Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin: Altay-Sayan Region, Siberia (GeoGuide) 3030295583, 9783030295585

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GeoGuide

Richard Ernst · Vassily V. Vrublevskii · Platon Tishin Editors

Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin Altay-Sayan Region, Siberia

GeoGuide Series Editors Wolfgang Eder, University of Munich, Munich, Germany Peter T. Bobrowsky, Geological Survey of Canada, Natural Resources Canada, Sidney, BC, Canada Jesús Martínez-Frías, CSIC-Universidad Complutense de Madrid, Instituto de Geociencias, Madrid, Spain Axel Vollbrecht, Geowissenschaftlichen Zentrum der Universität Göttingen, Göttingen, Germany

The GeoGuide series publishes travel guide type short monographs focussed on areas and regions of geo-morphological and geological importance including Geoparks, National Parks, World Heritage areas and Geosites. Volumes in this series are produced with the focus on public outreach and provide an introduction to the geological and environmental context of the region followed by in depth and colourful descriptions of each Geosite and its significance. Each volume is supplemented with ecological, cultural and logistical tips and information to allow these beautiful and fascinating regions of the world to be fully enjoyed.

More information about this series at http://www.springer.com/series/11638

Richard Ernst Vassily V. Vrublevskii Platon Tishin •

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Editors

Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin Altay-Sayan Region, Siberia

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Editors Richard Ernst Carleton University Ottawa, ON, Canada

Vassily V. Vrublevskii Tomsk State University Tomsk, Russia

Platon Tishin Tomsk State University Tomsk, Russia

ISSN 2364-6497 ISSN 2364-6500 (electronic) GeoGuide ISBN 978-3-030-29558-5 ISBN 978-3-030-29559-2 (eBook) https://doi.org/10.1007/978-3-030-29559-2 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved 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

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In this book, we want to show the geological manifestations of large igneous provinces in southwestern Siberia. We present two field trips that show magmatism, ore formation, and environmental effects of large igneous provinces of different ages. The first field trip is dedicated to representation of Early Devonian intraplate magmatism of Altai-Sayan region. Early Devonian magmatism reveals itself on a huge territory including North-Minusinsk and South-Minusinsk depressions, South-Tuvinian basin, and a number of graben structures belonging to Kuznetsk Alatau, Eastern and Western Sayan regions. Total amount of volcanic rocks within all these structures is more than 2,00,000 km3 at the modern level of erosional truncation. Besides volcanic rocks, Early Devonian magmatic rocks include alkali-gabbroid associations of Kuznetsk Alatau and Western Sayan region. Isotopic, geochemical, and petrological features of the rocks indicate their abyssal plume nature. In such a way, Early Devonian magmatism in all its forms may be considered as one of standard examples of large igneous provinces formed in regions of increased thickness of continental crust. Within the field trip, it is planned to see: 1. Nepheline (high-aluminous) ore deposit (Object 2, Fig. 1). The ores (urtites) formed during one of the stages of Kiya-Shaltyr alkali-gabbroid massif formation (Goryachegorsk complex). This is one of the largest and most representative objects belonging to the province of alkaline rocks of Kuznetsk Alatau; 2. Early Devonian Saralinsky graben (Object 3). This structure is crossing the Kuznetsk Alatau from south to north. It’s composed of volcanic rocks with increased alkalinity. It is seen in a cross section that there is a distinct homodromous sequence beginning with picrobasalts and ending with trachytes; v

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Fig. 1 Routs of field trips with geological setting

3. North-Minusinsk Depression (Object 5). This is a typical postorogenic volcano-sedimentary depression. Fragments of old volcanic edifices may be mapped out at its basement. Students of Tomsk State University study structural relationship between volcanic and sedimentary rocks here. Besides that, participants may observe: 4. Shestakovo I—one of the largest sites with dinosaur fauna remnants (Early Cretaceous) in the Central Asia (Object I). It’s supposed that the age of sedimentary host rocks corresponds to time of a large igneous province formation (130 Ma); 5. A swarm of Permian and Triassic dykes of dolerites and essexites (Kopievsky complex). We suppose that this swarm is a part of a concentric dyke swarm located at the distance of 1200 km from the center of Siberian traps LIP. The aim of the second field trip is to observe leucocratic constituents from large igneous provinces of Early Paleozoic age. In such a way following objects will be seen: 1. Ordovician-Silurian Kachinsk-Shumihinsk magmatic area in Krasnoyarsk city and its surroundings. The area includes hypabyssal bodies of syenites, volcanic structures, and volcanic sheets of basalts and trachybasalts (Object 7);

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2. Gabbro-monzodiorite-monzonite massifs of Kuznetsk Alatau and Mo, Cu, W ore deposits related to them. Geochemistry of the rocks indicates abyssal origin of primary magma (PREMA, EM) though the ages vary from 500 to 475 Ma (Object 8). Additionally, participants are going to see: 3. Late Cretaceous (79–74 Ma) diatremes (blowholes), which cut Devonian and Carboniferous rocks of North-Minusinsk depression and contain inclusions of mantle olivinites and peridotites (Object 9). 4. Early Cretaceous sediments of Ileksk suite, which contain Mesozoic vertebrate fauna remnants (Object 6). The researches in this book was supported by the Government of the Russian Federation (project 14.Y26.31.0012).

Contents1

The Field Trip 1: Early Devonian Large Igneous Provinces in SW Siberiа Continental Sediments of the Early Cretaceous from Western Siberia. Part 1. Mesozoic Continental Sediments: Shestakovo Yar (Ilek Formation, Lower Cretaceous, Kemerovo Region), Vertebrate Fossils Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. V. Fayngerts Plume-Related Alkaline Basic Magmatism of the Kuznetsk Alatau: The Kia-Shaltyr Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I. F. Gertner, O. M. Grinev, V. V. Vrublevskii, A. M. Sazonov, I. A. Oparin, P. A. Tishin, T. S. Krasnova and A. A. Mustafaev

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Saralinsky Graben—Devonian Rift of the Kuznetsk-Minusinsk Zone, Altai–Sayan Folded Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. M. Grinev, O. R. Grinev, R. R. Adylbaev and A. A. Bogorodov

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Characterization of the Kopievsky Igneous Complex and Its Geological Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V. P. Parnachev, N. V. Arkhipova and A. L. Arkhipov

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Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin—Altay-Sayan Region, Siberia. Guide for field trips for participants of VII International Conference “Large igneous provinces through earth history: mantle plumes, supercontinents, climate change, metallogeny and oil-gas, planetary analogues” (Tomsk, Russia, 28 August–8 September 2019). ix

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Guide for Field Geology of the Lower Devonian Byskar Series on the Educational Geological Ground of Siberian Universities (Republic of Khakassia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. A. Makarenko, A. D. Kotelnikov, S. A. Rodygin, A. L. Arkhipov and N. V. Arkhipova

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The Field Trip 2: Early Paleozoic Large Igneous Provinces in SW Siberiа Continental Sediments of the Early Cretaceous from Western Siberia. Part 2. Continental Mesozoic Sediments—Stratotype of the Lower Creataceous Ilek Formation (Bolshoi Ilek) at the Chulym River (Achinsk, Krasnoyarsk Region) . . . . . . . . . . . . . . A. V. Fayngerts Igneous Rocks of the Kachinsk-Shumikhinsky Magmatic Area of Late Ordovician-Early Silurian Age (East Sayan) . . . . . . . . . . . . . . O. Yu. Perfilova, A. M. Sazonov, M. L. Makhlaev and A. A. Vorontsov Cambro-Ordovician Ultramafic-Mafic and Granitoid LIP of Kuznetsk Alatau . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. E. Izokh, V. V. Vrublevskii, A. D. Kotelnikov, G. S. Fedoseev and A. Yu. Falk Late Cretaceous Intracontinental Alkaline-Basaltoid Magmatism of the Chebakovo-Balakhta Depression . . . . . . . . . . . . . . . . . . . . . . . . . A. E. Izokh, G. S. Fedoseev and V. A. Kutolin

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The Field Trip 1: Early Devonian Large Igneous Provinces in SW Siberiа

Continental Sediments of the Early Cretaceous from Western Siberia. Part 1. Mesozoic Continental Sediments: Shestakovo Yar (Ilek Formation, Lower Cretaceous, Kemerovo Region), Vertebrate Fossils Site A. V. Fayngerts

The geological tour is aimed to review the depositional environment of the Cretaceous continental deposits at the Ob river outcrops in southeastern part of West Siberia. The participants of the tour will see a river outcrop 35 m high and 800 m long, examine the change of the deposits up the stratigraphy and laterally, as well as depositional environment and sedimentogenesis conditions. The main types of alluvial, lacustrine and deltaic depositional environments will be examined, both modern and ancient ones. In the territory of the former Soviet Union the Psitaccosaurus sp. fossils were first found in situ at the Shestakovo Yar (steepbank river outcrop) in 1953 (Fig. 1). Since 1995 a paleontological team of Tomsk State University has been conducting field surveys in the Chulym river basin (the Kiya River, Bolshoi Kemchug River and others). There found 15 sites of dinosaur fauna and identified the largest complex of the Early Cretaceous continental vertebrate fauna in Russia. Many vertebrate taxa have been described for the first time. The holotype of Psitaccosaurus sibiricus is on display in Paleontology Museum of Tomsk State

A. V. Fayngerts (&) Tomsk State University, Lenin Avenu, 36, 634050 Tomsk, Russia e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_1

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Fig. 1 Geographic position and geological structure of the Shestakovo 1 locality (Averianov et al. 2018). A—a Map of Russia showing the position of Kemerovo Province (red). b Map of Kemerovo Province showing the position of Chebula District (red) and Shestakovo 1 locality (asterisk). c Photograph and geological interpretation of the Malyi Yar section at Shestakovo 1 locality (the rate of vertical scale to horizontal scale is 1:2). a-c, Lower Cretaceous deposits (a, mudstones and muddy silts; b, muddy and silty sand and silt; c, sand); d, Quaternary deposits; e, Kiya River; f, Talus. Numbers 1 and 2 denote position of sections in Fig. 3. Asterisk shows the position of the sauropod vertebrae found in situ

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University. On the basis of lithofacial characteristics the Lower Cretaceous sediments of the Shestakovo Yar are considered to be of alluvial origin. The area of interest is located in the Chulym-Yenisei basin that is a southwestern part of the vast Mesozoic West Siberia basin. This relatively poorly-defined Mesozoic basin originated on highly tectonically disturbed rocks of the Paleozoic basement and Early Triassic rift system. Jurassic continental clastic sediments formed predominantly in the extensive lacustrine alluvial plain and contain coal beds. Lower Cretaceous sediments of the Ilek Formation lie unconformably on the Jurassic and Paleozoic rocks. The Ilek Formation will be used to demonstrate alluvial, lacustrine, and deltaic depositional environments. Ilek Formation deposited in semiarid conditions. The sediment supply for Chulym-Yenisei basin came from the Altai-Sayan mountain country located to the south and experienced denudation. The next stage of the Chulym-Yenisei basin development (predominantly downward movement) resulted in deposition of the thick Upper Cretaceous succession overlain on the Ilek Formation. Therefore, the objects of our interest are: the Shestakovo Yar and Bolshoi Ilek (Fig. 1). Paleontological data (vertebrate fossils) give evidence for the existence of refugium in the south-east of West Siberia from Bathonian (Jurassic) to Aptian (Cretaceous). Refugium is an area in which a population of organisms survived or survive through a period of unfavorable conditions after extinction in extensive surrounding areas. The existence of the refugium is confirmed by the presence of the transitional (relict) taxons: salamanders, crocodiles, and mammals from the Lower Cretaceous Ilesk Formation. To the end of the Early Cretaceou at the Albian-Cenomanian boundary angiospermae appeared and were widely distributed (findings of fossil leaf flora in the superposed deposits). The change in food rations of the fauna resulted in the change of faunal composition. For this reason, mammal complexes from sites Shestakovo 1 and Shestakovo 3 are totally different, with not one common taxon. The same holds true for other paleontological sites where Tritylodontidae (therapsids, theromorphs) were found. Possible cause for rapid distribution of angiospermae was climate change leading to the appearance of the newly adapted forms with better survival potential in new conditions. Climate change was caused, in turn, by the change in tectonic setting of the sourceland (provenance). Shestakovo Yar Site Shestakovo Yar sediments accumulated in an alluvial plain environment (Figs. 1, 2 and 3). Sedimentation occurred due to migration of the distributaries during periodic flooding sand overflowing of water into subjacent lacustrine (floodplain)

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Fig. 2 Braided river system (Bjorlykke 1989). a—Mid-channel bar: b—active channel

Fig. 3 Alluvial plain system (Galloway and Hobday 1996). a—Splay grading to lake delta; b—lake; c—active channel; d—abandoned channel; e—stacked low sinuosity channel

basins. Prevailing facies are: braided and sinuous channels, mid-channel bars, floodplains, fans, etc. Many large slightly sinuous sand rivers turned into braided channels due to the various mid-channel bars formed in their channels. This braiding is more clearly seen during low water seasons when large portions of the river bed come out of the water. The braided channels divided and rejoined around alluvial bars (Fig. 2). Water discharge of the interlaced channels was high, they rapidly and continuously transported sediments and shifted the positions of their beds. It should be noted that

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Cretaceous vegetation had no root system and could scarcely prevent soil from erosion. The channels demonstrate vertical sand accretion and successively change each other. Lateral and vertical relationships of the sand bodies are shown in Figs. 1, 2 and 3. Lithological columns for the site are shown in Fig. 4, the observation point is shown in Fig. 1. Lenticular channel bodies with concave bottom surface were formed in slightly sinuous rivers, the channels of which, after their down cutting, were filled through a combination of vertical and lateral accretion. These bodies are included in fine-grained sediments and well-defined in Shestakovo Yar (upstream from the steep bank) (Fig. 1). The positions of some erosion surfaces in compound bodies formed by the numerous smaller bodies of channel deposits are difficult to interpret. Multiple cut-and-fills resulted from the “switching of activity between the channels” within the valley. In alluvial system with high solid discharge and when deposition of suspended solids on the areas between the channels is subtle, the channels are generally mobile and migrate with little accumulation of fine-grained deposits (Fig. 5). Among other factors controlling sedimentation and erosion are: rate of subsidence, avulsion frequency, and the width of the floodplain. In alluvial system with a bedload transport of mixed-type sediment or lack of sand load, the fine-grained floodplain deposits are more widely developed and the channels are more stable (less movable), being shifted due to avulsion. In this case the sand bodies are included in fine-grained sediments. More extensive sheet-like bodies composed of very coarse-grained sediments have a complex architecture. They contain erosion surfaces of different scales between which sandstones with planar bedding and trough cross-bedding prevail (Fig. 5). The completeness of stratigraphic record of the cross section depends on relation of the rate of lateral migration and rate of subsidence. When the rate of subsidence is low and channel migration is intense, significant portion of the sediments newly formed on the floodplain surface is systematically cut by further channel erosion. In such a case only deposits of the midstream and meander bars are being preserved in stratigraphic record (Fig. 6). Erosional and depositional activity of the rivers do not fully destroy all the sediments and very often the sediments are preserved as mud, sandy-silty and carbonate intraclasts in midstream and meander bar deposits (Fig. 6). A typical cross section exhibits upward fining trend. Sandstones lie on the horizontal surface of erosion. They become finer grained upward and usually demonstrate transition from cross-lamination to parallel or thin ripple lamination;

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Fig. 4 Lithological columns (observation point is shown with star in Fig. 1)

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Fig. 5 Sedimentary architecture of the Shestakovo Yar

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Fig. 6 Channel facies, mud intraclasts at the bottom

up the stratigraphy they pass into a very fine-grained member. At the bottom of the cross section are conglomerates (Fig. 7). The upward fining is assumed to be due to decrease in river current force, beginning with stage of erosion. This results from lateral migration of the river reaching a base level. In many instances a very coarse bed 2 meters thick is the result of the catastrophic sheet flooding (laterally extensive flooding). The character of the river bed depends on hydrological regime, water depth, amount of sediment (i.e., load) transported by a river, as well as riverbed stability. There is some evidence that a bed 1 cm thick may accumulate during a short period of 24 h. “Pure” sedimentation occurs only in certain periods while at all other times the riverbed remains stable and even can be washed. Figure 8 shows mud cracks formed during seasons of low water. Rainy seasons and spates cause the wash-out of the beds and generation of the basal horizons (gravel conglomerate) composed of the mud intraclasts. Sandstone occurs in beds up to 10 m thick, clayey boulders are up to 1 m in size. Clayey and silty deposits are not present here. Clayey boulders are presumably of colluvial origin. They formed as a result of the flood when high river banks were laterally eroded and large fragments of the rocks fell to the river bed where

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Fig. 7 Sedimentary cycle beginning (river flow rate falls, direction of a stream form right to left). 1—Basal pebble horizon (pebbles are mud intraclasts), 2 and 4—planar cross-bedding, 3 and 5—horizontal lamination

they were buried. Further channel migration in floodplain area totally washed away floodplain clayey sediments, but preserved only sands of channel and mid-channel bars (Figs. 9 and 10).Characteristics of the sediments produced by low-sinuosity streams: 1. Upper channel deposits lie almost horizontally. Bottom surface is concave and eroded. Sediments are formed in shallow water; 2. After avulsion the surface of the very coarse-grained deposits is covered by very fine-grained material; 3. Large-scale cross bedding is well-developed; 4. Sediments of the meanders bars occur very seldom, being observed only on sides of the channel deposits;

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Fig. 8 Mud cracks

Fig. 9 Buried colluvial sediments

A. V. Fayngerts

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Fig. 10 Buried colluvial sediments

5. Paleocurrent studies results evidence that river flow pattern did not fluctuate much. Cross bedded units made up of foreset laminae produced from the migration of small-current ripples are called small-ripple bedding (Reineck and. Singh, 1981). Here the boundary surfaces, both low and upper, are the surfaces of erosion. Small-ripple bedding is developed when small amount of sediments is deposited. The bedding is characteristic of the upper parts of natural levees and meander bars (Fig. 11). Figures 12 and 13 (left) shows cross-bedding in modern and Cretaceous deposits. The image of the Cretaceous Ilek sediments is on the right. Sometimes foreset beds look overturned. This is due to speedy and overloaded currents affecting the upper portions of the foresets. Moving mass of sand and water bends upper portions of the foresets forming overturned folds (Fig. 13, right). This is characteristic for the channel deposits (Reineck and Singh 1981). Sedimentary deformational structures encompass deformed and upturned foresets, rolls and intraclasts, load structures and convolute bedding. All the structures are almost coeval with sedimentation. The main reasons for them are

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Fig. 11 Small ripple bedding

rapid rise and fall of water level in the river, large amount of fine-grained material, flow of water intensely penetrating into, and eroding the banks. Upturned and contorted beds occur in the lower foreset with large-scale cross-bedding (Fig. 14). Determination of paleo-current direction Paleo-current direction coincides with the dip azimuth of cross bedding, while pebbles (mud intraclasts) are oriented upstream (Fig. 15). Convolute lamination in hydroplastic sediments is produced by localized differential forces, differential liquefaction of the sediment layer or member, achieved by overloading and the driving force of the river current. Convolute lamination is typical for floodplain and sand-bars deposits (Fig. 16). Crevasse splays Crevasse splays In Low Cretaceous deposits occur as the breaches clogged by sandy material in muddy sediments of natural levees (Fig. 17). Orientation of the splays

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Fig. 12 Cross-bedding in modern and Cretaceous deposits

Fig. 13 Large-scale cross-bedding in modern and Cretaceous deposits

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Fig. 14 Deformational structures in Cretaceous sediments

Fig. 15 Direction of paleo-current (right to left)

A. V. Fayngerts

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Fig. 16 Convolute lamination

Fig. 17 Incised channel (levee break)

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Fig. 18 Calcretes

differs remarkably from that of the sandy sediments of the main channel. Some of them form thin sand beds in flood facies sediments. Initially very fine-grained material suspended in the water was deposited in flood basins, and then coarser material was accumulated in natural levees and breaches. Flood basins are, therefore, the areas of long-term deposition of fine-grained sediments. Sedimentation rate is very low, usually not greater than 2 cm per one flood period. Deposition of thick sedimentary successions within flood basins is restrained by braided streams with high rates of horizontal migration When the river channels are immobile thick successions of sediments are accumulated. Development of the flood basins in semiarid climate did not always result in the formation of valley marshes. At high rates of evaporation various salts originated (Fig. 18). Sedimentary material of the flood basins dried out at the ground surface forming mud cracks and other structures. High rates of evaporation at the surface of the sediments led to the development of the carbonate grains, boxstones and alkali salts. Calcretes were formed under semiarid conditions by evaporation of water near the water table, in the capillary fringe zone.

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This study was supported by the Government of the Russian Federation (project 14.Y26.31.0012).

References Averianov A, Ivantsov S, Skutschas P, Faingertz A, Leshchinskiy S (2018) A new sauropod dinosaur from the Lower Cretaceous Ilek Formation, Western Siberia, vol 51. Russia. Geobios, pp 1–14. https://doi.org/10.1016/j.geobios.2017.12.004 Bjorlykke K (1989) Sedimentology and petroleum geology, 363 p Galloway WE, Hobday DK (1996) Terrigenous clastic depositional systems: applications to fossil fuel and groundwater resources, 489 p Reineck HE, Singh IB (1981) Depositional sedimentary environments. Nedra Publ., Moscow, 439 p (in Russia)

Plume-Related Alkaline Basic Magmatism of the Kuznetsk Alatau: The Kia-Shaltyr Complex I. F. Gertner, O. M. Grinev, V. V. Vrublevskii, A. M. Sazonov, I. A. Oparin, P. A. Tishin, T. S. Krasnova and A. A. Mustafaev

The alkaline igneous province of the Kuznetsk Alatau occupies the northern part of the Altai-Kuznetsk segment of the Altai-Sayan Fold System. In many regional descriptions, this segment is named Mariinsky taiga (wild forest), or Martaiga. This I. F. Gertner (&)
O. M. Grinev
V. V. Vrublevskii
I. A. Oparin
P. A. Tishin
T. S. Krasnova
A. A. Mustafaev Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia e-mail: [email protected] O. M. Grinev e-mail: [email protected] V. V. Vrublevskii e-mail: [email protected] I. A. Oparin e-mail: [email protected] P. A. Tishin e-mail: [email protected] T. S. Krasnova e-mail: [email protected] A. A. Mustafaev e-mail: [email protected] A. M. Sazonov Institute of Mining, Geology, and Geotechnology, Siberian Federal University, ave. Gazety Krasnoyarskii Rabochii 95, Krasnoyarsk 660025, Russia e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_2

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province is a manifestation of the Middle Paleozoic alkaline basic magmatism that marks rifting and destruction of the Caledonian structural units of the Altai-Sayan Fold System. Other igneous complexes which are similar in composition and age are known in the Minusinsk Trough, Tuva, northern Mongolia, and Gorny Altai. The uniqueness of the Martaiga area consists in the wide occurrence of nepheline-bearing leucotheralite and feldspathic and feldspar-free urtites, which may be mined as a raw material for production of aluminum. Nowadays, about 20 deposits and occurrences of high-grade nepheline ores are known (Fig. 1). The Kiya-Shaltyr pluton, where urtite is spatially associated with basic rocks of moderate alkalinity is the most important. The Kiya-Shaltyr deposit is currently the main source of nepheline for the Achinsk Alumina Integrated Works. The open-pit mining provides an opportunity for direct examination of relationships between different rock associations. In addition, the outcrops of the host metasedimentary rocks allow a reconstruction of dynamics and kinematics of pluton emplacement. However, the most recent geochronological data let us assume a significant range in ages between alkaline-gabbro complexes of this province (Vrublevsskii et al. 2014; Gertner et al. 2015), including adjacent provinces in Tuva and Northern Mongolia. This age range of alkaline-gabbro magmatism is possibly from Late Cambrian all the way to Early Permian.

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Tectonic Setting of Alkaline Plutons

The Kuznetsk Alatau is a typical Caledonian fold system that consists of three lithotectonic units (from bottom to top): (1) fragments of the Neoproterozoic sub-oceanic crust, (2) Early-Middle Cambrian island-arc complexes, and (3) Late Cambrian and Early Ordovician marginal continental complexes (Berzin and Kungurtsev 2003). The Martaiga segment, where most alkaline basic intrusions are localized, has a block structure with alternation of the lithotectonic units listed above. Such a structural grain is a result of multifold tectonic reactivation of the region initiated by strike-slip offsets along the Kuznetsk Alatau Fault (Alabin 1983). Magmatism of elevated alkalinity is related to the Early Hercynian stage of tectogenesis accompanied by formation of large basins (Nazarovo, Minusinsk, etc.) along the northern and eastern foothills of the Kuznetsk Alatau and a series of narrow grabens on its slopes, which are largely filled with Lower and Middle

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b Fig. 1 Localization of alkaline basic intrusions in the northern Kuznetsk Alatau, compiled

after Grinev (1990), Makarenko and Kortusov (1991), Shokal’skv et al. (2000), Gertner et al. (2007). Inset: rectangle outlines the geographic location of the study area: I, Kuznetsk Alatau; II, Gorny Altai; III, West Sayan; IV, Kuznetsk trough; V, Minusa trough. Map: (1) Kuznetsky Basin: (2, 3) Devonian basins and grabens: (2) terrigenous and (5) volcanic fill; (4) Ordovician Taidon graben; (5) Lower and Middle Cambrian carbonate and volcanic rocks; (6) Upper Riphean-Lower Cambrian cherts, volcanic, and carbonate rocks; (7) Middle and Upper Riphean metamorphic complexes of the Tomsk Inlier; (5) granitoids of elevated alkalinity; (9) granitoids of normal alkalinity; (10) moderately alkaline gabbroic and syenite rocks; (11) mafic rocks of ophiolite association; (12) ultramafic rocks of ophiolite association; (13) thrust fault; (14) normal fault; (15) other faults; (16) geological boundary; (17) swarms of alkaline basic dikes; (18) alkaline basic massifs (numerals in map): 1. Kiya-Shaltyr; 2. Universitetsky; 3. Belogorsk; 4. Svetlinsky; 5. Podtaiginsky 6. Kiya outcrops; 7. Kurgusul; 8. Batanayul; 9. Verkhnepetropavlovsk; 10. Cheremukhino; 11. Goryachegorsk; 12. Zagomy; 13. Dedovogorsk; 14. Mount Pestraya; 15. Malosemenovsky; 16. Tuluyul and Medvedkinsky; 17. Maly Kiya-Shaltyr; 18. Barkhat-Kiva; 19. Andryushkina Rechka: 20. Uchkuryup; 21. Mount Lysaya; 22. Dmitrievsky Creek

Devonian clastic and volcanic rocks. These structural elements are interpreted as a result of intracontinental, late collision or post collision rifting (Grinev 1990). A distinctreal petrological type of Devonian magmatism is expressed in the only Kiya-Shaltyr Pluton (age 398.9 ± 5.5 Ma, U/Pb isotope data) and its satellite, Dedogorovsk Massif (age 401 ± 2 Ma, U/Pb isotope data), which has similar composition to middle alkaline gabbroic rocks from this deposit. However, it should be noted that University Massif with a similar petrographic composition was recently dated with an older age, around 480–490 Ma, using Sm–Nd isotopic data. At the same time, an important structural element of alkaline rocks in the Kiya-Shaltyr formation is foidolite dikes, which contain phenocrysts of nepheline, “xenoliths/autoliths” of urtites or pegmatiod ijolites. This dike belt is about 20 km long, and it crosses Kiya-Shaltyr Massif,and also cuts the Belogork Massif also (Grinev 1990). These massifs, which are round in plan view and are distributed over an area about 100 km in diameter, are spatially related to the Early Paleozoic island-arc and marginal continental blocks. The localization and morphology of alkaline gabbroid plutons is controlled by the NW and N-S-trending tectonic zones of elevated permeability, which are marked by dikes of alkali basalt (Fig. 1).

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Petrographic Variety of the Alkaline and Basic Rocks in Region and Its Geochemical Specifity

The studied objects comprise intrusive bodies of basic and alkaline rocks and carbonatite veins, including olivine gabbro of moderate alkalinity; theralite; feldspathic ijolite and urtite; feldspar-free melteigite, ijolite, and urtite, nepheline and alkali syenites. Dikes of pegmatoid, porphyry, and fine-grained varieties similar in bulk composition with plutonic rocks of main intrusive phases are abundant, as well as dikes of camptonite, nepheline camptonite, and tinguaite. The assortment of rocks and their relationships are variable. While some plutons consist of one or two rock types, the others comprise virtually the entire set of rock types listed above. The plutons of simple composition and structure are mainly located in marginal zone of igneous aureole, whereas composite plutons cluster in its central portion. Almost all researchers share an opinion that feldspar foidolites were emplaced after the gabbroic rocks; nepheline and alkali syenites and carbonatites completed the formation of particular plutons. Three independent volcanic series of elevated alkalinity-alkali basalt, basanitephonolite, and nephelinite are recognized in the northern Kuznetsk Alatau. The intrusive bodies of the Goryachegorsk Complex correspond to three autonomous rock associations: (A) gabbro-alkali syenite, (B) theralite-basic foidolite-nepheline syenite, and (C) ijolite-urtite (Fig. 2). The rocks of the aforementioned groups do not reveal gradual transitions and always make up separate bodies separated by intrusive contacts. Some plutons are homogeneous in their petrochemical characteristics. For example, the Dedovogorsk and Barkhatny Ku plutons represent the gabbro-syenite association of Type A, the Goryachegorsk pluton of basic foidolite and nepheline syenite belongs to Type B, whereas the Svetlinsky, Podtaiginsky intrusions, and Kii outcrops are composed of the ijolite-urtite series of Type C. Other plutons are combinations of rocks that pertain to different associations: Kiya-Shaltyr (A + C), Kurgusul and Verkhnepetropavlovsk (A + B), Belogorsk and Universitetsky (A + B + C). The quantitative proportions of specific associations are variable. The common petrochemical attribute of alkaline rocks in this region is enrichment in alumina along with low Ti content. In trace element contents, the alkaline basic rocks do not reveal appreciable differences. Nevertheless, in the series of subalkali gabbroic rocks-basic and ultrabasic foidolites-nepheline syenite, the progressive decrease in magnesian number accompanied by depletion in siderophile elements and steady enrichment in HFSE indicate a magmatic trend. In comparison with petrographic counterparts from continental rift systems of Africa, Germany, and polar Siberia, basic rocks

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Fig. 2 Petrochemical trends of intrusive rocks, which belong to the Goryachegorsk Complex. (A) ijolite-urtite series, (B) theralite-basic foydolite-nepheline syenite series, (C) gabbro-syenite series. Plutons and intrusive bodies (numerals in circles): 1. Kiya-Shaltyr; 2. Universitetsky; 3. Belogorsk; 4. Svetlinsky; 5. Podtaiginsky; 6. Kiya outcrops; 7. Kurgusul-Listvenny; 8. Batanayul; 9. Verkhnepetropavlovsk; 10. Cheremukhino; 11. Goryachegorsk; 12. Bolshoi Taskyl; 13. Dedovogorsk: 14. Mount Pestraya

and foidolites of the Kuznetsk Alatau are markedly depleted in incompatible elements. In Ce/Y–Zr/Nb and Th/Yb–Ta/Yb discriminant diagrams (Fig. 3), their compositions fall into a transitional region between E-MORB and OIB testifying to predominance of oceanic E-MORB component in the source and to the existence of fragments of the relatively primitive Earth’s crust in the Early Paleozoic framework of the Siberian paleocontinent. The elevated Th/Yb ratios against the background of low La contents indicate a shift of compositions toward igneous rocks of the island-arc and marginal continental geodynamic settings.

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(a)

(b) AB, GB, BN

10

Ce/Y

10

Th/Yb

OIB

IA

ACM

OIB

1

Enriched mantel

E-MORB

Depletion mantel

1

0,1

Mantel array

E-MORB

N-MORB 0,01

N-MORB 0

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0,01

50

0,1

1

2

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4

1

10

Ta/Yb

Zr/Nb

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10

Fig. 3 a—Ce/Y versus Zr/Nb and b—Th/Yb versus Ta/Yb in moderately and highly alkaline rocks of the Goryachegorsk Complex in comparison with oceanic basalts. (1–6) Kiya-Shaltyr pluton: (1) melano- and mesocratic gabbro, (2) leucogabbro, (3) urtite, (4) pegmatoid ijolite, (5) microijolite, (6) nepheline syenite; (7–9) Verkhnepetropavlovsk, Goryachegorsk, and Dedovogorskplutons: (7) subalkali gabbro, (5) theralite and basic foidolite, (9) nepheline syenite; (10) ijolite of the Khibiny pluton. Kola Peninsula (Arzamastev et al. 2001). Nephelinite (dark gray field) and basaltic rocks (light gray field) of the Krestovsky volcanic-plutonic association in the Maimecha-Kotui province; basaltic series (AB) from rift systems of eastern Africa (Franz et al. 1999; Furman and Graham 1999), basaltic (GB) and nephelinitic (GN) series from rift systems of central Germany (Jang and Hoemes 2000) (dashed contour); N-MORB, E-MORB, and OIB are given after Sun and McDonough (1989); active continental margins (ACM), and island arcs (IA)

3

Age of the Alkaline-Basic Association

The results of recent geochronological studies cast doubt that all alkaline gabbroic plutons belong to the common Early Devonian Goryachegorsk Complex. In particular, the Sm–Nd isochron based on whole-rock samples of feldspathic urtite, carbonatite and apatite and clinopyroxene separated from these rocks yielded a much older age of the Verkhnepetropavlovsk pluton (509 ± 10 Ma, eNd(t) = 5.1 ± 0.2, MSWD = 0.1). A similar age (502 ± 46 Ma) has been obtained from Rb-Sr mineral isochron for theralite of this pluton. An Early Ordovician age can be proposed for gabbro rocks of the University massif based on Sm–Nd isotopic data (for leucocratic gabbro—492 ± 28 Ma with MSWD = 2.1; for other gabbro units—498 ± 33 Ma with MSWD = 2.0).

