaltic road. It assumes 59 m in thickness and consists of entirely dark green and grey shale with thin intercalation of calcareous sandstone and siltstone (Abdallah and Adindani 1963) (Fig. 7.18d). The basal shales are rich in crinoidal columnals, bivalves, corals, brachiopods and bryozoans (Kora 1998). The middle unit (limestone series) is well exposed at the cliff that borders Wadi Aheimer. It comprises crinoidal limestone and fossiliferous limestone with interbeds of sandstone and siltstone (Abdallah and Adindani 1963) (Fig. 7.16b). The upper unit (silt-sandstone series) is exposed at the cliff, which forms the eastern termination of the great limestone plateau of the northern Galala (Abdallah and Adindani 1963). It mainly comprises intercalation of pale brown and white sandstone and dark grey, black fossiliferous shale.

7.3.4.4

Distribution and Thickness

The Aheimer Formation is exposed along the western coast of Suez Gulf, at the footslope of northern Galala. It also occurs north of Wadi Sweillim, where it upthrow

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171

against the Cenomanian Galala Formation (Abdallah and Adindani 1963). the thickness of the Aheimer Formation is about 123 m. It also occurs at the cliffs bordering Bir Aheimer between road marks 67, 6 and 79 km of the Suez- Gharib road, with an average thickness of 162 m (Kora 1998). The thickness of the highly faulted Aheimer Formation changes significantly from place to place within short distances. It assumes 65 m around Wadi Qiseib, 200 m south of Ain Sukhna (Kora 1998).

7.3.4.5

Age Assignment and Correlation

Abdallah and Adindani (1963) identified Orthis sp., Lophophyllidum sp., Neospirifer, sp. and corals in the lower and middle units that indicate Carboniferous/Permian age. The lower member is rich in fossils, e.g. rugose coral (Herbig and Kuss 1988; Kora and Mansour 1992). These corals are associated with Late Carboniferous brachiopods like Anthracospirifer sp. and Rugosochonetes Californians Watkins. In the Wadi Araba, a typical Permian flora dominated by Callipteris conferta (Sternberg) and Cordaites sp. is identified as an upper member of the Aheimer Formation (LejalNicol 1990; Kora 1998). Therefore, the Aheimer Formation ranges in age from the Late Carboniferous in its lower member to the Early Permian in its upper member (Abd El Shafy 1988; Kora 1998). The upper part of the Aheimer Formation that dated early Permian is separated in thesubsequent chapter (8) into an independent rock unit, named Wadi Dome Formation. However, Said and Eissa (1969) assigned it as the Carboniferous age. This formation can be correlated with the Safi Formation in the Siwa basin, the northwestern Desert, North Wadi Malik Formation at Gilf Plateau, and Abu Durba Formation in Sinai. Moreocer, this formation can be correlated with the Unayzah Formation in Saudi Arabia (Powers et al. 1966), Dimabah Formation in Lybia, Qaara Formation inIraq (Fig. 7.6, Table 2.7).

7.3.5 The North Wadi Malik Formation 7.3.5.1

Definition

The Northern Wadi Malik Formation was established by Klitzsch and Wycisk (1987): Its type locality occurs north of Wadi Abdel Malik and occurs as low-hills (Fig. 24) (klitzsch and Lejal-Nicol 1984).

7.3.5.2

Stratigraphic Contact

The lower contact of this formation is erosional and undefined, probably above the Ordovician Karkur Talh or on the Silurian Umm Ras Formation (Klyitzsch 1990). Its upper contact is presumably unconformable below the Permo-Triassic rocks (Klitzsch and Wycisk 1987; Lejal-Nicol 1987). Moreover, Its upper boundary

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unconformably underlies the Lower Cretaceous Six Hills Formation at Abu Ras Plateau and north Wadi Abdel Malik or the Permian Lakia Formation (eastern slopes of G. Uweinat) (Ouda 2021).

7.3.5.3

Lithology

This formation differs radically from the Wadi Malik Formation as it contains two units (Fig. 7.23a). The lower unit comprises fluvioglacial sediments comprising sand, conglomerate, boulders and blocks of older strata embedded in a clayey groundmass in the lower part with some channel tills (Fig. 7.24a) (klitzsch and Lejal-Nicol 1984; Ouda 2021). On the top of glacial-fluvial beds, there are parallel sandstone and siltstone, look-like varves (30 m thick) enriched with plant remains (Fig. 7.24b) (Klitzsch and Schandelmeir 1990). Further southward, at the northeastern (KarkurTalh) and southeastern (Karkur Murr) slopes of Gebel Uweinat, the formation is made up of 40–120 m. The varve-like siltstone dominates the whole formation (Fig. 7.22c) (Klitzsch and Schandelmeier 1990).

7.3.5.4

Distribution and Thickness

This formation occurs at Wadi Abdel Malik and south of Gebel Uweinat, and extends southward north of Sudan (Klitzsch and Schandelmeier 1990). It ranges in thickness from 30 to 60 m.

7.3.5.5

Age Assignment and Correlation

No fossil content has been recorded, but the top part of this formation at its type locality north of Wadi Abdel Malik is made up of parallel-bedded sandstone containing plant fossils of the Late Carboniferous age (klitzsch and Lejal-Nicol 1984; Klitzsch and Schandelmeier 1990). This formation can be correlated with the Abu Durba Formation in Sinai, Rod El Hamal, Abu Darag and Aheimer formations, west of northern Galala. It also, can be correlated with the Dimbaba Formation in Libya, Unayzah Formation in Saudi Arabia and with the Qaara Formation in Iraq (Fig. 7.6, Table 2.7).

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Fig. 7.23 Lithostratigraphic section of North Wadi Malik Formation (a) and the Safi Formation (b)

7.3.6 The Safi Formation 7.3.6.1

Definition

Keeley (1989) coined Safi Formation to describe the Upper Carboniferous rocks in the Siwa basin, northwestern Desert. Its type section occurs at Siwa well-1, between intervals 812–967 m (Fig. 7.23b). Its name was attributed to the spring Ain es Safi.

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Fig. 7.24 Field photograph showing the general view of the North Wadi Malik Formation, which includes low scattered hills, the Gilf Kiber plateau, northeast Gebel Uweinat (Klitzsch and Wycisk 1987)

7.3.6.2

Stratigraphic Contact

The lower contact of the Safi Formation with the underlying Dhiffah Formation is believed to be abrupt, without a significant break in sedimentation (Keeley 1989). Keeley (o.p.) mentioned that there is no stratigraphical conformable relation with the underlying Dhiffah Formation due to the effects of ‘Variscan’ erosion. Its upper contact was only encountered in three wells. Indeed, sediments no older than Cenomanian lie unconformably over the Safi Formation.

7.3.6.3

Lithology

Sandstones and siltstones are the dominant lithologies; mudstones and oolitic limestones become volumetrically important north of 30° N. Low hinterland relief and a steadier sea level contributed towards a more homogeneous vertical sequence (Fig. 7.23b).

7.4 Carboniferous Rocks in Adjacent Countries

7.3.6.4

175

Distribution and Thickness

This formation is only preserved in the three westerly wells (Siwa-1, Faghur FRX-l and West Faghur-lx) due to ‘Variscan’ erosion. Therefore, knowledge of the facies represented in the Safi Formation is incomplete. Nevertheless, it is apparent that the Tehenu Basin was still active during Safi Formation times, with indications that fluvial-deltaic sands in the east probably pass westward and northward first into pro-delta claystone and then a carbonate ramp [46].

7.3.6.5

Age Assignment and Correlation

The probable age of this formation is Late Namurian to Early Permian (Keeley 1989). It can be correlated with the North Wadi Malik Formation in the southwestern Desert, the Abu Durba Formation in Umm Bogma, central Sinai and the Aheimer Formation (Abdallah and Adindani 1963) on the western side of Suez Gulf (Fig. 7.6). It also can be correlated with the Upper Carboniferous Unayzah Formation (Al Laboun 1987, 1988) in Al Qasim Province, Central Saudi Arabia, with the Upper Carboniferous Dimbabah Formation in Lybia and with the Qaara Formation in Iraq (Fig. 7.6, Table 2.7).

7.4 Carboniferous Rocks in Adjacent Countries 7.4.1 In Libya The Carboniferous rocks were studied under three rock units, the Marar Formation at the base, Assedjefar Formation in the middle and Dimbabah Formation at the top. Lelubre (1946) first defined the Marar Formation by referencing a type section at Qararat a1 Marar northwest of the A1 Qarqaf Arch. At the type location, the Marar Formation comprises two members (Hallett 2002), the lower member consists mainly of interbeds of siltstone, claystone and thin fine sandstone (Fig. 7.6a). The upper member is made up of coarsening-upward cycle, each of which begins with claystone and siltstone, capped by planar cross-bedded sandstone (Hallett 2002). This formation assumes about 400 m thick, and its age ranges from an Upper TournaisianEarly Viseanage. The Assedjefar Formation was defined by Lelubre (1952) in the Hamadat Tanghirt area west of Libya. The formation conformably overlies the Marar Formation, while its upper contact is conformable with the overlying calcareous marine bed of the Dimbabah Formation (Massa et al. 1974). This formation includes two members (Hallett 2002). The lower member consists of dominantly sandy facies comprising coarse-grained, cross-bedded sandstones with fossil wood. The upper member comprises a shallowing-upward cycle, which starts with claystone and is followed by cross-bedded sandstone and dolostone. Its thickness ranges from 50 to

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120 m. The Assedjefar Formation contains rich faunas of brachiopods, pelecypods, corals and foraminifera. The lower part contains faunas indicative of the Visean, while the upper part contains Serpukhovian fauna (Massa et al. 1974). The Dimbabah Formation was originally defined by Lelubre (1952) and comprises series of mainly carbonate rocks overlying the Assedjefar Formation in the Hamadat Tanghirt. The Dimbabah Formation comprises claystone, siltstones and thin-bedded argillaceous limestones in the lower part and dolomites and dolomitic limestones interbed in the upper part (Hallett 2002). This formation has an average thickness of 65 m. It is enriched with brachiopods, echinoderms and gastropods, which give a Bashkirian age for the lower unit and a Moscovian to Gzelian age for the upper unit (Lelubre 1952).