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The Early Devonian U-Pb zircon age (400.9 ± 6.8 Ma) was defined for pegmatoid nepheline syenite that completed emplacement of the Dedovogorsk pluton of alkali gabbroids (Vrublevsky et al. 2004). According to the previous K-Ar determinations, these rocks were regarded as products of the final alkaline magmatism on the northern slope of the Kuznetsk Alatau (Andreeva 1968). Later, this age was confirmed by LA-ICP dating for several zircon crystals/grains (401 ± 2 Ma). The most plausible dating that corresponds to crystallization of the Kiya-Shaltyr pluton is an age obtained from Rb-Sr isochron based on whole-rock sample analysis of poikilitic gabbro and pyroxene and biotite from this rock. The slope of this isochron indicates an age of 406 ± 2.2 Ma, Sri = 0.70475, and MWSD = 0.73. Later Sm–Nd and U-Pb dating defined the age of subalkalic gabbro from Kiya-Shaltyr and Dedovogorsk Massifs (taking into account their mineral phases) at around 407 ± 14 Ma (MSWD = 2.2, eNd(t) = 5.3), and similar geochronological data was obtained for foidolites from Kiya-Shaltyr Massif (405 ± 17 Ma with MSWD = 0.9, eNd(t) = 5.0). Using LA-ICP method, accessory zircons were dated to define the age of the latest intrusive phases of Kiya-Shaltyr Massif. We obtained the following dates for pegmatiod ijolite from an urtite body (398.8 ± 5.5 Ma with MSWD = 0.58), and 387.5 ± 2.8 Ma (with MSWD = 0.28) for nepheline syenites. Thus, we can confidently say that the age of Kiya-Shaltyr massif is Early Devonian and ranges between 405 and 390 Ma.

4

Internal Structure of the Kiya-Shaltyr Pluton

The Kiya-Shaltyr pluton crops out as a peak that bears the same name at the eastern drainage divide in the upper reaches of the Kiya River. This is a differentiated intrusion of stock-like shape with almost vertical lateral contacts that cut through the Lower Cambrian carbonate and volcanic rocks of the Ust-Kundat and Usa Formations. The pluton consists of three intrusive bodies (Fig. 4). The northeastern body is elongated in the near-meridional direction (N-S) is composed of leucocratic trachytic gabbroic rock of moderate alkalinity. The central body that extends in the northwestern direction is composed of melano- and mesocratic poikilitic gabbroids, and finally, the southwestern crescent body consisting of urtite frames the

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central body in the south and southwest. Urtite is a nepheline ore. Two small occurrences of ijolite-urtite at the western and eastern flanks of the northeastern body are not mined currently. The tectonic deformations of the host volcanic-sedimentary sequence suggest that the magma chambers of the main phases in the Kiya-Shaltyr pluton were formed as a result of strike-slip faulting. A pull-apart structural trap acts as a pump

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b Fig. 4 Geology of the Kiya-Shaltyr pluton. (1, 2) Lower Cambrian rocks: (1) Ust-Kundat

Formation, (2) Usa Formation; (5 7) intrusive rocks: (3a) urtite and (3b) jiolite, (4) poikilitic melano- and mesogabbro, (5a) trachytoid and (5b) porphyritic leucogabbro; (6) dikes: (a) foidolite, (b) subalkali and alkali gabbroids, (c) nepheline and alkali syenites; (7) theralite, (8a) contact pyroxenite and (8b) skamified rocks; (9) faults: (a) thrust faults and (b) auxiliary faults; (10) direction of displacement in zone of ductile deformation; (11) textural anisotropy of igneous rocks (trachytoid structure, mineral flattening and layering), (12) strike and dip of beds with (a) normal and (6) overturned attitude; (13) axial plane of thrust antiform; (14, 15) zones of ductile deformation: (14) in limestone and (15) in volcanic and carbonate rocks. Intrusive bodies (letters in circles): A. northeastern (leucocratic trachytoid gabbro); B. central (poikilitic meso- and melanocratic gabbro); and C. southwestern (urtite). Big black points are the localities of observation time in during field trips

that provides the supply of magmatic melt from a deep-seated source. In this view, the complex morphology of the urtite body is a combination of two cavities whose opening is related to strike-slip displacement along a NW-trending curvilinear path, in combination with local extension oriented in the northeastern direction (Voitenko et al. 2001). The strike-slip faulting model for emplacement of magma melts is supported by extremely complex morphology of basic and foidic dikes at the flanks of larger intrusive bodies and in the host rocks. Despite the possible tectonic nature of magmatic chamber formation, the active thermal and metasomatic effects of main intrusive bodies on host rocks is widespread and expressed in marble and formation of melilite-bearing calc skarn. The sequence of emplacement of the intrusive phases in the Kiya-Shaltyr pluton, and especially urtite and poikilitic gabbro pulses, has remained a matter of debate until now. A concept of older urtite is supported by Drozdov and Chaiko (1978), Drozdov (1990), Correlation (2000), whereas Mostovoskoi (1978) and Grinev (1990) suppose that the poikilitic gabbro is older. These different interpretations are due to the complex geological relationships between these rock types and various contact effects of hybridism and nephelinization. Furthermore, the contact between poikilitic and trachytoid gabbros is probably tectonic. The relationships of basic and foidic dikes with rocks of main intrusive phases are regarded as evidence for sequence of emplacement. However, this evidence is also ambiguous, because dikes mark the activity of deep-seated magmatic chambers that might have functioned much longer than the period of crystallization of plutonic bodies. Two generations of ijolite dikes with pegmatoid and fine-grained textures, one of which contains xenolith-like inclusions of urtite, is an example. Only the youngest age for nepheline syenite and plagiophyric dikes is not doubted.

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Petrography of the Kiya-Shaltyr Pluton

Urtite is a bi-mineral rock with large (up to 5 cm) clinopyroxene oikocrysts with incorporated euhedral nepheline crystals (Fig. 5). In this structure, urtite resembles meso- and orthocumulates of layered plutons. Titanomagnetite, apatite, titanite, and pyrrhotite are accessory minerals (Sazonov et al. 2000). The late metasomatic alteration is expressed in small veinlets of blue sodalite or the pinkish violet variety of this mineral (hackmanite), cancrinite, and zeolites. Abundant veinlets in local areas resulted in the formation of specific metasomatic breccia. The peculiar nepheline- pyrrhotite isometric and linear segregations in urtite are noteworthy. Their origin is interpreted as manifestation of immiscibility of silicate and sulfide melts at the late magmatic stage. The pegmatoid foidolite veins differ from urtite in their more melanocratic outer appearance with approximately equal amounts of nepheline and clinopyroxene. These allotriomorphic-granular rocks are markedly enriched in accessory minerals. According to microprobe results, both nepheline and clinopyroxene are heterogeneous in composition (Voitenko et al. 2004). Three nepheline varieties with different proportions of silica and alkali metals are distinguished. The high-Na nepheline is close to stoichiometry in chemical composition and is the most abundant in the southern segment of the urtite body. The high-Si nepheline with an

Fig. 5 Microstructure of urtite from the Kiya-Shaltvr pluton. a cumulative structure of urtite with elements of agpaitic structure; b euhedral nepheline (Ne) crystals in clinopyroxene (Cpx) oikocryst; thin section 55-3b, crossed polars

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excess of Si and Al dominates in the central and northern portions of this body. Nepheline with high content of the calsilite end member is typical of the late stage ijolite. Clinopyroxene corresponds to salite grading to ferrosalite. The high-Mg clinopyroxene, which is typical of the conduit zone at the southern end of the urtite body, is associated with high-Na nepheline. The assemblage of high-Si nepheline and calcium clinopyroxene with excess of wollastonite and tschermakite end members occupies the northwestern portion of the urtite body. The poikilitic and trachytic gabbroic rocks of the Kiya-Shaltyr pluton are characterized by occurrence of low-Ti salite in association with plagioclase. Thus, nepheline syenite may be regarded as a late derivative of the basic melt.

6

Ore Potential and Mineralization of Kiya-Shaltyr Pluton

One of the most important specifics of Kiya-Shaltyr deposit’s metallogeny is sulfide mineralization. Its sub-liquid nature is proved by the fabric characteristics of the ores, where sulfides (and not pyroxenes) act as a cementing or interstitial component between idiomorphic nepheline crystals (Fig. 6). The main component

Fig. 6 Sulfide mineralization in foidolites of the Kia-Shaltyr massif rocks (It is the contact between urtites and ijolite dyke)

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of the sulfide phase is pyrrhotite. However, other sulfides are present as inclusions, including noble metal minerals. An important element of this structure is a relationship between sulfides and nephelines, which points out the subsolidus nature of liquation. The presence of idiomorphic nepheline crystals indicates its crystallization at an early stage in an intermediate magma chamber and later introduction/admixing of a “mushy” melt. This intrusion type is quite common and suggests accumulation of an early crystallization phase. It is very possible that there was early crystallization of nepheline caused by a specific interaction of ultrabasic-basic plume-type melts and host carbonate sequences. This process assumes rock enrichment in alumina. Another proof of this process is “xenoliths/autoliths” of holocrystalline urtites in fine-grained ijolite dikes, which were found in southeastern flank of the deposit, as well as inside of it, in the northeastern part of it at the “Universitetsky-1” location, and in the Universitetsky Massif itself. The presence of sulfide inclusions (mostly pyrrhotite) was noticed within the urtite body and its margins endocontacts in the very beginning of exploration and exploitation of this deposit. However, the limited scale of this mineralization and the established value of nepheline as an aluminum ore meant that the sulfides were ignored as potential ore. The presence of sulfides was rather an unwanted admixture, which made the technological process of obtaining alumina from nepheline ores more difficult. However, these sulfide inclusions are in fact “storage units” for noble metals. Mineralogical studies showed presence of silver sulfides (argentite) in their composition. In addition, many data demonstrated a high content of platinoids.

6.1 Sulfide Mineralization in Margin Zones of the Urtite Body We had look a few pyrrhotite-rich pyroxenites with an insignificant admixture of nepheline and plagioclase in the northeastern part of the urtite ore body. Thus, we can assume that there is a broken/discontinuous zone of pyrrhotite-rich nepheline-pyroxene rock formation at the contact of the urtite body and mesocratic gabbro body. Authors suggest liquation nature of the sulfide formations inside of the urtite body, which is indicated by sideronitic textures of the nepheline ores. Pyrrhotite clusters, which are present as exotic nepheline-pyroxene-pyrrhotite rocks, form the first magmatic type of sulfide mineralization predominantly with pyrrhotite composition. Dikes of trachydolerites and plagioporphyrites localisat in the mesocratic gabbro and urtite body. These dikes are enriched in sulfides, all the

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way to sideronitic textures and mono-mineral sulfide assemblages, which apparently belong to this magmatic type as well. In some wells drilled in 2010 there were found low-thickness sulfide-carbonate veins with pyrrhotite-pyrite and a more complex composition. We suggest formation of these veins is caused by final stages of the urtite body development, more than likely before post-magmatic processes started occurring appearing broadly. This sulfide mineralization was recognized as the second type. A bigger accumulation/cluster of sulfide mineralization (mostly pyrrhotitic) is found in the exocontact zone (adjacent host rocks) of the urtite body. This zone is characterized by processes of broad skarn/tactite formation and marbleization of host rock s/sequence, and is recognized as the third type.In the host sequence, beyond the exocontact band/frame of the urtite body, we have found series of poly-mineral sulfide and sulfide-carbonate veins with pyrrhotite and cobaltite predominating in composition. Besides that, a series of nepheline and alkali syenite dikes with fine-grained texture was found. This series underwent hydrothermal transformation with superimposed sulfide (predominantly pyrrhotite) mineralization. These manifestations of sulfide mineralization are the forth (pyrrhotite-cobaltite) and fifth (superimposed pyrite) types of post-magmatic hydrothermal mineralization. There are quartz-carbonate-sulfide stringers and veins, tracing zones of small-scale fault deformation, and jointing zones in the aureole/area of the urtite body. Within these veins, the host sequences show cleavage foliation and formation of thread-like sulfide-carbonate and sulfide-feldspar stringers. Formation/development zones of these stringers are usually accompanied by intensive development of iron hydroxides and argillization, which gives them rusty yellow/brownish yellow color, that indicates post hydrothermal and possibly exogenic transformations of superimposed dikes and earlier veins. Apparently, these formations also belong to the fifth mineralization type of alterations by exogenic processes. Thus, based on geological position and rock compositions near and inside the urtite body’s aureole, we can define: (1) magmatic high-temperature nepheline-pyroxene-pyrrhotite rocks and scattered pyrrhotite mineralization on the endocontact (margin of the intrusion); (2) ore mineralization (sulfide and magnetite) of dike bodies with the same magmatic type but at a later formation stage. During a detailed mineralogical analysis, platinum group minerals (isoferroplatinum, tetraferroplatinum) were also found in the nepheline ores and drill cuttings/sludge of the Achinsk alumina complex, which more than likely relate to the sulfide mineralization. An important question remains regarding the presence of palladium minerals (Sazonov et al. 2000). Based on many analyses of the ores themselves and their utilization/waste products, palladium content is higher than platinum concentrations.

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Sources of Alkaline Gabbroic Intrusions of the Kuznetsk Alatau and Geodynamic Setting of Their Formation

The recent data on Nd, Sr, and O isotopes demonstrate a rather complicate nature of sources of alkaline basic plutonic rocks in the Mariinsk Taiga (Vrublevsky et al. 2004). These data suggest that the parental magma was derived from a mantle source. At the same time, the igneous activity was characterized by large-scale crustal contamination. This process affected the Nd isotopic composition to the least degree, and its parameters correspond to the moderately depleted mantle of PREMA and HIMU types. All plutons reveal an approximately similar degree of depletion of a mantle source: eNd(t) varies from +7.2 to +3.4 with predominant values close to +5. A wider variation from +3.2 to +27.4 is established for eSr(t), which increases in urtite, nepheline syenite, and carbonatite (Fig. 7). The shift toward the enrichment in radiogenic Sr may be interpreted as a result of 87Sr supply into magmatic system from mobilized brines buried in carbonate sedimentary sequences. The isotopic compositions of rocks, the scale of crustal contamination, and geological setting of alkaline basic plutons of the Kuznetsk Alatau are consistent with the modern ideas suggesting that the evolution of the Early and Middle Paleozoic basic magmatism in northern Asia was controlled by a PREMA-type mantle superplume on the lithosphere (Yarmolyuk and Kovalenko 2003).

8

Field Excursions

The 1.5-km-long route across the Kiya-Shaltyr pluton (Fig. 4) provides for examination of 10 outcrops of host rocks and urtite orebody in the open pit. The Kiya-Shaltyr open pit is situated near the settlement of Belogorsk. The road goes from Tisul to Goryachegorsk and farther through mountainous taiga. The examination of the open pit starts with outcrops that demonstrate folds and faults related to the formation of the magma chamber filled with urtite (Fig. 8). The rhomb-shaped bodies of urtite and poikilitic gabbro may be explained by transformation of thrust faults into a nonlinear strike-slip fault owing to the change in direction of tectonic detachment in the hinge of anticline.

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εNd(T)

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4 HIMU

10

2

0 EMII

-2

εSr(T)

EMI -4 -40

-30

-20

-10

0

10

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30

40

Fig. 7 Nd and Sr isotopic compositions of alkaline rocks from the Kuznetsk Alatau. (1–3) Kiya-Shaltyr pluton: (1) melano-gabbro, (2) foidolite, (3) leucogabbro; (4, 5) Dedovogorsk pluton: (4) leucogabbro, (5) nepheline syenite; (6–8) Verkhnepetropavlovsk pluton: (6) subalkali gabbro, (7) feldspathic ijolite, (5) carbonatite; (9, 10) Goryachegorsk pluton: (9) feldspathic urtite and leucotheralite, (10) nepheline syenite. Today’s isotopic compositions of PREMA, HIMU, EMI, and EMII reservoirs are shown after Zindler and Hart (1986). The field of prevalent isotopic compositions of basic rocks from Early and Middle Paleozoic igneous associations of the Altai-Sayan region (Yarmolyuk and Kovalenko 2003) is contoured by dashed line

Station 1. A zone of ductile flow in carbonate rocks of the Ust-Kandat Formation; ijolite porphyry, subalkali dolerite, and camptonite dikes of complex morphology as evidence for strike-slip faulting; rhomb- and wedge-shaped swells are typical (Fig. 9). Station 2. A hinge of anticline in carbonate rocks of the Ust-Kundat Formation close to the northwestern pinch-out of the urtite body. A system of tight isoclinal folds (Fig. 10) is regarded as evidence for considerable compaction of host rocks that prevents the shearing and changes its direction.

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Fig. 8 The Kiya-Shaltyr open pit. View from the northern sight point. The urtite body is limited by lower benches. The skarnified carbonate rocks are exposed on the left (white rocky outcrops and talus). Observation points are indicated

Station 3. Camptonite dike at the northeastern end of the unite body (Fig. 11a). Orientation of normal faults and basic dikes that completed emplacement of the Kiya-Shaltyr pluton attracts attention. Station 4. Veins of pegmatoid and inequigranular ijolites hosted in urtite (Fig. 11b). Contacts of veins are tortuous and diffuse. These veins were formed as a result of crystallization of residual foiditic melt. Station 5. The contact between urtite and gabbroid reflects the reaction between the two intrusive phases.In the zone of endocontact urtites (ijolites, less often Melteigites), plagioclase is noted. The contact-reaction zone is represented mainly by pyroxene rocks. In this zone, both urtite and gabbro segregations are noted. In the endocontate zone of gabbroids, nepheline appears in pyroxenites. The work is conducted within the State Task of the Ministry of Science and Higher Education of the Russian Federation. Geochemical and geochronological data were obtained by the Government of the Russian Federation (project 14. Y26.31.0012).

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Fig. 9 Dikes at the northwestern pinch-out of urtite body. (1) ijolite porphyry, (2) subalkali dolerite, (3) camptonite, (4) boudinage zone in limestone, (5) foliated limestone

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Fig. 10 A fragment of the overthrust anticline core. Red lines are limestone beds.

Fig. 11 A dykes in the urtite body: one of the dykes of camptonite, intrusion to urtites (a); a fragment of pegmatiod ijolite dyke

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References Alabin LV (1983) Lithotectonic amd Metallogening Zoning of the Kuznetsk Alatau. Nauka, Novosibirsk, p 102 (in Russian) Andreeva ED (1968) Alkaline magmatism of the Kuznetsk Alatau. Nauka, Moscow, p 168 (in Russian) Arzamatsev AA, Bea F, Glaznev VN et al (2001) The Kola Alkaline Province in the Paleozoic: estimation of composition of primary mantle melts and condition of magma generation. Russian Earth Sci 3(1):1–35 Berzin NA, Kungurtsev LV (2003) Geodynamic interpretation of the Altai-Sayan geological complexes. Russian Geol Geophys 37(1):56–73 Correlation of Magmatic and Metamorphic Complexes of the Western Part of the Altai-Sayan Folded Region (2000) In: Shokalsky SP, Babin GA, Vladimirov AG, Borisov SM (eds) Novosibisk: Publishing House of SB RAS, p 187 (in Russian) Franz G, Steiner G, Volker G et al (1999) Plume-related alkaline magmatism in Central Africa—the Meidob Hills, W Sudan. Chem Geol 157, pp 27–47 Furman T, Graham D (1999) Erosion of lithospheric mantle beneath the east African Rift system: geochemical evidence from the Kivu Volcanic Province. Lithos 48, 238–262 Gertner IF, Vrublevskii VV, Krasnova TS (2015) Evolution of high alumins alkaline magmatism in the Central Asian Fold Belt. In: Abstract volume of international conference “Large Ignorus Provinces-2015. Publishing House of SB RAS, pp 35–36 Grinev OM (1990) Evolution of alkaline-basic magmatism of the Kuznetsky Alatau/Manuscriht of PH dissertation. Tomsk, TSU, p 324 (in Russian) Jang S, Hoernes S (2000) The major- and Irace element and isotope (Sr, Nd, O) geochemistry of Cenozoic alkaline rift-type volcanic rocks from the Rhon Area (Central Germany): petrology, mantle sources characteristics and implication for asthenospherelithosphere interaction. J Volcanol Geotherm Res 99:217–228 Rodygina VG, Grinev OM (1988) Nepheline-pyrrhotite rocks of the Kia-Shaltyr massif (Kuznetsk Alatau). Notes of UMS 6, part 117, pp 668–674 (in Russian) Sazonov AM, Leont’ev SI, Grinev OM et al (2000) Geology and Gold and platinum potential of Nepheline Rocks in the Western Siberia. Tomsk. Publishing House of TPU, pp 248 (in Russian) Sun S-S, Mc Donough WF (1989) Chemical and isotopic systematics of oceanic basalts: implication for mantle composition and processes, magmatism in the oceanic bassins. Geol Soc Spec Publ 42:313–345 Voitenko DN, Gertner IF, Vrublevskii VV, Sazonov AM (2001) Structural aspects of localization of Urtite dody of the Kia-Shaltyr pluton. Petrology of Magmatic and Metamorphic complexes. Tomsk: CSTI, pp 197–201 (in Russian) Voitenko DN, Selyatitsky AM, Gertner IF, Vrublevskii VV (2004) Urtite of the Kia-Shaltyr Pluton. Variation of chemical composition of rock-forming minerals as the reflection of the structural and petrological formation conditions. Petrology of Magmatic and Metamorphic complexes. Tomsk: CSTI, pp 18–28 (in Russian) Vrublevsky VV, Gertner IF, Vladimirov AG et al (2004) Geochronological boundaries and geodynamic interpretation of alkaline magmatism in the Kuznetsky Alatau. Dokl Earth Sci 398(7):990–994

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Vrublevsky VV, Gertner IF, Gutierrez A et al (2014) Isotope (U-Pbm Sm-Nd, Rb-Sr) gejcronology of alkaline basic plutons of the Kuznetsk Alatau. Rassian Geol Geophys 55:1264–1277 Yarmoluk VV, Kovalenko VI (Deep geodynamics and mantle plumes: their role in the formation of the Central Asian Foldbelt. Petrology 11(5):504–531

Saralinsky Graben—Devonian Rift of the Kuznetsk-Minusinsk Zone, Altai–Sayan Folded Area O. M. Grinev, O. R. Grinev, R. R. Adylbaev and A. A. Bogorodov

1

Introduction

The first studies of the Devonian grabens of the northeastern part of the Kuznetsk Alatau were obtained by the Krasnoyarskgeologiya and Zapsibgeologiya Geological Surveys in the 1950s–80s. The research was aimed at characterizing the grabens, and other structures of the region, and any associated ore mineralization and geochemical anomalies. Summaries of this early research are reported in Mustafin et al. (1966), Kryukov et al. (1969) and Turchenko, (1975). Subsequent research has provided additional insights, and in this chapter we review the current understanding of these Devonian grabens.

O. M. Grinev (&)
O. R. Grinev
R. R. Adylbaev
A. A. Bogorodov Tomsk State University, 36 Lenin Ave, Tomsk 634050, Russia e-mail: [email protected] O. R. Grinev e-mail: [email protected] R. R. Adylbaev e-mail: [email protected] A. A. Bogorodov e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_3

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Мариинск

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k ets p zn ar Ku wnw do

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Batenevsky Ridge

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о

Fig. 1 Tectonic map of the Devonian stage of development of the Kuznetsk Alatau (KA) and its bordering structures. Devonian paleorift system: 1—Saralinsky graben; 2—Goryachegorsk volcanic plateau (north-western part of the North Minusinsk trough); 3—Balyksin graben (south-western part of the South Minusinsk trough); 4—Rastai graben; 5—Talanovsky graben; 6—Palatninskaya graben-syncline; 7—Telbesky graben. Hercynides of the folded Central-West Siberian-Ob-Zaisan belt: 8—the northern part of the Kolyvan-Tomsk folded area. 9—contours of the territory of the Kuznetsk-Alatau alkaline-basic volcanic-plutonic province

Saralinsky Graben—Devonian Rift …

45

The Saralinsky graben is the largest of the Devonian grabens in the region. It is located in the intersection of the Kuznetsk Alatau anticlinal structures and the largest terrigenous-volcanogenic Devonian trough of Altai–Sayan Folded Area (ASFA) the Minusinsk trough. It has a direct structural connection with the North Minusinsk and Nazarovskaya sub-basins of the trough, and its terrigenous-volcanogenic section is fundamentally similar in structure and composition to the stratotypical Shunet-Matarak section of the Lower Devonian of the Minusinsk zone (Grinev 1990, 1994) (Fig. 1).

2

Importance of Studying the Saralinsky and Other Devonian Grabens

Studying of this graben is important for a number of reasons: 1. The Saralinsky graben, along with other grabens of a northeast part of Kuznetsk Alatau (Rastaysky and Talanovsky), represents an important part of the regional Devonian rift system; 2. Together with adjacent Goryachegorsky volcanic plateau, they provide structural link between the North Minusinsk and Nazarovsky troughs and the widely known Kuznetsk and Alatausky alkaline volcano-plutonic province. 3. The Saralinsky graben along with the Balysky graben follow BalyksinskoSaralinsky fault, which is a branch of the Kuznetsk-Alatau transregional lineament, extending in the axial zone of the Kuznetsk Alatau. This fault branch cuts Early Caledonian and Baikal Structures (R3-V), and also contains lenticular fragments of tectonized ophiolites (Fig. 2); 4. Volcanic rocks of the Saralinsky graben belong to the basalt-trachytic series, which is a distinctive feature of continental rifting. In the northern part of the graben, there is a large extrusive-subvolcanic body of trachyte, whereas in the other grabens of the region, trachytes are present only in the form of dikes; 5. A number of deposits and ore occurrences are located in close proximity or even in the margins of the Saralinsky graben, including deposits of gold-sulfide-quartz type, placer gold and copper-molybdenum ores, and promising occurrences of other minerals.

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Geology of the Saralinski Graben

The origin of the Saralinsky graben is linked to the Balyksinsko-Saralinsky Fault, which has a complex structure of converging and diverging branches, which contributed to the local fragmentation of the Baikal- Early Caledonian basement. In the regional plan view, this fault represents the western boundary of the Minusinsk

Saralinsky Graben—Devonian Rift …

b

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Fig. 2 Geological and tectonic map of the northeastern part of the Kuznetsk Alatau (territory of the Kuznetsk-Alatau basic alkaline province) (Grinev 2003): Upper structural level: 1— arrays of alkaline-gabbroid rocks; 2–4—strata of terrigenous-volcanogenic molasoic strata of the Lower Devonian: 2—Ashpanskaya, 3—Bereshskaya, 4—Bazyr Middle structural level (Є1–2 − O): 5—gabbro, diorite, granite, syenitic intrusives; stratified formations: 6—the strata of the Poltava Formation (Є1-2) and mainly volcanic rocks of the Berikul Formation (2). Lower structural level (R3- Є1): 7—Lower Paleozoic hyperbasite intrusives (ophiolites); 8— the Baikal- Early Caledonian formations (R3—Є1). 9—geological boundaries: a—contours of intrusive massifs, b—interformational angular disagreements, c—intraformational angular unconformities, 10—tectonic disturbances, 11—main types of rocks of alkaline-gabbroid plutons: a—nepheline syenites, b—main foidolites, в—ultrabasic foidolite, g—theralite, d— alkaline gabbro. 12—complex differentiated alkali-gabbroid plutons. 13—borders of conventionally distinguished petrographic zones of an alkaline province: I—the southern zone, II—the central zone, III—the northern zone. 14—Ring structure of the North-Eastern Kuznetsk Alatau. Ordinal numbers of alkaline plutons: 1—p. Dmitrievsky, 2—Lysaya, 3— Dedovoy, 4—Barhatno-Kiysky, 5—Kyi outlets, 6—Little-Kiya-Shaltyrsky, 7— Kiya-Shaltyrsky, 8—p. Podtaiga, 9—Universitetsky, 10—Belogorsky, 11—Svetninsky, 12 —Verkhnee-Petropavlovsky, 13—Tuluyulsky, 14—Medvedkinsky, 15—Uchkuryuk, 16— Kurgusulsky, 17—Cheryomushinsky, 18—Goryachegorsky, 19—Andryushkina River, 20 —p. Semenovskogo, 21—p. Wet Berikul; 22—Little Semenov body

intermountain trough. The Batenevsky Ridge is cut off from this axial zone of the Kuznetsk Alatau. To the west of the Balyksin-Saralinsky fault and the Saralinsky graben within the northeastern part of the Kuznetsk Alatau, there is a peculiar zonal-ring structure (radius of about 60 km) of Caledonian age (Є2—O Its inner ring zone is composed of relics of volcanoes of the central type of Middle Cambrian (Berikul Formation), and the outer zone—includes granitoid batholiths Middle and Later Cambrian (Fig. 2). The size of the Saralinsky graben along the strike is about 123 km, with a width in the northern part up to 13 km. In topographic relief, it is ridge with height about 600–900 m with local elevations to and 1302.2 m (the Lysaya ridge). Saralinsky graben locate between structures of the Eastern slope of the Kuznetsk Alatau on the one hand and the North Minusinsk depression and the Bateniov Ridge on the otherhe. Saralinsky graben is limited deep faults (Figs. 1 and 2). The graben is broadening to the north and cut by a north-east fault. North of the fault there are small remnants of basal beds that transgressively overlie folded Predevonian rocks. Presence of such remnants indicates that the graben used to occupy a larger area but was subsequently eroded.

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Along the eastern and western sides, the graben is bounded by branches of the Balyksinsko-Saralinsky Fault. The contacts of the graben with the enclosing strata were offset by tectonics and enhanced by river valleys; this is especially characteristic of the eastern side of the northern part of the graben. In the northern part, the graben is dissected by faulting into several slightly displaced blocks. The western edge of the graben is somewhat elevated by tectonics relative to the eastern one. Rocks of the graben have a mainly north-northeast trend. The dip of the layers varies from 5–10° to 15–20° in both western and eastern directions. Steeper dip angles of 25 to 50° to the E and SE occur on the east side, and a dip angle of 23 to 70° to the E and NE on the western side near the graben edges. The northern (trachyte) part of the graben remains particularly complex and undeciphered. On topographic maps and satellite imagery, the contours of a number of ring structures are visible. They are traced by the presence of ledges with sharp elevation differences with rocky outcrops. On the segment of graben between the Zhundelev river and to the north-northeast, (at an altitude of about 910 m, over a distance of about 2 km) (opposite the village of Podvinsk) geologists map the core part of the symmetric synclinal fold with angles of inclination of opposite flanks of about 20°. At its base, there are frequent thin layers of tuff sandstones, higher flows of amygdaloidal basalts, and a rather large portion a porphyry trachybasalts with a thickness of at least 200–220 m, not including the upper part destroyed by erosion) (Fig. 3).

3.1 Morphotectonic Analysis of the Northern Part of the Saralinski Graben The following is a brief description of the volcanic-tectonic morphostructures (TMV) of the northern part of the Saralinski graben (Fig. 3). Glavstanskaya VTM. It is located betweeen the village of Glavstan (Teply creek) to the bed of the Left Sarala river. The diameter of the cuesta-type structure is about 7 km. It transgressively overlaps rhythmically with the basal Ustkundustulylsky terrigenous stratum. In the erosional section, the north-western part of the structure is well preserved, the southeast part is offset by the northeast fault and is deeply eroded. The internal structure of the northwestern part of the part of the morphostructure is established quite accurately by erosional exposure of roof of the cuesta which is composed of bundles of volcanic rocks separated by thin layers of tuff sandstones, gravelites and sandstones. This VTM has three magmatic pulses.

Saralinsky Graben—Devonian Rift …

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Fig. 3 Diagram of the main types of volcanic-tectonic morphostructures (VTM) of the Saralinsky graben in scale 1: 200 000: a—general plan of the graben; b—its northern part; in—its southern part. The names of the VTM: 1—Glavstanskaya; 2—Zhundelevskaya; 3—Andryushkinskaya; 4—Karasukskaya; 5—Lapinsky; 6—Levolapinskaya; 7—Dorozhnyy; 8—Yusik. The boundary points in the diagram are observation sites for the most typical outcrops of graben volcanics. Red lines are the most optimal lines for making cuts of morphostructures

The structure of the eroded south-eastern part of the TMV is only weakly visible, in the form of small, multi-shaped depressions with ring geometry. The morphostructure includes thick batches of basaltoids. The Zhundulevskaya VTM is located in the watershed between the Left Sarala and Andryushkina rivers. Its shape is elongated in the sublatitudinal (E-W)

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direction. The eastern part of the structure is cut by the faults near the graben margin. The Zhundulevskaya VTM has the shape and structure of a flat, layered and symmetrical trough with the south and north flanks dipping towards each other at angles of 15–20. The erosion increases to the center of the syncline. Zhundulevskaya VTM unconformably overlaps the Andrushkinskaya VTM located from the south of Glavstanskaya and from the north. Volcanic rocks are represented by basalts. The Andryushkinskaya VTM consists of two substructures – a larger southern one and a smaller northeastern structure that builds on it. In the aggregate, the large and small structures have a shape resembling a triangle with rounded corners. A large southern morphostructure is located in the watershed between the Andryushkina and Kamennaya rivers. The plan view shape is an almost regular semicircle, the eastern flank of which is cut off by the Saralinsky boundary fault. The southern flank of the morphostructure is partly blocked by Zhundulevskaya VTM. The internal structure of the Andryushkin morphostructure is shown indistinctly in the form of bundles of effusives that overlap each other with a common sublatitudinal (E-W) strike. In the axial part, it has two concentrations of magmatism: the western one is probably represented by a subvolcanic body cutting the effusive, while the eastern one resembles a small isometric trough which is stacked with VTM basalt. A smaller northeastern VTM has the shape of an asymmetric arc with the bulge to the northeast. Its extreme eastern flank is also cut by the Saralin Fault. This VTM is located on the watershed of the lower course of the Kamennaya and Maly Karasuk rivers. Its internal structure is not emphasized by cuesta, but instead it has a massive shape. Near the main concentration of the morphostructure, rounded lava flows are poorly visible, and the outcrop of the subintrusive trachytic body (reddish photo tone) is possible. In general, the Andryushkinskaya VTM resembles a shield volcanic structure with several eruption centers. The southern morphostructure is composed of basaltic lavas, the northeastern—by trachyte formations. The section of volcanic rocks here is elongate in the north-north-east direction. Karasuk-Lapinskaya VTM has the largest north-east trending cuesta consisting of two half-arcs which are interfolded. Like the previous one (Andryushkinskaya), Karasuk-Lapinskaya VTM has a twin structure, in which the morphostructures are nested into each other and collectively form a triangle with a rounded north vertex. This VTM occupies the most elevated part of the Lysaya mountain range. South Karasukskaya VMT differs with its synformal structure. In plan view it has the outlines of an unilateral triangular triangle elongated in a sublatitudinal

Saralinsky Graben—Devonian Rift …

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(E-W) direction. In the western part of the synform, S-shaped curved basaltic layers are formed, forming three cuestas with extension in the northeastern direction. A small dome-shaped body of trachytes is mapped in the western flank of the synform. Lapinskaya VMT has a synformal structure, it’s located in the watershed between the Left-Karasuk river in the south and the Right Lapinsky river in the north. The plan-view shape of the morphostructure approximates a distorted semicircle truncated from the south by the cuesta traced by the Left Karasuk river. The internal structure is characterized by large massive magmatism of a lenticular-shaped sublatitudinal trend. This VTM is composed of trachytes. In a number of places in the west, there are structures with the appearance of a radial-ring structure. To the north of Lysogorsky synform, the outlines are similar to those of the Left-Lapinsk VTM are visible. Left-Lapinskaya VTM in shape and size closely resembles the northern part of the Lapinskaya synform. On its right flank the ridge-shaped trachytes, bordering it and forming a scarp, are clearly distinguishable in space images. The layers are tucked here to a steep occurrence and together form a relatively large * curved lens of a layered structure. The morphostructure is composed of trachytes. Further north, the structure of the graben volcanic fields is complicated and poorly understood. However, at the intersection of this part of the graben on the way to the gold ore range, there are marked step-shaped relief forms, indigenous and artificial outcrops of trachytes in roadside quarries. Yuzimskaya VMT is located at the northern end of the graben, where a large circular structure is mapped out. Its north-west and north flanks are outlined by the path of the Yuzik river, while its west and south flanks are outlined by Quartzevy and Dorozhny creeks. Due to the abrupt change of the appearance in the satellite images, the inner annular zone of this morphostructure is noticeable. The diameter of the structure is approximately 8 km. The morphostructure is composed of basalts and possibly represents a dome-ring complex. Represented data demonstrate complex structure of Saralinsky graben, which is composed by a series of circular volcano-tectonic morphostructures. Hence, the assembly of volcanogenic rocks of the graben should consist of particular series of separate VTM, which fractionally differ with their type, structure, composition and formation time.

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To summarize the following graben morphostructures can be distinguished: (1) zonal-ring structures close to stratovolcanoes (Glavstanskaya); (2) surface areal with small calderas (Andryushkinskaya) and dome-ring caldera (Yuzikskaya), representing the lower basalt structural substage of Early Devonian volcanism; (3) The Zhundulevskaya and the South-Karasukskaya types, closer in structure to the multi-dome type stratovolcano structures and the basalt composition of the second volcanic substage. The massive domed semi-ring morphostructures (Karasuk-Lapinskaya, Left-Lapinskaya), occupying the top of Lysaya Mountain, are composed of trachytes and represent the third (upper) structural substage of early Devonian volcanism and volcano-plutonism. It is quite obvious that at the end of volcanism, the volume of lavas far exceeded the size of the graben and spread onto the “shoulders”, representing a high-mountain multi-center volcanic chain. After the end of volcanism, the relief of a volcanic chain was partially eroded. In post-Devonian time, the graben was affected by deformations, which caused uplift of its western side, disruption of the eastern side strata and offsetting by (Right-Saralinsky, Yuziksky, etc.) into several equal parts (Yuziksky, Right-Saralinsky, etc.).

4

Stratigraphy and Composition of Terrigenous-Volcanogenic Strata

Despite of the complexity of Saralinsky graben structure, the structure and composition of sediments of it may be described as a following sequence. The lower part of the cross section consists of basal conglomerates, coarse sands, sandstones with interlayers of siltstones, with Pre-Devonian rocks predominating. Then there is rather thick (up to 300–600 m) sequence of flood basalts (Fig. 4). At the top there are analcite basalts and trachyandesites (about 300 m), above which there is a thick bed of trachytes, trachydacites and trachyrhyolites. Graben sediments are multicolor and red terrigenous-volganogenic molasse (Grinyov 1994; Uvarov and Uvarova 2010). Excursion participants are suggested to become familiar with Saralinsky graben cross section along the road from the Glavstan to Podvinsk village (Fig. 4). Detailed characterization of Saralinsky graben cross section based on Boltukhin et al. (1972) and Turnichenko (1976) is given below.

B

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Fig. 4 1—Geological and petrographic section along the river Sarala (Byskari series): 1—Proterozoic marbled limestone; 2—thin-layered gray argillites and siltstones; 3—coarse layered conglomerates and gravelites; 4—basalt porphyries of aphyric and small porphyries, amygdaloidal; 5—interbeds of tuff, tufflava, tuffstone; 6—basalts of large porphyry, amygdaloidal; 7—sandstone and tuff sandstone interlayers; 8—amygdaloidal basalts; 9—trachybasalt porphyry, including analcime basalts; 10—observation points of characteristic incisions of the section (Grinev 2003)

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Shkolniy creek

Scale horizontal: 1:20 000 vertical: 1:20 000

Zhundelev creek

Geological and petrographic section along the Saral river (Byskari series)

Saralinsky Graben—Devonian Rift … 53

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Fig. 5 Basal conglomerate in lower part of stratigraphic section of Sarala Graben Ustkundustulsky suite

Field Stop 1 The basal terrigenous stratum is part of the Ustkundustulsky suite of Early Devonian. In the middle part of the graben at its western edge, the sediments of the suite are represented by gray, greenish-gray, purple and cherry-gray, brick-red conglomerates (Fig. 5), sandstones, siltstones with rare lenticular limestone interlayers. The sediments have a thickness of 200–370 m, which are conformably overlain by mostly basaltic strata. The upper part of the section, is marked a gradual transition to the volcanogenic accumulations. The transition is expressed in the form of terrigenous-sedimentary layers interbedded with separate basalt flow and tuffs.

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The most complete section of the suite in the Saralinsky graben is on the left side of the Right Sarala river (western side of the middle part of the graben). This Glavstan village section has the following section (from bottom-up): 1. Brown small-medium pebble conglomerates with well-rounded pebbles of schistose early Paleozoic basalts, rhyolite, limestones, marbles, sometimes with remnants of epiphytonous algae and quartzites 2. Gray, coarse-grained polymictic sandstones 3. Sandstones are gray, greenish-gray, fine-medium-grained polymictic with carbonized plant residues 4. Aleurolites greenish gray coarse slabs with Psilophiton goldschmidtii Hall., Hostimella sp. (definition by A.R. Ananyev, fees by A.M. Yekhanin), often carbonated. Thin and frequent sandstone interlayers, rare and thin—limestones with fragments of algae are noted in the top 5. Interbedding of large-pebbly gray conglomerates with sandstones, often cross-laminated, and gravelites. Pebbles are composed of quartzites, limestones, less often sandstones, rarely plagio-granites, schistose basalt and vein quartz. Carbonate rock cement contains shell fragments. The rocks are fractured and cut by dikes of subvolcanic basalts 6. Conglomerates with large pebbles to boulder, red-colored, with thin layers and lenses of red-brown and brown sandstones, lenses of sandy limestone with remains of algae. Pebbles are represented by lilac-gray and cherry basalts of Devonian appearance, limestones and dolomites, quartzites, siltstones and sandstones, fine-grained granites

15 m

10 m 30 m 18 m

132 m

100 m

The total thickness of the exposed section is 320 m, and it has a pronounced layering expressed in a regular alternation of coarse-grained and fine-grained (sand-silt) layers and packs. Field Stops 2 and 3 Volcanogenic basaltic stratum. To the north the terrigenous strata overlaps the basaltic strata, which is similar with the Bazaar stratum of the volcanogenic Goryachegorsk Plateau and correlates with the Lower and Upper Matarak strata of the Matarak-Shunet stratotype. The following section (from the bottom up) starting with the basal (Ustkundustuyulskaya) strata, is after Turnichenko (1976).

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1. Sandstone with aleurolite interlayers and remains of psilophyte flora 2. Conglomerates with pebbles up to 30 cm in diameter. Composed of cherry-coloured porphyrites, felsites. limestone and shale 3. Porphyry and small porphyry basalt flows. Basalt porphyrites 4. Small porphyry basalts 5. Six flows of fine grained amygdaloidal olivine-pyroxene basalt porphyries. In the upper parts transition to tuff breccia. The contacts between the flows are irregular and wavy…..160 m 6. Flows of aphyric basalt 7. Tuff breccias of the basalts 8. Aphyric basalt 9. Tuff breccias of the main composition 10. Aphyric basalt 11. Coarsely disseminated plagioglase porphytic basalt 12. Tuff-conglomerate 13. basalt porphyry 14. Aphyric basalt 15. Volcanic sandstones 16. Aphyric basalt 17. Volcanic sandstones 18. Aphyric basalt 19. Large plagiobasalt porphyrites 20. Large plagiotrachibasalt porphyrites

120 m 250 m 400 m 50 m

690 m 420 m 170 m 20 m 450 m 60 m 20 m 35 m 110 m 15 m 50 m 10 m 30 m 50 m 120 m

The total thickness of the Devonian sedimentary-volcanogenic stratum of this section is estimated at 2830 m. The age of the stratum, according to the flora collected by G M Yekhanin, and defined by A R Ananev as Early Devonian (Philophyton goldschmidtii Halle, Taeniocrada cf. Decheniana Goepp., Hostimella sp., Spongiophyton sp.). Boltukhin et al. (1972), characterized the sequence, and noted that three zones are clearly distinguished in the structure of basalt flows: the lower one, which is represented by slightly amygdaloidal basalts; the central one by folded massive flows; and the top is almond-stone amygdaloidal, often brecciated, turning into tuffs and slag. According to the data of these researchers, basalt porphyries make up 80% of the section, trachybasalt porphyries 4%, sedimentary rocks 14% of the thickness of the sequence. The explosivity index is 2.

Saralinsky Graben—Devonian Rift …

Fig. 6 Porphyry and small porphyry basalt flows

Fig. 7 Flows of aphyric basalts

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The erosional section ends with a thick sequence of—plagiotrachybasalt porphyrie with analcime, which serves as the core of the synclinal fold (Fig. 4). On closer examination, it is possible to distinguish the corresponding paleovolcanic edifice and the subsidence caldera. In order to study the cross section the following observation points were chosen. Field Stop 2 Malinovy creek mouth. Porphyry and small basalts flows are well exposed here (flood series №3 in the given cross section) (Fig. 6). Field Stop 3 500 m to the south from the junction of the Right Sarala and Left Sarala creeks. Rhythmically alternating basalt flows and interlayers of tuffaceous sediments of Zhundelevskaya VTM are observed here (Fig. 7). Upper trachybasalt-trachyandesite-trachyte-trachytic series. A sequence compiled by Yarmak (1967) at the 1205 m elevation in headwaters of the Small Karasuk creek (at the watershed of Krutoy and Left Karasuk creeks) was taken as a reference section of the lower part of this series. It’s represented by the following rocks (from bottom to top). 1. 2. 3. 4. 5. 6. 7. 8.

Olivine-analcime basalts are greenish-gray Basalts are greenish-gray Trachyandsite gray amygdaloidal The basalts are dark and greenish-gray, sometimes amygdaloidal Brownish-gray hematitized basalts The basalts are brownish-gray with spherical weathering Brownish-gray trachyandesite Basalts almond-gray, gray with a lilac shade

50 25 25 35 40 20 35 40

m m m m m m m m

The total thickness of the section is about 270 m. At this stratigraphic level are volcanics and Zhundelevskoy VTM. Apparently, the study of the upper part of the section of basic graben volcanic rocks cannot yet be considered complete. Volcanics of Zhundelevskaya VTM belong to this stratigraphic datum.

Saralinsky Graben—Devonian Rift …

59

It’s important to note that there is a large field of trachytes, trachyandesites and trachydacites in the close proximity to this section. These rocks form an extrusive-subvolcanic edifice crowning the volcano-sedimentary sequence of the graben. There is no information in the literature about the structure of this large trachyte body. It is not shown on different geological maps, nor it is depicted as an intrusive-subvolcanic formation. A similar uncertainty on the facies of trachytic constructions is also present in the Batanayul-Semenovsky area of the Goryachegorsk volcanic plateau. Field Stop 4 The Saralinsky trachyte unit has the shape of an arcuate curved ellipse elongated in the meridional (N-S) direction and opening to the west.. Its dimensions along the long axis are about 20 km, and along the transverse axis is about 7.5 km; its area, therefore, is at least 140–150 km2. Apparently, this is the largest trachy body in the northeastern part of the Kuznetsk Alatau. The total thickness of trachyte units in its central part can reach 550–600 m (at the present level of erosion).

Fig. 8 banded texture of trachytes from Sarala Graben

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The Salalinsky trachyteis well-expoed in a roadside quarries Dorozhnyy on the northern slopes of the graben. Here trachytes have a subvolcanic appearance and banded texture (Fig. 8). Lighter, light brown bands alternate with dark brown, enriched with melanocratic minerals and, above all, an little size inclusions of ore minerals. Banded trachytes with disseminated ore mineralization, manganese dendrites and overprinting quartz and calcite in pores and cracks are exposed here. In the the Lysaya Gora range, at elevations of 750–800 m, the eastern slopes are completely covered with stone scree of amygdaloidal trachytic (with, amygdule composed mostly of quartz). The petrographic composition of the trachyte rocks, observed from the bottom of the section and to the upper portion exposed inroadside quarries, showed that the body below is represented by trachy-andesites, and higher in the section by trachytes, trachydacites, including massive, amygdaloidal. In the upper part of the body, massive, banded trachytes, trachydacites are subject to intensive potassium autotasomatosis. These are mostly trachyte breccias.

5

Magmatism of the Saralinsky Graben

Volcanism in the Saralinsky graben consists of local volcanic centers with subsidence calderas and volcanic cones, and also dykes and sills. In addition to volcanic rocks within the northern part of the graben several bodies of nepheline gabbro and theralites, are also present and indicate a direct link between the magmatism of the graben of the volcanic-plutonic alkaline-basic formation of the northern Kuznetsk Alatau and the volcanism of the adjacent North-Minsk and Nazarov basins. Early Devonian Volcanism in the Saralinsky graben was preceded by the block tectonic movements. At the peak of tectonic movements of the graben, the Ustkundustiulskaya basal stratum was formed, followed by formation of a basalt plateau consisting of a series of VTM. For the Bazyr Formation of the graben, trachytes were not observed, although rarely along the left tributaries of the Right Sarala River there are fragments of trachytes and amygdaloidal trachytes characteristic of the northern part of the graben. The Goryachegorskoye plateau, also hosts minor trachyte. The basis of the section consists of major basalt flow packs with weak but idnetifiable cyclicality. Sub-alkaline and alkaline analcime basalts overlapping Bazyr Formation have a more diverse petrographic composition, increased alkalinity and more local distribution over the area in the form of small paleovolcanic apparatus, whose

Saralinsky Graben—Devonian Rift …

61

stratigraphic position is problematic. Either they belong to the Ashpansky level of the Goryachegorsky Plateau, or to the Bereshka-Ashpansky level, based on taking into account the volcanic-plutonic character of the alkaline-basic magmatism of the region and the presence of a series of bodies of nepheline gabbro and theralite graben. The end of early Devonian volcanism (in the grabens), was marked by the formation of a large lava-explosive-subvolcanic structure similar to the trachytic domes in the field of the Ashpansky stratum of the Goryachegorsk volcanic plateau, with an exposed area of about 150–600 m. It is characteristic that the base of the edifice is composed of a trachyandesites, which are replaced by flow-banded trachytes-trachydacites, and even higher are of amygdaloidal trachytoids with quartz-shaped amygdule. The early Devonian volcanism (associated with the graben), are dominantly basalt-trachyte series of rocks with a subordinate rocks of intermediate composition (trachyandesites). Intrusion of nepheline gabbro and theralite bodies, which were mapped by A. A. Yarmak in 1964–1967, occurred next. The Saralinsky graben has the same type of volcano-plutonic structures, as other grabens of the North-Eastern part of the Kuznetsk Alatau—Rastaysky and Talanovsky region (Figs. 1 and 2). Together, these grabens and the Goryachegorsk volcanic plateau constitute a kind of structural volcanic-tectonic framework for the alkali-gabbroid magmatism of the region.

6

The Composition of the Graben Volcanics

The volcanism of Saralinsky cross section (Fig. 4), including trachyte bodies in the northern part of the graben, have been geochemically characterized on data X-ray fluorescence analyses for 43 original samples (made Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russia) and augmented with analyses of basalts from Boltukhin et al. (1972). Variations of contents of major oxides are given in the Table. Main petrochemical features of the volcanism (Table 1) are their moderate silica acidity, medium and high contents of titanium, medium contents of alumina, high mafic index, medium contents of magnesium and calcium in basic rocks. High phosphorus contents are quite typical both for basic rocks and trachyandesites. It’s important to note that relatively high contents of titanium, iron and phosphorus are inherent in plume originated magmas.

1.31–2.58 14.16–18.88

10.7–15.29

1.77–2.89 14.73–17.77

TiO2 Al2O3

RFe2O3 10.35–14.93 15.28

2.58 14.96

44.08

Analcime Basalt

5.04–12.12

1.1–1.95 14.16–16.10

41.73–46.7

Basanites, Tefrites

12.1

2.07 16.00

48.7

0.2–1.19 1.15–4.9 0.38–0.96

10.75–14.32

1.26–2.4 14.75–16.9

52.98–55.98

61.64– 62.88 0.52–0.94 13.52– 16.79 6.32– 12.12 0.2–0.92 0.58–1.5 0.1–0.27

Fonotefrite Trachiandesitis Trachyte

MgO 5.44–9.10 3.04–8.00 6.12 1.66–6.39 1.91 CaO 8.45–12.18 7.43–13.38 8.78 4.93–13.38 4.99 0.30–0.67 0.22–1.22 0.63 0.3–0.79 0.73 P2O5 Note analysis of analcime basalt Table 1 analysis from (Mustafin et al. 1966)

44.02–47.9

41.68–45.75

SiO2

Oxsides The main species of rocks Picritobasalts Basalts, Trachybasalts

Table 1 Variations in the contents of petrogenic oxides of the main varieties of volcanic rocks of the Saralin graben

0.52–1.12 0.31–2.57 0.06–0.07

7.38–8.77

0.64–0.68 12.52–13.8

64.12–66.3

Trachydacites

62 O. M. Grinev et al.

Saralinsky Graben—Devonian Rift …

63

(a)

Na2O +K 2O . %

12 10

Tefrifonolite

Foidit

Fonotephrite

8

Tefrites

6

-1 -2 -3

Trachytes and Trachydacites

Trachiandesites

-4 -5 -6

Basalt. Trachiandezit Trachy basalts

4 Basalts

2 0 35

PicritoBasalt

40

45

50

Basalts Andesitе Andesite

55

60

Dacite

65

K2 O/Na2O, %

14

2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0

(b) K - series

K-Na - series

Na - series

25 30 35 40 45 50 55 60 65 70

SiO2, %

70

SiO2, %

-1

-2

-3

-4

-5

-6

Fig. 9 a—Classification diagram K2O/Na2O—SiO2. b—TAS diagram of volcanic rocks of the Saralinsky graben (Na2O + K2O)—SiO2: 1—basalts, trachybasalts; 2—trachyandesites; 3—trachytes, trachydacites; alkaline series: 4—picrobasalt; 5—tephrites; 6—phonotephrite

The classification diagram (Na2O + K2O)—SiO2 (Fig. 9a) reveals a completely regular pattern characteristic of contrasting differentiated series. (1) the main trend is subalkaline basalt, trachybasalt ! trachiandesite ! trachyte, trachydacite; and (2) the additional trend—alkaline picrobasalt ! basanite, tephite ! phonotephrite. Tephrites, phonotephrites and, in some measure, picrobasalts are mostly sodium-containing (Fig. 9b). Basalts, trachybasalts, trachyandesites and trachytes belong to K-Na series with an alkali content increase (mainly of К2O in trachytes and trachydacites). The double trend of geochemical evolution of the volcanic series is reflected on Harker diagrams (Fig. 10) and AFM and ABC diagrams (Fig. 11). AFM diagram shows that compositions of initial volcanism of the series correspond to calc-alkaliine rocks while trachyandesites belong to tholeiitic rocks taking places of andesybasalts and andesites (of the calc-alkaline rocks (Fig. 11a). ABC diagram compares the degree of differentiation of Saralinsky graben magmatism with reference chemistry: gabbro-diorite-granite, central-type volcanism of Iceland and alkaline gabbro series rocks of Kuznetsk Alatau (Fig. 11b). Basalts of mafic series of the graben volcanism and all the alkali series obviously have a tendency for an alkali-gabbroid trend of differentiation, while trachytes and trachydacites follow the differentiation trend of Iceland volcanism.

64 4

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10

MgO,%

8

3

6

2

4

1

2 0

0 1,5 P2 O5, %

16

Fe2O3, %

14 12

1

10 0,5

8 6

0 10

4 Na 2 O, %

6 K2O, %

8

5 4 3

6 4

2 1 0

2 0 20

Al 2 O 3, %

14 12 10 8 6 4 2 0

18 16 14 12 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

CaO, %

40 42 44 46 48 50 52 54 56 58 60 62 64 66 68

SiO 2 Picritobasalt Basalts, trachybasalts

SiO2 Tefrites Trachyadesites

Fonotefrite

The trend of differentiation

Trachytes, Trachydacites

Fig. 10 The distribution of petrogenic oxides relative to SiO2 in the volcanic rocks of the Saralinski graben

7

Geochemical Features of Rocks

Geochemical study of Saralinsky graben volcanic rocks is based on analysis of rare and trace elements in 36 samples. Analysis was carried out by means of inductively coupled plasma mass-spectrometry (ICP-MS) in Analytical center of geochemistry of natural systems » of Tomsk State University.

Saralinsky Graben—Devonian Rift …

65

Fe 2 O 3

(a)

(b)

0,00 1,00

Tholeiitic

0,25

0,75

FB

В

0,00 1,00

0,25

0,75

АBT BT 0,50

0,50

D

0,50

R

AB 0,25

0,75

1,00 0,00

0,50

0,25

-1

-2

-3

0,75

-4

0,25

0,75

Calc-alkaline

K 2o+Na2O

0,50

B

-5

-6

0,00 1,00

Mg

1,00

А

0,00

0,25

0,50

-7

0,00 1,00

0,75

-8

-9

С

Fig. 11 a—Triangular diagrams for volcanic rocks of the Saralinsky graben: subalkaline series: 1—basalts, trachybasalt; 2—trachyandesite; 3—trachyte, trachydacite; alkaline series: 4—picrobasalt; 5—tephite; 6—phonotephrite. a—AFM after Irvine and Baragar (1971): the arrows show the trends of the evolution of magmas, the dotted line shows the boundary between the series. Tholeiitic series: BT—basalt, FB—ferrobasalt, ABT—andesibasalt; calc-alkaline series: B—basalt, AB—andesibasalt, A—andesite, D—dacite, R—rhyolite. b —evolutionary trend ofvolcanic differentiation: A—SiO2; B—Al2O + Fe2O3 + Na2O + K2O; C—FeO + MgO + CaO + TiO2 + P2O5. Reference geochemical trends: 7— gabbro-diorite-granite series (Korzhinsky, 1977); 8—series of volcanic rocks of the central type of Iceland (Gerasimovskiy et al., 1978); 9—alkaline gabbroids of the Kuznetsk-Alatau provinces (Grinev 1994)

The most striking geochemical features are the following: Picrobasalts, basanites, tephrites, phonotephrites and basalts, trachybasalts are enriched (g/t): Sc (3.2–31.8), Ti (1288.4–12564.4), V (28.5–240.8), Cr (4.0–128.4), Ni (3.1–50.4), Zn (2.3–1283), Sn (50.0–922.6), Y (6.5–34.4), Zn (38.5–193.05); the contents of Th (0.28–3.9) and U (0.17–2.9) are slightly higher; relatively low contents are characteristic of Be, Ce, Cu, Ga, Rb, Nb, Cs, Ba (3.2–238.3), REE, Hf, Ta. Trachyandesites, trachytes, trachydacites have elevated concentrations (g/t): Be (0.25–7.8), Sc (0.7–38.4), Ti (761–13331.7), V (0.56–401.2), Cr (1.05–64.0), Co (0.78–45.5), Zn (14.6–147.7), Ga (4.6–23.3), Rb (5.0–148.3), Sn (13.3-895.8), Y (7.3–97.4), Zr (37.7–1019.0), Nb (4.1–60.8), Ba (57.5–973.3), REE, Hf (0.03– 22.4), Th (0.9–17.4) and U (0.43–7.7). Geochemical affinities are established using multi-element diagrams and REE distribution diagrams (Fig. 12a, b).

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1000

(a) Picrobasalts - Trachybasalts - Bazyrskaya stratum

Sample / Primitive mantle

100

OIB

E-MORB 10

N-MORB

1

0,1

0,01

Cs Ba Rb Ga Th U Nb Ta La Ce Pr Sr Nd Hf Zr Ti Sm Eu Gd Tb Dy Y Ho Er Tm Yb Lu

Sample / Chondrites

(b)

Picrobasalts -Trachybasalts - Bazyrskaya stratum

OIB

E-M ORB

N-M ORB

La

Ce

Pr

Nd

Sm

Eu

Gd

Tb

- Picrobasalts, Tefrites 39 -Fonotefrites

N-MORB

Dy Ho

Er

Tm

Yb

Lu

- Trachybasalts E-MORB

OIB

Fig. 12 Multielement a and rare-earth b spidergrams for the Saralinsky graben basalt; the gray field is the spectrum of basalts of the Bazyrskaya stratum

Saralinsky Graben—Devonian Rift …

67

Rare and trace elements distribution spectra of Saralinsky graben basaltoids correspond to E-MORB and OIB spectra but differ with strong negative Ta, Sr and Hf anomalies (Fig. 13a). REE distribution allows the basaltoids to be divided into two groups. The first group includes rocks with REE contents varying from 117 to 154 ppm (Fig. 13). The second group includes rocks depleted with REE (RTR 23– 64 ppm). Comparison of microelement compositions of basaltoids of Saralinsky graben and Goryachegorsk volcanic plateau shows a similarity of rare and trace elements distribution, but REE contents in subvolcanic basaltoids of Goryachegorsk plateau are intermediate between high and low contents in enriched and depleted basaltoids of Saralinsky graben. Considering this all one may suppose that geochemical irregularity of Saralinsky graben mafic rocks is caused by variations of fractionation degree of E-MORB magma in intermediate chambers. Dissimilarity of Goryachegorsk plateau mafic rocks is caused by successive crystallizational differentiation the same magma. Rare and trace elements distribution in more silicic rocks of Saralinsky graben (trachyandesites, trachytes and trachydacites) is in n general similar to that of basaltoids (Fig. 13a, b). Sialitic rocks differ with increased non-coherent elements accumulation (RTR up to 460 ppm in trachydacites), more contrast negative Ta, Sr, Hf and Ti anomalies, and negative Eu anomaly. In a similar way as basaltoids, sialitic rocks differ among themselves according to REE contents, being either medium (RTR varies from 60 to 117 ppm) or enriched with REE (RTR more than 350 ppm). These data indicates a cogenetic relationship of all the rocks belonging to the series and contrast of differentiation of magma in intermediate chambers both for basaltoid (alkaline) and sialic (subalkaline) subseries. It’s interpreted that Saralinsky graben volcanic rocks are similar to Goryachegorsk volcanic plateau rocks and that both crystallized from E-MORB-type magma. Proposed geochemical analogues may be, for example, olivine-basanite melts of moderate alkalinity of the East African Rift System, which are considered one of the parental magmas of this system or rift-related basalts of Lower Saxon (Hessen). In terms of the concentration of REE, the data from Saralinsky graben volcanic rocks are also similar to the basalts of the islands of of, Hawaii, as well as the Siberian Traps., according to a well-known report (Uvarov and Uvarova 2010). The geochemical benchmarks of the basaltic volcanism. Modern geodynamic parameters using discriminant ternary diagrams make it possible to estimate the formation conditions of the studied Devonian volcanic rocks of the Saralinsky graben (Fig. 14a–c).

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1000

(a)

Trachyte- Bazyrskaya stratum

Sample / Primitive mantle

100

OIB

E-MORB 10

N-MORB 1

0,1

0,01 Cs Ba Rb Ga Th U Nb Ta La Ce Pr Sr Nd Hf Zr Ti Sm Eu Gd Tb Dy Y Ho Er Tm Yb Lu 1000

(b)

Sample / Chondrites

Trachyte- Bazyrskaya stratum

100

E-MORB

10

1

OIB

N-MORB

La

Ce

Pr

Nd

Sm

Eu

Gd

Tb

Dy

- Trachyte, trachyandesites, trachydacites N-MORB

E-MORB

Ho

Er

Tm

Yb

Lu

39 - Fonotefrites OIB

Fig. 13 Multielement (a) and rare-earth (b) spidergrams for trachytes of the Saralinsky graben; the gray field is the spectra of basalts of the Bazyrskaya stratum

Saralinsky Graben—Devonian Rift …

69

Hf/3

(a)

(b)

0,00 1,00

2Nb 0,00 1,00

A - N-MORB B - E-MORB C - WPB D - VAB 0,50

0,25

0,75

A1, A2 - WPA A2, C - WPT B - E-MORB D - N-MORB C, D - VAB

A 0,50

D

B

0,25

0,50

A2

B

0,25

0,75

0,75

A1

0,75

43

C

0,25

D

C 1,00 0,00

Th

0,50

0,25

-1

-2

-3

0,75 -4

0,00 1,00

1,00

-5

0,00

0,00

Ta

0,50

0,25

0,75

Zr/4

1,00

Y -1

-2

-3

-4

-5

Y/15 0,00 1,00

(c)

0,25 1С

3D

0,75

3С

1В 0,50

0,50

3В 0,75

0,25

1А 1,00 0,00

0,25

2

3А

0,50

0,75

La/10 -1

-2

-3

-4

-5

0,00 1,00

Nb/8

Fig. 14 Th–Hf-Nb, Zr, -Nb-Y, La-Y-Nb diagrams for: 1—trachybasalts; 2—picrobasalts; 3 —tephites; 4—phonotephrite; 5—basalts, Bazyrskaya stratum; a A = normal MORB (mid-ocean ridge basalts), B = enriched MORB (mid-ocean ridge basalts) and Tholeiitic WPB (intraplate basalts), and differentiates, C = alkaline WPB (intraplate basalts) and differentiates, D = basalts of destructive margins of continents and differentiates. b A1, A2 = WPA (intraplate alkaline basalts), A2, C = WPT (intraplate tholeiites), B = depleted MORB (basalts of the mid-ocean ridge), C, D = VAB (basalts of volcanic arcs), D = normal MORB (basalts of the mid-ocean ridge). c 1—island arc basalts (1A—calc-alkaline; 1B— overlap area; 1C—tholeiites); 2—continental basalts; 3—oceanic basalts (3A—alkaline basalts of inland continental rifts, 3B, 3C—enriched and slightly enriched with E-MORB; 3D—N-MORB)

On the Th–Hf-Ta diagram (Fig. 14a) the basaltic data plot in the field destructive continental margins (only few points plot in the N-MORB field). On the Zr-Y-Nb diagram all the data densely plot within volcanic arc basalts

70

O. M. Grinev et al.

(a)

10 Nb/Y

(b)

100 La/Yb

Plume sources

OIB

REC

EM-1

1

OIB

EM-2

10 PM

0,1 IAB

Nonplume sources

E-MORB N-MORB

N-MORB

0,01

1

10

1

100

0

5

10

Zr/Y

OIA

20

25

30

35

Zr/Nb

(c) 10 Th/Yb

15

(d) ACM

WPVZ

WPB

La/Yb 100 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12

OIB

1

II

CIAB

10

E-MORB

0,1

Evolution trend of sources of mantle basaltoid magmas

Hawaii Iceland

I

N-MORB

0,01 0,01

0,1

1

10

1

0,1

Picrobasalt Tefrit-Basanite Basalts, Trachybasalts Trachyandesites

1

5

10

K,%

Ta/Yb Footefrit Trachytes, Trachydacites

Basalts of the Bazyrskaya stratum

(VAB) field also touching the adjacent within-plate tholeiites (WPT) field (Fig. 14b). On the La-Y-Nb diagram (Fig. 14b) the data plot in continental basalts field and only those data for the Bazyrskaya series (Goryachegorsk plateau) plot on the island arc calc-alkaline basalts field. In order to restore geodynamic conditions of formation and to define sources of material for alkaline and subalkaline rocks of Saralinsky graben Nb/Y–Zr/Y, La/Yb–Zr/Nb, Th/Yb–Ta/Yb discrimination diagrams are used (Fig. 15 a, б, в, г). The Nb/Y–Zr/Y diagram (Fig. 15a) clearly indicates that studied rocks originated from a plume. Data plot on the ocean plateau basalts (OPB) and ocean island basalts (OIB) fields revealing a distinct trend of evolution from primitive mantle (PM) source to enriched reservoir EM-2 and then EM-1 compositions. On the

Saralinsky Graben—Devonian Rift …

71

b Fig. 15 Geochemical indicators of volcanic sources: a Nb/Y–Zr/Y, b La/Y–Zn/Nb,

c Th/Yb–Ta/Yb; d La/Y-K: (a)—Nb/Y–Zr/Y; b—La/Yb–Zr/Nb; Points and fields of reference compositions are after Sun and McDonough (1989), and Condie (2005) N-MORB —mid-ocean ridges (depleted), E-MORB—mid-ocean ridges (enriched with rare lithophilic elements), basalts of active continental margins and island arcs (IAB), intra-plate continental and ocean basalts (OIB); PM—primitive mantle, REC—recycling component, EM-1— enriched mantle with high Nd/Sm, EM-2—enriched mantle with high Rb/Sr; c—Th/Yb– Ta/Yb by (Gorton and Schandl, 2000): OIA—oceanic island arcs, ACM—active continental margins, WPVZ—intraplate volcanic zones, WPB—intraplate basalts, N-MORB—normal mid basalts -Oceanic ridges, E-MORB—enriched basalts of the mid-ocean-ridges, CIAB— the average composition of basalt continental island arcs (Kelemen et al. 2003); d— Correlation of the ratio La/Yb with the K concentration in primary magmas: tholeiites, high-alumina and alkaline basalts of various provinces (Mustafin et al. 1966) and their comparison with the rocks of the Saralinsky graben: 1—oceanic bottom tholeiites; 2— Reykjanes Ridge tholeiites; 3—high-alumina differences of tholeiites of oceanic ridges; 4— continental tholeiites—traps of the Siberian platform (Siberian Traps LIP); 5—high-alumina and normal sub-alkaline basalts of the Steens Mountain (Columbia River LIP); 6— high-alumina basalts of the Kuril Islands and Kamchatka; 7—picrites and basalts of moderate alkalinity of the East African and West African rifts and the Comoros; 8—alkaline basalts of the Hawaiian Islands; 9—picrite basalts of the island of Gough; 10—subalkaline basalts of the Comorian archipelago and the island of Saint-Paul; 11—melanocratic differences of the potassium alkaline series of the West African Rift; 12—Melilite basalts of the high alkalinity series of the East African Rift; I—in the field of tholeiites and high-alumina basalts; II—the field of alkaline and subalkaline basalts of oceanic islands and the East African rift system

La/Yb–Zr/Nb diagram (Fig. 15b) data from Saralinsky graben rocks plot along the OIB—N-MORB line with concentration towards the ocean basalt field. Th/Yb– Ta/Yb diagram (Fig. 15c) also shows that within-plate nature of volcanism is dominant. Data plot in the field of within-plate volcanic zone (WPVZ). A few data point that correspond to trachytes and trachyandesites compositions instead plot in the ocean island arc (OIA) and active continental margin (ACM) fields. In such a way, Saralinsky graben volcanisim is supposed to originate from an mantle source similar to ocean plateau basalts (OPB) or ocean island basalts (OIB). Geochemical features of within-plate and continental margin magmatism are probably caused by crustal contamination. Analysis of the data in the table shows that all types of magmatic of the Saralinsky graben are specialized in Ag, Au and platinoids. The contents of the analyzed elements in most of the samples exceed the Clarke values both in the Earth’s crust and in the main rocks by 1 or more orders, and up to significant and industrial values. The highest concentrations (g/t) Ru (0.09–0.32) and Au (0.6–

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25.87) were found in trachyandesites, Pt (0.65) in picrobasalts, Pd (0.32) in trachyte, and silver (0.39–14.78) in tephrites. These data confirm the previously published results on the increased gold and silver contents of the Devonian volcanism of the Tuva trough and the other graben of the Western Sayan (Grinev and Sazonov 1996). Moreover, the established petrogenetic relationship between the volcanic rocks of the Saralinsky graben and the Bazyrsky stratum of the Goryachegorsky volcanic plateau confirms the previous view the Kuznetsk-Alatau alkaline-gabbroid province and the Devonian volcanism of the plateau are a single magmatic province. For this province, industrially significant gold-platinum-bearing minerals with rather rich mineralogical were identified and evaluated (Grinev 1996, 2001, 2003, 2010; Grinev and Kotelnikov 2002; Grinev and Sazonov 1996, 1997; Sazonov and Grinev 1996; Sazonov et al. 1996, 1997, 1998, 2000) (Table 2).