7.4.2 In Jordan The Carboniferous rocks were not deposited in Jordan. Because no sediments Carboniferous sediments are exposed in Jordan were deposited between early Devonian and late Permian (Fig. 7.6c). Either there was no deposition or former deposits were eroded (Bandel and Salameh 2013).

7.4.3 In Saudi Arabia The Carboniferous rocks include two rock units, the Berwath Formation at the base and the Unayzah Formation at the top (Fig. 7.6d). The Berwath Formation was established by Hemer and Powers (1968), and its name derived from Wadi Aba ar Ruwath northwest of Saudi Arabia. This formation only occurs in the subsurface in the Widyan basin (Al Laboun 1982). Its base is unexposed, while its upper boundary disconformably underlies the Unayzah Formation (Fig. 7.6d). This formation assumes about 190 m and comprises medium- to coarsegrained with some intercalation of claystone (Al Laboun 1987). Its age ranges from Early to Late Carboniferous. The Unyazah Formation was derived from the Unayzah town in Al Qasim Province, central Saudi Arabia (Al Laboun 1987). At Its type locality, this formation disconformably overlies the Ordovician Anz Formation and unconformably underlies the Middle Permian Khuff Formation (Khalifa 2015). It assumes 30 m in thickness and consists of intercalation of sandstone, claystone, and dolomitic limestone containing fossil plants, indicating Late Carboniferous to Early Permian (El Khyal et al. 1980).

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7.4.4 In Iraq The Carboniferous rocks include three formations, the Ora Shale at the base, the Harur Formation at the middle and the Ga’ara Formation at the top (Arqawi 1998) (Fig. 7.6e). The Ora Shale Formation (Early Carboniferous) is described from northern Iraq as dark calcareous shales interbedded with silty marls, lenticular organic limestones and fine-grained limestones, with a thickness of up to 220 m (Wetzel 1952). The Harhur formation (50–60 m thick) conformably overlies the Ora Shale Formation, but a sedimentation break marks the formation”s top. It consists of organic detrital limestone interbedded with thin micaceous shales (Arqawi 1998). This formation is dated as Early to Middle Carboniferous (early Tournaisian). The Qaara Formation comprises 850 m intercalation of sandstones and shales and constitutes the Upper parts of the Upper Carboniferous rocks (Westphalian to Early Stephanian age). The latter formation is widely-distributed throughout the Western Desert, and most probably the Southwestern Desert, and extends in age up to the Early Permian (Buday 1980).

7.5 Depositional Environments In the North African region, the Late Devonian Acadian movement continued into the Carboniferous, making a stable platform that was characterized by a cessation in sedimentation during the Early Carboniferous time ((Tournaisian–Visean) (Craig et al. 2008). This tectonic event was registered along North Africa, e.g. Libya, Egypt, Jordan, and Saudi Arabia. This cratonic setting is evidenced by the absence of sediments in such countries (Echikh 1998). During this event, there are frequent breaks in the cycles and the development of angular unconformities (Guiraud et al. 1987; Guiraud and Bosworth 1999). Deformations associated with this event correspond to the movement of major NW–SE trending strike-slip faults, which are associated with local folding and uplifts. This tectonic event corresponds to the first stage of the Hercynian Orogeny (Acadian Unconformity) (Guiraud and Bellion 1995). This event resulted in the nondeposition of Early Tournaisian in the Ghadames in Libya (Echikh 1998). In addition, during the Early Carboniferous (Tournaisian age), there was no record of sediments in Egypt, Saudi Arabia, Jordan and Iraq. This indicates there is significant hiatus between the Devonian and Carboniferous. Sea-level rise during the Early Carboniferous (Visean time) resulted in widespread shallow marine to deltaic facies across large parts of North Africa. In Egypt, the Carboniferous rock units with different lithology were deposited in separated or disconnected basins, separated by platform due to the tectonic uplift dominated during this period. These basins are the Umm Bogma basin (southwest Sinai), Eastern Desert platform, Siwa basin (northwestern Desert) and fluvial area (Eastern Desert northeast of Gebel Uweinat and Gilf Kebir) (Fig. 7.26). In Umm Bogma basin that extends northwest-southeast direction include the Lower Carboniferous

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Umm Bogma and Abu Thora formations. The Umm Bogma Formation comprises three members, bedded dolostone with manganese pockets and lenses at the base, marl and thin beds of dolomitic limestone in the middle and thin-bedded dolostone in the upper part (Kora 1986, 1995; Ernst et al. 2020). It contains mega fossils of brachiopods, bryozoan and corals (Kora 1986, 1995). This indicates that it was deposited early as limestone in a subtidal marine environment. Restriction of the Umm Bogma basin, evidenced by decreasing thickness in all directions, had resulted in the dolomitization of all formerly deposited carbonate rocks. The restriction gave rise to shallowing of water and an increase in evaporation. This increased Mg ions at the expense of calcium ions needed to replace limestone with dolostone. In the Umm Bogma basin, there was shallowing upward at the end of the Lower Carboniferous, resulting in the deposition of sandstone, black claystone, thick sandstone, and fine sandstone at the top of the Abu Thora Formation. The presence of black to dark green shale enriched with plant remains indicates deltaic environments. In the geological record, the swamp is regarded as a forested wetland and considered transition zones between land and water (Keddy 2010). However, the black shale was interpreted to be deposited in semi-deep to deep water shelves, where the input of terrigenous quartz was less abundant (Yi et al. 2018). The common presence of wood trunks and plant remains in the upper sandstone facies can also suggest coastal marine, swamps and deltaic environments. In the Eastern Desert platform, the Lower Carboniferous rocks were not encountered in the west of Suez Gulf, they may have occurred in the subsurface, but they appear in Wadi Qena and Quseir-Qift road. In the latter locality, the facies are closely similar to the Abu Thora Formation and, in turn, their depositional environments on a flat platform in a fluvio-marine environment (Fig. 7.26). This platform continues westwards until they reach the southwestern Desert, northeast Gebel Uweinat. In the latter locality, the lower Carboniferous rocks are represented by the Lower Carboniferous Wadi Malik Formation. Most of the facies comprise coarse-grained sandstone with thin interbeds. These rocks contain Lepidodendron sp., Sigillaria sp. and calamite Sp. Plant remains (Klitzsch 1984; Klitzsch and Wycisk 1987). These facies associated with plant remains confirms the fluvial condition closely similar to those found in AbuThora Formation. In the Siwa basin, the lower Carboniferous rocks are represented by the Desouqy and the Dhiffa formations. The Desouqy Formation consists of kaolinitic sandstone with thin interbeds of claystone. Such facies were possibly deposited in coastal to deltaic settings, similar to the Abu Thora Formation in Sinai. Further westwards in Libya, slight subsiding deposited the Marar Formation (Fig. 7.26). Subsiding or increase in sea level occurred in the Siwa basin, giving rise to sedimentation of shallow subtidal limestone and claystone of the Dhiffah Formation and the Assedjefar Formation in Libya (Figs. 7.25, 7.26). In Late Carboniferous time, there was a limited basin in Gebel Abu Drba and west of Suez Gulf, platform in southwestern and northwestern Deserts and synchronous basin in Libya (Fig. 7.27). In these basins there was a marked increase in sea-level, depositing deep subtidal marine facies, consisting of green, and black claystone with intended of thin beds of limestone and dolomitic limestone. This appears in the Upper Carboniferous Abu Durba Formation (in the Umm Bogma basin), Rod El Hamal,

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179

Fig. 7.25 a Field photograph showing the tillite glacial sediments of the lower unit of the North Wadi Malik Formation, Gilf Kiber plateau, northeast Gebel Uweinat (Klitzsch and Wycisk 1987). b Field photograph showing the thin-bedded siltstone (look-like varves) sediments of the upper unit of the North Wadi Malik Formation, Gilf Kiber plateau, northeast Gebel Uweinat (Klitzsch and Wycisk 1987)

Fig. 7.26 East–west schematic cross section illustrating the vertical and lateral facies changes and correlation of the Egyptian Lower Carboniferous basins (the Umm Bogma basin, western Suez Gulf basin, southeastern Gebel Uweinat, Siwa basin) and Libya

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Fig. 7.27 East–west cross section illustrating the vertical and lateral facies changes and correlation of the Egyptian Upper Carboniferous basins (the Umm Bogma basin, western Suez Gulf basin, southeastern Gebel Uweinat, Siwa basin) and Libya

Abu Darag and Aheimer formations (west of the Suez Gulf basin), and Dimbaba Formation in Libya (Fig. 7.27). Most of the lithofacies comprise shale, claystone with interbeds of limestone and dolomitic limestone, enriched with corals, bryozoa, and brachiopods (Kora and Mansour 1992; Kora 1991, 1992). These facies were probably deposited in outer ramp settings and outer neritic environments (Burchette and Wright 1992; Flugel 2004, 2010). On the platform setting, occurring in the southwestern Desert, the glacial sediments of the North Wadi Malik were deposited. Northwards in Siwa basin the sandstone, claystone and oolitic limestone of the Safi Formation were deposited on that platform. In Egypt, northwest-southeast domal structures have been particularly active in the Umm Bogma area. This is particularly noticeable; for example, one northwest fold occurs in south Wadi Feiran and north of Gebel Ekma. This prevented the deposition of the Early Carboniferous sediment (Umm Bogma and Abu Thora formations) and permitted the deposition of the Upper Carboniferous Abu Durba Formation above the Ordovician Naqus Formation. The second trend domal structure occurs northeast of the Umm Bogma area and southwest of the Tih escarpment; this trend prevented the deposition of the Early and Late Carboniferous sediments (Umm Bogma, Abu Thora and Abu Durba formations). This is evidenced by the Lower Cretaceous Malha Formation that directly overlies the Ordovician–Silurian Naqus Formation, especially at Gebel Gunna. Based on facies types, their distribution and the associated tectonics, it can be possible to draw a general paleogeographic covering the studied countries, e.g. Libya, Egypt. Jordan, Saudi Arabia, and Iraq. On this map, different depositional environments have been reported. These are (1) cratonic region, (2) fluvial environment, (3) marginal marine, and (4) deep subtidal environment and (5) glacial sediments, (Fig. 7.28).