8

Discussion of Results and Key Findings

The Saralinsky graben is located at the junction of the large Minusinsk segment in the axial zone of the overall rift-continental system (RCS) with the western Kuznetsk-Alatau anticlinorium (rift shoulder) that surrounds it. The graben formed during the final growth stage of a large transregional upwarpingin the late Silurian —early Devonian. The formation of the basal multicolored-red-colored molasse of the graben of Ustkundustulskaya (Krasnogorsk Formation) is associated with this stage. This was followed by the subsidence of the central area of the transregional arch, which led to the initiation and development of the axial depression of the paleorift (Tuva-Minusinskaya), accompanied by voluminous early Devonian volcanism (Grinev 1990, 1994, 2003, 2007, 2008, etc.). The subsidence of the arch was accompanied not only by dip-slip and strike-slip movements along the north-north-western faults of the paleorift, but also by movement along a system of transverse (transform) east-northeast faults. This system of transform (east-northeast) faults, led to the formation depressions of the Tuva-Minusinsk segment of the axial zone, expressed in the formation of a series of transverse uplifts: Batenevo-Bellyksky, Solgonsky, Arginsky and others. In combination with the shear (strike-slip) movement along the longitudinal faults of the paleorift, this led to the formation within the Minusinsk trough of two systems of north-northeast and north-north-west faults, intersecting in the Sydo-Yerbinsk depression of the Minusinsk trough.

Rock Picrobasalts

0.00–0.01

0.01–0.07

0.28–1.31

0.02–0.65

0.00–0.56

4

Elements

Ru

Pd

Ag

Pt

Au

Number of analyzes

0.01– 0.02 0.02– 0.03 0.39– 14.78 0.02– 0.04 0,03– 0.32 3

Tephrites

3

0.01–0.17

0.03–0.05

0.49–0.66

0.03–0.04

0.00–0.03

Trachyb-asalts

3

0.6–25.87

0.11–0.20

1.19–4.96

0.11–0.16

0.01–0.04

Trachyandesites

6

0.00–0.46

0.09–0.30

1.28–4.4

0.09–0.32

0.00–0.02

Trachytes, trachydacites

Table 2 Content of noble metals in the volcanic rocks of the Saralinsky graben (ppm)

Ivanov, 1994–1997

0.04

0.02

0.1

0.02

0.006

Clarke In the mafic rocks

Vinogradov, 1962

0.0043

0.05

0.07

0.01

0.02

In the Earth’s crust

Saralinsky Graben—Devonian Rift … 73

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Owing to these structural and tectonic features, the volcanism in the internal structures of the Minusinsk trough and the uplifting rims (rift arms) was noticeably different (Grinev 2008; Vorontsov et al. 2010, 2013; Vorontsov and Yarmolyuk 2017). The structure of the sections of volcanic graben. One of the characteristic features of the structure of the lagoon-continental volcanogenic-terrigenous molasses of the Devonian, not only ASFA, but also other regions of northern Eurasia, is a cuesta-like type of relief. In the classical version, this implies the monoclinal structure of the sediments. In the northern part, we have singled out: Glavstanskaya, Zhundelevskaya, An-Dryushkinskaya, Karasuk-Lapinskaya, Levo-Lapinskaya and Yuzikskaya morphostructures, which form the multilevel structure of the volcano-tectonic relief of the graben (Fig. 3). VTM of the lower tier have substantial basalt composition and form platobasalts (with, thin interlayers of tuff-terrigenous rocks).. They are similar to shield volcanoes with elements of stratovolcanic structures. The second tier of morphostructures is formed by more local in the area of the VTM, such as the Zhundelev structure, the components are noticeably more differentiated in composition by low-thickness bundles of basaltoid volcanics and with a large participation in the sections of tuff-terrigenous rocks. They are characterized by a smoothed character of the surfaces of the strata. They are similar in type to stratovolcanoes, complicated by caldera subsidences. And the third tier, crowning the volcanic incision, is represented by massive, flowing forms such as large extrusive trachytic domes, underlain by thin packs of trachiandesites. In the structure of all these VTM, a cuesta-like type of relief is manifested in different degrees and different forms. Petrographic and geochemical composition of volcanic rocks. There are two subseries belonging to the volcanic series associated with the Saralinsky graben: the main subalkaline one (basalt, trachybasalt-trachyandesite, trachyte, trachydacite) and the secondary alkaline one (picrobasalt, tephrite (basanite), phonotephrite). The main features of the geochemical composition of the studied volcanics are their moderate silicic acidity, medium and mostly high titanium, medium alumina content, high iron content, medium magnesia, and calcareous content (in basites). High phosphorus of basites and trachyandesites is very characteristic. According to the specificity of alkalinity, rocks are partially characterized as sodium and mainly sodium-potassium. According to traceelement data the studied rocks are quite similar to medium alkaline basalts of East African rift system, picrobasalts and basalts and traps of the Siberian Platform, as well as basalts and picrobasalts of some oceanic islands, including Hawaii. Comparisons are made betweeen the development of the East African rift system and Devonian rifts of Altai-Sayan folded area (ASFA)

Saralinsky Graben—Devonian Rift …

W (a) 0

Kuznetsk Alatau S. graben Т. graben R. graben

75 Minusinsk trough

Ag. graben

E

Fragile bark

50

Plastic bark over asthenosphere and upper mantle

100

W (b) 0

East Sayan

Asthenosphere and mantle diapirs

E

50 100 150

Fig. 16 Schematic cross-sections of rift-induced arch-flexure structures: a—KuznetskMinusinsko-East Sayan (Grinev 1994); b—Kenyan (Logachev 1976)

(Fig. 16). Mostly they differ in the age and state of the basements: solid Archean and fractured Neoproterozoic-Early Paleozoic ones, respectively. When assessing the geodynamic conditions of the formation of Saraliakyn volcanics using discriminant geochemical diagrams, the most unambiguous conclusion is that they belong to continental basalts comparable to ocean island basalts (OIB) and ocean plateau basalts (OPB). Their primary magma is relatively similar with differentiates of enriched or E-MORB type magmas. Besides that, Saralinsky graben volcanites (trachytes and trachydacites especially) have some geochemical characteristics relating them to continental margin magmas, which implies crustal contamination taking part. The mantle-plume nature of the volcanic rocks causes an increase of precious metals contents. This indicates that Devonian basic magmatism of ASFA was a source and a carrier of gold and platinum group elements. Under certain conditions, Devonian magmatismitself can serve as sources of gold and platinoids, such as in the nepheline rocks of the alkaline gabbroid province of the Kuznetsk Alatau. In other cases, superimposed processes that change the composition of volcanics can lead to the formation of post-magmatic noble metal deposits. This study was supported by the Government of the Russian Federation (project 14.Y26.31.0012).

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References Boltukhin VP (1972) Correlation of reference volcanic sections of the Devonian age of the southeastern frame of Kuzbass. On Sat Izv. Kuznetsk Department of the Geographical Society of the USSR, vol. Kemerovo, pp 81–85 (in Russian) Grinev OM (2010) Gold-platinoid potential of the rocks of the Kuznetsk-Alatau and Maimech-Kotui alkaline provinces. In the book: IV International Seminar: ”Platinum in the geological formations of the world.” Theses of reports. Subsurface Management Administration for the Krasnoyarsk Territory; Institute of Mining, Geology and Geotechnology, Siberian Federal University; Association of geologists and miners of the Krasnoyarsk Territory; KNIIGiMS; Russian Mineralogical Society of RAS, Krasnoyarsk Branch, Krasnoyarsk (in Russian) Grinev OM (2001) Province of alkaline rocks as areas of complex gold-platinum metal ores. In the collection: Petrology of magmatic and metamorphic complexes. Materials of the All-Russian scientific conference, Tomsk: CNT, pp 216–226 (in Russian) Grinev OM (1996) Tectonics and gold-platinum-bearing rocks of alkaline provinces of the rift zones of the Siberian platform framing. Problem of Siberian Geology. 75 years of geological education at TSU/ Abstracts. T.2, Tomsk, pp 105–107 (in Russian) Grinev OM, Kotelnikov AD (2002) Features of the conditions of formation and minerageny of the Tuva trough according to the data of the structural-formational analysis. Materials of the scientific All-Russian conference “Petrography of magmatic and metamorphic complexes”. Tomsk: Publishing House Tomsk. University, vol 3(2), pp 59–78 (in Russian) Grinev OM, Sazonov AM (1997) Features of geochemistry, minerageny and the problem of extracting precious metals from the nepheline rocks of the Mariinsky taiga. Questions of geology and paleontology of Siberia. Tomsk: NTL, pp 165–172 (in Russian) Grinev OM, Sazonov AM Kuznetsk-Alatau (1996) Province—a new gold-platinum-bearing region of Southern Siberia. Problems of Siberian Geology/ Abstracts of the reports of the regional anniversary conference “75 years of geological education at TSU”. Tomsk: TSU, pp 105–107 (in Russian) Grinev OM (1990) Evolution of alkaline-gabbroid magmatism of the Kuznetsk Alatau 1990 District of the Candian of geology miner sciences, p 18 (in Russian) Grinev OM (2003) Morphotectonics of rift-based framing systems of the Siberian Platform and the ore content of their formations 2003 Alkaline complexes of Central Siberia. Coll. Scientific Papers, pp 36–54 (in Russian) Grinev OM (1994) On the mechanism of the formation of graben structures of the northern part of the Kuznetsk Alatau 1994 Questions of the geology of Siberia, pp 237–259 (in Russian) Grinev OM (2007) Rift systems of Siberia 2007 Tomsk, p 434 (in Russian) Grinev OM (2008) To the problem of classification and characterization of rift structures 2008 Geology and minerals of the Krasnoyarsk Territory 9:21–31 (in Russian) Kryukov VG, Mustafin VZ, Lykina VS (1969) The history of the formation of Talanovsky graben (the northern spurs of the Kuznetsk Alatau) 166, Tomsk, pp 80–85 (in Russian) Mustafin VZ, Kryukov VG, Lykhina NS (1966) The main features of the geological structure of the Talanovsky graben (North-West spurs of the Kuznetsk Alatau) T.151 Tomsk (in Russian)

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Sazonov AM et al (2000) Geology and gold-platinum nepheline rocks of Western Siberia. Tomsk: TPU, p 248 (in Russian) Sazonov AM et al (1997) Unconventional platinoid mineralization of Central Siberia. Tomsk: TPU Publishing House, p 148 (in Russian) Sazonov AM, Grinev OM (1996) The platinum content of the alkaline-gabbroid formation of the northeastern part of the Kuznetsk Alatau. Domestic Geol 10:15–21 (in Russian) Sazonov AM, Shvedov GI, Zvyagina EA, Grinev OM, Agafonov LV (1998) Nefeline rocks from Kuznetsk Alatau. Repots Earth Sci 363(9):1195–1196 (in Russian) Sazonov et al (1996) Noble metal ore content of the Kiya-Shaltyr gabbro-urtite l luton. Ores Metals 1:17–24 (in Russian) Turchenko GP (1975) Geology and petrography of the Devonian volcanic complexes of the northern part of the Kuznetsk Alatau: Author Dis. of the cand. of geolminer. Sciences 20 (in Russian) Uvarov AN, Uvarova NM (2010) Petrotype Bazyrsko-Ashpansky trachit-tefrit-trachybasalt complex 2010 Novosibirsk, p 180 (in Russian) Vorontsov AA, Fedoseev GS, Andryushchenko SV (2013) Devonian volcanism of the Minusinsk depression of the Altai-Sayan rift region: geological, geochemical, isotope Sr-Nd characteristics and magmatic sources 2013 Geology and Geophysics 9:1283–1313 (in Russian) Vorontsov AA, Yarmolyuk VV (2017) Geochemistry and isotope (O, Sr, Nd) evidence of the interaction of mantle and crustal magmas during the formation of the basalt-andesite-trachyt-rhyolite series of the Batenevsky uplift of the Minusinsk trough 2017. Geosph Stud 1:16–27 (in Russian) Vorontsov AA, Yarmolyuk VV, Fedoseev GS, Nikiforov AV, Sindimirova GP (2010) Isotope-geochemical zonality of the Devonian Altai-Sayan rift area magmatism: assessment of the composition and geochemical nature mantle magmatic sources 2010. Petrology 6:45–58 (in Russian) Yarmolyuk VV, Kovalenko VI (2003) Deep geodynamics, mantle plumes and their role in the formation of the Central Asian fold belt. Petrology 11(6) with. 556–586 (in Russian)

Characterization of the Kopievsky Igneous Complex and Its Geological Setting V. P. Parnachev, N. V. Arkhipova and A. L. Arkhipov

A large number of subvolcanic bodies cut through Devonian and Carboniferous volcanogenic and sedimentary rocks within the territory of North-Minusinsk depression (Fig. 1). These subvolcanic bodies belong to two magmatic associations. The first one is known as Kopievsky complex (State geologic map of Russian Federation 2007, 2008). It includes picrodolerite, dolerite, trachydolerite, essexites, crinanites and other basic rocks with increased alkalinity. These rocks form dykes, necks, stocks and sills. The second association is known as Tergeshsky complex. It includes diatremes (blow holes) and dykes of alkaline basalts with mantle xenoliths of lherzolites and pyroxenites. According to results of U-Pb dating of zircons Tergeshsky complex rocks have ages between 79 ± 2 Ma and 74 ± 5.5 Ma. There are no precise dating results known for Kopievsky complex rocks. It’s supposed that they are Early or Middle Triassic because dykes of dolerite cut through sediments, which contain remnants of Late Carboniferous and Early Permian flora (State geologic map of Russian Federation 2007, 2008). The history of the geological study of the Kopievsky magmatic complex goes back to the last century and is associated with the names of I. P. Rachkovsky, Ya.

V. P. Parnachev
N. V. Arkhipova (&)
A. L. Arkhipov Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia e-mail: [email protected] V. P. Parnachev e-mail: [email protected] A. L. Arkhipov e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_4

79

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V. P. Parnachev et al.

Fig. 1 Geological map of of the border zone between the Kuznetsk Alatau and the North Minusinsk through (State geologic map of Russian Federation 2007). Legend: 1–2 Sedimentary Sequences of the North Minusinsk through: the Sequences Lower Carboniferous (1) and Devonian (2) not separated. 4–5 Sedimentary Sequences of the Kuznetsk Alatau: Kanash-Tyurim Sequences of the Vendian and Early Cambrian age (4), Ust-Kundat Sequences of the Early Cambrian age (5). 6—Explosion pipes of alkali basalts of Tergesh formation of the Late Cretaceous age. 7—Sills and dikes of basalts, andesibasalts, trachybasalts of Kopievsky formations of Permian and Triassic age. 8—Granosyenites and granites of Karnayul formation of Upper Cambrian age. 9—Monzonites and monzogranites of Kogtakh formation of Upper Cambrian and Ordovician age. 10—Faults. Yellow quadrilaterals show the outlines of the maps of the Figs. 2 (I) and 7 (II)

S. Edelstein, A. N. Churakova, I. V. Luchitsky, N. A. Okhapkina and many other researchers. The geology of the region was well covered in the Guidebook, for participants of the 17th International Geological Congress (Edelstein 1937), where basic data on stratigra phy, tectonics and magmatism of Minusinsk

Characterization of the Kopievsky Igneous Complex …

81

intermountain trough were provided, which were later refined in subsequent numerous work. The region was studied in greatest detail during large-scale (1:50,000) geological survey of the region in 1978–1982 (Kosorukov et al. 1982). Based on geological mapping the authors established that the Devonian-Carboniferous deposits are mainly developed in the zone of igneous rocks of the Kopievsky Complex. These deposits are subdivided into the Lower Devonian volcanicsedimentary formations, Middle- and Upper Devonian terrigenous-carbonate strata, and Lower Carboniferous terrigenous-pyroclastic sedimentary formations (Fig. 2). Information on the composition of the basement of the Devonian-Carboniferous deposits lying with angular unconformity on the underlying strata was obtained as a result of a drillhole near the railway station Kopievo on the left bank of the Chulym river. Here, at a depth of 800 m under the Lower Devonian volcanogenicsedimentary complex, the Lower–Middle Cambrian carbonate-terrigenousvolcanogenic formations were discovered (Mossakovsky 1963). The Lower Devonian units include volcanogenic-sedimentary deposits (from bottom to top): Kopievsky and Kagayevskaya groups, and Upper Chulym Formation, identified and characterized as composing the Byskarsky Group (Kosorukov et al. 1982). The Kopievsky Group is composed of alternating plagiophyric (labradorite porphyries) and aphyric basalts, andesi-basalts, trachy-basalts with interlayers of tuffogenic-sedimentary rocks with a thickness ranging from 200 to 1,500 m. The erupted rocks form covers with a thickness of 40–45 m, often separated by slag zones; they show signs of ground effusion, contain horizons (up to 40 m thick) of tuffs, conglomerates, volcanoclastic sandstones, siltstones, limestones, and marls. In the latter ones, remains of the fossil psilophytic flora, as well as shells of pelecypods, are found. The stratified structure of the Kopievsky Group within the Chernoiyussky (Black Iyus) structure is complicated by paleovolcanic structures saturated with intrusive bodies of venting and subvolcanic facies. The chemical composition of effusive rocks of the Kopievsky Group, given in Table 1 and also in the work of Zubkov et al. (1989) indicates a clear predominance of basalts and trachybasalts among them. The Kagaevskaya Group has a break and a thin crust of weathering the base overlies the Kopievsky basaltoids. The rocks border the Chernoiyussky anticline in the form of semiring and are overlapped by the red-colored sedimentary rocks of the Upper Chulym and Kozhikovosky formations. At the base of the Kagaevskaya Group lies the cover of trachyandesites, alternating upward along the section with trachytes, alkaline trachytes, and alternating with thin layers of tuffs, ignimbrites, volcanomictous sandstones, siltstones, and conglomerates. Volcanic breccias that

82

V. P. Parnachev et al.

Fig. 2 Geological map of the location area of the intrusive bodies of the Kopievsky Complex (the “Podzaploty” area of the Khakassky Reserve) (by Geological map..., 1997). Legend: 1— The Holocene. The channel and floodplain alluvium: sand, gravel, loam, clay, boulder deposits. 2—The upper stage. Alluvium of low floodplain terraces: sand, gravel, loam, clay. 3–6—The Lower Carboniferous: 3—Samokhvalskaya Formation: sandstones, tuffites, mostly green-colored tuffs, interlayers of limestones and conglomerates; 4—Kamyshtinskaya Formation: tuffs, sandstones, tuffites, siltstones, intercalations of limestones; 5—Altai Formation: sandstones, tuffs, tuffites, predominantly red-colored siltstones; 6—Bystryanka Formation: tuffites, sandstones, mainly gray-colored siltstones; interlayers of limestones, tuffs, mudstones, conglomerates. 7–9—The Upper Devonian: 7—Tubinskaya Formation: red-colored cross-stratified sandstones, siltstones, mudstones, interlayers of conglomerates, gravelites, marls; 8—Kokhai Formation: variegated siltstones, sandstones, mudstones, marls, interlayers of limestones, gypsum; 9—Oydanovskaya Formation: red-colored sandstones, siltstones, mudstones, interlayers of gravelites, marls. 10–12—The Middle Devonian: 10—Beya Formation: gray limestones, siltstones, mudstones, occasionally basal conglomerates and gravelites; 11— Ilemorovsky Formation: gray-green sandstones, siltstones, mudstones, interlayers of marls, limestones, gravelites, mudstones, marls; 12—Askiz Formation: siltstones, marls, intercalations of limestones, sandstones. 13—The Lower-Middle Devonian, Toltakovo Formation: red-colored sandstones, siltstones, mudstones, gravelites, conglomerates. 14—The Lower Devonian, Kopievsky Group: basalts, andesibasalts, trachybasalts, tuffs. 15—Permian-Triassic Kopievsky intrusive complex: dikes and necks of dolerite. 16—Early Devonian subvolcanic complex: trachyandesite-porphyries, 17—geological boundaries, 18—faults, 19—faults, hidden under Quaternary formations, 20—occurrence elements, 21, 22—fossil remains: 21—fauna, 22—flora

Al2O3

Fe2O3

47.79 1.18 19.76 0.93 45.87 1.22 17.82 5.09 50.03 1.51 16.51 9.34 47.42 1.48 19.51 6.43 52.56 1.37 18.35 5.84 46.92 1.25 16.63 5.11 45.34 1.60 14.84 8.71 50.52 1.41 16.81 6.30 8—trachybasalts; 5—trachyandesibasalt;

1 2 3 4 5 6 7 8 Note 1,

TiO2

SiO2

No 4.96 3.81 2.74 2.28 1.32 4.55 3.87 3.41 2, 3, 4,

FeO

CaO

0.28 7.57 0.25 10.24 0.09 3.60 0.26 9.11 0.16 7.30 0.21 9.66 0.16 11.62 0.31 8.13 6, 7—basalts

MnO 5.93 6.68 7.30 3.16 1.48 6.22 6.66 4.50

MgO 5.01 2.60 4.31 3.31 4.00 1.80 2.35 3.48

Na2O 1.24 1.54 1.08 2.00 2.45 0.72 0.44 1.64

K2O

1.44 0.53 0.60 0.64 0.70 0.60 0.50 0.59

P2O5

3.69 3.57 2.13 2.68 4.10 6.30 3.26 2.78

LOI

Table 1 Chemical composition of volcanic rocks of the Kopievsky Group of the Kopievsky Dome (Luchitsky 1960) 99.78 100.45 99.24 100.85 100.00 100.28 99.65 99.88

Sum

Characterization of the Kopievsky Igneous Complex … 83

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compose vent structures are also part of the sequence. Paleo-vents are confined mainly to systems of annular faults, have an oval shape with an exposure area on a modern erosional section up to 1 km2. In some cases, small stocks of syenite-porphyries and trachyte-porphyries of the Voznesensky Complex, intruding through both the Kopievsky basaltoids and volcanic breccias, are spatially associated with the vents. Among the debris in the volcanic breccias there are trachyte porphyries, syenite porphyries, basalts, and less often limestones. In the composition of the clastic material of sedimentary rocks, in addition to the erupted volcanic rocks, there are fragments of intrusive subvolcanic syenite-porphyries, trachyte and dolerite. In the upper part of the group, there is a horizon of limestones and calcareous dolomites with a thickness of 10–45 m. It should be noted that some limestones within the Kopievsky dome were considered by Okhapkin (1961) as travertine formations. Fossil remains of psilophytic flora characteristic of the Early Devonian are found in the sedimentary rocks of the sequence. A section of the Kagayevskaya Group is crowned with green-colored siltstones and mudstones; its thickness ranges from 350 to 550 m. The mudstones are overlain by conglomerates of the Upper Chulym Formation. The Upper Chulym Formation is identified by Kosorukov et al. (1982) in composition of the Toltakovo Formation by Mossakovsky (1963) and corresponds to the Kokorevskaya Formation by Luchitsky (1960). A fragment of the formation is exposed in the near-fault wedge on the right side of the Black Iyus river valley, where, it transgressively overlaps the Kagai terrigenous rocks, with conglomerates at the base. From the above-lying red-colored rocks of the Kozhukhovo Formation, the Upper Chulym sediments are separated by a fault, in the zone of which both of them (Kozhukhov and Upper Chulym formations) are intensely dislocated and in some places have an overturned bedding (Fig. 2). Conglomerates (boulder conglomerates in places) predominate in the lower part of the strata; upward the section they are gradually replaced by gravelites and sandstones, and siltstones. A clastic material of the conglomerate, basaltic and trachybasalt effusives prevail (up to 90%); pebbles of quartz, quartzite, trachyte, granite, syenite and sedimentary rocks are less common. Sandstones are characterized by parallel-, oblique- and wavy-layered structures, often contain plant detritus, bear signs of ripples and shrinkage cracks, which can be attributed these sediments to the channel, floodplain and valley alluvial facies. The thickness of the deposits varies from 120 to 800 m. The Middle Devonian deposits consist of gray-colored carbonaceousterrigenous sediments of the Kozhikovskaya, Askiz, Ilemorovskaya and Beya formations.

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The Kozhikovskaya Formation was identified by Kosorukov et al. (1982) from the Toltakovo or Abakan formations of Anatolieva (1960) and Mossakovsky (1963). The formation is represented by interbedding of red-colored siltstones and mudstones, containing thin interlayers of greenish siltstones and marls in the middle and upper parts of the section. Sometimes carbonate concretions and nodules, and gleying spots are observed in siltstones, which can be interpreted as ancient formations of the caliche type. All the rocks contain abundant plant detritus, fossil plant debris, which makes it possible to consider the series to be of the Middle Devonian (Eifelian) age (Kosorukov and Parnachev 1994a, b). The thickness (sometimes incomplete) of the series varies from 35 to 130 m. The Askiz, Ilemorovskaya and Beya formations were united into a lagoon-sea gray-colored carbonate-terrigenous formation. The Askiz carbonate-siltstonemudstone deposits contain autoclastic breccias, intercalations of dolomite, and lens-shaped lodes of gypsum, testifying to the arid climate and the increased salinity of the basin waters during sedimentation. The Ilemorovskaya Formation is composed of thinly intercalated siltstones, mudstones, and sandstones, which have accumulated in alluvial-deltaic environments. In the tops of the section, the role of carbonate rocks is increasing, and the imprints of the brachiopods and fillopods are noted, which indicate shallow-water sedimentation conditions. The Beya sediments are mainly represented by gray-colored limestones. They are interbedded with thin-plate dolomites, marls, calcareous sandstones, siltstones and mudstones, as well as rare gypsum interlayers. In the Beya sediments there are brachiopods, gastropods, conodonts, corals, which determine their Late Givetian age. The estimated thickness of the Middle Devonian gray-colored carbonateterrigenous formation does not exceed 550 m. The Upper Devonian is represented by the red-colored deposits of the Oydanovskaya, Kokhai and Tubinskaya formations, united by Kosorukov et al. (1982) in a surface terrigenous molassoid red-colored formation. The Oydanovskaya Formation is composed of red-colored rhythmic-layered sandstones, interbedded with siltstones and mudstones and bearing signs of accumulation in alluvial, deltaic, and lake environments. In the lower horizons of the formation there are gypsum interlayers, suggesting their formation in salty lagoons. The sediments of the formation are broken by a neck of Mt. Chirya. The Kohai deposits were recognized by a 2-K drillhole in the Podzaplotskaya exploration area in 1954, where they are represented by layered siltstones, mudstones, marls, limestones with nests and lenses of gypsum, and, in a subordinate number, by sandstones, gravelites and conglomerates (Teodorovich and

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Ilyushina 1959). Pebbles (up to 3 cm) of limestone are found in some interlayers of siltstones; carbonized vegetable remains and fish imprints, shells of ostracods and fillopodes are noted. The thickness of the formation reaches 550 m. The Tubinskaya Formation is characterized by the alternation of red-colored sandstones, siltstones and mudstones. The presence of imprints of the archeopteris flora indicates sediments accumulation in the Famennian stage. The total thickness of the Upper Devonian terrigenous red-colored formation reaches 1500 m. The Lower Carboniferous deposits in the Bystryanka, Altai, Kamyshtinskaya, Samokhvalskaya, Krivinskaya, Solominskaya formations of Kosorukov et al. (1982) are considered as a lake-lagoon terrigenous telepyroclastic formations. The lithology of the formations is most fully characterized by Brovkov et al. (1967). The Bystryanka Formation lies on the Upper Devonian red-colored rocks with traces of erosion and begins from the horizon of conglomerates, then changes for interbedding gray and greenish-gray sandstones, siltstones, mudstones, conglomerates with rare tuffite interlayers. In the upper part of the suite Ananiev (1979) identified a thin horizon with imprints of narrow branches of cyclostigma flora (morass) in outcrop 8.4 km south of village of Podzaplot. The Altai Formation is represented by the alternation of variegated yellowishand greenish-gray, sometimes brownish-red sandstones, siltstones, tuffs and tuffites. In the red sandstones near the village of Podzaplot the imprints of cyclostigmatic flora (morass) were found by Ananiev (1979). The Kamyshtinskaya Formation is composed of gray, yellowish- and greenish-gray, less often—purple sandstones, limestones, tuffs and tuffites. Sands dominate in the lower parts of the formation, calcareous rocks in the upper horizons. The Samokhvalskaya Formation is represented by the alternation of variegated green, yellow-green, greenish-gray, grayish-yellow and gray sandstones, siltstones, tuffs and tuffites bearing signs of accumulation in the lagoon-type basin. The Krivinskaya Formation consists of variegated interbedded siltstones, sandstones, tuffs and tuffites containing lenticular interlayers of limestone. Psammitic differences prevail in the middle part of the strata, and carbonate rocks increase to the top of the section. The Solominskaya Formation combines interlayered variegated tuffites, tuffs, limestones and sandstones, with rare interlayers of gravel-pebble material, containing debris of lepidophyte trunks. The total thickness of the lake-lagoon terrigenous telepyroclastic formation varies from 1,200 to 1,300 m. The Quaternary system includes the deposits of the Lower-Upper Neopleistocene and the Holocene, which almost everywhere overlap the DevonianCarboniferous stratified and magmatic formations.