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Fig. 7.28 Paleogeographic map manifesting the possible depositional environments of the Carboniferous rocks in Libya, Egypt, Jordan, Saudi Arabia and Iraq

1. The uplifted and cratonic region covers most of Jordan and central and northeastern Sinai. No sediments are exposed in Jodan between the early Devonian and late Permian. The missing of these rocks either there was no deposition or the former deposited were eroded (Bandel and Salameh 2013). Moreover, in northern and northeastern Sinai, there is no record of the Carboniferous rocks except for the presence of the lower and Upper Carboniferous rocks (Umm Bogma, Abu Thora and Abu Durba formations), were filled the local basin in southwestern Sinai. As mentioned earlier, the missing Carboniferous rocks in the areas were due to significant uplift during Famennian (late Devonian) to early Tournaisian (early Carboniferous) times. This gave rise to erosion which removed most of the Devonian, Silurian and Ordovician sediments from the area of Jordan, Palestine and Israel, including Sinai (Bandel and Salameh 2013). The area was uplifted again at the end of the Carboniferous or early Permian, and much of the former sediments were removed by erosion. In addition, the missing of Carboniferous rocks in such regions was most probably due to the effect of Hercynian orogeny. The Hercynian unconformity cuts enormously across various Palaeozoic stratigraphic units, reaching as deep as the Cambro-Ordovician (Craig et al. 2008). 2. Fluvio-marine environment occurs in most Saudi Arabia and Egypt (Fig. 7.27). In Saudi Arabia, this environment is represented by the lower Carboniferous Berwath and the Unayzah formations. This formation was encountered in the subsurface only and described in the Widyan basin, northern Saudi Arabia (Al Laboun 1982). This formation was deposited in the nonmarine environment (Hemer and Powers 1968) due to the presence of abuudant spores and vascular plants and the absence of marine fauna (Hemer and Powers 1968). Also, the

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dominance of sandstone facies with thin claystone stacked vertically into finingupward cycles suggests the fluvial regime. Fining-upward cycles are present in the sandy braided fluvial units of the West water Canyon Member, an Upper Jurassic Morrison Formation in northwestern New Mexico (Godin 1991) and the fluviatile sedimentation (Allen 1970). The probable main factor in the deposition of pure sandstone facies of the Berwath Formation is the deposition on uplifted area, as found in Hail-Rutbah Arch that extended NWW-SEE direction, covering Saudi Arabia and Iraq (Powers et al. 1966; Al Laboun 1986). While in Egypt, the Wadi Malik Formation covers most of the Eastern and Western Deserts and a limited area at Umm Bogma in Sinai (Abu Thora Formation). This formation comprises sandstone entirely with thin beds of siltstone enriched with plant remains and wood trunks. 3. Deep subtidal or inner neritic environment: This environment covers most of Libya, Iraq and a limited area in Egypt (the wadi Araba and west of Suez Gulf. In this environment, seawater dominantly covers this area. The facies are mainly of claystone, sandy clay, marl and fossiliferous limestone as found in the Assedjefar and Dimbaba formations in Libya, Ora Shale and Harhur formations in Iraq, Rod El Hmamal, Abu Darag and Aheimer formations (western Suez Gulf basin in Egypt) (Fig. 7.27). The mixing of siliciclastic-carbonate facies can be attributed to the following factors: (1) eustatic sea level, (2) climatic changes, and (3) tectonic pulses. Eustatic sea levels can affect the vertical distribution of the mixed facies. The claystone facies is commonly interpreted to reflect a transgressive deepening phase, while carbonate represents progressive shoaling. Osleger and Montanez (1996) mentioned that during long-term progradation during highstand system tract siliciclastics were migrated on top of carbonate by Aeolian or fluvial processes, while, during the early phases of the subsequent relative sea-level rise, siliciclastic source area was pushed back toward the craton margin and depositing carbonates. Climatic changes are responsible for the supply of fine siliciclastics; this may take place during humid conditions. This hypothesis was described in the southern Alpine Rhaetic sediments by Burchell et al. They stated that the high-frequency terrigenous clay can be derived from the humid condition, and is the same time, the carbonate sedimentation was negligible. During dry climates, clays’ derivation is minimal, and carbonate formation increases to reach a maximum at the top. The structural control can create the source area that supplies the fine siliciclastic influx onto the platform (Oslegerand Montanez 1996). In addition, the siliciclastic influx may have partially “poisoned” the carbonate production factory. 4. Glacial environment: The Permo-Carboniferous ice sheet on the PalaeoGondwana continent increased in mass periodically and withdrew again (Bandel and Salameh 2013). The glacial sediments were recognized in the different geographical places representing parts of the ancient Gondwana continent, e.g. India, Antarctica, Africa-Arabia and South Africa (Visser and Kingsley 1982; Visser 1997). The glacial sediments have limited occurrence in north Africa and Arabia. In Egypt, the glacial sediments are found in the basal part of the North Wadi Malik Formation, represented by diamictites, boulders and gravel-sized

References

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sediment embedded in claystone (Klitzsch and Wycisk 1987). At the same time, the upper part of the formation, as mentioned earlier, comprises thin siltstone sediments that look like varves. Such sediments most probably represent deglacial sediments (Klitzsch 1990). In Saudi Arabia, glacial sediments are recognized in the Carboniferous Unayzah Formation, which is exposed in the central part of Al Qasim Provine (Khalifa 2015). The lower member consists of stratified diamictite (glacial outwash deposits), mottled mudstone–diamictite embedded in claystone and horizontal groves (Khalifa 2015). By Late Carboniferous times, the deposition of marine siliciclastics was restricted to northwest Africa and the northernmost parts of northeast Africa, e.g. Cyrenaica and the Gulf of Suez area. The uplift may be associated with the ejection of alkaline magmatic basalt in eastern Egypt (Grabowski et al. 2002). This basaltic lava or sheets covered the Abu Thora formation in the Umm Bogma area, southwestern Sinai.

References Abd El- Shafy E., 1988. On some problematic Mesozoic exposures on the western side of the Gulf of Suez, Egypt. Bull Fac. Sci., 10: 53–78. Abdalla, A. M., and Adendani, A., 1963. Stratigraphy of the upper Paleozoic rocks, western side of Gulf of Suez. Egypt. Geol. Surv. Egypt. Paper 25, 18 pp. A1 Laboun, A A. 1986. “Stratigraphy and hydrocarbon potential of the Paleozoic succession in both Tabuk and Widan basins, Arabia”. In: Future Petroleum Provinces of the world. Halbouty, M. (ed.) AAPG Memoir, Vol. 40, p. 373–396. Al Laboun , A.A. 1987. Unayzah Formation: A new Permian-Carboniferous unit in Saudi Arabia. – American Association of Petroleum Geologists, Bulletin, 71: 29–38. Al Laboun A A, 1988. The distribution of Carboniferous-Permian siliciclastic rocks in the greater Arabian basin. Geol. Soc Am. Bull. 100: 362–373. Al Laboun, A. A 1982. The subsurface stratigraphy of the pre-Khuff Formation in central and northwestern Arabia. Ph. D. dissertation, King Abdulaziz Univ. Allen, J. R. L. 1970. Studies in fluviatile sedimentation: a comparison of fining-upwards cyclothems, with special reference to coarse member composition and interpretation. J. Sedim. Petrol. 40, 298–323. Aqrawi, A. A. M. 1998. Paleozoic Stratigraphy and Petroleum Systems. Ball, J. 1916. The geography and geology of west-central Sinai. 219 p. Egyptian Survey Department, Cairo. Bandel, K., Salameh, E., 2013. Geologic development of Jordan. Evolution of its rocks and life. The Hashemite Kingdom of Jordan. The deposit Number of the National library,690/3/2013. Barron, T. (1907): The topography and geology of the peninsula of Sinai (Western portion): Survey Dept., Cairo, 241 p. Brenckle, P.L. and Marchant, T.R 1987. Calcareous microfossils, depositional environments and correlation of the Lower Carboniferous Urn Bogma Formation at Gebel Nukhul, Sinai, Egypt. Journal Foraminiferal Research 17, 74–91. Brugge, N. 2020. Structure and Geology of Jebel Uweinat in the three-country triangle EgyptSudan-Libya, internet report. Carbo. Evap. 30, 207–227.pp Buday, T. 1980. The Regional Geology of Iraq. Stratigraphy and Palaeogeography. Dar Al-Kutub Publishing House, University of Mosul, Iraq. v. 1.