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The lower undifferentiated part of the Neopleistocene consist of lake sediments that are widespread along the shores of the salty lakes of the Lestvenka, where they compose flattened coastal areas 100–200 m wide. The upper part of the Neopleistocene (undifferentiated) includes alluvial and proluvial deposits of cones at the boundaries of uplifts and depressions, in the mouths of dry valleys. Alternating layers of coarse and fine crushed stone, cemented by loam, with a total thickness of 3–5 m, are observed in the cones. The first and second terraces above the floodplain of the Black and White Iyus rivers can be conditionally dated with this age. The first terrace above the floodplain has a radiocarbon age of about 17,900 years (Sartan age). In 2010, bone remains of a woolly rhinoceros, elk, reindeer, bison, argali, horse, ram, marmot, ground squirrel were found here and identified by A. V. Spansky (Shpansky and Malikov 2015). The Holocene combines lake-marsh and alluvial floodplain, oxbow and channel deposits of the White Iyus and Black Iyus rivers. Eluvial, talus, colluvial, proluvial, and solifluction deposits that are common on flat watersheds, tops and slopes of elevations should be attributed to this age level. Their thickness in places reaches 5–10 m. Loess-like loams almost everywhere cover (in a cloak-like manner) genetically different sediments and underlying Paleozoic formations. Intrusive magmatism in the region is represented by two different-aged complexes: Lower Devonian Voznesensky and Permian-Triassic Kopievsky (Kosorukov et al. 1982). The Voznesensky Complex is considered as a formational and temporal intrusive analogue of the trachyte-trachyandesite volcanics of the Kagaevskaya Group. Small (2–5 km2 and less) stock-like, sometimes sill-like and dike-like bodies intruding and metamorphizing the Kopievsky basaltoids and sedimentary-volcanogenic deposits of the Kagaevskaya Group, are attributed to the complex. Within the Black Iyus (Chernoiyussky) volcano-dome structure, these bodies are confined to zones of ring and linear faults. They are the relatively well-studied massifs of the Golaya and Bezymyannaya mountains (Fig. 2) and a series of spatially associated smaller bodies. In plan view, both of the massifs are somewhat elongated in the submeridional direction (2.8 km and 2.0 km, respectively) with a maximum width of 0.8 km, and are composed of reddish- and yellowish-brown trachyte-porphyries, sometimes, of syenite porphyries. It should be noted that trachyte porphyries, and syenite porphyries are found in abundance in the detrital material of tuffs, volcanoclastic sandstones and vent breccias of the Kagaevskaya Group, which can be explained by their broad similarity in age, but multi-phase formation of those and other rocks. Features of the chemical composition of the rocks of the Voznesensky Complex are given in Table 1. According to the total contents of alkali oxides

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(Na2O + K2O) = 8.3–10.5% and silica (SiO2 more than 50%), the rocks of the Voznesensky complex are compositionally similar to the effusives of the Kagayevskaya Group, which confirms their comagmatism and belonging to a single volcano-plutonic association. The age of complex formation was adopted as the Early Devonian because the complex rocks intruded the Kagaevskaya volcanic-sedimentary deposits, characterized by Early Devonian fossil flora. The Kopievsky Complex includes dykes, necks and explosive pipes of alkaline basaltoids, which penetrate the Middle-Upper Devonian and Lower Carboniferous deposits in the region of the Kopievsky Dome, as well as the dikes and numerous sills of “fresh” dolerite-basalts occurring among the Lower Devonian volcanic-sedimentary series. The questions of recognizing of this complex and its age have been debated from the beginning of the last century (Kotelnikov 1936; Luchitsky 1960; Zubkov et al. 1989; Rikhvanov et al. 1991; Kosorukov and Parnachev 1994a, b; Ershov et al. 2003, etc.) and is still far from a final decision. Dikes to the west of the Kopievsky uplift form the Northern and Southern sublatitudinal swarms. The Northern Belt includes dikes in the area of the Uchum Lake; here the explosion pipes Kamyshtinskaya-1 and Kamyshtinskaya-2 have been also mapped (Parnachev et al. 1996a, b). The South Belt dikes in the Podzaploty area intersect the Ustinkinsky syncline (Fig. 2), are predominantly sublatitudinal, sometimes northeast oriented, and in their location are controlled by a system of amplitude-free or low-amplitude faults (Figs. 2 and 3). Their length reaches several kilometers, and their thickness is a afew meters. The dikes have the compositions of dolerite, microdolerite, krinanites, ankaramites, essexite-dolerite, essexites, and amygdaloidal basalts. The Kozhikovskaya dike has been studied most thoroughly (Okhapkin 1969; Kosorukov et al. 1982). The dike is located at the northwestern margin of the village of the same name (railway crossing 208 km), extends in the latitudinal direction for 490 m with a thickness of 5.2–7.5 m and has vertical contacts with individual sinuses and apophyses (Fig. 4) It often bifurcates and contains lenticular xenoliths of enclosing rocks. The dike breaks through the carbonate-terrigenous rocks of the Askiz Formation and turns them into hornfelses with a contact width of up to 2.5 m. The dike is composed of greenish-gray crinanites and essexites that are well crystallized and often brecciated. The rocks have a subophytic, poikilophytic, intersertal textures and are composed of (about 40%) zonal plagioclase (oligoclase-labradorite), potassium feldspar (up to 5%), pseudomorphs on olivine (up to 10%), diopside and titanium augite (15–35%), ore minerals (magnetite, titanomagnetite with leucoxene rims, pyrite—up to 2%), sometimes of analcime (up to 5%). The rocks are

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Fig. 3 The Podzaploty area (sublatitudinal dike with displacement). Photo by A. L. Arkhipov

Fig. 4 Scheme of the structure of the Kozhikovskaya dike (according to Kosorukov et al. 1982)

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intensively changed; the groundmass is chloritized; Okhapkin (1969) also has found analcime dia base (crinanites). In the western direction, among the rocks of the Ilemorovskaya Formation, there are also known some sublatitudinal (E-W) linear dike bodies of medium- and fine-grained essexites and crinanites. The Neck of Mount Chirya is characterized by Strukulenko and Dedyukhin (1961), Okhapkin (1969) and Kosorukov et al. (1982) and is known as the Klyuchiki stock or intrusion. The neck is located to the south of the Listvenki lakes among the sandstone of the Oydanovskaya Formation and stands out in relief on the hilly plain in the form of a rounded sharp hill with a diameter of about 80 m and a relative height of about 40 m (Figs. 5 and 6). In its central part the neck is composed of black spotted glassy breccias and is accompanied by a series of close sublatitudinal dikes of olivine dolerite and trachydolerite. The western extension of the neck is a dike of carbonated crinanite. Volcanic breccias in the form of a ring frame the central part of the neck and consist of an iron-rich and carbonated mesostasis, with fragments of feldspar crystals, pyroxene, magnetite, biotite, and heavily modified sedimentary rocks. Exocontact changes are expressed in the hornfelses development and lightening of sandstones. The chemical composition of the rocks of the Kopievsky Complex (Table 2) indicate subalkaline, to more rarely, highly alkaline rocks of trachy-meso-trachymelano-basaltoids and even trachy-picrito-basalts, which clearly distinguishes them from the Lower Devonian basaltoids. The rocks of the Kopievsky Complex have consistent SiO2 contents—from 39.2 to 47%, high alkalinity of the sodium type (Na2O + K2O) = 2.5–5.5%, relatively high MgO content (5.5–12.6%), which also distinguishes them from the Lower Devonian volcanites. Nepheline is present in the normative composition of most of the mafic intrusive rocks, which unambiguously indicates their increased alkalinity. The trace element composition of the complex rocks is characterized by elevated contents (compared to Clark values) of lead, molybdenum and strontium, and lower contents of niobium, zirconium and titanium. Several dikes of the Kopievsky Complex were found in the area of Chernoye Lake, where they are represented by dolerite, trachydolerite and crinanites. Here, dike rocks break through the volcanogenic-sedimentary deposits of the Lower Carboniferous, including the Baynovskaya, Yamkinskaya, and Solomenskaya Formations (Figs. 7 and 8). In some places, dikes have a fairly significant length (from several hundred meters to 2–3 km) with a close to vertical dip and thickness up to 20 m.

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Fig. 5 Geological plan and section of the mountain Chirya (according to Kosorukov et al. 1982)

Fig. 6 View of the neck of Mt. Chirya from the southeast. Cuestas of the Rocky Mountains rise from the left side. Photo by N. V. Arkhipova

SiO2

TiO2

Al2O3

Fe2O3

FeO

MnO

CaO

MgO

Na2O

K2O

P2O5

LOI

Sum

1 41.44 2.32 12.70 6.60 6.07 0.16 14.00 6.10 2.10 0.54 0.35 7.16 99.54 2 41.14 2.36 13.43 4.76 6.42 0.17 14.51 6.10 2.36 0.56 0.35 7.80 99.96 3 43.98 2.26 13.22 4.28 10.77 0.20 9.58 9.18 2.69 1.04 0.40 2.05 99.65 4 44.76 2.37 14.67 5.84 6.93 0.16 10.63 6.10 3.12 0.95 0.33 3.79 99.65 5 42.54 2.80 13.43 8.55 7.91 0.18 10.87 6.33 2.60 0.75 0.30 3.40 99.66 6 41.98 2.84 14.06 8.41 7.59 0.17 10.87 6.04 2.60 0.85 0.30 4.23 99.94 7 39.20 2.53 11.45 5.31 7.58 0.17 14.27 7.45 2.00 2.17 0.82 6.73 99.68 8 45.42 2.53 12.97 13.95 2.12 0.15 7.80 5.52 2.15 0.26 0.30 6.85 100.02 9 62.64 0.35 15.83 1.15 2.35 0.11 4.16 0.60 8.62 0.15 0.10 1.62 99.68 10 66.74 0.42 16.73 1.75 2.00 0.10 0.69 0.30 7.56 2.46 0.18 0.71 99.64 11 64.64 0.42 17.00 1.34 2.92 0.13 1.66 0.50 6.30 3.89 0.18 0.78 99.76 12 68.26 0.32 16.46 1.75 1.19 0.02 0.54 0.19 4.67 5.79 0.09 0.83 100.11 Note 1, 2—olivine dolerites, dikes near the neck of Mt. Chirya; 3—dolerite, dike at the Listvenki Lake; 4, 5, 6—essexites: 6—neck of the Mt. Chirya; 7—ankaramite, dike close to the Kagayevo village; 8—crinanite, dike at the Kagayevo village; 9—trachyte porphyry, the massif of the Mt. Golaya; 10—orthoclase-porphyry, ibid; 11—syenite-porphyry, ibid; 12—orthoclase-porphyry, ibid

No.

Table 2 Chemical composition of intrusive rocks of the Kopievsky (1–9) and Voznesensky complexes (10–12) (by Kosorukov et al. 1982)

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Fig. 7 Geological map of the location area of the dike bodies of the Kopievsky Complex in the Chernoye Lake region. (according to Geological map..., 1997). Legend: 1—The Holocene. Channel and floodplain alluvium: sand, gravel, loam, clay, boulder deposits. 2–6 —The Lower Carboniferous: 2—Samokhvalskaya Formation: sandstones, tuffites, tuffs of predominantly green color, interlayers of limestones and conglomerates; 3—Krivinskaya Formation: tuffs, sandstones, tuffites, siltstones, intercalations of limestone; 4—Solomenskaya Formation: sandstones, tuffs, tuffites, siltstones, predominantly red-colored; 5— Yamkinskaya Formation: tuffites, sandstones, siltstones, mostly gray-colored; interlayers of limestone, tuff, mudstone, conglomerate; 6—Bayanovskaya Formation. 7—Permian– Triassic Kopievsky Complex: dolerite dikes. 8—geological boundaries. 9—faults, 10— occurrence elements. 10—numbers of dikes indicated in the text

There is a clear zoning in the cross-section of the dikes. The central parts of thick dikes for the most part are typically coarse-grained, often with clearly manifested spheroidal jointing (Fig. 9). The near-contact zones have an amygdaloidal texture and are saturated with xenoliths of the host rocks (Figs. 10, 11 and 12). All the basaltic Chernoye Lake dikes are characterized by a fresh appearance, a dark, almost black color, and a glassy groundmass. The texture of the rocks is mostly porphyritic, the groundmass is cryptocrystalline or vitrophyric, in some places trachytoid; and in the central parts of most coarse-grained varieties it is

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Fig. 8 Contact of the sublatitudinal trachydolerite dyke No. 2 (in Fig. 7) with terrigenous rocks of the Yamkinskaya Formation (photo by A. L. Arkhipov)

intersertal or doleritic. In the matrix, there are numerous small (up to 5 mm) predominantly idiomorphic crystals of olivine and pyroxene, xenomorphic analcime grains, as well as labradorite laths, and biotite flakes. Olivine (Fo35Fe65) is partially replaced by serpentine and iddingsite, pyroxene (En37Wo36Fs27) by chlorite, and plagioclase by sericite and calcite. The matrix of basaltic rocks has a vitrophyric texture with numerous small labradorite laths, and grains of monoclinic pyroxene and titanomagnetite. The Permian-Triassic age of the basaltic rocks of the Kopievsky Complex is determined on the basis of them crosscutting Permian strata and their absence in Jurassic deposits (Luchitsky 1960). In general, Permian-Triassic age of the Kopievsky magmatism is well correlated with the formation time of trap manifestation in the Kuznetsk trough, on the Siberian platform and in the rift structures of the West Siberian plate (and would suggest a link with the 252 Ma Siberian Trap large igneous province. In discussing the problem of the tectonic structure and development of the troughs of the Minusinsk intermountain trough in recent years, most researchers have come to the conclusion about the continental rift nature of the Devonian

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Fig. 9 Spheroidal jointing and shell-like cleavage in dolerite dike No. 2 in Fig. 7. Photo by A. L. Arkhipov

trough structures and post-rifting features of sedimentation in the Middle-Late Devonian and Carboniferous (Parnachev and Smagin 1985; Parnachev et al. 1993, 1994, 1996a, b; Grinev 2007, and others). When analyzing the internal structure of the Minusinsk basin and, in particular, the Chebakovo-Balakhta basin and the Uzhursky synclinal trough, three structural stages are clearly distinguished: the lower (Lower Devonian), middle (Middle-Upper Devonian) and upper (Carboniferous-Permian), and which differ in the composition of the formations, and in the nature of their occurrence. The lower structural stage is composed of Lower Devonian volcanicsedimentary sediments (Byskarskaya Formation), which are characterized by significant variations in their composition and thickness of the sections (Luchitsky 1960; Kosorukov et al. 1982; Parnachev et al. 2009). In the structure of the stage, a regular change of mainly volcanogenic formations by terrigenous molasse is observed from the bottom to top. The formation of the lower structural stage is accompanied by a reactivation of existing faults and the formation of new linear and circular faults that control the intrusion of dikes and explosion pipes. Within

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Fig. 10 Crinanite dike No. 3 in Fig. 7, intersecting the Chernoye Lake. Photo by A. L. Arkhipov

the limits of the Kopievsky structure, the rocks of the lower stage are deposited with angular unconformity on the folded strata of the basement. The middle structural stage is composed of Middle-Upper Devonian terrigenous-molasse weakly deformed sediments, with angles of inclination of structural limbsnot exceeding 20–30°. The total thickness of the sediments composing the structural stage does not exceed 2000 m (Kosorukov et al. 1982). According to Kosorukov et al. (1982), the upper structural stage includes the Lower Carboniferous lake-lagoon terrigenous telepyroclastic formation, including the Bystryanka, Altai, Kamyshtinskaya, Samokhvalskaya, Krivinskaya, Solominskaya formations. The formation of this stage was preceded by the diastrophism phase, which led to uneven uplifting of individual blocks, the formation of angular unconformities in several places, small open synclinal structures (often complicated by flexures), and weathering crusts. The sections of all the formations, the total thickness of which varies from 1,200 to 1,300 m, are saturated with pyroclastic material, indicating the reactivation of active volcanic activity outside the Minusinsk trough.

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Fig. 11 Xenoliths in the Chernoye Lake crinanite dike No. 3 in Fig. 7. Photo by A. L. Arkhipov

The deposits of all structural stages underwent plicative (folded) and disjunctive discontinuous deformations in the Late Permian–Triassic time in connection with the renewal and formation of new faults, the intrusion of dikes and explosion pipes of the Kopievsky magmatic complex. Modern structures include folded (plicative) and fault (disjunctive) tectonic formations. The distribution area of the studied igneous formations of the Kopievsky Complex is tectonically localized in Tchebakovo-Uzhur synclinal deflexion of the Tchebakovo-Balahta depression of the Minusinsk intermountain trough, to be exact—at the junction zone of northern Salbatsky and southern Chebakovsky moulds forming the deflection (Luchitsky 1960). These structures are separated from the Saralinsky uplift located to the west by the submeridional (N-S) fault. Here the Chernoiyusskaya anticline and the Ustinkinskaya syncline were distinguished (Fig. 3). Disjunctive dislocations (faults) play a decisive role in the structural plan of the entire Minusinsk trough and, in particular, in the structure of the region. In general, faults of several orders are distinguished. The first order faults divide the Minusinsk intermountain trough from the surrounding mountain structures of the

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Fig. 12 Amygdaloidal structure and xenoliths in the Chernoye Lake crinanite dike No. 3 (Fig. 7). Photo by A. L. Arkhipov

Eastern, Western Sayans and Kuznetsk Alatau. The second-order faults (Berezovsky, Ashpansky, Ozerny, Belozersky, Bereshsky, Uchumsky, and others) outline relatively large uplifts and deflections (Kopievsky, Salbatsky, etc.). The faults of the third and fourth order complicate the positive and negative structures. In the studied area, they include the Ustinkinsky and Karagachinsky fault zones which are often complicated by flexures. In the fault zones, the angles of inclination of the layers noticeably increase up to 50–80°; sometimes even an overturned bedding is noted (Fig. 3). The Karagachinsky fault had the character of a varying-amplitude overthrust, the uplift along which reached 1 km in the south (volcanic rocks of the Kopievsky Group and limestones of the Beya Formation were derived at one hypsometric level). In the northern direction, the displacement amplitude along the fault decreases to 150–200 m. Kosorukov et al. (1982) distinguished separately ring faults and sublatitudinal dislocations without considering fault amplitude. Ring faults, as a rule, contour and are associated with paleovolcanic structures and stocks of subvolcanic rocks of the Voznesensky Complex. Basically, they are fixed within the volcanic-dome

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structures (the Chernoiyussky structure) (Fig. 3). Sublatitudinal (E-W) non-amplitude disturbances usually control dikes and dike swarms and correspond to latitudinal permeable zones in the folded basement. This study was supported by the Government of the Russian Federation (project 14.Y26.31.0012).

References Ananiev VA (1979) The main locations of the early Carboniferous floras in the North Minusinsk depression. TSU, Tomsk, 114 p (in Russian) Anatolieva AI (1960) Stratigraphy and some problems of the Devonian paleogeography of Minusinsk intermountain trough. Siberian Branch of the Academy of Sciences of USSR, Novosibirsk, 53 p (in Russian) Brovkov GN, Bucharskaya GS, Mogilyov AI et al (1967) Lithology of the middle Paleozoic volcanogenic-sedimentary complex of depressions in the East of the Sayan-Altai folded area. P.H. “Science”, Moscow, 221 p (in Russian) Edelstein YS (1937) General information about the geological structure of the southern part of the Krasnoyarsk Territory. In: International 17th geological congress. Siberian excursion. Krasnoyarsk Territory. ONTI, Moscow-Leningrad, 46 p (in Russian) Ershov VV, Korobeynikov AF, Rikhvanov LP (2003) New data on the geochemistry of alkaline basaltoids of the Minusinsk trough. In: Problems of the geology and geography of siberia. Bulletin of the TSU. Appendix 23. TSU, Tomsk, pp 51–52 (in Russian) Geological map of the Republic of Khakassia scale 1: 500 000 / comp. Makhlaev M. L. [and others]. Ministry of natural resources of the Russian Federation; Committee on Geology and subsoil use of the Republic of Khakassia, state enterprise “Krasnoyarsk geological Survey”. - Krasnoyarsk, 1997. 1 sheet. (in Russian) Grinev OM (2007) Rift systems of Siberia. Methodology of study, morphotectonics, metallogeny. TSU, Tomsk, 434 p (in Russian) Kosorukov AP, Parnachyov VP (1994a) About alkaline basaltoids of the Kopievsky anticlinal rise. In: Problems of the geology of Siberia, vol 1. TSU, Tomsk, pp 177–178 (in Russian) Kosorukov AP, Parnachyov VP (1994b) Geological structure and stratigraphy of the volcanogenic-sedimentary series of the western part of the Kopievsky dome of the Chebakovo-Balakhtinskaya basin. In: Problems of the geology of Siberia, vol 3. TSU, Tomsk, pp 27–36 (in Russian) Kosorukov AP, Savushkin MP et al (1982) Report of the Sharypov party on specialized geological prospecting of 1:50 000 scales in the western part of the North Minusinsk depression for 1978–1982. Public Fund “Krasnoyarskgeologia”, Krasnoyarsk, 278 p (in Russian) Kotelnikov LG (1936) Devonian and post-Carboniferous basalts of the Kuznetsk Alatau and Minusinsk depression. In: Trudy TSNIGRI. Iss. 63. Leningrad-Moscow, 34 p (in Russian)

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Luchitsky IV (1960) Volcanism and tectonics of the Devonian depressions of the Minusinsk intermountain trough. P.H. Academy of Sciences of the USSR, Moscow, 275 p (in Russian) Mossakovsky AA (1963) Tectonic development of the Minusinsk depressions and their framing in the Precambrian and Paleozoic. P.H. Gosgeoltekhizdat, Moscow, 216 p (in Russian) Okhapkin NA (1961) Devonian travertines of the Kopievo region (Minusinsk intermountain trough). Geol Geophys 5:80–82 (in Russian) Okhapkin NA (1969) Post-Devonian alkaline rocks of the south-western part of the North Minusinsk Depression. In: Problems of petrology and metallogeny of the western framing of the Siberian platform. Iss. 61. KO SNIHGIMS, Krasnoyarsk, pp 171–180 (in Russian) Parnachev VP, Smagin AN (1985) On the composition, conditions of manifestation and metallogeny of Devonian volcanism in the northwestern part of the Eastern Sayan. In: General volcanological maps and metallogenic specialization of the volcanic regions. UCSC of Academy of Sciences of the USSR, Sverdlovsk, pp 91–107 (in Russian) Parnachev VP, Makarenko NA, Vyltsan IA (1993) Continental paleorift systems of Southern Siberia. In: Continental riftogenesis of Siberia. TSU, Tomsk, pp 5–7 (in Russian) Parnachev VP, Makarenko NA, Rodygin SA, Smagin AN (1994) The main features of the Devonian volcanism in the central part of the Altai-Sayan folded region. In: Problems of geology of Siberia. Iss. 2. TSU, Tomsk, pp 220–236 (in Russian) Parnachev VP, Vyltsan IA, Makarenko NA et al (1996a) Devonian riftogenic formations of the South of Siberia. TSU, Tomsk, 239 p (in Russian) Parnachev VP, Vyltsan IA, Makarenko NA (1996b) Continental rifting and post-rift sedimentation basins in the geological history of Southern Siberia. TSU, Tomsk, 102 p (in Russian) Parnachev VP, Vasiliev BD, Koptev II et al (2009) Geology and minerageny of Northern Khakassia. Guidebook to the educational geological training ground of universities in Siberia. TPU, Tomsk, 236 p (in Russian) Rikhvanov LP, Ershov VV, Sarnaev SI (1991) Geochemical features of alkaline basites and ultrabasites of the Minusinsk trough. In: Geochemical associations of radioactive and rare elements in ore and magmatic complexes. P.H. “Nauka”, Novosibirsk, pp 97–109 (in Russian) Shpansky AV, Malikov DG (2015) New locations of quaternary mammals in the interfluve of the white and black Iyus rivers (Republic of Khakassia). TSU Bull 396:245–257 (in Russian) State geologic map of Russian Federation (2007). Scale 1:1 000 000 (third generation). Altai-Sayan series. Sheet N-45—Novokuznetsk. Explanatory note.—SPb.: VSEGEI, 665 p (in Russian) State geologic map of Russian Federation (2008). Scale 1:1 000 000 (third generation). Altai-Sayan series. Sheet N-46—Abakan. Explanatory note.—SPb.: VSEGEI, 391 p (in Russian)

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Strukulenko AF, Dedyukhin NE (1961) About the post-Carboniferous alkaline hypabyssal intrusions of the North Minusinsk depression. In: Proceedings on geology and minerals of the Krasnoyarsk territory. Iss. 1. Krasnoyarsk, pp 113–115 (in Russian) Teodorovich GI, Ilyushina MK (1959) To the stratigraphy and petrography of the Devonian sediments of the margins of the region of the Minusinsk depressions. In: Proceedings on geology and oil and gas potential of the region of the Minusinsk depressions. Academy of Sciences of the USSR, Moscow, pp 5–47 (in Russian) Zubkov VS, Smirnov VN, Plyusnin GS et al (1989) The first К-Ar dates and Sr isotopic composition of basanites of the explosion pipes of the Chulym-Yenisei depression. Doklady Acad Sci USSR 307:466–1469 (in Russian)

Guide for Field Geology of the Lower Devonian Byskar Series on the Educational Geological Ground of Siberian Universities (Republic of Khakassia) N. A. Makarenko, A. D. Kotelnikov, S. A. Rodygin, A. L. Arkhipov and N. V. Arkhipova 1

Introduction

The educational geological ground of Siberian Universities (including for Tomsk State University, TSU), where field student practices are held annually, covers a vast area (*5,000 km2) on the eastern slope of the Kuznetsk Alatau, partly of the Bateniov Ridge and the North Minusinsk depression of the Minusinsk Intermountain Trough (Parnachev and Vasilyev 2007). In the mountainous areas there are many geological features of a huge age range—from Proterozoic to Cenozoic, and various types of mineral deposits. All these features have been well studied by

N. A. Makarenko
A. D. Kotelnikov
S. A. Rodygin (&)
A. L. Arkhipov
N. V. Arkhipova Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia e-mail: [email protected] N. A. Makarenko e-mail: [email protected] A. D. Kotelnikov e-mail: [email protected] A. L. Arkhipov e-mail: [email protected] N. V. Arkhipova e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_5

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several generations of geologists, and remain fully accessible for modern examination and study, both by young trainees and professionally oriented specialists. All three divisions of the Devonian system are widely distributed in the steppe zone of the study area (Shira district, Republic of Khakassia) within the south-western margin of the North Minusinsk Depression, where the field stations of four Siberian universities are located (Fig. 1, inset). Historically, the main features of study here are deposits of the Lower Devonian Byskar series, which are developed in two sections—Shira–Marchengash and Matarak–Shunet. The concept of “Byskar series” was introduced into the scientific literature by Schneider and Zubkus (1962) as a large stratigraphic unit in the Minusinsk intermountain trough, consisting mainly of effusive rocks of acidic, medium, mafic and alkaline composition, as well as tuff, tuff breccia, tuff with layers of variegated terrigenous sediments. The age of the series was adopted as Early–Middle Devonian, and later—as Early Devonian. At present, the term “Byskar series” is widely used, although it is absent in the Legend of the Minusinsk series of sheets of the State Geological Map of the Russian Federation 1: 200 000 because it is replaced by the names of specific Early Devonian formations without combining them into larger taxonomic units. We describe general and specific geological features of the Lower Devonian Byskar series deposits of the two above-mentioned sections.

2

Geological Features of the Shira–Marchengash and Matarak-Shunet Areas

According to published literature (Krasnov 2012), the two areas both belong to the Matarak structural-facies subzone (SFS) of the Minusinsk structural-facial zone (SFZ). The Lower Devonian stratigraphy in this document is based on the classical Matarak-Shunet section, known since the 1950s thanks to the works of Meleschenko (1953), and later by Krasnov and Ratanov (1974). The two Lower Devonian formations (Matarak and Shunet) in the Matarak-Shunet section were suggested to be a type section, representative of the entire area of the Matarak SFS. However, at that time (Makarenko et al. 1982), the presence of a different set of sedimentary formations in the eastern and western sectors of the training ground was not yet recognized. Only after the publication of Makarenko et al. (2017, 2018b) which had an improved regional stratigraphic scheme, that was approved (Krasnov et al. 2018), were appropriate corrections made. Thus, in the framework of the Matarak SFS, along with the classical Matarak-Shunet area, the

Fig. 1 Geological map of Shira–Marchengash (a) and Matarak-Shunet (b) areas on the field school grounds of Siberian universities in the Republic of Khakassia, modified after Makarenko et al. (2018b). 1—Quaternary deposits; 2–8—Formations: 2—Oydanov; 3—Beya; 4—Ilemorov; 5 -Marchengash; 6—Pridorozhnaya; 7—Aramchak; 8—Shunet; 9–10—subformations: 9 – Upper Matarak; 10—Lower Matarak; 11—rocks of the pre-Devonian basement; 12—geological boundaries: a—reliable, b—overlapped by loose sediments, and c— approximate; g – layers with facies changes; 13—tectonic discordances (faults): a—reliable, b—covered by loose sediments; 14—axes of the main synclinal (a) and anticlinal (b) folds and their labelling: (1—Shirinskaya, 2—Bezymyannaya, 3—Kruglinskaya, and 4—Itkul synclines; 5—Pridorozhnaya, 6—Prirazlomnaya, 7—Marchengashskaya, and 8—Itkul anticlines); 15—subvolcanic bodies of trachydacite and trachyrhyodacite; 16—subvolcanic bodies of trachyte and trachyte porphyry of the Karysh paleo-volcanic structure; 17—Traverses of this guidebook chapter and their numbers; 18 – key outcrops: a—with lithostratigraphic, and b—with biostratigraphic marker horizons, c—with remains of Propteridophyte (Rhiniophyte) flora. Inset map- field school grounds of Siberian universities: Tomsk State University (TSU), Tomsk Polytechnic University (TPU), Novosibirsk State University (NSU), and Siberian Federal University (SFU) in Krasnoyarsk

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Shira–Marchengash area was also characterized. In the first section, from bottom to top, the following formations are established: the Lower Matarak and Upper Matarak subformations of the Matarak Formation, the Shunet and Aramchak Formations; in the second, the Lower Matarak is completed, the Pridorozhnaya (Roadside) and the Marchengash Formations (Krasnov et al. 2018, p. 95, sheet 17, column 24). The generalized geological structure (Fig. 1), defines the boundaries and areas of distribution of all Devonian formations in the Shira–Marchengash and Matarak– Shunet areas. The scheme fully reflects the main features of the geological structure of the territory, and in particular, the widespread development of folds and faults. The oldest strata of the Byskar series, the Lower Matarak subformation, is present in two areas in the form of a narrow strip, following the contour of the south-western periphery of the North Minusinsk depression. This subformation unconformably overlies the pre-Devonian basement, and has a variable thickness (300-900 m) and consists of layers of trachyandesite, trachyte, tuff, basalt, trachybasalt and lenses of gray sandstone with rhyniophyte flora. In the Shira–Marchengash area, the Pridorozhnaya Formation lies on the Upper Matarak subformation, with a thickness of 750 m, represented by variegated conglomerate, gravelite, sandstone, pelite, tephra, tuff, basalt, trachybasalt, interbedded with the basal conglomerate. Rhyniophyte flora and stromatolites are widely distributed; isolated ichthyofaunas (Osteostraci) were also found. The Pridorozhnaya Formation is divided into three subformations—the Lower subformation consists of terrigenous coarsely clastic rocks (conglomerate, gravelite, and coarse-grained sandstone). The Middle consists of volcanogenic-terrigenous clastic rocks (sandstone, pelite, and rarely gravelite). The Upper is tuffogenousterrigenous with a widespread development of secondary silicification processes. The listed lithologies are interspersed with basaltic layered bodies, rarely dolerite, the number of which naturally increases laterally in a westerly direction. The Marchengash Formation (up to 550 m thick) has inconsistent contacts with the Pridorozhnaya formation and consists at 85% of the effusive units (basalt, trachybasalt, and andesibasalt) accompanied by sills of subvolcanic dolerite. The remaining 15% is tuff-conglomerate, red sandstone, tuff, tephra; rare fossils of rhyniophyte flora are noted. In the Matarak-Shunet area the Lower Matarak subformation overlies, with a gradual transition, the Upper Matarak subformation which consists of sandstone, gravelite, siltstone, tuff, and basalt with a total thickness of 400 m (250 m in the stratotype). Flora of Rhyniophytes is abundant; there are rare fossils of Eurypterides, and Phyllopod valves. The section of the Byskar series in this area is crowned by the Shunet Formation, with a thickness of 340 m, consisting of

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yellowish-gray tuff-pelite, tuff-argillite, tuff, basalt, and rarely limestone. This suite also contains rare Rhyniophyte remains. It conformability overlies the Upper Matarak Formation and is disconformably overlain by the red colored Aramchak Formation of indeterminate age (Lower or Middle Devonian). Despite the detailed study of the Byskar series, there is no complete understanding among specialists on many issues of a theoretical and practical nature. Currently there is debate about whether the bedrock mafic units of the Byskar series are volcanic or subvolcanic; if the basaltic units are intrusions rather than extrusives then it is more difficult to make a reliable correlation between even closely located stratigraphic sections. These topics can be debated at the outcrops during the excursion.

3

Guided Traverses

The traverses cover the entire stratigraphic section of the Byskar series, from the Lower Matarak subformation to the Marchengash Formation. Of course, due to lack of time, the study of outcrops will be “point-like”, and the materials of the “Guide” should be used as a reference tool for the broader picture. Traverses No. 1–3 are focussed on the material compositions of the basal part of the series which vary laterally—essentially basaltic in the Matarak-Shunet area and alkaline-silicic in the Shira–Marchengash area. There also is debate about the affinity of the bedded mafite of the Lower Matarak subformation. Traverse No. 4 introduces the excursion participants to basaltic magmatism at the base of the terrigenous section of the Pridorozhnaya Formation, where the intrusive channel (neck), controlling the distribution of the basaltic flows, is preserved. Traverse No. 5 as it demonstrates not only the features of the volcanogenic-sedimentary section of the Byskar series in the middle part of the stratigraphic column, but also the unique locations of the “Sokhochul” solid (resin) and viscous (malthite) bitumen of natural (and man-made origin). Traverse No. 6 focuses on the internal structure of the basalt flows of the Marchengash formation, completing the stratigraphic section of the Byskar series, as well as showing the peculiarities of the interrelationships of the red-colored “intra formational” sediments and the basalt flows. This traverse is of fundamental importance, since papers have been repeatedly suggested that these mafic rocks of the Marchengash formation actually consist of a series of parallel intrusive bodies rather than flows. If this reinterpretation were correct then this formation (defined

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on the basis of these being flows) would be invalid, and then this formation name should be removed from the stratigraphic column (Fedoseev et al. 2002). Participants of the traverse will have an opportunity to develop their own opinions on this issue. Traverse No. 7 introduces the excursion participants to the youngest portion of early Devonian volcanism that is located in the area of the field school. This magmatism is expressed as a series of dikes of trachy-rhyodacite composition, which can be hypothesized to have been the feeders for younger volcanics that are not preserved in the field school area, and not currently recognized elsewhere either. Let us consider in detail the proposed excursion traverses, the locations of which are shown in Fig. 1 (green numbers).

4

Traverse No. 1

The distance from the TSU field station is 35 km on good highways. The purpose of this traverse is to familiarize participants with the occurrence and the variety of the mafic rocks of the lower subformation of the Matarak formation (D1mt1) of the Matarak-Shunet area. The traverse begins on the northern shore of Matarak Lake (479.7 m), and finishes at the Mount Shunet (621.5 m), a traverse length of 1200 m. In 1950 this was established as the stratotype section for the Lower Devonian Matarak and Shunet Formations and was briefly described (Meleschenko, 1953). It was studied in further detail by Krasnov and Ratanov (1974). In the course of the excursion traverse, which runs transverse to the strike of geological structures, effusives (mafic rocks) and subvolcanic rocks (dolerite) of the Lower Matarak subformation, with few layers of pelitic-psammitic composition, are revealed (from bottom to top). Higher up the section, these formations are covered by terrigenous deposits of the Upper Matarak subformation (D1mt2) with abundant fossils of the Early Devonian flora (rhyniophytes) and with the marker horizon of tuff and tephra on the Mount Shunet. A complete schematic section of the lower subformation of the Matarak formation in this area was compiled by Khomichev et al. (2008) in a section slightly east of Traverse 1 and can be presented as follows. On the granitoids of the pre-Devonian basement (from the bottom up) occur:

Guide for Field Geology of the Lower Devonian Byskar … 1. Burgundy-red tuff and volcanic conglomerate 2. Black dense crystalline diabase representing, obviously, the sill 3. Thin horizon of gray and dark gray sandstone, siltstone, gravelite, marl and limestone, facies replacing each other 4. Fine crystalline dolerite sill 5. Cherry brown basalt, lava-breccia, tuff 6. Black dense fine-crystalline basalt of intrusive appearance (sill?) 7. Covered interval 8. Black dense crystalline dolerite 9. Cherry brown basalt, amygdaloidal and vesicular 10. Dark dirty gray (to black) and reddish-brown basalt with spherical structures (pillows?), with tectonic cleavage 11. Cherry-red and red-brown basalt similar to layer 9 12. Covered interval 13. Black dense dolerite (sill) 14. Covered interval

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8–9 m 7– 10 m 2m 15 m 7m 20 m 40 m 15 m 15 m 35 m 3-4 m 13 m 15 m 30 m

The total thickness of the subformations in this section is 230 m. The proportion of basalt flows in the section is 31%, subvolcanic dolerite 32%, sedimentary layers 1%, and covered intervals 36%. Stratigraphically above are, gray sandstone, siltstone, and mudstone of the Upper Matarak subformation which contains Rhyniophyte flora. The geological section of the Lower Matarak subformation that was compiled during GDP-200 (second generation of geological mapping of Russia) is located 25 km to the northeast of the Lake Matarak (Sekretaryov et al. 2015) and shows that the total thickness of the subformation increases dramatically from *300 m in the stratotype section to 900 m on the Skalistyi Ridge. The Lower Matarak subformation consists of an alternation of basalt and trachybasalt, separated by interlayers of sandstone and mafic tuff. Rare beds of trachyandesite and trachyte are noted. The proportion of dolerite in this section is minimal. In the literature it has often been proposed that all Matarak-Shunet mafic units are intrusive dolerites (sills), combined into the so-called Kuzmensky intrusive complex, and that there are no basalt flows in this area (e.g., Sekretaryov et al. 2015, etc.). However, based on field observations, the present authors note that many Lower Matarak mafic unit have rubbly tops (a’a flows?), abundant amygdaloidal and vesicular textures, lateral color fluctuations—from dirty gray to cherry

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red, all features suggestive of a volcanic flow. We interpret that the magmatic units of the Lower Matarak subformation are dominated by mafic flows with some subvolcanic dolerites also present and that the proportion of dolerite is maximum in the area of the stratotype and decreases to the east. Judging by the sharp increase in the thickness of the Lower Matarak subformation to the northeast of Lake Matarak, it can be assumed that the center of the Early Matarak basaltic activity was located in the area of the modern Skalistyi Ridge in the spurs of the Batenev Mountain.