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Burchette, T.P.; Wright, V. P. 1992. Carbonate ramps depositional systems Carboniferous unit in Saudi Arabia. Am Assoc Pet Geol Bull, 71:29–38. Conybeare, W. D.; Phillips, W., 1822. Outlines of the geology of England and Wales: with an introductory compendium of the general principles of that science, and comparative views of the structure of foreign countries. Part I. London: William Phillips. OCLC 1435921. Craig J, Rizzi C, Said F et al (2008) Structural styles and prospectivityin the Precambrian and Palaeozoic hydrocarbon systems. In Conference proceedings, geology of east Libya symposium 2004, Binghasi, 52 pp (preprint). Cossey, P.J.; Adams, A.E.; Purnell, M.A.; Whiteley, M.J.; Whyte, M.A.; Wright, V.P. (2004). British Lower Carboniferous Stratigraphy. Geological Conservation Review. Peterborough: Joint Nature Conservation Committee. p. 3. ISBN 1-86107-499-9. Darwish, M. 1992. Facies developments of the Upper Paleozoic–lower Cretaceous sequences in the Northern Galala Plateau and evidences for their hydrocarbon reservoir potentiality, Northern Gulf of Suez, Egypt. Cairo University, Cairo, 75–214. Darwish, M. H. and El Safori, Y. 2016. Late Carboniferous Macroflora from Rod El-Hamal Formation Wadi Araba, North Eastern Desert, Egypt. Taeckholmia 2016(36): 45–60. Darwish, M.H. & El-Kelani, A. 2001. Lower Carboniferous plants from Abu-Thora Formation in Southwest Sinai. Taeckholmia 21(1):27–34. Davydov, V.I.; Korn, D.; Schmitz, M.D.; Gradstein, F.M.; Hammer, O. (2012), “The Carboniferous Period”, The Geologic Time Scale, Elsevier, pp. 603–651. El Feky, A. A. 2018. Sedimentological studies of the Carboniferous rocks on the western side of the Gulf of Suez, northeastern Desert, Egypt. M. Sc. Thesis, Menoufia University. Echikh, K., (1998). Geology and hydrocarbon occurrences in the Ghadamis Basin, Algeria, Tunisia, Libya. In: Petroleum Geology of North Africa (eds D.S. Macgregor, R.T.J. Moody, D.D. ClarkLowes). Geol. Soc. London, Sp. Publ., 132, 109–129. El Kelani A., El Hag I., Bakry H. and Shaira M. 1999. Type and stratotype sections of the Paleozoic in Sinai, Sp. Pub. No. 77, 94p., EGSMA, Cairo. El Kelani, A. Darwish, M. 2001. Lithostratigraphy and plant fossils of the Lower Carbniferous Abu Thora Formation, southwest Sinai, Egypt. Ann. Geol. Surv. El Khyal, A. A.; Chaloner, W. G.; Hill, C.R. 1980. Paleozoic plants from Saudi Arabia. Natur, 285: 33–34. Ernsta A.; Mahmoud Korab, M.; Heba El-Desoukyb, H.; Hans-Georg Herbigc, H.G.; Patrick, N. Wyse Jacksond, W. 2020. Stenolaemate bryozoans from the Carboniferous of Egypt. Jou. Afr. Ear. Sci. 165: 103811. Flügel, E. 2004. Microfacies of Carbonate Rocks, Analysis, Interpretation and Application Springer – Verlag, New York. Flügel, E. 2010. Microfacies of Carbonate Rocks: Analysis, Interpretation and Application (second ed.), Springer, Heidelberg Dordrecht London, New York. Geological Society of South Africa, v. 85, p. 71–79. Guiraud, R.; Bosworth, W., 1999. Phanerozoic geodynamic evolution of northeastern Africa and the northwestern Arabian platform. Tectonophysics 315: 73–108. Guiraud, R., Bellion, Y., (1995). Late Carboniferous to Recent, Geodynamic evolution of the west Gondwanian, cratonic, Tethyan margins. In: Nairn, A. E. M. et al. (Eds.), The Ocean basins and margins, vol. 8. Plenum Press, New York, 101–123. Guiraud, R., Bellion, Y., Benkhelil, J., Moreau, C., (1987). Post-Hercynian tectonics in Northern and Western Africa. Geological Journal, 22, 433–466. Godin, P. D., 1991. Member (Upper Jurassic), Morrison Formation, New Mexico. Sedi. Geol., 70: 61–82. Grabowski, G. J., Sullivan, M. A., Steritz, J. W., Ferderer, R.J. and Creaney, S., Gulf PetroLink, Bahrain. Hallett, D. 2002. Petroleum Geology of Libya, Second Edition. PP.427. Hassan, A.A., 1967. A new Carboniferous occurrence in Abu Durba, Sinai, Egypt (abstract). In: 6th Arab Petroleum Conference, Baghdad, 39 B-3.

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Hemer, D.O.; Powers, R.W. 1968. Lexico stratigraphique international: Saudi Arabia, v.III, Asie, fasc. 10b 1: center national de la Recherche Scientifique, Paris, 170 p. Herbig H. G. & Kuss J. 1988. The youngest Carboniferous rugose corals from northern Africa (NE Egypt)- Paleoenvironments and systematics. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte. (1): 1–22. Horowitz A. 1973. Noeggerathia dickeri from the Carboniferous of Sinai. Rev. Palaeobot.Palynol., 15(1): 51–56. Issawi, B. and Jux, U., 1982, Contribution to the stratigraphy of the Paleozoic Rocks in Egypt. Geol. Surv. of Egypt. Cairo, No. 64, 24. Issawi, B., Francis, M. H., Youssef, E., A.,A., Osman, R. A. 2009. The Phanerozoic Geology of Egypt: A Geodynamic Approach. Special Publication No. 81. Ministry of Petroleum, The Egyptian Mineral Resources Authority. Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Keeley, M. L., 1989, The Paleozoic history of the Western Desert of Egyp. Basin Research, 2: 35–48. Keeley, M. L., 1994, Phanerozoic evolution of the basins of Northern Egypt and adjacent areas. Geol. Rundsch., 83: 728–742. Khalifa, M. A., 2015. Glacial and post-glacial deposits of the Unayzah Formation. Klitzsch, E. & Lejal-Nicol, A. (1984): Flora and fauna from strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Berliner geowiss. Abh., (A) 50, p. 47–79 Klitzsch, E. 1984. Northwestern Sudan and bordering areas: geological development since Cambrian time. Berliner geowiss. Abh., 50: 23–45. Klitzsch, E. and Wycisk, P., 1987, Geology of Sedimentary Basins of Northern Sudan and Bordering areas. Berl. Geowiss. Abh. Vol 75 a, 1: pp. 97–136. Klitzsch, E., 1990. The Paleozoic. In: Said, R. (Ed.), The Geology of. Klitzsch, E., and Squyres, C., 1990, Paleozoic and Mesozoic geological history of northeastern Africa based upon new interpretation of Nubia strata; Bull, Am. Assoc. Petroleum Geologist, V. 74, P. 1203–1211. Klitzsch, E., Harms, J., Lejal-Nicol, A., List, F. K., 1979. Major subdivision and depositional environments of Nubia strata, southwest, Egypt. AAPG, 63: 967–974. Klitzsch, E.; Schandelmeier, H., 1990. Southwestern Desert. In In Said, R. (ed): The Geology of Egypt.Balkema, Rotterdam, Brookfield: 249–257. Klitzsch, E; Lejal-Nicol, A., 1984. Flora and fauna from strata in southern Egypt and northern Sudan (Nubia and surrounding areas). Geowiss. Abh., 50: 47–49. Kora, M. 1984. The Paleozoic outcrops of Umm Bogma area, Sinai. Ph.D. dissertation Mansoura University 28 p. Kora, M. 1984. The Palaeozoic exposures of Urn Bogma area, Sinai. Ph.D. dissertation 280p. Mansoura University, Mansoura, Egypt. Kora, M. 1986. Lower Carboniferous microfauna from Um Bogma Formation, Sinai. Bull. Fac. Science, Mansoura University, 13: 127–150. Kora, M. 1989. Lower Carboniferous (Visean) fauna from Wadi Budra, west-central Sinai, Egypt. Monatshefte Neues Jahrbuch Geologie Palaontologie 1989 (9), 523–538. Kora, M. 1991. Lithostratigraphy of the Early Palaeozoic. Kora, M., 1992. Carboniferous macrofauna from Wadi Khaboba, western-central Sinai (Egypt). Geologica et Paleontologica, 26: 10–27. Kora, M. 1995. Carboniferous macrofauna from Sinai, Egypt. Biostratigraphy and Paleogeography. Journal of African Earth Sciences, 20:37–51. Kora, M., 1998. The Permo-Carboniferous outcrops of the Gulf of Suez region, Egypt.Stratigraphic classification and correlation. Geodiversitas 20 (4): 701–721. Kora, M.; Hans-Georg Herbig, H.G.; Heba El Desouky, H., 2019. Late Moscovian (midPennsylvanian) rugose corals from Wadi Araba (Egypt, Eastern Desert): Taxonomy, palaeoecology and palaeobiogeography. Geobios 52: 1–25.