5

Traverses No. 2, 3

These traverses are located 6–8 km east of the TSU field station and are reached by dirt roads with Traverse 2 being on the eastern side of Traverse 3. The terrain is slightly hilly with absolute elevation in the range from 522.5 m to 620 m. The length of each traverse does not exceed 1500-1600 m. The purpose of this traverse is to familiarize participants with the alkaline-silicic rocks of the Lower Matarak subformation (D1mt1) of the Shira–Marchengash area. Traverse No. 2 (Eastern) begins at an erosion “window”, revealing the pre-Devonian granitoids of the Tigertysh complex basement, which are disconformably overlain by alkaline-silicic rocks. A schematic section along the traverse line (Fig. 2) can be summarized as follows (from bottom to top):

Fig. 2 Geological section and stratigraphic column in the left bank of the Tuim River (East section). 1—Pridorozhnaya Formation, 2—Lower Matarak subformation, 3—Tigertysh granite complex, 4—sandstone, siltstone, mudstone, 5—conglomerate, gravelite, coarse grained sandstone, 6—tuff of trachyte and trachyandesite-trachyte composition 7— trachyandesite and trachyte lavas; 8—subvolcanic dolerite, 9—granite, granodiorite, 10— fossil flora locations. See Fig. 1, green number 2 for location

Guide for Field Geology of the Lower Devonian Byskar … 1. A platy psephite-psammitic litho-crystal-vitroclastic trachyrhyolite-trachyandesite-trachyte tuff (lilac-colored in places, ashen-gray with pinkish and orange spots along the cracks), interlayered with lenses of red-brown coarse platy trachyte. In the central part of the thin black dolerite sill 2. Light gray polymictic sandstone with aleurolite and argillite interlayers with poorly preserved Rhyniophyte flora 3. Slate purple-gray tuffs of trachyte, sometimes with ignimbrite macrostructures

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250 m

14 m 106 m

The total thickness of the sediments along the section is 370 m. Stratigraphically higher, one can observe the inconsistent occurrence of clastic terrigenous rocks of the Pridorozhnaya Formation (D1pr) on the irregular surface of the underlying volcanogenic-terrigenous formations. Traverse No. 3 (Western) runs alongside the “Maral” farm at a close distance (* 1.5 km) to the previous one (Traverse 2) but has a more complex structure (Fig. 3). It is represented by a dense alternation of trachyandesites and trachytes lava flows with tuffs of the trachyrhyolite-trachyandesite-trachyte composition, which are disconformable to the granosyenites of the Yulinsky (?) basement complex and covered by coarse-grained terrigenous rocks of the Pridorozhnaya formation. The total thickness of the Lower Matarak subformation in this section is

Fig. 3 Geological section and stratigraphic column in the “Maral Farms” area (West section). 1—Pridorozhnaya Formation, 2—Lower Matarak subformation, 3—Yulinsky syenite-granosyenite complex, 4—conglomerate, gravelite, coarse-grained sandstone, 5 — trachyte, 6 — tuff of trachyandesite-trachyte composition, 7—trachyandesites, 8— trachyrhyodithite, 9—subvolcanic dolerite, 10—granosyenite, nordmarkite, granite. See Fig. 1, green number 3 for location

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600 m (without subvolcanic dolerites). The ratios of the main rock components are as follows (in decreasing order): tuffs (46%), trachytes (37%), trachyandesites (17%). Single sills of intrusive dolerite appear in the upper part of the section. The macroscopic appearance of these listed varieties of volcanic units are similar to those in Section No. 2. These units are lilac-gray, maroon-brown, and yellow-brown formations with distinct fine, and less often coarse platy jointing. Often present is selective reddening of the plagioclase porphyritic phenocrysts (in lavas) and pyroclasts (in tuffs), often along cracks and leading to the appearance of a mosaic of orange and brick-red spots (Fig. 4a, b). This appearance may be due to the processes of auto-metasomatic albitization, since the secondary albite is always brightly-colored red with thin hematite dust during microscopic examination in transmitted light, which was first noticed by Bognibov (1974). Another proposed explanation for the origin of spotted appearance is the burn effect of dry hot gas jets moving along cracks during the cooling of lava flows (Peshekhonov et al. 1991). There are different ratios of tuffs and lavas in the two adjacent sections, with an almost twofold increase in the total thickness of the volcanism in the western direction, clearly demonstrating the extreme facial variability of volcanic rocks even over this short lateral distance.

Fig. 4 Albitization of tuffs of the Lower Matarak subformation concentrated along glassy lenses (a) and along cracks (b)

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Note that the above-described geological sections of the Lower Matarak subformation consisting of lavas and pyroclastics of the alkaline-silicic composition are incompatible with the basaltic section of the Matarak-Shunet section in terms of formal features (see the excursion traverse No. 1). This difference led to the interpretation of the existence of multiple stages of volcanism on a short spatial interval (15–20 km). Five separate volcanogenic strata of different compositions are currently recognized in the subformation (Peshekhonov et al. 1991; Parnachev and Vasilyev 2007). Comparison of the eight stratigraphic columns compiled by TPU (Tomsk Polytechnical University) geologists (Vasiliev et al. 2006) shows a steady change from the Lake Matarak area to Lake Beryozovoye, with a decrease in the thickness of “Lower Matarak” mafic units and gradual increase in lavas and pyroclastics of trachyrhyolite-trachyandesite-trachyte composition. The mafic units completely disappear upon reaching the left bank of the Tuim River (see the description of the eastern and western traverses, 2 and 3, respectively). In our opinion (Makarenko et al. 2018b), this pattern indicates that spatially-separated volcanic units of the central type (Karysh paleo-volcanic structure with subvolcanic trachytes of the vent (?) facies) and the fissure volcano type (the area of the modern Skalistyi Ridge) were active simultaneously in the Early Matarak time. In the first case, alkaline-silicic and acid magmatism are dominant. In the second case the basaltic compositions dominate. The most complex relationships of the mafic, intermediate, and acidic rocks should be expected where both volcanic types are abundant, as is observed in Lake Beryozovoye area.

6

Traverse No. 4

This traverse is located on the southwestern slope of the hill with altitude of 635.4 m near the southern margin of the village Shira, a 9 km distance from the TSU field station along a dirt road; the length of the traverse is 0.5 km. The purpose of this traverse is to study the basaltic magmatism in the basal horizons of the Pridorozhnaya formation stratotype (D1pr), the full section of which was published in Makarenko et al. (2017). Here is an abbreviated description of the section (bottom to top):

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1. Basal conglomerate is variegated boulder, pebble, interbedded with gravelite and gravelly sandstone. The lamination is distinct. The matrix of coarse clastic rocks is sandy-silty greywacke. The size of individual boulders reaches 50–60 cm. Composition of the fragments: 80%—well-rounded fragments of psephite-psammitic and agglomerate lithocrystalline tuff of trachyrhyolite-trachyandesite-trachyte composition, 15%—fragments of trachyte and trachyandesite lava, 5%—granite, monzodiorite 2. Pinkish-gray thick-slabby gravelite with angular fragments with “floating” (matrix supported) pebbles (5-7 cm) of trachyte, trachyandesite, with aleurite filler 3. The basalt is dark gray, more rarely greenish gray olivine-plagioclase, porphyritic in the central part, with amygdaloidal and vesicular structures. The phenocrystals are composed of plagioclase; olivine is completely replaced by iddingsite. In the lower part is an olivine-pyroxene-plagioclase dolerite sill with fresh olivine phenocrysts 4. The interbedded gravelite, coarse-grained sandstone, siltstone with thin layers of argillite with lenses of gravelite and conglomerate. Secondary carbonatization and silicification are noted, the remains of fossil plants are contained on three levels. The following species dominate: Margophyton goldschmidtii (Halle) Zakharova, Chakassiophyton krasnovii Ananievet Krasnov 5. Gray limestone and ferruginous limestone with stromatolite bumps Collenia undosa.

more 76 m

16 m

80 m

124 m

1m

The total thickness of the subformation in this section is 297 m. The share of mafic units is 27%, terrigenous and carbonates rocks—73%. A volcanic neck (representing a paleovolcano) is observed on the steep slope near the mafic flows mentioned above in point 3. In our opinion this paleovolcano is spatially and genetically linked to these mafic units of the Pridorozhnaya formation’s stratotype. The morphological parameters of the neck are as follows: the height above the modern erosion surface is 8–10 m, the cross-section diameter is 20–25 m, and the shape is sub-cylindrical. The neck is composed of mega-porphyritic dolerites (labradorite porphyries) with large (2–4 cm) abundant plagioclase crystals immersed in the main olivine-clinopyroxene—plagioclase groundmass with a dolerite microtexture. As can be seen from Fig. 5, the neck’s dolerites are cut by a low-amplitude submeridional fault, which is probably associated with intense hematitization of both dolerite and basaltic blanket facies. Note that the mafic volcanic rocks surrounding the neck are, in places, saturated with volcanic bombs of various sizes, up to very large (>20 cm in diameter), which emphasizes the explosive nature of the volcanism of this location. The general

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Fig. 5 Portion of the geological map of the North-Sokhochul section (Parnachev and Vasilyev 2007), with modifications. 1—Quaternary deposits; 2–3—Pridorozhnaya Formation: 2—Middle subformation, 3—Lower subformation; 4—interbedding of different-grained sandstone, siltstone, and argillite with rare lenses of gravelite and conglomerate; 5—basalt, trachybasalt of the volcanic cover facies; 6—conglomerate, gravelite; 7—subvolcanic dolerite; 8—marker horizon of stromatolite limestone; 9— structural lines; 10—tectonic discordances (faults); 11—the attitude of layering; 12—fossil Propteridophytes (Rhyniophytes). See Fig. 1, green number 4 for location

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Fig. 6 Subvolcanic neck cutting the Lower Pridorozhnaya subformation of the Shira-Marchengash area. Inset photo on the left:—the internal structure of the roof of a volcanic paleo flow with large bombs (red outline); inset photo on the right: subvolcanic megaplagioclase porphyritic dolerite (labradorite porphyry) of the intrusive feeder channel

view of the neck, as well as the macroscopic appearance of dolerites and basaltic units with volcanic bombs are illustrated in Fig. 6. Of the other features, it is possible to note the rapid pinch-out (to the west) of basalts, which are replaced by terrigenous rocks along strike and contain (at a distance of nearly * 300 m from neck) the fossil rhyniophytes which are unique in their excellent degree of preservation as described by Prof. A. R. Ananiev and his students (Zakharova and Ananiev 1990).

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Traverse No. 5

This traverse is located on the left side of the Sokhochul valley. The distance from the TSU field station is 6 km along a dirt road.

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Purposes—(1) field observations of the features of the volcanogenic-sedimentary section of the Middle Pridorozhnaya subformation (D1pr2); (2) detailed observation of the unique location of natural solid bitumen (resin) in lava-breccia and in the amygdaloidal “Pridorozhny” basalts; (3) bitumen “hat” of man-made origin. The beginning of the traverse is on the southern slope of a hill (585.5 m), with a spectacular staircase of cuestas extending over an elevation range of *70 m. This section (Bazhenov et al. 1992) reveals the Middle Pridorozhnaya subformation at almost full thickness, and consists of interbedded sedimentary rocks (sandstone, siltstone, and rarely limestone) with paleo flows (basalt, trachybasalt, and andesibasalt). The flows exhibit a practically complete set of traditional “effusive” signs: an abundance of slaggy and amygdaloidal zones, the presence of lava-breccia, areas with slab parting and spherical parting. Cracks and cavities contain numerous inclusions of solid bitumen (resin). The thicknesses of individual lava paleo flows do not exceed 17 m, and lava-breccia is 8 m, the length of bodies is up to 600–700 m. The proportion of basaltoids in the section is 44%, and sedimentary rocks is 56%. The quantity of subvolcanic dolerites is minimal. On this traverse we observe one body with a “micro-gabbro” appearance and with high mechanical strength. In the stratigraphic section (Fig. 7) ordered from bottom to top: 1. Sandstone cream-color irregular coarse-grained

10 m

2. Basalt dark gray color, almost black 3. Cream sandstone, similar to layer 1, with aleurolite interlayers 4. Lava-breccia basalt dirty lilac color with nests of bitumen 5. Basalt massive, fresh, greenish-black color, with globular jointing 6. Cream sandstone of various grains with aleurolite and argillite interlayers. There are rhyniophyte fossils in the upper part of the sandstone layer 7. Massive greenish-gray basalt 8. Cream-colored sandstone and siltstone 9. Massive fresh greenish-black basalt 10. Basaltic lava-breccia with lilac and muddy green color, highly fragmented. Small bitumen nests located in the calcification zones 11. Sandstone light-layered, variously grained, creamy, with pink and yellow tinge 12. Limestone grayish-brown, flag-like, fine-crystalline 13. Cream-colored sandstone with interlayers of greenish-gray calcareous siltstone

12 m 30 m 8m 11 m 44 m 16 m 11 m 17 m 5m 8m 0,7-1 m 38 m (continued)

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(continued) 1. Sandstone cream-color irregular coarse-grained

10 m

14. Massive, fresh, greenish-black basalt 15. Basalt slaggy zone 16. Basalt similar to layer 14 17. Basalt, amygdaloidal, greenish-gray; in the upper part of the layer, voids are filled with black bitumen. The bituminization zone can be traced up to 500 m to the west; and, in the eastern direction it quickly disappears 18. Tuff of trachyandesite-trachyte composition of lilac color with interlayers of tuffaceous conglomerate and gravelite (at the base of the upper Pridorozhnaya subformation)

11 m 4m 14 m 13 m

7m

The total thickness of the volcanic-sedimentary deposits in the section is 260 m. There are two morphological types of bitumen discharge. Bitumens in crushed, silicified, hematitized (less often limonitized), porous and cavernous lava-breccia fill voids (vesicles) of round and irregular shape, up to 4 cm in size, and are represented by black shiny substance in association with calcite, quartz, prehnite, malachite—layers 4, 10 of the above section (Fig. 8a). Bitumens in amygdaloidal greenish-gray basalts are observed in the form of abundant black shiny inclusions ranging in size from 0.5 to 5 cm (rarely more) in voids of various shapes (from rounded to lens-shaped). The amount of bitumen sometimes amounts to 20% of the rock volume, they are accompanied only by calcite, which either occurs in the central part of the bitumen ‘nests’ or, on the contrary, composes the fringes around the asphalt bitumen (Fig. 8b). Bitumens of both types are black with a brilliant, shell-like fracture, and when heated do not melt or soften. Compositionally they are asphalt pyrobitumens— kerites (impsonites). They are formed as a result of thermal destruction of organic matter from the host rocks (limestone, sandstone), followed by sublimation by hydrothermal solutions. The mobile bituminous substance was deposited in cracks and open cavities along with other minerals of hydrothermal genesis: calcite, quartz, malachite, prehnite (Bazhenov et al. 1992). There is another point of view on the origin of hard bitumens of the Sokhochulsky location, which postulates the genetic connection of bitumens with an endogenous oil source, which may indicate the potential oil-bearing capacity of the North Minusinsk Depression (Silaev et al. 2017). In the immediate vicinity of the above-described solid bitumen, there is also the occurrence described in Serebrennikova et al. (2003). It was established that this bituminous “hat” with a total area of 85–90 m2, located among the fractured basalts, has a technogenic character and emerged at the beginning of the XXI century as a result of a one-act discharge of waste oil (motor oils) onto the earth’s

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b Fig. 7 Map of the geological structure of the bitumen occurrence west of the village of

Shira and the cross-section along the line A–B–C (Bazhenov et al. 1992). 1—basalt and trachybasalts 2—lava-breccia and rubbly zones of basalt; 3—subvolcanic dolerite; 4— cream-colored sandstone and siltstone; 5—limestone; 6—trachyandesite-trachyte tuff (tuff “cap visors”); 7—bitumen “hat”; 8—areas with solid bitumen; 9—the attitude of layering; 10—locations of Proteridophyte (Rhyniophyte) flora. Inset diagram, upper right: sketch of a crack (5 cm wide) in basalt lava-breccia filled with bitumen: 1—basalt lava-breccia; 2— silicification zones; 3—bitumen “nests”; 4—streaks of malachite; 5—fault zone. See Fig. 1, green number 5 for location

Fig. 8 Solid bitumen in the lava-breccia (a) and in the amygdaloidal basalt (b) in the Middle Pridorozhnaya subformation in the Shira-Marchengash area

surface, which soaked the soil to a small depth—up to 5–7 cm (Makarenko et al. 2013). Over time, the viscous nature of the “hat” underwent a significant transformation, which led to a change in the color and consistency of bitumen from saturated black, asphalt-like to dark gray, coal-like, sooty, and dusty. The location of the bitumen “hat” is shown in Fig. 7. As a result of the anthropogenic spill of oil products, the concentration of harmful substances inside the hat considerably exceeds the existing environmental standards. So it is advisable to reclaim this, small, but environmentally harmful formation, which is currently used in field trips as a good example of unacceptable economic activities. Such local spills of petroleum products, along with uncontrolled garbage dumps on the outskirts of the village of Shira, pose a danger to the environment, grazing, tourism and recreation areas. The very high contents of lead, barium, manganese and other harmful elements in such spills are dangerous especially since they can contaminate lakes, rivers.

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Traverse No. 6

This traverse is located 1.5 km north-west of the Shira train station in a hilly terrain with maximum relative elevations of up to 70–75 m, and with absolute elevations of up to 577.1 m. The distance from the TSU field station is 15 km along a hard-surface road (7.5 km on the ground). The purpose of this traverse to familiarize participants with Lower Devonian mafic rocks of the Marchengash Formation (D1mr, as well as their relationships with sedimentary rocks. Along this traverse, numerous lava flows (basalt, trachybasalt, andesi basalt, trachyandesi basalt) of various thicknesses from 5–7 to 30–40 m can be observed. They have blocky top contacts; an abundance of brown (lilac-colored) slag and amygdaloidal zones; the presence of lava-breccia, tuffs, as well as interlayers of differently fragmented red-colored sedimentary rocks; elements of the columnar jointing, horizontal joints, minor bulbous texture, low mechanical stability, leading to the appearance of secondary fracturing. Note that the crack and cavities in basaltic units (sometimes very large) are filled with various secondary minerals: chalcedony, calcite, chlorite, prehnite, zeolites, etc. The latter two minerals often form spectacular clusters. In addition to effusive mafic units, there are also sills of subvolcanic dolerite distributed extremely irregularly in space, from single bodies to local clusters. Intrusive sills are characterized by relatively flat contact surfaces (without slag “hills” and lumps); dense uniform structure, high mechanical strength, full-crystal (“microgabbro”) macrotexture; lack of lava-breccia and volcanic bombs; weak development (or complete absence) of amygdaloidal and vesicular textures; increased magnetism; and a specific structure of weathering surfaces (“crusts” of the desert “varnish”). Note that the various macroscopic appearances of volcanic and subvolcanic varieties of mafic units are clearly visible even after a quick inspection of the outcrops (Figs. 9 and 10). Of particular interest, in our opinion, are observations on contact relationships between terrigenous and volcanogenic rocks, which can be studied both in the numerous fragments of the mafic units exposed in outcrop near high-voltage power transmission towers and in small open-cast mines, where low-thickness (up to 10 m) lenses were emplaced in red-colored tuffs–sedimentary rocks filling the irregularities of the intensely dissected ancient volcanic relief. It is appropriate to give several examples illustrating the more “young” character of sedimentary material with respect to host mafic rocks (Figs. 11, 12 and 13).

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Fig. 9 Subvolcanic dolerite in the Marchengash Formation of the Shira-Marchengash area

In sample 1 (Fig. 11), terrigenous volcanic rocks fill a small pocket in the top of the flow of trachybasalts with porous and amygdaloidal textures. The contact area of sedimentary and volcanic rocks is uneven, with small protrusions and cavities). One of these depressions (1) is in the central part of the sample; it is filled with psammitic sedimentary material without any signs of thermal processing by the mafic unit. In the lower left part there is a small inclusion (2) which looks like sandstone xenolith in trachy basalt. In fact, this is a small pore, filled not with secondary calcite, but with terrigenous material of later (post-emplacement) origin. A possible mechanism for the formation of such “xenoliths” can be observed in the left upper part of Fig. 11, where a small square void is completely filled with terrigenous material, which is connected with the main depression only by a thin link (3). If this link would be absent, then a fully formed pseudo xenolith would be observed. A characteristic feature of this sample is the presence of gradational layering of terrigenous rocks: coarse-grained sandstone with fragments of effusive rocks of varying degree of roundness at the base of the sedimentary basin, fine and

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Fig. 10 Trachybasalt of the volcanic cover of the Marchengash Formation with spherical jointing, highlighted by secondary hematitization

medium-grained sandstone with lenses and argillite micro-layers in the middle and upper parts parallel to the upper boundary of the effusive rock. Sample 2 (Fig. 12). Fine-grained volcanic sandstone is in contact with the uneven rough surface of amygdaloidal and vesicular basalt. At the base of the sedimentary lens, there is an active filling with the terrigenous red-colored non-layered material of any, even small, negative “pits” and cavities, which leads to the leveling of the roof of the paleo-flow. After the “filling” of all cavities then continued sedimentation leads to sandstones with horizontal microlamination of a parallel flattened surface which are visible because of alternation of layers of different degrees of coloring, mainly due to iron hydroxides. Sample 3 (Fig. 13). In the lower part of the figure, there is a convoluted contact between the amygdaloidal basalt (1) and brown mudstone (2), which not only traces the irregularities of the roof of the effusive flow, but also forms small holes, cavities, and cracks. In the middle part, light gray fine-grained quartz sandstones (3) overlie the mudstones, which, in turn, are covered by argillite (4), similar to layer 2. In the

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Fig. 11 Terrigenous deposits associated with basaltic units of the Marchengash Formation (sample 1)

center of the figure, there is deformed (broken) layering, namely, a horizontal layer of mudstone, with a thickness of 1 mm (6) knee-shaped bends at an angle of 35°, connecting with the “lower” mudstones. This, in our opinion, is related to the gravitational sliding downslope of a weakly consolidated sediment, down to the base of the large cavity (relics of which are seen in the figure as black depressions). This was formed in the top of the ancient lava flow and partially filled with terrigenous material. Approximately 2.5 cm above the section, a few layers of mudstone (5) which are flat and do not change in dip, i.e. they were formed after the final filling and compaction of terrigenous sediments within the cavernous cavity. The above examples, in our opinion, clearly indicate the cold contacts of uneven effusive crusts with “young” terrigenous rocks. This is not consistent with the views of some researchers (Krasnov and Fedoseev 2000; Fedoseev et al. 2002;

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Fig. 12 Terrigenous sediments associated with basaltic units of the Marchengash Formation (sample 2)

Fedoseev 2015), who believe that all sedimentary deposits located within the Marchengash formation are an “ancient” sedimentary matrix subsequently injected by numerous dolerite sills constituting the framework of the Marchengash formation. Consequently, according to the authors of these publications, sedimentary rocks could be preserved only as residues and xenoliths in the total intrusive mass, and there would be no effusive rocks in the Marchengash lava field at all. A criticism of such ideas is contained in (Makarenko and Kotelnikov 2018a). Summarizing the above, we note that: 1. The volcanic rocks of the Marchengash suite are represented by basaltic flows separated by slaggy and amygdaloidal zones, as well as interlayers of terrigenous rocks. They possess a complete set of features that are characteristic of classical lava formation. 2. Subvolcanic dolerite is distinguishable from volcanic rocks at the macroscopic level, and their share in the total mass of magmatism is insignificant (according to our estimates, on average no more than 10–15%). 3. Red sedimentary rocks with respect to host mafic units have a younger age. They arose when the loose terrigenous material filled any negative surfaces— from cracks to cavities in the top of lava paleo-flows, to large irregularities of the “ancient” relief, carved by paleo-rivers and streams.

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Fig. 13 Terrigenous sediments associated with basaltic units of the Marchengash Formation (sample 3)

9

Traverse No. 7

This traverse is located 2.5 km from the TSU base in the “Krasnaya Gorka” (Red Hill) tract on the steep slope of the left side of the Sokhoshul valley. The traverse length is hundreds of meters. The purpose is to get acquainted with the youngest Early Devonian volcanism at the training ground.

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In the traverse, one can observe the northern end of a set of closely-spaced dikes (rarely small stocks) of north-western orientation with a thickness ranging from 5–7 to 10–20 m, cutting almost all the rocks of the Byskar series. Dike-shaped bodies, sometimes with distinct columnar jointing, can be traced along both sides of the Sokhochul valley over a total length of up to 4–4.5 km (see Fig. 1). The rocks have a characteristic brick-red color of varying intensity, which leads to the appearance of spotty and banded macrostructures. They contain small phenocrysts of albitic plagioclase, less often of potassium-sodium feldspar, and also of quartz. The bulk of the microfelsitic texture is intensely colored red with fine hematite. The absolute age of the Krasnaya Gorka dikes, determined by the Rb-Sr method, when conducting the GDP-200, is 398 million years (Sekretaryov et al. 2000). The contact of dikes with host rocks (basalt, sometimes tuff) are subject to intense quartz-feldspar metasomatism with the occurrence of silicified and albitized zones, which leads to the appearance of veinlets, and nests, which consist mainly of aggregates of granoblastic and aligned grains of secondary quartz. Less commonly, well-formed metacrystals of this mineral are observed. There are single veins of quartz-barite composition. The width of the dike is variable and in the bulges can reach 100–150 m. A general view of outcrops of the dike-like bodies is shown in Figs. 14 and 15.

Fig. 14 View of the “Krasnaya Gorka” (marked by an arrow). In the foreground are the trachyrhyodacites on the right side of the Sohochul river

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Fig. 15 Outcrop of trachyrhyodacytes. Columnar jointing is clearly visible

In earlier publications these dikes were described as “plagioporphyries” (Bognibov 1974), however, due to the uncertainty of this term, it was recommended not to use it even when macroscopically diagnosing rocks (Makarenko and Parnachev 2005). In the TAS diagram, fresh rocks occupy a moderately alkaline trachy-rhydacite field, and quartz—feldspar metasomatites are rhyolite-trachy-rhyolite. Thus, the subvolcanic rocks of the Krasnaya Gorka should be certified as trachy-rhyodacites, or as trachy-rhyodacites porphyries, with an increased content of feldspathic phenocrysts, and for metasomatites it is desirable to add the “meta” to the root name. On geophysical maps the trachy-rhyodocites and their contact halos form distinct negative magnetic anomalies and are characterized by zones of elevated (relative to the background) values of U, Th, and K. In conclusion, we emphasize that this swarm of alkaline-silicic dikes can be hypothesized as a supply channel for “young” silicic volcanic rocks that were not preserved in this area (Parnachev and Vasilyev 2007).

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Key Outcrops

This category includes a series of primary outcrops that are important for constraining the geological age of the Byskar series, as well as for detailed correlation of Lower Devonian sections with closely-spaced strata in the Shira-Marchengash and Matarak-Shunet areas. There are three types of outcrops of this kind: (1) with Early Devonian fossil flora; (2) with lithostratigraphic marking horizons; and (3) with biostratigraphic markers. In Fig. 1 the most important outcrops are shown; it is recommended to get acquainted only with some of them, namely with the main exits along the dirt road —the TSU field station—Transport street, village Shira (10 km long), where all three types of outcrops are widely represented. We briefly describe the main features of the three selected types. Outcrops with fossil flora are not uncommon, for example, they are found in excursion traverses No. 4 and 5, but the most informative and well-studied is at the Transport Location, discovered by TSU professor A.R. Ananiev in the Lower Devonian Pridorozhnaya formation on the southern outskirts of the village Shira, where he discovered 11 species of rhyniophyte flora with two dominant species Margophyton goldschmidtii (Halle) Zakharova and Jenisseiphyton rudnevae (Peresvetov) Ananiev (Zakharova and Ananiev 1990). The general macroscopic appearance of fossil plants from the Transport and Kazarma site is shown in Figs. 16 and 17. The Transport and other locations (Kazarma, Pridorozhnoye, Matarak and others) are in the middle part of the stratigraphic sections of the Byskar series. Unfortunately, the basal and upper parts of the sections lack Early Devonian flora. However, this flora was later found by N. A. Makarenko in the lens of the sandstones of the Marchengash Formation and by S. A. Rodygin in the Lower Matarak subformation, which allowed us to give a paleontological characteristic for almost the entire stratigraphy of the Byskar series. The only feature that was sterile with respect to the paleontological finds was the Aramchak Formation, whose age is still being debated (Emsian or Eifelian). The above data provided a reliable regional biostratigraphic correlation of the Lower Devonian formations of two areas, for which a Pragian— Emsian age of the beds within the Saghlin and Tashtyp horizons has been determined (Krasnov et al. 2018). A wonderful collection of fossil flora of the training ground can be found in the geological museum in the TSU field station near Shira. Lithostratigraphic marking horizons (tuff “cap visors”) are established in the middle and upper parts of the stratigraphic sections of the Byskar series in two sections (Makarenko et al. 1982). They are most fully represented in the Upper

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Fig. 16 Propteridophytes (rhyniophytes) Sawdonia ornata (Dawson) from sediments of the Pridorozhnaya Formation (Transport location)

Pridorozhnaya Formation of the Shira-Marchengash and in the Upper Matarak subformation of the Matarak-Shunet areas. These are the rocky outcrops of the lenticular bodies of red-colored rocks of various lengths (up to 800–900 m) and low thickness (up to 10 m), occupying two stratigraphic levels in the section and having a complex internal structure: lenses, spots of tephra and volcanic-sedimentary rocks (tuff-conglomerate, tuff-gravelite, tuff-sandstone). The simultaneous presence of angular and rounded fragments in rocks indicates a partial erosion of pyroclastics (tephra) synchronous with two episodes of large-volume volcanism. The complex structure of tuff “cap visors” led to an ambiguous interpretation of the lithology of these formations. An example is the well-known outcrop in the city of Shunet, whose lithological characteristic have been interpreted differently by different authors: tuff (Krasnov and Fedoseev 2000; Krasnov and Ratanov 1974; Makarenko et al. 1982); volcanic conglomerate (Krasnov and Ratanov 2000); lava conglomerate (Khomichev et al. 2008); lahar breccia (Parnachev and Vasilyev 2007); diamictite breccia, intraformational conglomerate with a volcanic matrix (Krasnov and Fedoseev 2000). The general view of the tuff “visors” of the Shira-Marchengash and Matarak-Shunet areas is

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Fig. 17 Propteridophytes Drepanophycus gaspeanus (Dawson) and Jenisseiphyton leclercae Ananiev et Zakharova from sediments of the Pridorozhnaya Formation (Kazarma location)

presented in Fig. 18, 19. The location of the main outcrops of tuff “visors” is shown in Fig. 1. Excursion participants are invited to explore several typical outcrops along the road: TSU field station—Transport Street of the Shira village. At least four tuff “visors” of the upper stratigraphic level and three levels of the lower one are exposed for 6 km along the road. In addition, at the end of excursion traverse No. 5, one can also see the tuff “visors” of the base of the Upper Pridorozhnaya subformation, and in the Matarak-Shunet area it is advisable to get acquainted with the lithostratigraphic marker of the Shunet Mount located among the Upper Matarak subformation deposits. Biostratigraphic markers are represented by stromatolite limestone (Pridorozhnaya Formation) and terrigenous layers with fauna (Upper Matarak subformation, Pridorozhnaya Formation). In the Shira-Marchengash area, the stromatolite

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Fig. 18 Mount Shunet of the Matarak-Shunet area. In the foreground, sediments of the Upper Matarak subformation (D1mt2), in the rear—a marker lithostratigraphic horizon (tuff “cap visor”). See Fig. 1, green number 1 for location

limestone occupies two stratigraphic levels: the lower one at the border of the Lower and Middle Pridorozhnaya subformation and the Upper one inside the lithostratigraphic pack, the base of which coincides with the lower tuff “visor”, and the top with the upper tuff “visor”. A total of 12 lenses are present— nine on the lower and three on the upper stratigraphic levels. The length of the bodies is different— ranging from the first dozen, to the first hundreds of meters, and with the thickness being not more than 2-3 meters. They are traced (with interruptions) over a considerable distance, right up to the outskirts of the village Maly Spirin (Makarenko et al., 2018b). The appearance of the organic structures of the form Collenia undosa (defined by S.N. Makarenko) is diagnostic due to the frequent accretion of several “balls” of different diameters (up to 20–30 cm) with shell-like separation and complex layering (Fig. 20a, b).

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Fig. 19 Lithostratigraphic marker horizons (tuff “cap visors”, marked by red arrows) in the Upper Pridorozhnaya Formation (D1pr3) of the Shira-Marchengash area

Fig. 20 Stromatolites of the form Collenia undosa from sediments of the Pridorozhnaya Formation. Appearance (a) and internal structure (b)

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Fig. 21 Ichthyofauna of osteopantic jawless (Osteostracki) of the species Ilemoraspis kirkinskayae Obruchev from sediments of the Pridorozhnaya Formation

Note that the stromatolite limestones are often silicified, which leads to the appearance of secondary chalcedony and chalcedonic quartz. Characteristic organic structures have arisen as a result of fossilization of algal-bacterial communities inhabiting saline reservoirs (Makarenko et al. 2012). In addition to the stromatolite limestone near the hill 536.5 m (see Fig. 1) the fossil ichthyofauna (Osteostraci) of the species Ilemoraspis kirkinskayae Obruchev is found in the sandstone of the Pridorozhnaya Formation at the lower stratigraphic level (Rodygin 2006; Sansom et al. 2008). This find is unique, not only because of its excellent preservation (Fig. 21), but also because in the Lower Devonian sediments of Northern Khakassia ichthyofauna remains were not be found previously. In the Upper Matarak subformation of the Matarak-Shunet area, terrigenous layers with fillopods and crab scorpions (eurypterides) are also known occupying two stratigraphic levels, one inside the lithostratigraphic layer, the other at the base of the subformation. These fossil organisms do not form clusters; they are rather miniature and can be missed during a quick inspection of the outcrops. The appearance of the scorpion’s head shield is captured in Fig. 22. Figure 1 shows the location of the most important outcrops with fossil fauna in the Matarak-Shunet and Shira-Marchengash areas.

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Fig. 22 The imprint of the scorpion crab head shield (right) and the counter-imprint (left) in the Upper Matarak subformation deposits on the Matarak-Shunet area

For acquaintance with biostratigraphic markers, the most suitable are stromatolite limestones, which are easily identified, fairly well exposed and can be traced laterally over a considerable distance. Participants of the excursion can get acquainted with the organic remains in the geological museum on the TSU field station (Fig. 22).

11

Sectional Correlation

Lateral tracing of litho- and biostratigraphic marker horizons made it possible to conduct a detailed complex correlation of sediments of the Byskar series between the Shira-Marchengash and Matarak-Shunet areas (Makarenko et al. 2018b), as well as to chart the stratified correlation of stratotype sections of the Pridorozhnaya, Matarak and Shunet Formations (Fig. 23). It is clearly seen that the Upper Matarak subformation deposits are on the same stratigraphic level with the volcanogenic-terrigenous rocks of the Middle and Upper Pridorozhnaya subformations, and the Shunet Formation is isochronous with the Marchengash basaltic rocks, which actively displace (facially replace)

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Fig. 23 Layer-by-layer correlation of the Lower Devonian formations in the stratotype sections of the Pridorozhnaya, Matarak and Shunet Formations in the Shira-Marchengash (a) and Matarak-Shunet (b) areas (Makarenko et al. 2018b). 1—limestone, marl; 2— sandstone, siltstone, rarely argillite; 3—tuff-aleurolite, tufа-argillite; 4—interbedding of sandstone, conglomerate, gravelite; 5—basal conglomerate; 6—basaltic units of the Marchengash Formation; 7—volcanic rocks of the Lower Matarak subformation: a— basaltic units, b—lava and tuff of trachyrhyolite-trachyandesite-trachyte composition; 8— geological boundaries: a—regular, b—irregular; Litrostratigraphic marker horizons: 9–10— sedimentary units: 9—Pridorozhnaya Formation and the Upper Matarak subformation: a— lower, b—upper horizons; 10—Marchengash and Shunet Formations: a—lower, b—upper horizons; biostratigraphic marker horizons: 11—stromatolite limestone: a—lower, b—upper horizons; 12—terrigenous layers with fauna: a—lower, b—upper horizons; 13—lithostratigraphic marker layer; 14—correlation lines: a—lithostratigraphic markers of the Pridorozhnaya Formation and the Upper Matarak subformation, and b—the Marchengash and Shunet Formations, c—for biostratigraphic markers

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the “Shunet” sandstones near the Kuzma Hill in the vicinity of the east termination (flank) of the Marchengash lava field (see Fig. 1). If we consider the peculiarities of basaltic magmatism in time and in space, we can see that the maximum thickness of basaltic units is at two chronostratigraphic levels: Early Matarak level in the east (see description of traverse No. 1) and Marchengash level in the west (traverse No. 6). This, in our opinion, testifies to the migration of the active basaltic magma chamber from the east (spurs of the modern Batenev ridge) to the west (foothills of the Kuznetsk Alatau), as the “rejuvenation” of the Early Devonian sedimentary-volcanogenic formations of the Byskar series takes place.

12

Conclusion

Summing up, we emphasize that the materials offered in the “Guidebook” in combination with personal observations will help the participants of field trips to get an idea: • about significant facies variability of sedimentary-volcanogenic rocks of the Byskar series even over short (hundreds of meters, few km) distances; • on the evolution of volcanic phenomena in lateral and vertical directions; • on the leading role of effusive cover of the facies over the entire interval of stratigraphic sections of the Byskar series, with a subordinate value of the subvolcanic bodies (dolerites); • on biostratigraphic constraints on the age of beds at the level of stages and horizons by studying organic fossils; • about the possibility of a detailed correlation of adjacent sections on the basis of a set of litho- and biostratigraphic features. The authors hope that this introduction to the geology of this small local area may be useful for understanding the general geology of the region. This study was supported by the Government of the Russian Federation (project 14.Y26.31.0012).

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References Bazhenov VA., Makarenko NA, Rodygin SA (1992) Bitumen occurrences in volcanogenic rocks of Khakassia. In: Questions of Siberian geology. Tomsk: TSU Publications House, vol 1, pp 155–160 (In Russian) Bognibov VI (1974) Early Devonian dyke plagioporphir complex on the eastern slope of the Kuznetsk Alatau. In: Middle Paleozoic granite and syenite intrusions of the Kuznetsk Alatau and northwestern part of the Eastern Sayan Novosibirsk, Nauka, pp 85–148 (In Russian) Fedoseev GS (2015) Guide to field excursions on mafic sills of the Shirinsky training ground of the NSU (Republic of Khakassia, Russia). Novosibirsk: RIC NSU, p 20 (In Russian) Fedoseev GS, Krasnov VI, Ratanov LS (2002). Intrusive complexes in the Byskar sedimentary-volcanogenic series of the Minusinsk Intermountain Trough. In: Formation analysis in geological studies. Tomsk: TSU, pp 106–108 (In Russian) Khomichev VL, Edintsev ES, Kosorukov, AP (2008) Etalon of the Shirinsky (Byskari) Trachyte-Trachybasalt Complex (Minusinsk Intermountain Trough)—Novosibirsk: SNIIGGiMS, p 278 (In Russian) Krasnov VI (2012) Regional stratigraphic scheme of the Devonian formations of the eastern part of the Altai-Sayan region, Novosibirsk: SNIIGGiMS, p 52 (In Russian) Krasnov VI, Fedoseev GS (2000) The Byskar series of the Minusinsk intermountain trough: a modern interpretation (to the perfection of the legend of the State Geological Map-200 and 1000). In: Siberian Stratigraphy and Paleontology. Novosibirsk: SNIIGGiMS, pp 93–99 (In Russian) Krasnov VI, Ratanov LS (1974) About the stratotypes of the Matarak and Shunet formations in the North Minusinsk Depression. In: Novosibirsk: SNIIGGiMS Proceedings, 173, pp 82–89 (In Russian) Krasnov VI, Ratanov LS (2000) Correlation of early Devonian sedimentary-tuff formations of the Minusinsk trough. In: Siberian Stratigraphy and Paleontology, Novosibirsk: SNIIGGIMS, pp 87–92 (In Russian) Krasnov VI, Peregoedov LG, Ratanov LS, Fedoseev GS (2018) Regional stratigraphic scheme of Devonian deposits of the eastern part of the Altai-Sayan region. In: Geology and Mineral Resources of Siberia, 7c, pp 54–101 (In Russian) Makarenko NA, Parnachev VP (2005) On the nomenclature of the Early Devonian subalkaline mafic volcanogenic rocks in the Minusinsk intermountain trough. In: Petrology of Magmatic and Metamorphic Complexes. In: Materials of the All-Russian scientific conference. Bd.1. Tomsk: CNTI, pp 196–198 (In Russian) Makarenko NA, Kotelnikov AD (2018a) Devonian volcanism of the Minusinsk trough in the light of two geological hypotheses—continental syllogenesis and alkaline-mafic petrogenesis (based on scientific publications). Geol Mineral Resour Siberia 4:105– 111 (In Russia) Makarenko NA, Rodygin SA, Yu M, Elistratov VE (1982) NomokonovNew data on the geology of the training ground of the Tomsk University in Khakassia. In: Questions of Siberian geology, Tomsk, TSU, pp 123–132 (In Russian) Makarenko NA, Makarenko SN, Rodygin SA et al (2012) Genetic features of the Lower Devonian carbonate sediments in the vicinity of village Shira (Republic of Khakassia) Geology and Mineral Resources of Siberia, No. 1c, pp 30–36 (In Russian)

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Makarenko NA, Arkhipov AL, Parnachev VP (2013) Some problems of the genesis of naftids at the Sokhochul tract (Republic of Khakassia). Tomsk State Univer Bullet 372, 180–183 (In Russian) Makarenko NA, Kotelnikov AD, Kotelnikova IV (2017). Lower Devonian Pridorozhnaya Formation—general characteristics, stratotype section (Shira District, Republic of Khakassia). Geol Mineral Resour Siberia 2:3–12 (In Russian) Makarenko NA, Kotelnikov AD, Kotelnikova IV (2018b) Lower Devonian formations of the educational geological ground of Siberian Universities in Khakassia: structural features, principles of mapping and correlation. Geol Mineral Resour Siberia 1:14–23 (In Russian) Meleshchenko VS (1953) On some issues of the Devonian stratigraphy of the Minusinsk depression. In: Paleontology and stratigraphy. Moscow: State Geology Publications, pp 90–100 (In Russian) Parnachev VP, Vasilyev BD (Eds) (2007) Geology and minerageny of Northern Khakassia. Guide to the educational geological ground of Siberian Universities, 3rd edn, Tomsk: TPU, p 235 (In Russian) Peshekhonov LV, Vasilyev BD, Ivankin GA et al (1991) Features of the composition and structure of the Early Devonian volcanogenic-sedimentary formation of the Sokhochul-Itkulsky region of the North Minusinsk trough. In: Geological formations of Siberia and their ore content, Tomsk: TSU, 8–14 (In Russian) Rodygin SA (2006) On the discovery of jawless in the Lower Devonian sediments of the environs of the village Shira (Khakassia). In: Modern paleontology: Classical and Nontraditional: Abstracts LII session of the Russian Paleontol. Soc, St. Petersburg, pp 111–112 (In Russian) Sansom RS, Rodygin SA, Donoghue PCJ (2008) The anatomy, affinity and phylogenetic significance of Ilemoraspis kirkinskayae (Osteostraci) from the Devonian of Siberia. J Vertebrate Paleontol, 38(3):613–625 Schneider EA, Zubkus BP (1962) Stratigraphy of the Lower and Middle Devonian deposits of the North Minusinsk and Sydo-Yerbinsk depressions. In: Materials on geology and mineral resources of the Krasnoyarsk Territory. Krasnoyarsk: Publishing House, pp 41– 56 (In Russian) Sekretaryov MN, Lipishanov AP, Zaitsev VN et al (2000) State geological map of the Russian Federation in scale 1: 200 000. Ed. 2nd. Minusinskaya series. Sheet N-45-XVIII (Shira). Explanatory note, St. Petersburg, VSEGEI, p 151 (In Russian) Sekretaryov MN, Lipishanov AP, Mikhailenko VV et al (2015) State geological map of the Russian Federation. Scale 1: 200,000. Ed. 2nd. Minusinskaya series. Sheet N-46-XIII (Sorsk). Explanatory note, Moscow, VSEGEI, p 205 (In Russian) Serebrennikova OV, Vasiliev BD, Turov YuP et al (2003) Naftids in the basalts of the lower Devonian of the North Minusinsk Depression. Reports of the Academy of Sciences. 390 (4):525–527 (In Russian) Silaev VI, Brokmans TM, Petrovsky VA, Sukharev AE, Khazov AF (2017) Mineralogical and geochemical properties of solid bitumen in the context of the forecast of petroleum potential (on the example of Minusinsk intermountain trough). Bulletin of the Institute of Geology, Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, no 6, pp 3–12 (In Russian)

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Vasiliev BD, Ananiev YuS, Falk AYu (2006) Guide to the magmatism of the region of the educational geological ground of Siberian Universities (Eastern slope of the Kuznetsk Alatau), Tomsk: TPU Publishing House, p 35 (In Russian) Zakharova TV, Ananiev AR (1990) On the stratigraphic position of the Devonian Byskar series of Minusinsk trough. Bulletin of Moscow Society of Naturalists. Geological Series, pp 44–50 (In Russian)

The Field Trip 2: Early Paleozoic Large Igneous Provinces in SW Siberiа

Continental Sediments of the Early Cretaceous from Western Siberia. Part 2. Continental Mesozoic Sediments—Stratotype of the Lower Creataceous Ilek Formation (Bolshoi Ilek) at the Chulym River (Achinsk, Krasnoyarsk Region) A. V. Fayngerts The Bolshoi Ilek outcrop is the stratotype of the Creataceous Ilek Formation. The outcrop here is recognizably different from that at the Shestakovo Yar. Lithofacial features give evidence for sedimentation in a large fresh-water basin (lacustrine delta complex). The lower part of the outcrop consists of siltstone deposited from the suspension at the toe of the delta front or the upper part of the prodelta and is characterized by horizontal bedding. The siltstones are overlain by the coarser siltstones and sandstones with planar bedding. They were formed by weakening currents which the transported materials. Upwards the beds increase in thickness and become undistinguished. The middle part the outcrop exhibits giant cross-bedding represented by the delta lobe and shoreline progradation (Figs. 1 and 2). The sediments form a steep and gradually moving subaqueous slope of delta complex. Slope accretion occurred due to the transport of terrigenous material during floods. The units are composed of fine-grained, well sorted, cross-bedded sandstones. Poorly developed clay-sized sediments of the subaqueous delta were accumulated at low and very low paleohydrodynamic levels during low-water periods. Some sandstone beds are laterally persistent, but lens-shaped layers also occur here.

A. V. Fayngerts (&) Tomsk State University, 36 Lenin ave, Tomsk 634050, Russia e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_6

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Fig. 1 Ilek Formation stratotype (Bolshoi Ilek outcrop)

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Fig. 2 Boundary between the middle and upper members (Bolshoi Ilek). (Giant cross bedding is shown with red arrows)

Fig. 3 Giant cross-bedding (delta lobe, shoreline progradation)

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Fig. 4 Distributary deposits

Fig. 5 Vertebrate fossils (sauropod vertebra fragment)

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The boundary between middle and upper parts of the outcrop is accentuated by the surface of shallow-depth erosion. In terms of depositional settings these sediments are the subaqueous prolongations of delta arms. They are represented by fine-medium-grained cross-bedded sandstone with mud intraclasts (Figs. 3 and 4). The sediments contain fossils of vertebrates (Fig. 5). They are overlain by sandy-silty deposits of the subaqueous beach. The fossil fauna is similar to that found in the Ilek Formation in terms of the presence of paleonisciforms tutles, lizards, theropods, crocodiles, sauropods, and ornithischian fossils. The occurrence of Psittacosaurus remains defines the Psittacosaurus biochron (Barremian-Albian age). Acknowledgements The work is conducted within the megagrant of the Government of the Russian Federation (project 14.Y26.31.0012).

Igneous Rocks of the Kachinsk-Shumikhinsky Magmatic Area of Late Ordovician-Early Silurian Age (East Sayan) O. Yu. Perfilova, A. M. Sazonov, M. L. Makhlaev and A. A. Vorontsov In the central part of the Altai-Sayan folded region (ASFR), intensive post-collisional continental magmatism of increased alkalinity has long been known. The products of this magmatism are widely distributed, both in the basal part of the Minusinsk basin section and in the smaller superimposed structures within their fold structures. The volcanogenic formations of various petrographic composition overlie, with a pronounced structural disconformity, the Late Riphean-Early Cambrian folded basement. Until recently, the formation of these rocks was associated exclusively with the Early Devonian tectono-magmatism. But several decades ago, scattered data began to indicate that part of the post-collisional formations in this region is of the pre-Devonian age (Berzin and O. Yu. Perfilova (&)
A. M. Sazonov
M. L. Makhlaev Institute of Mining, Geology, and Geotechnology, Siberian Federal University, av. Gazety Krasnoyarskii Rabochii 95, Krasnoyarsk 660025, Russia e-mail: perfi[email protected] A. M. Sazonov e-mail: [email protected] M. L. Makhlaev e-mail: [email protected] A. A. Vorontsov A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, St. Favorskogo 1a, Irkutsk 664033, Russia e-mail: [email protected] © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_7

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Kungurtsev 1996; Vorontsov et al. 2018; Makhlaev et al. 2014; Kruk et al. 2002; Kuzmin and Yarmolyuk 2014; Perfilova 1998). In recent years, samples of volcanic rocks of unclear age, selected in different parts of the region, were dated by isotope-geochronological methods. The obtained dates fit mostly in the interval 420–460 Ma, which corresponds to the Late Ordovician or Early Silurian (State Geological Map of the Russian Federation 2008a, b; Kruk et al. 2002; Perfilova et al. 2003, 2004; Perfilova and Makhlaev 2010; Rublev and Shergina 1996). In some cases, these dates are supported by the results of paleomagnetic studies (State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Perfilova et al. 2004; Rudnev 2013). Currently, the most reliably substantiated is the presence of volcanogenic and related intrusive formations of the Late Ordovician to Early Silurian within the Kachinsk-Shumikhinsky magmatic area, spatially confined to the basin of the same name covering the vicinity of Krasnoyarsk (Vorontsov et al. 2018; State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Kruk et al. 2002; Perfilova et al. 2004; Rudnev 2013). This Kachinsk-Shumikhinsky volcanic-tectonic basin has a sublatitudinal (E-W) orientation, and is superimposed with structural unconformity on the complexly faults and folded complex of Upper Riphean to Lower Cambrian age (Fig. 1). This structure extends in the latitudinal (E-W) direction for 50 km west of the outskirts of Krasnoyarsk and has a width of up to 30 km along the meridian (N-S). In this structure, volcanic formations, form a continuous differentiated series (from trachybasalt to trachyrhyolite) and are spatially aligned, not only with subvolcanic formations, but also with relatively large comagmatic hypabyssal and meso-abyssal intrusions of the Stolbovsky syenite granosyenite-granite complex (Stolbovsky, Abatak, Shumikhinsky, Listvensky, and Zeledeevsky massifs). In the north and northeast, the volcanic and intrusive formations of this basin plunge under the gently dipping sedimentary cover composed of Middle-Upper Devonian and Mesozoic rocks (Fig. 2). Mesoabyssal intrusions of Kachinsk-Shumikhinsky magmatic area are represented by Stolbovsky, Abatak, Shumikhinsky, and Listvensky massifs. After correcting for post emplacement deformation, the Stolbovsky massif is interpreted to have had an original shape as a gently dipping laccolith plunging in the north-east direction, beneath the river valley of the Bazaikha and Torgashinsky ridge. The shape of the body is indicated by the occurrence of sheet jointing, as well as by the nature of the crystallization zoning (a significant decrease in the grain size of the rocks with the approach to the marginal part of the intrusion, and to a lesser extent near the sides of the intrusion).

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Fig. 1 Location map of the Kachinsk-Shumikhinsky depression and their composing rocks in the regional structure (Perfilova et al. 2004). 1—Mesozoic deposits; 2—deposits of the Minusinsk intermountain trough (Devonian to Permian); 3—intrusions of the Ordovician VPA; 4—Kachinsk-Shumikhinsky volcanic-tectonic basin; 5—Cambrian-Early Ordovician granitoid plutons; 6—Riphean to Late Cambrian formations; 7—Proterozoic formations of the Derbinsky block; 8—intrusive massifs of the Ordovician VPA and their numbers: 1— Zeledeevsky massif, 2—Listvensky massif, 3—Shumikhinsky massif, 4—Stolbovsky massif, 5—Abatak massif; 9—geological boundaries; 10—major faults

This intrusion entirely lies considerably below the base of the Ordovician volcanogenic sequence, among the sediments of Late Riphean-Early Cambrian age (see Figs. 2, 3, and 17). Its section shows vertical petrographic zoning—from syenite and quartz syenite (composing the bulk of the massif) to the granosyenite of the marginal zone. Almost the entire volume of the intrusion is composed of large- and medium-grained rocks. Fine-grained textures are characteristic only for the granosyenite of the marginal part (State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Perfilova et al. 2003, 2004; Perfilova and Makhlaev 2010; Sazonov et al. 2010; Rudnev et al. 2013). Two phases of crystallization (formation) of the rocks are distinguished. The main phase comprises the bulk of the intrusive body and consists of quartz syenites and granosyenites (State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Perfilova et al. 2003, 2004; Perfilova and Makhlaev 2010; Sazonov et al. 2010). Quartz syenite predominates and has a mineral composition

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Fig. 2 Fragment of the State Geological Map of 1: 200 000 scale (according to Berzon et al. (2008); M. I. Semenov, L. K. Kachevsky et al. (2009) with additions by O. Yu. Perfilova and M. L. Makhlaev). The numbers in the circles show the structures of the Kachinsk-Shumikhinsky magmatic area: 1—effusive rocks of the Divnogorsk volcanic complex; 2—subvolcanic intrusion (laccolith) of microsienites (Dolgaya Griva ridge); microsyenites (Dolgaya Griva ridge); 3—Stolbovsky Massif; 4—Abatak Massif; 5— Listvensky Massif; 6—Shumikhinsky Massif; 7—Kotursky massif; 8—Zeledeevsky Massif. Yellow quadrilaterals show the outlines of the maps of the Figs. 3 (I); 17 (II); 27 (III)

of potassium feldspar (65–70%), plagioclase An30–32 (5–10%), quartz (3–10%), dark-colored minerals (hornblende and biotite, partially substituted by chlorite and epidote, which total up to 15%) (Fig. 4). Granosyenites are related to the quartz syenites by gradual transitions, and the granosyenite differs in having a higher content of quartz and plagioclase (about 20%), due to a decrease in the contents of dark-colored minerals. Accessory minerals in the granosyenite are apatite, magnetite, and titanite. Some authors (Sazonov et al. 2010; Gavrichenkov et al. 1968) noted the presence of a small fraction of rocks of increased alkalinity (nordmarkites), containing alkaline amphibole instead of hornblende, in contact with carbonate rocks.

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Fig. 3 Portion of geological map of sheet N-46-III. It was compiled by Guseinov et al. (2002) with additions by Perfilova and Makhlaeva (2010). 1—zone of the northeastern contact of the Stolbovsky Massif (Tubil Formation); 2—deep faults; 3—ophiolite protrusions of the Akshepsky Complex; 4—carbonate rocks of the Torgashinsky Range (Torgashinsky and Shakhmatovsky Suites); 5—Vendian—Early Cambrian terrigenous and carbonate rocks (Tybil and Ungut Formations), forming the base of high terraces on the left bank of the Yenisei River; 5—the serpentenitis of Sliznevskaya massif of the Akshepsky Complex

The rocks of the second phase (the phase of the residual melt crystallization) form small (up to tens of centimeters in thickness) dikes and thin veins composed of microsyenite and granosyenite. In the rocks of the main phase of crystallization, metasomatic (possibly autometasomatic) alteration is unevenly manifested. Albitization processes are most developed, during which newly formed albite replaces potassium feldspar and sometimes corrodes other primary rock-forming minerals. The widest extent of albitization occurs in the marginal part of the massif. At deeper levels of erosion, albitization is confined to separate linear zones. Secondary biotitization and

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Fig. 4 Fine-grained (left) and medium-grained (right) quartz syenites of the main phase of the Stolbovsky intrusion

silicification are noted locally (State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Perfilova et al. 2003, 2004; Perfilova and Makhlaev 2010; Sazonov et al. 2010). The rocks enclosing the massif form a faulted folded complex of Upper Riphean to Lower Cambrian age. All sedimentary and volcanic rocks in the exocontact zone (within the adjacent host rock) of the Stolbovsky Massif are turned into hornfelses or marbles. As a result of intensive processes of denudation, erosion and weathering, the Stolbovsky Massif was dissected into a series of buttes—quaint rock pillars (State Geological Map of the Russian Federation 2008a, b; Makhlaev et al. 2014; Perfilova et al. 2003, 2004; Perfilova and Makhlaev 2010; Sazonov et al. 2010). The age of the rocks of the Stolbovsky Massif has been determined by A. G. Rublev in the laboratory of VSEGEI using the U-Pb method for mediumgrained quartz syenite of the main crystallization phase. An age of 449 ± 3 Ma was obtained (Kruk et al. 2002; Rublev et al. 2013).

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Field Stop 1—the observation point of the national park “Krasnoyarskie Stolby”. There is panorama of syenites outcrops of the Stolbovsky massif. Passing about 1 km in the eastern direction along the rocky road past small crags composed of medium-grained quartz syenites (Fig. 5), you can reach Takmak, which is one of the largest crag groups of the “Stolby” (Fig. 6). Field Stop 2—Syenite pit. Until 2010, the pit was exploited for quartz syenites, which were widely used as a facing stone for the exterior and interior of many buildings in Krasnoyarsk, as well as for stairs, borders and sculptures (State Geological Map of the Russian Federation 2008a, b; Perfilova et al. 2004; Sazonov et al. 2010). Note: Since the geological excursion will take place within the security and touristic zones of the National Park “Krasnoyarsk Pillars”, the excursion participants must follow all the park rules while in the protected area, namely, do not

Fig. 5 A small crag of medium-grained quartz syenites of the Stolbovsky complex

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Fig. 6 View of the Takmak crag

destroy the rocks, do not take samples, move only along the paths, do not pick flowers, etc. In the area of the Mokhovoi stream we can see exocontact (baked contact) zone a rock exposure of hornfels. The hornfels is black in color, very dense with sharp edges and a conchoidal fracture. The texture is fine-grained; the structure is massive, less often banded and spotty. The hornfels formed on the contact of the Stolbovsky syenite intrusion with the enclosing polymictic sandstones and siltstones of the Tubil Formation of the Vendian to Early Cambrian age as a result of the recrystallization of sedimentary rocks under the influence of high temperature (contact-thermal metamorphism). Separate fragments with thin (up to 7 cm) veins of microsyenites, apparently composing the apophyses of the Stolbovsky intrusion, located here at a relatively shallow depth (State Geological Map of the Russian Federation 2008a, b; Perfilova et al. 2004; Sazonov et al. 2010), are observed in the kurums at the foot of the rocky exposure of the hornfelses. From the hornfels outcrop, the route continues along a dirt road upstream along the Mokhovoy creek. After 120 m, a panorama of a partially reclaimed syenite pit (Mokhovskoye deposit) opens (Fig. 7); the pit is located at the foot of the Ermak crag near the famous group of Takmak crags (Sazonov et al. 2010).

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Fig. 7 General view of the Syenite pit

In the Field Stop 2, one can see rather fresh rocks which were artificially opened and therefore not affected by weathering (Fig. 8). Medium-grained low porphyritic and equigranular biotite-hornblende and hornblende syenites and quartz syenites of a grayish-pink and pink color with a massive structure, which are attributed to the first (main) phase, are predominant. Porphyritic quartz syenites are distinguished by the fact that they contain feldspar grains, the size of which is several times larger than the grains of the groundmass. Here it is most convenient to get acquainted with the mineral composition of the rocks of the Stolbovsky complex. Practically all rock-forming minerals are well distinguished here even visually (Fig. 9). They are represented by pink albitized potassium feldspar composing 70–80% of the rock volume (its color determines the pink color of the whole rock), plagioclase (10–25%) and dark-colored minerals (up to 15%)—green prismatic hornblende crystals and shiny flakes of black biotite. Plagioclase in the rock is recognized by a grayish-white color (bright spots on a pink background). In a small

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Fig. 8 Manmade accumulative deposits consisting of large blocks of syenites of the Stolbovsky massif in the area of the Mokhovoy stream

amount (up to 5–7%) there are fine grains of smoky gray quartz, which have a greasy luster. Accessory minerals are apatite (up to 1%), magnetite, titanite, and hematite. A secondary mineral is chlorite, which partially replaces the primary dark-colored minerals—biotite and hornblende. Carbonate rarely occurs (Sazonov et al. 2010). Microscopic examination of thin sections has shown that the microtexture of syenites and quartz syenites is hypidiomorphic-grained (Fig. 10). Potassium feldspar in the rock is represented by large pink crystals ranging in size from 7–10 mm to 15 mm. Most crystals are zoned. Pelitization is sharply uneven and sometimes intense. Intensive albitization (up to 30% of all crystals) is manifested, especially along the periphery of the crystals (with the formation of rims) and inside the cracked grains. In some areas you can observe the microcline gridding (tartan twinning). Plagioclase (25–30%) is represented predominantly by albite, which develops on potassium feldspar. Rare grains of unchanged, polysynthetically-twinned oligoclase are observed (An9–12). It occurs in the spaces between the K-feldspar crystals. Dark-colored minerals are represented by large

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Fig. 9 Slightly porphyritic medium-grained quartz biotite-hornblende syenite of the first phase of the Stolbovsky massif

xenomorphic clusters of 5–7 mm in size. In thin sections, there are aggregations of brown-green chlorite, which are probably entirely chloritized biotite crystals. Carbonate also develops on them. In addition, there are small (0.2 mm) relics of amphibole, pleochroic in brown-green tones. Quartz in thin sections is observed as a few xenomorphic grains of 2–4 mm in size. Ore minerals are represented by black, opaque, box-shaped crystals, perhaps a titanium-containing mineral. There are aggregations of red-brown iron hydroxides. Accessory apatite occurs as relatively large (0.2–0.4 mm) isometric crystals included in other minerals. Titanite is represented by numerous, small crystals and clusters. They can often be found inside the ore minerals having a box-like structure. The secondary thin-flaky chlorite is widely developed. It fills the gaps between feldspar crystals or almost completely replaces dark-colored minerals—biotite and amphibole. Another secondary mineral, carbonate, develops together with chlorite (Sazonov et al. 2010).

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Fig. 10 Thin section of syenite from the Stolbovsky Massif. Nicols are crossed. On the left, a zoned crystal of orthoclase is among a fine-grained aggregate of albite, orthoclase, and biotite

In medium-grained slightly-porphyritic syenites and quartz syenites of the main phase, numerous xenoliths or autoliths of more melanocratic thin- and fine-grained rocks are observed, the sizes of which vary from centimeters to tens of centimeters (Fig. 11). The rocks composing xenoliths (autoliths) correspond to gabbro, diorite, or quartz diorite. Their size is several centimeters in diameter. When weathering, xenoliths fall out relatively easily from the enclosing syenites, and in their places hollows (pits) remain (Sazonov et al. 2010). Rocks of the main phase are cut by thin veinlets of fine-grained quartz syenite and granosyenite of pink or pinkish-gray color. These veinlets belong to the second phase of the Stolbovsky intrusion. They are clearly visible in the walls of the pit and in some large blocks (Fig. 12). These small dikes and veinlets were formed as a result of solidification of the youngest portions of the magmatic melt, which penetrated the already crystallized rocks of the first phase along cracks. Any regularity in the orientation of the veinlets was not observed.

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Fig. 11 Xenolith of basic rock composition in fine-grained biotite-hornblende quartz syenite

In the cracks one can also observe hydrothermal mineralization, represented by small (5–10 mm), idiomorphic crystals of smoky quartz, fluorite grains, the color of which varies from pale yellow to purple (Fig. 13), and fine ore impregnations of pyrite, and sometimes molybdenite (Fig. 14) (Sazonov et al. 2010). In the syenite pit one can best see the sheet jointing. As a result of a decrease in the volume of the intrusion during its cooling, three mutually perpendicular systems of cracks form. The cracks that are oriented parallel to the contact of the intrusive body are the best developed; therefore, by measuring the occurrence of the sheet jointing, we can conclude about the position and configuration of the contacts of the intrusion. Such sheet jointing, parallel to the roof of the Stolbovsky Massif, is best seen in the northern wall of the pit (Fig. 15). Here, these individual cracks are very clearly expressed, as giant “steps” in the pit. The main system of cracks slope gently (at an angle of 15°) to the northeast beneath the host rocks (Sazonov et al. 2010).