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Kora, M.; Herbig, H.; El Desouky, H. 2019. Late Moscovian (mid-Pennsylvanian) rugose corals from Wadi Araba (Egypt, Eastern Desert): Taxonomy, palaeoecology and palaeobiogeography. Geobios 52 (2019) 1–25. Kora, M., Mansour, Y., 1992. Stratigraphy of some Permo-Carboniferous successions in the Northern Galala, Gulf of Suez région, Egypt. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 185: 377–394. Kora, M, and Schultz, G. 1987. Lower Carboniferous palynomorphs from Um Bogma, Sinai (Egypt). Grana 26: 53–66. Kostandi, A.B. 1959. Facies maps for the study of the Palaeozoic and Mesozoic sedimentary basins of the Egyptian region. 1st Arab Petroleum Congress, Cairo 2, 54–62. Lejal-Nicol, A. 1987. Flores nouvelles du Paleozoique et du Mesozoique de L Egypte et du Sudan septentrional. Berl. Geowiss, Abh, 75 (A); 151: 248. Lejal-Nicol, A. (1990) Chapter 29. Fossil flora, In: “The Geology of Egypt”, Said, R. (Ed.), pp. 615– 625. Rotterdam: Balkema. Lelubre, M. 1946. Sur la Paleozoique du Fezzan. C. R. Hebd. Seanc. Accad. Sci. Vol. 223, No.11. pp. 359–361. Lelubre, M. 1952. Apercu sur la geologiendu Fezzan. Bull. Serv. Carte Geol. d’Algerie, Travaux Recents Collaborateurs, No. 3, pp. 109–148, Alger. Mamet, B. and Omara, S. 1969. Microfacies of the Lower Carboniferous Dolomitic Limestone Formation of the Urn Bogma Terrane (Sinai, Egypt). Contributions Cushman Foundation Foraminiferal Research 20, 106–109. Massa, D.; Termier, G. ; Termier, H. 1974. Le Carbonifere de Libyeoccidentale Comp. Fr. DE Petrol, Notes Eem., No. 11, pp. 139–206 Paris. North American Commission on Stratigraphic Nomenclature (1983): North American Stratigraphie Code. American Association of Petroleum Geologists, Bulletin, 67: 481–875. Omara, S. 1965. A micropalaeontological approach to the stratigraphy of the Carboniferous exposures of the Gulf of Suez. Monatshefte Neues Jahrbuch Geologie Palaontologie 1965 (7), 409–419. Omara, S. 1971. Early Carboniferous tabulate corals from Urn Bogma area, southwestern Sinai, Egypt. Rivista Italiana Paleontologia 77, 141–154. Omara, S., Schultz, G. (1965). Carboniferous microflora from southwestern Sinai, Egypt. Palaeontographica B., 117, 47–58. Osleger DA, Montanez IP (1996) Cross-platform architecture of a sequence boundary in mixed siliciclastic-carbonate lithofacies, Middle Cambrian, Southern Great Basin, USA. Sedimentology 47:197–217. Ouda, K. A., 2021. The Nubia Sandstone (Nubia Group),Western Desert, Egypt: An Overview. International Journal of Trend in Scientific Research and Development (IJTSRD), 5: 2456–6470. Powers, R.W., 1968. Lexicoque stratigraphique international, Saudi Arabia. V.111, Asic. Fasc. 10 b1. Cenre National de la Rechereche Scientifque, Paris, 177 p. Powers, R.W., Ramirez, L.F., Redmond, C.D., Elbery, E.L., 1966. Sedimentary Geology of Saudi Arabia, United States Geological Survey Professional. Paper 560-D, 147 p. Quaternary, Carboniferous-Permian, and Proterozoic: Oxford, Oxford. Said, R. 1971. Explanatory notes to accompany the Geological map of Egypt. Geol. Surv., Egypt, paper no. 56, 123 pp. Said, R. 1990. The geology of Egypt. Balkama, Rotterdam 734 pp. Said, R., Eissa, R. 1969. Some microfossils from Upper Paleozoic rocks of western coastal plain of Gulf of Suez region, Proc. Third African Microplaeon.Colloq., Cairo, pp. 337–34. Seilacher, A. 1983. Upper Paleozoic trace fossils from the Gill Kebir Abu Ras Area in southwestern Egypt. J. Afr. Earth Sci. 1, 21–34. Soliman S. M. & Abu El Fetouh M. 1969. Lithostratigraphy of the Carboniferous Nubian type sandstone in west-central Sinai. Egyptian Journal of Geology 13 (2): 61–143.

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Soliman, H. E. 2009. Lithofacies, environments of deposition and provenance of the Upper Carboniferous Abu Durba Formation, southwest Sinai, Egypt. Sci. J. Fnc. Sci. Minufa Univ., 2009, Vol. XXIII, 1–23. Stanley, S. M., 1999. Earth System History. New York: W.H. Freeman and Company. ISBN 978-07167-2882-5. Swedan A. & Kandil A. E. 1990. A note on a new outcrop of Upper Palaeozoic “Aheimer Formation” in northern face of El Galala El Bahariya, north Eastern Désert. Annals Geological Survey Egypt 16 (1986–1989): 330, 331. Visser, J. N. J.; Kingsley, C. S., 1982. Upper Carboniferous glacial valley. Visser, J. N. J., 1997. A review of the Permo-Carboniferous glaciation in Africa. Weissbrod, T. 1969. The Paleozoic of Israel and adjacent countries: Part I, The subsurface Paleozoic stratigraphy of S. Israel. Bull. Geol. Surv., Israel, 47:1–25; Part II, the Paleozoic outcrops in SW Israel and their correlation with those of S. Israel, 48: 1–32. Weissbrod, T. 1980. The Paleozoic of Israel and adjacent countries (lithostratigraphic study). Ph.D. thesis, Hebrew Univ. Jerusalem, 275 pp. (in Hebrew, English abstr.). Wetzel, R. 1952. Stratigraphic Survey in Northern Iraq. MPC Report, NIMCO Library, No. 139, Baghdad. (Internal Report). Yi, X. F., Zhao, L., Duan, T. Z., Huang, Y. F., Chen, B., 2018. Shale Facies from the Wufeng-Lower Longmaxi Formations in the Huangying Section of Wulong County, southeastern Sichuan Basin, China. Interpretation. 6: 133–151.

Chapter 8

The Permian Period

Abstract This chapter describes the Permian period’s geology, including definition, classification, fauna and flora, palaeogeography, and associated tectonics. In this chapter, two Permian rock units are introduced. The Wadi Dome is exposed on the western side of the Suez Gulf, the Eastern Desert, while the Misawag Formation is named after the Misawaeg well, Siwa basin, north of the Western Desert. The addition of these rock units in this work is in order to facilitate correlation with corresponding rock units in neighbouring countries, such as Libya, Jordan, Saudi Arabia, and Iraq. Each rock unit is described in detail, including its definition, stratigraphic contacts, lithological characteristics, distribution and thickness, age assignment, and correlation between Egypt and neighbouring countries (Libya, Jordan, Saudi Arabia and Iraq). Two paleographic maps are drawn to manifest the possible depositional environments of the Permian rock units. The depositional environments of Egyptian rock units and their equivalent rock units in adjacent countries are interpreted using lithological types and faunal and floral associations. Keywords Permian · Wadi Dome · Misawag · Eastern Desert · Western Desert · Libya · Jordan · Saudi Arabia · Iraq

8.1 Introduction 8.1.1 Definition Senior scientist Roderick Murchison (1841) first used the word Permian and gave it the Russian region of Perm as its type locality. The Permian is the 47 million-year geologic period that spans from the end of the Carboniferous Period (298.9 Mya) to the beginning of the Triassic Period (251.9 Mya) (Olroyd 2005; Ogg et al. 2016). It is regarded as the final stage of the Paleozoic Era (Fig. 8.1). The senior geologist introduced the term Permian in the geological record.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. A. G. Khalifa, Ediacaran-Paleozoic Rock Units of Egypt, Earth and Environmental Sciences Library, https://doi.org/10.1007/978-3-031-27320-9_8

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Fig. 8.1 Geological chart shows the Permian Period’s classification (After, ICS, 2022; Chart time scale 2022)

8.1.2 Classification The Permian Period is classified into three epochs, the Cisuralian (Earl Permian), Guadalupian (Middle Permian), and Lopingian (Late Permian) listed from oldest to youngest (Cohen et al. 2013, ICS, Fig. 8.1).

8.1.3 Fauna and Flora N Permian time the fauna of the sea and on land was extremely diversified during the Permian Period. During the Early Permian, there was a progressive warming of the climate, which led to significant evolutionary expansion (diversification) of both marine and terrestrial faunas. Essential fossils are molluscs, echinoderms, and brachiopods. Brachiopods were highly diverse during the Permian (Carlson 2016).

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Conodonts experienced the lowest diversity of their entire evolutionary history during the Permian (Samuel and Nicolas 2020). Goniatitida were an influential group of ammonoids throughout the Early-Mid Permian, but they started to disappear during the Late Permian. The Ceratitida underwent moderate diversification in the middle of the Permian and significant diversification in the late Permian (McGowan and Smith 2007). Before falling during the Late Permian, trilobites had a diversification Early Permian tetrapods, which included herbivorous edaphosaurids and carnivorous sphenacodontids, diadectids, and amphibians, first arrived in North America and Europe (Huttenlocker and Rega 2012). Lycophytes, a class of vascular plants that includes scale trees and club mosses, were the dominant group of fossilised plants from the Early Permian epoch (Wang et al. 2020). These plants thrived in wet and marshy areas. For most of the Permian, a group of woody gymnosperm plants that reached high southern latitudes dominated the Gondwanan floristic region (Zhuo et al. 2017). The tree-like calamities, which are distantly related to current horsetails, thrived in coal swamps and grew in vertical thickets resembling bamboo. The Late Permian is when the earliest fossils that may be identified as belonging to modern cycads were discovered (Zhuo et al. 2017) during the Kungurian-Wordian, the final period of their evolutionary history (Rudy and Raimund 2012). During the preceding Carboniferous, when they initially appeared and increased in number, insects underwent a remarkable increase in variety. There was a significant decrease in both origination and extinction rates at the end of the Permian (Labandeira 2018), Tetrapods: Early Permian tetrapods, which included herbivorous edaphosaurids and carnivorous sphenacodontids, diadectids, and amphibians, first arrived in North America and Europe (Huttenlocker and Rega 2012). Lycophytes, a class of vascular plants that includes scale trees and club mosses, were the dominant group of fossilised plants from the Early Permian epoch (Wang et al. 2020). These plants thrived in wet and marshy areas. For most of the Permian, a group of woody gymnosperm plants that reached high southern latitudes dominated the Gondwanan floristic region (Zhuo et al. 2017). The tree-like calamities, which are distantly related to current horsetails, thrived in coal swamps and grew in vertical thickets resembling bamboo. The Late Permian is when the earliest fossils that may be identified as belonging to modern cycads were discovered (Zhuo et al. 2017).

8.1.4 Tectonics and Paleogeography The supercontinent Pangaea, which formed due to the collision of Euramerica and Gondwana during the Carboniferous, ruled the world during that time (Scotese and Langford 1995). The superocean Panthalassa encircled Pangaea. Earth’s history saw a terrible mass extinction during the Permian period (Stemmerik 2000). The K/T Extinction Event is what is being described. There were at least three extinction events during the Permian Period (Lucas 2017). The first occurrence occurs at the Kungurian age, the second at the height of the Capitanian age, and the third at the Changhsingian age (the end of the Permian) (Fig. 8.1).

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8.2 Permian Rock Units in Egypt 8.2.1 Introduction There are debates and disagreements among geologists about the occurrence of the Permian rocks on the surface of Egypt. Abdallah and Adindani (1963) gave the western side of the Suez Gulf’s Qiseib Formation the Permo-Triassic age. Kora and Mansour (1992), Issawi et al. (2009) and Lejal-Nicol (1990) thought this formation was Permo-Triassic. However, because of the lithologic similarities between the Qiseib Formation and the Lower Triassic Sudair Shale in Saudi Arabia (Powers et al. 1966) and the Lower Triassic Beduh Shale in Iraq (Beydoun 1993), we thought the Qiseib Formation in Egypt was closely related to and seemed to be Lower Triassic. To support the lower Triassic for the Qiseib Formation, earlier stratigraphic studies suggested that the Qiseib Formation belonged to the Lower Triassic (Druckman et al. 1970; Said 1971; Weissbord 1976; Gvirtzman and Weissbrod 1984; Weissbrod et al. 1989). We believe that the Permian fauna and plants previously found in the Qiseib Formation by geologists may have derived from the upper part of the underlying Aheimer Formation, which has been attributed to the earlier Permian age. We propose introducing a new rock unit that represents the Early Permian period. This rock unit is named Wadi Dome Formation which includes the upper two members of the Aheimer Formation of Kora (1998), and the rocks named before as the transitional zone between the top of the Aheimer Formation and the base of the Qiseib Formation (Abdallah and Adindani 1963). The addition of this rock unit in the present work is due to the following reasons: (1) To prove to the stratigraphers that there is an exposed Permian rock unit, occurring west of the Suez Gulf. (2) to find a solution to the issue of correlation between the Lower Permian rocks in Egypt and their corresponding rock units in Libya, Saudi Arabia, and Jordan, and (3) to facilitate comparisons between the exposed Permian rocks in the Eastern Desert with its corresponding subsurface rock units in the northern Western Desert. In the subsurface, the Permian rocks are encountered at Misawag and Faghour wells in the northwestern Desert near the Libyan borders (Hantar 1990) (Fig. 1.2). The thickness of these rocks varies, from 1300 m at Misawag to 55 m at Faghur well (Hantar 1990). Because all subsurface Paleozoic rocks have formational names, except the Permian rocks have no formational nomenclature. Therefore, we introduced the Misawag Formation to describe the Permian rocks in the subsurface in the northwestern Desert. The name Misawag Formation refers to the Misawag well (Fig. 1.2), representing the oldest borehole reaching the Permian strata and the presence of maximum thickness of Permian rocks (1300 m). Therefore, there are two rock units representing the Permian period in Egypt, one of them is called Wadi Dome Formation on the surface, and the second is the Misaweg Formation in the subsurface.

8.2 Permian Rock Units in Egypt

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8.2.2 The Wadi Dome Formation 8.2.2.1

Definition

The term Wadi Dome Formation is used in the present investigation for the first time to characterise the exposed Lower Permian rocks along the western side of the Suez Gulf (Fig. 8.2). Rocks of this formation were previously known as the transitional strata of Abdallah and El Adindani (1963), which constrained between the Carboniferous Aheimer Formation below and the Triassic Qiseib Formation above. This transitional zone was named before as member no four of the Aleimer Formation by Abdel-Shafy et al. (2000). In addition, the middle and upper members of the Aheimer Formation (Kora and Mansour 1992; Kora 1998) are also part of this formation. The addition of Wadi Dome Formation in the present work to describe the exposed Lower Permian rocks at the western side of the Suez Gulf. This formation differs in facies (mainly sandstone) compared to the Aheimer Formation, which consists of the intercalation of claystone and sandstone (Fig. 8.3a). Its type locality is exposed at Wadi El Dome (Fig. 8.2). The measured section is located between Lat. 29° 25' 42'' , 29° 25' 36'' N and Long. 32° 30' 14'' , 32° 30' 19'' E. Wadi El-Dome is situated on the western side of the Gulf of Suez, in the distance between the Suez area and Wadi Araba (Fig. 8.2), lying about 30 km to the north of the latter and only about 10 km northwest of Abu Darag Lighthouse (Fig. 8.2).

8.2.2.2

Stratigraphic Contact

At Wadi Aheimer, its lower boundary is unconformable and lies between the shale facies of the uppermost Aheimer Formation and the massive brown sandstone of the basal Wadi Dome Formation (Fig. 8.3a). Also, its base is defined when the first appearance of crinoidal dolostone beds. While, its upper boundary shows unconformable contact with the overlying Qiseib Formation. The contact lies between the massive sandstone of uppermost Wadi Dome and the reddish sandy siltstone of the Lower Triassic Qiseib Formation. In some places on the northern footwalls of Wadi Aheimer, where the red beds of the Qiseib Formation are missed, the Wadi Dome Formation unconformably underlies the Early Cretaceous Malha Formation.

8.2.2.3

Lithology

This formation includes three lithologic units (Fig. 8.3a). The lower unit assumes about 42 m and comprises brown and yellow sandstone intercalated with grey claystone and thin beds of dolomitic limestone. The sandstones are medium to coarsegrained with herringbone crossbedded (Kora 1998). The thin carbonate bed contains crinoids and thin-shelled brachiopods (Kora and Mansour 1992). The middle unit

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Fig. 8.2 Location map showing the type locality of Wadi Dome Formation, west of the Suez Gulf

measures about 90 m and entirely consists of fine to massive coarse-grained sandstone with thin dark-grey siltstone. The sandstone beds usually contain planar and Tabular cross-bedded sandstone and are mostly quartz arenite with ferruginous claystone layers (Kora 1998). The upper unit comprises cyclic sequences with a total thickness of about 65 m. Each cycle begins with shale and sandy claystone, capped by massive coarse-grained sandstone (Abdel-Shafy et al. 2000).

8.2.2.4

Distribution and Thickness

This formation has a limited geographic distribution. It is exposed at Wadi Aheimer, Wadi Qiseib and Wadi Dome on the footslope of the Northern Galala, overlooking the Suez Gulf (Fig. 8.2). Its thickness ranges from 60 to 120 m.

8.2.2.5

Age Assignment and Correlation

A typical Early Permian flora was identified by Lejal-Nicol (1987, 1990) at Wadi Dome west of Suez Gulf that includes Sphenophyta, Filicophyta, Peltaspermaceae

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Fig. 8.3 Measured lithostratigraphic section of Wadi Dome Formation (a) and its correlation with the Misawag Formation at Misaweg-well (b) and Faghour-well (c) (After Hantar 1990)

and Cordiatophyata were encountered in the uppermost Aheimer Formation that equivalent to the Wadi Dome Formation. Moreover, brachiopods (Rhipidomella cordialis, Composita sp.), fusulinid foraminfera and calcareous algae indicate Early Permian (Kora 1998; Kora and Mansour 1992). In addition, Early Permian impressions of fragments of stems and leaves of Sphenophyta sp., Pterophyta sp. and Cordaitophyta sp. are described from Wadi El-Dome, Western side of the Gulf Sue (El Kelani and Darwish 2001; El Saadawi et al. 2016). Abdel-shafy et al. (2000) recognized mega fossils in the transitional zone above the Aheimer Formation and the

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Qiseib Formation, indicating Late Carboniferous to Early Permian. This formation can be correlated with the Lower Permian Al Watyah in Libya (Fig. 8.4; Table 8.1).

Fig. 8.4 Correlation of the Lower Permian Misaweg Formation (b) with corresponding rock units in Libya (a), Jordan (c), Saudi Arabia (d) and Iraq (e)

8.2 Permian Rock Units in Egypt

197

Table 8.1 Correlation of the Wadi Dome and Misawag formations with corresponding rock units in Libya, Jordan, Saudi Arabia and Iraq

8.2.3 The Misawag Formation 8.2.3.1

Definition

Because every subsurface Paleozoic rock in Egypt from the Cambrian to the Carboniferous has been given a formational name or rock name, except for the Permian sediments, which do not. As a result, the term “Misawag Formation” was attributed in this work to refer to the subsurface Permian rocks found in the northern Western Desert of Egypt. The term Misawag was chosen since it was the first well to contain Permian rocks and because its maximum thickness (1320 m) was found there (Fig. 8.3b).

8.2.3.2

Stratigraphic Contact

In Misawag well, the lower boundary of the Misawag Formation disconformably overlies the Lower Carboniferous, while its upper boundary unconformably lies below the Bahrein Formation (continental Jurassic) (Fig. 8.3b) (Hantar 1990). In Faghour well, its lower boundary is undefined, while its upper limit lies unconformably overlying the Cenomanian Bahariya Formation (Fig. 8.3c) (Hantar 1990).

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Lithology

This formation is found in the Misawag well-1 (south of the Abu Gharadig basin). It is comprised chiefly of sandstone with some intercalation of claystone and coal seams (Fig. 8.3b). In Faghour well-1, it exhibits radical facies changes toward the northwest, where it consists of dolostone and dolomitic limestones with thin intercalations of shale and sandstone (Fig. 8.3c) (Hantar 1990). Just west of long.27 E, the Permian rocks are mostly clastic. Their facies changes to mixed clastic and carbonate as one travels near the Libyan borders. In general, the Permian rocks are mainly clastic just west of long.27 E, and their facies change to mixed clastic and carbonate west toward the Libyan borders.

8.2.3.4

Distribution and Thickness

Due to the Hercynian orogeny’s impact and the elevation of southern and central Egypt, the Permian rocks were not exposed in the Western Desert, Eastern Desert, or Sinai (Klitzsch 1983; El Hawat 1997). However, 70 m thick shallow water carbonates, sandstone, and some shale from the Permian are encountered in the subsurface north of the Western Desert in the Siwa Basin (El Hawat 1997). They were, however, positively detected in two wells in the northwest Desert: Misawag Well-1 (South of the Abu Gharadig basin) and Faghour Well-1 (Hantar 1990). While this formation’s average thickness at Misawag well-1 is 1320 m, it is just 55 m thick at Faghur well-1 (Hantar 1990) (Fig. 8.3b, c).

8.2.3.5

Age Assignment and Correlation

In the Siwa basin, the encountered sediments contain Early Permian fossils, including Waagenocencha montepelierenses and Anisopyge cf. Prerassulata (Dakkak 1988). This formation can be correlated with the Permian A1Watyah Formation in the Jiffara basin in Libya (Menning et al. 1963) and with the lower Permian Wadi Dome Formation west of the Suez Gulf (Fig. 8.4; Table 8.1).

8.3 Permian Rocks in Adjacent Countries 8.3.1 In Libya The Permian rocks include two rock units: Al Watyah Formation at the base and the Bir Al Jaja Formation at the top (Fig. 8.4a). The name A1Watyah Formation was proposed by Menning et al. (1963) for a subsurface formation drilled in western Jeffara Plain northwest of Libya. Its base is unexposed, while its upper boundary

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199

unconformably underlies the Bi’r al Jaja Formation (Banerjee 1980). This formation is made up of a sequence of claystone and sandstones with ferruginous cement occurring. These facies are stacked vertically into fining-upward cycles, each one begins with thin pebbly sandstone to pebbly conglomerate, followed by sandstone and capped claystone (Fig. 8.4a) (Banerjee 1980). The formation is unfossiliferous, and its age is attributed to the Early Permian based solely on its stratigraphic position (Banerjee 1980; Hallett 2002). In the Bir al Jaja well in the Jiffara plain, northwest of Libya, Menning et al. (1963) named the formation the Bi’r a1 Jaja Formation. In well B1-23, which has a thickness of just 61 m, Hammuda et al. (1985) officially declared a type section for the Bi’r a1 Jaja Formation. This formation overlies the Upper Permian A1 Watyah Formation and unconformably underlies the Lower Triassic Al Guidr Formation (Hammuda et al. 1985). A thin conglomerate makes up the formation’s base, which is covered by claystone and sandy clay with a thin interbreed of crystalline dolostone (Fig. 8.4a) (Hallett 2002). Glauconitic and phosphatic sandstone are also present (Banerjee 1980). The deposit has foraminifera and a rich collection of palynological evidence, which support an age range of Late Permian to Early Triassic) (Hallett 2002).

8.3.2 In Jordan In Jordan, the Permian rocks are represented by the Umm Irna Formation (Fig. 8.4c) (Bandel and Khoury 1981). This name is derived from Wadi Zarqa Ma’in from Wadi Himara, the northeastern slope of the Dead Sea. The type section of this formation occurs at Wadi Himara, north of the Zarqa Ma’in hot springs (Bandel and Abu Hamad 2013). The Umm Irna Formation is observed in wells in the north and northwest of Jordan (Bandel and Khoury 1981; Andrew 1992; Makhlouf et al. 1991). Its lower boundary unconformably rests on the Cambrian sandstone of the Um Ishrin Formation, while its upper boundary unconformably underlies the Lower Triassic Main Formation. The Um Irna Formation assumes 85 m thick and comprises six members, each of which comprises fining-upward cycles (Fig. 8.4c). Each cycle consists of pebbly sandstone at the base, and tabular fine-grained sandstone in the middle, capped by rippled reddish to grey siltstone and dark grey to green claystone with plant fossils and coals (Bandel and Abu Hamad 2013). The presence of Pollens of Protohaploxypinus uttingii suggests an age range from Middle to early Late Permian (Stephenson and Powell 2014).

8.3.3 In Saudi Arabia The Permian carbonate rocks were studied under the term Khuff Formation by Steineke and Bramkamp (1952) (Fig. 8.4d). Steineke et al. (1958) formalized the type section of this formation at Ayn Khuff near the Riyadh-Jiddah road. Powers

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et al. (1966) described in detail the lithological characteristics of the Khuff Formation along its exposure from Bani Khaimah in the extreme southeast (19° N) up to the northwest of the Great Nefud (28° 10' N). North of Latitude 24° N in the vicinity of Wadi Maghib, the Khauff Formation was subdivided into three formal members: the lower is the Khuff Member, the middle is the Midhnab Shale Member and the upper is the Khartoum Member (Powers et al. 1966; Powers 1968). It unconformably overlies the Carboniferous Unyazah Formation and conformably underlies the Lower Triassic Sudair Shale. As the Khuff Formation was dated to the Late Permian to Permo-Triassic age (Powers et al. 1966). Khalifa (2010) subdivided the Khauff Formation of Powers et al. (1966) into two rock units the Khuff Formation (Late Permian) at the base and the Al Watah Formation at the top (Early Triassic).

8.3.4 In Iraq The Chai Zairi Formation in Iraq resents the Permian rocks (Fig. 8.4e). The lower contact unconformably overlies the Carboniferous Qaara sandstone, whereas the upper contact is gradational with Triassic rocks (Aqrawi 1998). This formation in northern Iraq comprises limestones, occasionally cherty, and dolomites (Wetzel 1950; Aqrawi et al. 2010). In the northern outcrops, its thickness varies between 750 and 800 m (Fig. 8.4e). The formation’s age is determined based on Middle-Late Permian coral and algae faunas (Hudson 1958). However, some Early Triassic fauna can be found in the formation’s top regions (Buday 1980). However, Singh (1964) and Omar (1990) dated the Chia Zairi Formation as the late Permian.

8.4 Depositional Environments The Late Permian and Late Early Permian experienced a significant tensional shift due to the Hercynian Orogeny. Magmatism was present along this, especially in the northwest African region of Nubia, which was invaded by numerous alkaline orogenic complexes and then raised again (Wilson and Guirand 1992, 1998; Guiraud and Bosworth 1999). Following that, tectonic activity along Northern Africa accentuated localised strike-slip fault renewal, small uplifts, and block tilting (Echikh and Sola 2000). During this time, severe denudations removed previously deposited sediments and halted deposition due to elevation. This denudation removed lower Permian rocks from Jordan, Saudi Arabia, and Iraq (Fig. 8.4c–e). Meanwhile, the lower Permian rocks were well preserved in the western side of the Suez Gulf represented by the Wadi Dome Formation. Also, they occur in the subsurface at the Faghur and Misawag wells in Egypt’s northwestern Desert and the Jiffara Basin in northwest Libya. Deep basins may have played a role in the events described above in Egypt and Libya (Fig. 8.4a, b). The structural configuration explains the type of facies associations predominated during sedimentation. Two paleogeographic maps have been

8.4 Depositional Environments

201

drawn based on the facies association stratigraphic position of the studied rock units in Libya, Egypt, Jordan, Saudi Arabia, and Iraq. The first depicts the distribution of paleoenvironments during the Early Permian period, while the second depicts the Late Permian paleoenvironments. During the Early Permian period, two environments predominated: upland regions and coastal to fluvial environments (Fig. 8.5). (1) The upland setting covers Saudi Arabia, Iraq, Jordan, and Egypt, except for the narrow western stretch of the Western Desert, parallel to the Libyan border and west of the Suez Gulf. In these localities, the Misawaga and Wadi Dome formations were filling rifted small basins (Fig. 8.6). These countries were all entirely exposed land (Fig. 8.6). The Hercynian Orogeny, which began in the Lower Carboniferous and lasted until the end of the Triassic periods, may have resulted in the creation of the cratonic and uplifted region (Klitzsch 1990). The upland or cratonic area contains specific structures such as uplift grabens, horsts, and small continental basins (Craig et al. 2008). In general, epirogenic movements and erosional processes can coexist in the cratonic region during the Early Permian period (Klitzsch 1990). The absence of lower Permian sediments in these countries (Egypt, Jordan, Saudi Arabia and Iraq) was most likely caused by Hercynian Orogeny. This orogeny created a significant hiatus in Egypt and Joran. In the Western Desert of Egypt, for example, the Upper Carboniferous North Wadi Malik Formation unconformably underlies the lower Cretaceous Six Hills Formation. This orogeny eroded and removed older rock units in this area (Ordovician Karkur Talh, Silurian Um Ras, lower Carboniferous Wadi Malik, and upper Carboniferous North Wadi Malik formations), where the Lower Cretaceous Six Hills Formation reaches the basement rocks west of Dakhla and Kharga Oases (Ouda 2021). This movement also removed the Jurassic, Triassic, and Permian in the Eastern Desert and central and southern Sinai, where the Lower Cretaceous Malha Formation unconformably rests on the Lower Carboniferous Abu Thora Formation. In addition, the Upper Permian Um Irna Formation overlies the Cambrian Umm Ishrin Formation in Joran. The impact of this movement decreases eastwards in Saudi Arabia and Iraq. In Saudi Arabia, the Upper Permian Kuff Formation unconformably rested on the Carboniferous Unyazah Formation (Al Laboun 1987, 1988). This movement has the most negligible impact in Iraq, where the upper Permian Chia Zairi Formation rests on the Carboniferous Qaara Formation. (2) The Fluvial-marine environments covered most of Libya and the western side of the Western Desert (Figs. 8.5 and 8.6). The lower Permian sediments in Egypt are known as the Wadi Dome Formation, which consists of crinoidal dolostone intercalated with siltstone and fine-grained sandstone at the base, followed by tabular to planar cross-bedded sandstone in the middle, and claystone and sandstone intercalation in the upper part. The presence of crinoids and carbonate rocks suggests inner shalf setting. The Wadi Dome rocks filled in a narrow rifted basin that extends nearly in a northwest-southeast parallel to the northern Glalala plateau. These facies also includes the subsurface Misawag Formation, the northwestern Desert, and Al Watyah Formation in Libya. These are made entirely of sandstone with thin claystone beds. The fining-upward cycle was formed by stacking this clastic sequence vertically. The cycle begins with pebbly conglomerate and progresses to coarse-grained sandstone before concluding with dark green claystone (Fig. 8.4a). The cycles of both

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Fig. 8.5 Paleogeographic map showing the possible depositional environments during the Early Permian time in Libya, Egypt, Jordan, Saudi Arabia and Iraq

Fig. 8.6 The east–west cross section shows the distribution of facies and possible depositional environments during Early Permian time in Libya, Egypt, Jordan, Saudi Arabia and Iraq

formations are nonfossil, implying fluvial, delta-front, tidal-channel, and distributary mouth bar characteristics (Hallett 2002). This conglomeratic facies is interpreted at the basal cycles as the gradual infilling of active fluvial-channel complexes (Muñoz et al. 1992). The cross-bedded pebbly sandstones were deposited due to the continuous gradual infilling of the active channel (Rust 1978). Rust and Koster (1984) interpret this facies association to represent a proximal braid plain. The upper cycle claystone was deposited in a shallow subtidal environment. During the Middle-Late Permian period, sea-level rose in North Africa and Arabia, depositing marine facies represented by limestone with thin claystone interbeds. The paleogeographic map depicts synchronous depositional environments, such as (1) cratonic areas, (2) fluvial environments, and (3) carbonate platform (Figs. 8.7 and 8.8). (1) The cratonic area is a region of the earth that has achieved stability and has experienced slight deformation for quite some time (Bates and Jackson 1983). The term only applies to the continental environment (Bates and Jackson 1983). The

8.4 Depositional Environments

203

upland areas are decreased as compared by those found during the Early Permian and only covers most of Egypt (Fig. 8.8). The absence of the Middle-Upper Permian facies may also be attributed to the on going Hercynian orogeny. This cratonic area was always present during the Permo-Triassic periods and is regarded as the primary source of rocks for the detrital grains that form the coastal marine facies in northern Egypt and other western Arabian countries. A large folding and uplifting occurred during the cratonic regions, which lasted until the Early Jurassic period (Klitzsch 1990). This orogeny resulted in extensive erosion and the accumulation of continental clastic sediments such as reddish sandstones, siltstones, and conglomerates. These sediments filled the topographic lows and bulid-up what is called the New Red Sandstone facies which is composed primarily of reddish sandstone, siltstone, and claystone. British geologists named the New Red Sandstone, which was deposited from the Late Permian to the end of the Triassic period. These sediments indicate that they were deposited in a hot and arid palaeoenvironment, such as a desert or lagoon (Benton and Walker 1985). In Egypt, these reddish rocks are known as the Qiseib Formation (Abdallah and Adindani 1963), the Sudair Shale in Saudi Arabia (Powers et al. 1966) and the Budeh Shale in Iraq (Buday 1980). (3) The fluvial environment occurs only in Jordan, depositing the Umm Iran Formation (Figs. 8.7 and 8.8). The facies are of clastics stacked vertically into finingupward cycles, each of which begins with pebbly sandstone, followed by reddish fineto coarse-grained sandstone and topped by reddish, brown siltstone to sandy clay (paleosol). This sequence is enriched with plant remains (Makhlouf et al. 1991). The pebbly sandstone forming the basal cycle comprises Porphyrite pebbles that were likely produced from neighbouring basement rocks that make up the pebbly sandstone at the base of each cycle (Makhlouf et al. 1991). The fine-grained sandstone and reddish paleosols were most probably deposited in praidplain and swamps. In general, the depositional environment of the Umm Irna Formation was that of a sandy meandering drainage system of a river with poorly aerated swamps and ponds

Fig. 8.7 Paleogeographic map showing the possible depositional environments during the Middlelate Permian time in Libya, Egypt, Jordan, Saudi Arabia and Iraq

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8 The Permian Period

Fig. 8.8 The east–west cross section shows the distribution of facies and possible depositional environments during the Middle-Late Permian Time in Libya, Egypt, Jordan, Saudi Arabia and Iraq

in which plant debris was concentrated (Mustafa 2003; Bandel and Salmeh 2013). These fining upward cycles’ deposition was formed by the allocyclic mechanism in which an episode of sedimentation was dominated. Each episodic phase started with a high-energy, frequently erosive flow, depositing the pebbly sandstone and progressing upward to sedimentation with waning or sluggish and quiet energy, giving rise to the deposition of claystone and paleosols. Large episodic storms that impacted the ecosystem along the shore and the coastal shelf were the causes of the fining-upward cycles. The carbonate platform covers most of Libya, Saudi Arabia and Iraq (Figs. 8.7 and 8.8). Most of the facies association limestone with thin claystone layers in Saudi Arabia and Libya, while pure oolitic limestones occur in Iraq. The Khuff formation includes dolomites, limestones and dolomitic limestones with subordinate anhydrite (Al Jallal 1987, 1989; Al Sharhan 1993). It includes several carbonate lithofacies, e.g. ooid-pellet grainstone, pelodid foraminiferal grainstone, bioclastic-intraclasts grainstone, mudstone-wackestone and nodular anhydrite (Al Jallal 1989). It was deposited in several synchronous environments such as supratidal (sabkha), lagoon, shoal and shallow shelf (Al Sharhan 1993). As the Kuff Formation contains several oolitic grainstone horizons, it is considered the main reservoir in eastern Saudi Arabis and the adjacent Gulf counties (United Arab Emirates, Qatar and Iran) (Khan et al. 2011). It was divided into four primary cycles. Each cycle starts with transgressive grainstone facies, which make up the Khuff reservoirs and ends with regressive, muddy and anhydrite facies, which make up the non-reservoir units (Al-Jallal 1987). In Iraq, the lithology of the Chia Zairi Formation is closely similar to the Kuff Formation. It comprises oolitic grainstone, carbonate mudstone, and oolitic-pelletal packstone with sparse anhydrite (Aqrawi et al. 2010). It was possibly deposited in a more restricted low-energy evaporitic-carbonate inner ramp. The formation can be interpreted as being deposited on a homoclinic carbonate ramp. Dolomitic facies with relicts of fusulinids, bryozoans and algae represent mid-ramp deposits, and inner ramp deposits are represented by lime wackestone and sandstones (Al-Juboury and Al-Hadidy 2005). The reservoir quality of this formation is less than that of the

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Khuff Formation due to the increase of muddy carbonate facies, which are dominant and coarser-grained (grainstones) are relatively minor, having anhydrite cement and being also deeply buried (Al-Jallal 1989, 1995). At the end of the Permian and the Permian–Triassic boundary, the temperature continuously increases, and the sediments are characterized mainly by reddish siliciclastic sediments (Sun et al. 2012). The sudden temperature rise may resemble the concrete evidence of the mass extinction at the end of Permian time. The mass extinction wiped out about 95% of the marine skeletal organisms and 80% of land animals (e.g., Knoll et al. 2007; Payne et al. 2007). In addition, at the end of the Permian, life was nearly completely wiped out (Erwin 1993, 2006). During this time, the eruption of the Siberian volcanic lava, which carbon dioxide concentrations, was released more than twice atmospheric (Scotese et al. 2021). Such volcanic eruptions may have been responsible for mass extinction during Late Permian. This eruption was enhanced by the emission of a large amount of carbon dioxide emitted by the pyroclastic eruption of the Siberian Traps (Rothman et al. 2014; Kunio et al. 2020), which elevated global temperatures, and in the oceans led to widespread anoxia and acidification (Ogdena and Sleep 2011). Several volcanic eruptions occurred in northeast Africa and Arabia at the Permo period’s end. In Egypt, for example, some volcanic eruptions connected to the Uweinat-Aswan arch occur in southern Egypt. The 235 Ma dating of these volcanic indicates the Late Permian-Early Triassic (Meneisy and Kreuzer 1974). There is also an olivine sheet with a 238 Ma date in southern Sinai, near Farsh El Azraq, south of Arief el-Naga (Meneisy 1986; Meneisy et al. 1976). Also, volcanic sheets covered the top of the Lower Carboniferous Abu Thora Formation in Sinai (El Kelani et al. 1999).

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