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Fig. 12 Small dike of quartz microsyenite of the second phase in medium-grained biotite-hornblende quartz syenite of the first phase

The combination of cracks of the sheet jointing with vertical cracks, some of which have a tectonic nature, cause the appearance of mattress-shaped jointing in syenites (Sazonov et al. 2010). Field Stop 5—The Shumikhinsk Massif. The Shumikhinsk Massif is almost the same the Stolbovsky massif but differs by the depth of crystallization. The intrusion area is about 35 km2. It is a laccolith, located in the lower part of the section of the Divnogorsk volcanogenic sequence. The massif is composed of hornblende and biotite-hornblende syenites, quartz syenites and granosyenites. In a vertical section of the intrusion, a gradual transition is observed from syenites composing the bottom and central parts of the body to the granosyenites of the upper marginal zone. A large (500 m) vertical thickness of the zone of thin- and fine-grained rocks in the upper margin of the intrusion is a characteristic feature. Quartz syenites and granosyenites of this zone are completely similar in their appearance to the rocks composing the marginal parts of the Stolbovsky massif. Only the internal and the bottom parts of the massif

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Fig. 13 Hydrothermal vein with violet fluorite in syenites of the Stolbovsky Massif

are composed of medium-grained rocks. The recent determinations of the age of the Listvennsky and Shumikhinsky massifs by the U-Pb method (426.6 ± 2.4 and 449.6 ± 3.6 Ma (Kruk et al. 2002) are in good agreement with the previous dating (Perfilova et al. 2004; Rublev et al. 2013). You can get acquainted with the rocks of this intrusion in a pit located on the right bank of the Yenisei River (on the left bank of the Listvyanka River) (Figs. 16 and 28), near the dam of the Krasnoyarsk Hydroelectric Power Plant. Crushed and facing stones were mined here during the construction of the Krasnoyarsk hydroelectric station. Now there is no mining in it, and not far from the pit there are dachas of the residents of Divnogorsk and Krasnoyarsk; therefore a well rolled dirt road leads to the pit. Field Stop 3 and 4—Dolgaya Griva paleovolcano In the central part of the Kachinsk-Shumikhinsky magmatic area on the outskirts of Krasnoyarsk (Oktyabrsky district) there is the Dolgaya Griva paleovolcano, representing vent and subvolcanic formations of the Divnogorsk volcanic complex

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Fig. 14 Impregnation of molybdenite in quartz syenite. From the collection of IGDG SFU

(Sazonov et al. 2010). The Nikolaevskaya Sopka Mountain is the easternmost pronounced peak in the sublatitudinal (E-W) low mountain ridge named Dolgaya Griva. The entire ridge and its spurs are composed of rocks of the Middle to Late Ordovician volcanic complex (Fig. 17). The main volume of the Divnogorsk volcanic complex in the area of the Dolgaya Griva ridge is a layered, mostly lava section (cover facies). The volcanic rocks of the cover facies here form a stratified monoclinal sequence, relatively gently dipping (about 30°) to the north-north-west. In its reference section, six sequences are distinguished (Makhlaev et al. 2014). The first two sequences are composed of basalts, trachybasalts and trachyandesibasalts; the third sequence consists of tuffs of trachyte-trachyrhyolite composition, the fourth and sixth sequences contain trachytes, and the fifth pack-trachybasalts. The total thickness of the section is more than 2,200 m. Subvolcanic formations are represented by quartz syenite-porphyry intrusions (near the peaks of the First and Second Sopka), as well as numerous dykes of moderately alkaline fine-grained gabbro and microgabbro, trachybasalt, and

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Fig. 15 Sheet jointing cracks of contractional nature, parallel to the roof of the Stolbovsky syenite massif in the syenite pit

trachyte-porphyry. Intrusion of quartz syenite-porphyry is a laccolith, the roof of which is well displayed under modern relief (the northern slopes of the First and Second Sopka) (Fig. 18) (Makhlaev et al. 2014; Sazonov et al. 2010). In the southern slopes of the same mountains a full section of the laccolith is exposed, from the roof to the footwall. The intrusion has a zoned structure. In its center, quartz weakly-porphyritic syenites of pink color with fine-grained groundmass (grain size about 1 mm) are developed. Phenocrysts (3–5 mm) are composed of potassium feldspar (10–15% of the volume). The groundmass is dominated by potassium feldspar (not less than 75%); prismatic crystals of hornblende (10–15%), and interstitial quartz grains (about 10%) play the subordinate role. The peripheral zone of the intrusive body is composed of microsyenites and syenite-porphyries with a fine-grained groundmass (grain size of about 0.5 mm) and phenocrysts of orthoclase ( 3 in amphiboles also indicate the magmatic nature of mineral formation.

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The composition of dark micas is limited by the isomorphic phlogopite–annite series with the predominant development of titanium biotite (TiO2 up to 4–5 wt. %; MgO * 10–13, FeO* * 18–23, Al2O3 * 2–15 wt%; Mg/Fe2+ * 0.7– 1.3, AlVI < 0.3 p.f.e. According to the ratio of magnesium, aluminum, and iron, the micas are comparable to the rock-forming biotites of calc-alkaline igneous complexes of orogenic regions. In the diagram (Na2O + K2O) – SiO2 (Fig. 5), the compositions of igneous rocks of the Kogtakh complex are grouped along the line separating the moderately alkaline and normal petrochemical varieties (Fig. 5a). An increase in the degree of differentiation from gabbroids to monzonites leads to an increase in silica (SiO2 * 41–66 wt%), alumina content (Al2O3 * 9–23 wt%), and alkalinity (Na2O + K2O * 1–10 wt%), with a simultaneous decrease in the contents of CaO, MgO, Fe2O3*, TiO2, P2O5. A decrease in the basicity of rocks (SiO2 > 50 wt. %) is accompanied by an increase in K2O and K2O/Na2O (from *0.2–2 wt%, 0.2–0.7 in gabbro to *2–6 wt. %, 0.5–1.5 in monzonitoids; Fig. 5b), which indicates that the rocks belong to the derivatives of the high-potassium calc-alkaline and partially shoshonite series, characteristic of the magmatic associations of active continental margins (Bogatikov et al. 2010). Compared with the Cambrian granitoids, which are spatially associated with the intrusions of the Kogtakh Complex (Vrublevskii et al. 2016a, b, c, 2018), the monzodiorites and monzonites have a lower calcareous content and often show a connection with a HFSE-rich intraplate source, like A-type granites. A decrease in the magnesia index of melts leads to the decrease in siderophile elements in rocks (Cr 12–436, Ni 9–182, V 32–574, Co 5–56, Sc 1–55 ppm) and the increase in Cs, Rb, Ba, Th, U contents, and, to a lesser extent, in Nb, Ta, LREE. Regardless of the sequence of intrusive phases in various plutons, a relatively constant Sr content is observed (*800–1400, less often *500–700, 1600– 2500 ppm). The distribution of rare-earth (average RREE *165 ppm; La/YbN *7–30) and other rare elements in the gabbroids of the Kogtakh Complex is usually comparable with the average composition of island-arc basalts (IAB) (Fig. 6). As for the volcanic rocks of subduction zones, a characteristic geochemical feature is the pronounced Nb–Ta and Zr–Hf minima on spidergrams. In more differentiated (RREE * up to 200–330 ppm; La/YbN * 14–34) derivatives, the normalized concentrations of LILE and HFSE reach or even exceed the enrichment level of oceanic basalt (OIB), but at the same time maintain complementarity with the multielement spectra of IAB. For the rocks of most of the studied plutons, the effect of plagioclase fractionation is observed, with the manifestation of a negative Eu anomaly (Eu/Eu* * 0.7–1.3) in later monzonitoids.

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Fig. 5 Petrochemical discrimination of gabbro-monzonite massifs of the Kogtakh Complex. 1—Gabbro; 2—monzodiorite, monzonite. a—The diagram of SiO2 – (Na2O + K2O), according to (Middlemost 1994); the dotted line separates the compositions of normal and subalkaline rocks. b—The SiO2–K2O diagram, according to (Peccerillo and Taylor 1976). c —Correlation of the major oxide contents in rocks with different silica contents from gabbro-monzonite intrusions

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Fig. 6 Distribution of rare-earth and rare elements in the rocks of the Kogtakh Massif (Vrublevskii et al. 2018)

Chondrite-normalized and PM (primitive mantle)-normalized spectra of gabbro (thin dotted line) and monzodiorite-monzonite (thin solid line). Normalizing values of chondrite and PM are from Sun and McDonough (1989). For samples with similar rare element contents, average values were calculated. Values of OIB and IAB are from Sun and McDonough (1989), and Kelemen et al. (2003). The U–Pb age on zircons from monzodiorites of the Kogtakh Massif gives concordant dates of 500 ± 4.3 and 500.8 ± 4.6 Ma (Fig. 7), which actually correspond to the boundary of the Late and Middle Cambrian and is comparable to the intrusion time (*500–485 Ma) of many Early Paleozoic granitoid intrusions on the northern and eastern slopes of the Kuznetsk-Alatau Range (Rudnev et al. 2004; Vrublevskii et al. 2018).The circles on cathodoluminescent images of zircon grains indicate sites of the isotopic analysis. The intrusive massifs of the Kogtakh Complex have similar parameters of the neodymium isotopic composition (143Nd/144NdT 0.512174–0.512227, eNdT * 3.5– 4.6 in gabbro; 143Nd/144NdT 0.512179–0.512273, eNdT * 3.6–5.4 in monzodiorite-monzonites), which may indicate a related mantle source that includes components of moderately depleted (PREMA) and enriched lithospheric (EM) mantle. According to the model age (TNd (DM) * 720–940 Ma), the mantle reservoir is comparable to that initiated the Paleozoic granitoid and alkaline-mafic intrusions in the region (Fig. 8.) (Vrublevskii 2015; Vrublevskii et al. 2014a, 2016a, b, c; Vrublevskii and Gertner 2017). The isotopic composition of strontium changes in a wider range (87Sr/86SrT 0.7039–0.7052, eSrT * 0–19) with a pronounced enrichment by 87Sr,

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Fig. 7 U–Pb diagrams and morphological features of zircons from the rocks of the Kogtakh gabbro-monzonite massif

which is accompanied by an increase in d18O (6.5–8.8‰) with respect to mantle values. A similar dependence is noted for the plutonic association of alkaline mafic rocks of the Kuznetsk Alatau and can be caused by crustal contamination processes of deep magmas (Pokrovsky et al. 1998).

2

The Ulen-Tuim Complex of Batholith Granitoids

In the Kuznetsk Alatau, several uneven-aged plutonic complexes are distinguished, differing in the rock composition and metallogeny. Among them are the complexes of the mafic (Byuysky, Kogtakh, and others), alkaline (Goryachegorsky,

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Fig. 8 Isotopic-geochemical features of the gabbro-monzonite association of the Kuznetsk Alatau. 1–2—Rocks of the intrusive phases of the Kogtakh complex: 1—gabbro, 2— monzodiorite, monzonite; 3—monzogabbro, monzodiorite, granosyenite of the Terandzhik pluton, Gorny Altai (247 Ma) [Krupchatnikov et al. 2015]. a—eNdT–eSrT diagram. The outlined fields 1–3 indicate the prevailing rock compositions: 1—alkaline rocks and carbonatites of the Edelweiss Complex of the Gorny Altai (*507 Ma) (Vrublevskii et al. 2012), 2—subalkaline and alkaline basaltoids of the Minusinsk Trough (*390 Ma) (Vorontsov et al. 2013), 3—alkaline rocks of the Kuznetsk Alatau (*510, 400, 265 Ma) (Vrublevskii and Gertner 2017). The gray background—Cambrian granitoids of the Kuznetsk Alatau (Kruk et al. 2001; Rudnev 2013; Vrublevskii et al. 2016a, b, c). The location of “Mantle array” and MORB, PREMA, EM I, EM II reservoirs are shown in accordance with their current isotopic parameters (Zindler and Hart, 1986). b–c—The ratio of d18O – 87Sr/86SrT (b), d18O – eNdT (c). The estimated isotopic composition of the crustal component is noted (Pokrovsky et al. 1998). The parameters of primitive mantle (M), mantle under island arcs (AM) and trends I–III of substance mixing are from (Davidson et al. 2005): I—basalt + young crust and pelagic sediments, II—basalt + ancient crust, III— mantle + ancient subduction sediments. The dashed lines 1:1 and 1:10 correspond to the ratios of Sr concentrations in the mantle (magma) and in the contaminant (Pokrovsky 2000). The fields of the predominant compositions of alkaline basic rocks of the Kuznetsk Alatau (KA) and carbonatites of the Eastern Sayan (VS) are contoured (Vrublevskii and Gertner 2017; Vladykin et al. 2004; Vladykin 2005). The arrow shows the trend of contamination of PREMA-mantle melts by the material of Phanerozoic marine carbonates (eNd –2; d18O +17.5‰ SMOW) (Pokrovsky 2000). D—The eNdT – Ba/Nb diagram (Li 1995), OIB parameters (Weaver 1991; Zindler et al. 1982), GLOSS (Plank and Langmuir, 1998). The contours are: Paleozoic granitoids (1), alkaline rocks (2) basaltoids (3) of the Kuznetsk Alatau and Minusinsk Trough. (e) – 87Sr/86SrT – Ba/Yb diagram (Barreto et al. 2016). OIB (Sun and McDonough 1989), GLOSS (Stracke et al. 2003), basalts and andesites of island arcs (Kelemen et al. 2003)

Sokhochulsky), granitoid (Martayginsky, Ulen-Tuimsky, etc.) and leucogranite (Tigertysh, Sora) series (Fig. 9). The rocks composing the complex are distributed mainly in the Tuim region, and also they form large complicated massifs: Tigertysh, Beloyiysky and others. The complex consists of three intrusive phases. Phase I (Askiz) is represented by fine- to medium-grained gray-green hornblende diorites and quartz diorites consisting of zoned oligoclase-andesine and green hornblende needles. Phase II (Tigertysh) is the main phase. It is represented by coarse porphyry biotite-hornblende granites and granodiorites. Granites are composed of quartz (10–25%), potassium feldspar (30%), oligoclase (30–50%), biotite, and hornblende (10–15%). 1–3 cm porphyry phenocrysts are represented by late microcline.

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Fig. 9 Map of plutons of the Cambrian-Ordovician granitic formation in the Kuznetsk Alatau (according to Yu. A. Kuznetsov et al. 1971, with simplifications). 1—Loose sediments of the cover of the West Siberian Platform (K-N); 2—volcanogenic-sedimentary deposits of intermountain troughs (D-P); 3—metamorphosed and faulted units of the basement of the young platform (PR-2), 4—Early Paleozoic formation of granitoid batholiths of “mixed” composition; 5—main tectonic faults; 6—pluton names: 1— Kozhukhovsky, 2—Dudetsky, 3—Tsentralninsky, 4—Saralinsky, 5—Tuim-Karysh, 6— Tigertysh, 7—Uibatsky, 8—Telbesky, 9—Porozhinsky, 10—Ortonsky, 11—Askiz, 12— Saksyr

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Phase III (Sora) is controlled by fissure prototectonics in massifs of Phase II. It is represented by dykes and small stocks confined to joints. These fine-grained granites are from the same magma that also yields aplites and pegmatites within the same body. The main minerals in them are: quartz (25–30%), pink microcline and white albite-oligoclase. Biotite and hornblende (no more than 5%) occur as small phenocrysts.

2.1 Tuim-Karysh (Tuim) Pluton The Tuim pluton is located among the pre-Ordovician effusive-carbonate rocks (marls and shales, effusives and tuffs of mafic composition), saturated with sheet intrusives and dykes (diabase, gabbro-diabase, gabbro and diorite-porphyrite). Ancient rocks are also preserved as outliers and roof hangings. Contacts with carbonate rocks are always sharp, and with aluminosilicate rocks are vague. Among the light-gray limestones and marls there are parts of quartz-feldspar, biotite-plagioclase, biotite-cordierite-plagioclase, andalusite-cordierite, andalusite-sillimanite-cordierite, and amphibole-plagioclase hornfels and cherts. Garnet and pyroxene-garnet skarns with magnetite, chalcopyrite, scheelite and molybdenite are widely developed (Kiyalykh-Uzen, Tuim, Ozhidaemoe, Alekseevskoe, Daryinskoe, Kladbischenskoe, Tansyvai, etc.). Magnesian skarns consist of forsterite, diopside, magnetite, spinel, and other minerals (Ziv 1939; Khomichev et al 1969). Aluminosilicate rocks in contact zones and xenoliths are turned into hornfelses and sodium-silica metasomatites. Intrusive margin zones are saturated with xenoliths. Here, there are also peculiar needle-like diorites, which are considered to be the result of recrystallization and alkaline-silica metasomatism of amphibole-plagioclase hornfelses (Kuznetsov et al. 1971). They have a taxitic structure and hypidiomorphic texture. The idiomorphism of hornblende is characteristic. Its quantity and grain size varies over a wide range. Hornblende is replaced by biotite, biotite is replaced by chlorite. Quartz is often surrounded by corroded grains of plagioclase. The Tuim pluton was formed in three stages (Kuznetsov et al. 1971). At the first stage, quartz syenite-diorites (quartz monzodiorites), quartz diorites and syenites were formed, at the second (main) stage—porphyritic granites, and on the third— granite-porphyries, leucocratic granites, aplites and pegmatites were formed. Coarse-grained quartz monzodiorites with trachytoid structure prevail among the rocks of the first stage. They consist of oligoclase (50–60%), microcline (10– 20%), quartz (10–15%), hornblende (up to 5%), titanite (up to 5%), biotite (1–2%) and diopside (relict grains among amphibole). Accessory minerals are apatite and

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magnetite. Quartz syenites, granosyenites, monzodiorites, and quartz diorites are less common. The dike series of mafic and middle-mafic rocks are rare. The most common dikes are of microdiorite and diorite porphyrite, much less often occur dikes of plagioclase porphyrite and diabase. The rocks of the second stage are represented mainly by medium-grained biotite and biotite-hornblende granites. Often they have a porphyric texture, due to the presence of relatively large (up to 2–4 cm) microcline phenocrysts. Granites are composed of oligoclase, microcline and quartz, present in approximately equal amounts. Hornblende and biotite make up no more than 10%. Accessory minerals are titanite, apatite and magnetite. The third stage includes dikes and stocks of leucocratic granites and granite porphyries. Leucocratic granites have more fine-grained texture and low content of biotite and hornblende (up to 5%). Granite porphyries differ from them only in texture. The phenocrysts in granite porphyries are represented by plagioclase, and less commonly by microcline and quartz. Aplite dykes and pegmatite veins are widely developed. The bodies of this stage usually have abrupt contacts with host rocks. The skarn deposits of the Tuim, Karysh, and Ulen groups, which were previously considered as copper deposit, but besides copper, they also have elevated concentrations of Mo, W, Au, Ag, Pb, Zn, Bi, As, Ni, and Co. In the right bank of the river Karysh are small skarn deposits of copper, tungsten and molybdenum (Daryinskoe, Ozhidaemoe, Kladbishchenskoe, Alekseevskoe, Tansyvai, etc.). Skarns are confined to the contacts of granitoid bodies. At the same time, not only host rocks and pyroxene-plagioclase metasomatites are skarned, but also rocks of the first phase of the Ulen-Tuim Complex. Garnet, diopside, wollastonite, scapolite with secondary actinolite, epidote, and magnetite are formed in the skarn stage. Scheelite, copper and molybdenum sulfides, quartz and carbonates were formed after skarns.

2.2 Kiyalykh-Uzen Deposit (Cu-Mo) Te copper and iron ore mineralization of this region has been known since ancient times. The “Chudskie Mines” (which were developed in the VII-VIII centuries BC) include the Kladbishchenskoe, Theresiya, Julia Mednaya and other deposits. In 1754 at the Alekseevskoye deposit south of Lake Itkul, a merchant, Vlasyevsky, mined copper ores. One of the largest deposits of the Tuim-Karysh ore district is the Kiyalykh-Uzen (“Skalisty Log”) deposit, located on Copper Hill, near the Tuim village. Since 1901, it has been known as a copper-iron ore deposit of the

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contact-metasomatic type. However, detailed study of this deposit began only in 1931. It was found that the skarn-ore zone with copper mineralization extends 267 m at a maximum thickness of 32 m (average thickness is 9 m). The main ore body was traced by halls to a depth of 150 m. On this horizon, the ore body had a maximum thickness of 75 m (with an average thickness of 29 m) and expanded with depth. At the same time, Ziv (1939) conducted a revision of copper deposits on scheelite and molybdenite. Copper reserves amounted to 70 thousand tons, molybdenite to 4.8 thousand tons. In 1934, L. D. Staroverov discovered the Tuim tungsten deposit on the right bank of the stream Tuim. Scheelite was also identified on the southern flank of the Kiyalykh-Uzen deposit, the supplementary exploration of which was carried out in 1947–1953, and exploitation was in the period from 1953 to 1974. The Kiyalykh-Uzen deposit is located in skarns, at the contact of granitoids of the Ulen-Tuim Complex (Є3–O1) with the siliceous-carbonate sediments of the Synnyg suite of the Middle Riphean (Fig. 10). The thickness of the zone of skarns and mineralization reaches 75 m at the place of the strike shift (inflection zone), decreasing and wedging out in the south-west and south-east directions. The ore zone starts from the surface, plunging steeply to the south parallel to the contact to the horizon of 470 m, and then flattened and wedged out on the horizon at a depth of 400 m, where ore bodies are represented by small lenses in limestone (Fig. 11). The structure of the ore zone involves skarns, as well as microdiorites, hornfelses, quartzites, and granites. Garnet-diopside-magnetite skarns predominate; brown diopside-garnet with a variable amount of magnetite are less common. Phenocrysts, nests and veinlets with pyrite, chalcopyrite, molybdenite, pyrrhotite, sphalerite, galena, tennantite, scheelite and gold are noted. Copper minerals are concentrated mainly in skarns, molybdenum minerals occur in granitoids and partly in microdiorites. The formation of the Kiyalykh-Uzen deposit occurred in several stages. Initially, wollastonite-diopside-garnet skarns were formed, in which andradite and magnetite were formed later. The hydrothermal stage was expressed in the replacement of skarns with epidote, tremolite, actinolite, chlorite and quartz. As a result, small bodies of metasomatic quartzites containing pyrrhotite, pyrite, magnetite, chalcopyrite, and scheelite were formed. The main stage of copper mineralization manifested itself in cracks: quartz-chalcopyrite mineralization with pyrite, pyrrhotite, sphalerite and molybdenite was superimposed on the brecciated skarns. With some interruption in time and displacement in space, the quartz-molybdenite stage follows with accompanying subordinate chalcopyrite and pyrite. It is noteworthy that quartz-chalcopyrite association was manifested mainly in iron-rich

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Fig. 10 Geological map of the Kiyalykh-Uzen deposit (according to Khomichev et al. 1969). 1—White and gray marbled limestone; 2—dikes and stocks of leucocratic granites; 3 —coarse-grained porphyry granites; 4—fine-grained hornblended quartz diorites, granodiorites; 5—mineralized diopside-garnet-magnetite skarns; 6—quartz veins

skarns, and quartz-molybdenite association was formed in granites, microdiorites and hornfels (Khomichev et al. 1969). The Alekseevskoye deposit is represented by copper, tungsten and molybdenum mineralization, spatially confined to the skarns bodies formed on the contact of the second phase monzonites of the Kogtakh gabbro-monzodiorite-syenite complex and Riphean limestones of the Tyurim Suite (R3tr). The main molybdenum ore mineral is molybdenite. At the Alekseevskoye deposit, mineralization has a superimposed nature, connected with the formation of the intrusion of the second phase of the Kogtakh Complex. Mineralization is represented by chalcopyrite, bornite and scheelite. The Daryinskoe molybdenum-copper deposit is located 14 km south-east of the Shira village. It is a part of the Tuim-Karysh copper-molybdenum-tungsten ore cluster. The first exploration works were carried out in 1907–1917. Later the deposit was explored in 1934 and 1943–1953. The skarn deposit is confined to the contact of limestone with syenite and diorite. Three industrial ore bodies of

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Fig. 11 Geological section along the line XI of the field of Kiyalykh-Uzen (after L. A. Sazonov). 1—Limestones, marbles; 2—diorites, microdiorites; 3—granodiorites, quartz diorites; 4—hornfelses; 5—garnet, garnet-magnetite skarns; 6—quartzites; 7—aplites; 8— geological boundaries (1), the contour of the ore body (2); 9—mine workings (1), exploration holes (2)

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plast-like, lenticular and vein-like shape, are identified. The extent of ore bodies are proven to a depth of 100–130 m. The ore bodies have a thickness of 10–35 m and a strike length of up to 180 m. The mineralogical composition of the ores consists of chalcopyrite, molybdenite, pyrite, scheelite, galena, and other ore minerals. Ore reserves are 191 thousand tons, including 2800 tons of copper. In ores of industrial importance, the copper content is 1.47 wt. % and tungsten trioxide is 0.37 wt%. The work is conducted within the State Task of the Ministry of Science and Higher Education of the Russian Federation. Geochemical and geochronological data were obtained by the grant of the RSF No 18-17-00240.

References Bryan SE, Ferrari L (2013) Large Igneous Provinces and Silicic Large Igneous Provinces: progress in our understanding over the last 25 years. Geol Soc Am Bull 125:1053–1078 Ernst RE (2014) Large igneous provinces. Cambridge University Press, 653 p Fedorovsky VS, Sklyarov EV, Izokh AE, Kotov AB, Lavrenchuk AV, Mazukabzov AM (2010) Strike-slip tectonics and subalkaline mafic magmatism in the Early Paleozoic collisional system of the Western Baikal Region. Russ Geol Geophys 51(5):534–547 Fedorovsky VS, Vladimirov AG, Khain EV, Kargopolov SA, Gibsher AS, Izokh AE (1995) Tectonics, metamorphism and magmatism of collision zones of the Caledonides of Central Asia. Geotectonika 3:3–22 Halfin SL (1965) Petrology of the Kogtakh gabbro-monzonite-syenite complex (Kuznetsk Alatau). P.H. Nauka, Novosibirsk, p 92 Izokh AE, Polyakov GV, Gibsher AS, Balykin PA, Zhuravlev DZ, Parkhomenko VA (1998) High-alumina layered gabbroids of the Central Asian fold belt (geochemical features, age and geodynamic conditions of formation). Geol Geophys 39(11):93–111 Izokh AE, Vishnevsky AV, Polyakov GV, Kalugin VM, Shelepaev RA, Egorova VV, Oyunchimeg T (2010) The Ureg Nuur Pt-bearing volcanoplutonic picrite-basalt association in the Mongolian Altay as evidence for a Cambrian-Ordovician large igneous province. Russ Geol Geophys 51(5):665–681 Izokh AE, Vishnevsky AV, Shelepaev RA, Polyakov GV, Gertner IF, Vrublevskii VV (2018) The Khairkhan dunite-troctolite-gabbro massif (Lake Zone of Western Mongolia) as an example of Middle Cambrian syncollisional gabbroids. In: Petrology of magmatic and metamorphic complexes: Proceedings of the X All-Russian petrographic conference with international participation. P.H. Tomsk CSTI, Tomsk, pp 169–173 Khain EV, Amelin YuV, Izokh AE (1996) Sm-Nd data on the age of ultrabasic-basic complexes in the subduction zone of Western Mongolia. Dokl Earth Sci 344:124–130 Khomichev VL, Soltsman AE, Shabalina ES (1969) Geological, structural and morphogenetic features of the Kiyalykh-Uzen skarn copper-molybdenum deposit. In: Geological, geochemical and morphological features of the magmatogenous ore deposits of the Altai-Sayan folded region. P.H. SNIIGGiMS, Novosibirsk, pp 178–182 (Tr. SNIIGGiMS, Iss. 104)

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Krivenko AP, Polyakov GV, Bognibov VI et al (1979) Gabbro-monzodiorite formation of the Kuznetsk Alatau. In: Basic and ultrabasic complexes of Siberia. Novosibirsk, pp 5–96 Kutolin VA (ed) (1990) Gabbroid formations of Western Mongolia. P.H. “Nauka”, Novosibirsk, 385 p Kuznetsov YuA, Bognibov VI, Distanova AN, Sergeeva ES (1971) The early granitoid association of the Kuznetsk Alatau. Publishing House “Nauka”, Moscow, 352 p Metelkin DV (2013) Kinematic reconstruction of the Early Caledonian accretion in the Southwest of the Siberian Paleocontinent based on paleomagnetic results. Russ Geol Geophys 54(4):381–398 Pokrovsky BG, Andreeva ED, Vrublevskii VV, Grinev OM (1998) Contamination mechanisms of alkaline-gabbroid intrusions in the southern framing of the Siberian Platform: evidence from strontium and oxygen isotopic compositions. Petrology 6 (3):237–251 Rudnev SN, Vladimirov AG, Ponomarchuk VA, Kruk NN, Babin GA, Borisov SM (2004) Early Paleozoic granitoid batholiths of the Altai-Sayan folded region (lateral-temporal zoning and sources). Dokl Earth Sci 396(4):492–495 Shelepaev RA, Egorova VV, Izokh AE, Zeltmann R (2018) Collisional mafic magmatism of the fold-thrust belts framing Southern Siberia (Western Sangilen, Southeastern Tuva). Geol Geophys 59(5):525–540 Shokalsky SP, Babin GA, Vladimirov AG et al (2000) Correlation of magmatic and metamorphic complexes of the western part of the Altai-Sayan folded region. P.H. “Geo”, Novosibirsk, 187 p Vladimirov AG, Gibsher AS, Izokh AE, Rudnev SN (1999) Early Paleozoic granitoid batholiths of Central Asia: abundance, sources, and geodynamic formation conditions. Dokl Earth Sci 369:1268–1271 Vrublevskii VV (2015) Sources and geodynamic setting of petrogenesis of the Middle Cambrian Upper Petropavlovka alkaline basic pluton (Kuznetsk Alatau, Siberia). Russ Geol Geophys 56(3):379–401 Vrublevskii VV, Gertner IF (2017) Evolution and chemical geodynamics of Paleozoic alkaline mafic intrusive magmatism of the Kuznetsk Alatau, Siberia. Petrology Vrublevskii VV, Kotelnikov AD, Izokh AE (2018) Age, petrological and geochemical conditions of the formation of the Kogtakh gabbro-monzonite complex of the Kuznetsk Alatau. Russ Geol Geophys 59(7):900–930 Vrublevskii VV, Grinev OM, Izokh AE, Travin AV (2016a) Geochemistry, isotope triad (Nd–Sr–O) and 40Ar-39Ar age of Paleozoic alkaline mafic intrusions of the Kuznetsk Alatau (by the example of the Belaya Gora pluton). Russ Geol Geophys 57(3):464–472 Vrublevskii VV, Kotelnikov AD, Krupchatnikov VI (2016b) Late Precambrian OIB magmatism in the Kuznetsk Alatau, Siberia: geochemical features of the Kulbyurstyug formation volcanics. Dokl Earth Sci 469(4):807–810 Vrublevskii VV, Kotelnikov AD, Rudnev SN, Krupchatnikov VI (2016c) Evolution of the Paleozoic granitoid magmatism in the Kuznetsk Alatau: new geochemical and U-Pb (SHRIMP-II) isotope data. Russ Geol Geophys 57(2):225–246 Ziv EF (1939) Scheelite in skarns of the eastern slope of the Kuznetsk Alatau. In: Transactions of the all-union scientific research institute of economic mineralogy 145, pp 1–163 (in Russian)

Late Cretaceous Intracontinental Alkaline-Basaltoid Magmatism of the Chebakovo-Balakhta Depression A. E. Izokh, G. S. Fedoseev and V. A. Kutolin

Late Cretaceous explosion pipes (diatremes) and dikes of alkali basalts with mantle xenoliths of lherzolites and pyroxenites are unique magmatic formations of Khakassia. They are concentrated in the North Minusinsk (Chebakovo-Balakhta) basin and are associated with a Late Mesozoic tectonomagmatic activation and the processes of intracontinental rifting (Fig. 1). The diversity of the xenolith compositions of and paragenetic associations reveals the lateral heterogeneity of the upper mantle in a relatively small area, which is of considerable theoretical interest (Sobolev et al. 1988). That’s why these formations were repeatedly visited by participants of a number of international meetings held in Novosibirsk: the sessions of the International Mineralogical Association IMA (1978), the symposium “Composition and processes of the deep zones of the continental lithosphere” (1988), and 6th Kimberlite Conference (1995) (Sobolev et al. 1988).

A. E. Izokh (&)
G. S. Fedoseev
V. A. Kutolin V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk Akademika Koptyuga Str., 3, 630090, Russia e-mail: [email protected] G. S. Fedoseev e-mail: [email protected] V. A. Kutolin e-mail: [email protected] A. E. Izokh
G. S. Fedoseev
V. A. Kutolin Novosibirsk State University, Novosibirsk Pirogova Str., 2, 630090, Russia © Springer Nature Switzerland AG 2020 R. Ernst et al. (eds.), Geological Tour of Devonian and Ordovician Magmatism of Kuznetsk Alatau and Minusinsk Basin, GeoGuide, https://doi.org/10.1007/978-3-030-29559-2_9

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Fig. 1 Distribution of the explosion pipes in the area of the Kopievsky uplift (according to Malkovets 2001, with simplifications). 1—alluvial deposits (Q); 2—sandstones, siltstones, mudstones (PZ3); 3—sandstones, carbonaceous siltstones (C1v); 4—sandstones, siltstones, limestones (C1t); 5—sandstones, siltstones, mudstones (D3fm); 6 — sandstones, siltstones, mudstones (D3fr); 7—conglomerates, sandstones (D2gv); 8—sedimentary-volcanogenic deposits of the Byskar series (D1); 9—explosion pipes: 1—Belye, 2—Krasnoozerskaya, 3— Dzhirim; 4—Chebaldak, 5—Tergeshskaya, 6—Tochilnaya, 7—Pridorozhnaya, 8—Intikol, 9 —Barajulskaya, 10—Dodonkov, 11—Sestra, 12—Kladbishenskaya, 13—Height 465, 14— Kongarovskaya, 15—Three Brata, 16—Botikha, 17—Uzhur, 18—Parilov, 19— Kamyshtinskaya-1, 20—Kamyshtinskaya-2

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Explosion pipes are a true decoration of the flat-hilly relief of Khakassia. They form peaked structures, from a distance resembling volcanic cones. Their first description was given by Y.S. Edelstein, who conducted geological studies in the Achinsk gold-bearing district in 1907. In the 1930s they were studied in more detail (Edelstein 1932; Churakov 1932; Kotelnikov 1936). In some pipes Okhapkin and Chubugina (1970) discovered mantle xenoliths containing pyrope, chrome-diopside and magnesial olivine (Kalmykov 1970; Kryukov 1964a–c) and ultrabasic nodules in basalts (Vakhrushev and Kutolin 1970; Kutolin and Frolova 1970, 1972). Currently, more than 40 diatremes are known, located mainly in the Upper Devonian sediments. The exception is the Inkol pipe, located in Lower Carboniferous strata.

1

Location of Diatremes

All the pipes and dikes are concentrated in the northern part of the Minusinsk Trough around the Kopievsky uplift, where they are confined to the flexures of the north-west strike of the deep faults (Kryukov 1964a). Most of the pipes form chains of the north-west direction along weakened tectonic zones. The Pridorozhnaya, Tochilnaya, Tergesh, Chebaldak and Krasnoozerskaya pipes are practically lying on one line. Three areas of development of pipes and alkaline basaltoid dykes are distinguished—Northern, Southern and Western (Sobolev et al. 1988; Malkovets 2001). The largest number of dikes is found in the Northern (18) and Southern (25) areas. In the Western range there are only single dikes (Itkolskaya, Chernozernaya, Chebaldakskaya and others). In addition to their linear arrangement, a confinement of the diatremes to certain zones of northwestern striking faults is also established. In one of such zones are Intikol, Barajulskaya, Kongarovskaya, Sestra, Klad, Three Brata, Botikha and Uzhur pipes. Most of these pipes are accompanied by basalt dykes of northeast and east-northeast strike. Some pipes (Kuzurbinsky, Barajulskaya, Chiri) and dikes (Dodonkovsky) are located away from this zone. They are inclined to occur near tectonic faults and flexures, which are considered as external manifestations of deep tectonic faults. So, there are five pipes near the Dzherimsky flexure, and near the Uchumskaya flexure there are two Kamyshtinskaya pipes and dikes of the north-east strike. The diatremes have an isometric shape with a diameter of approximately hundred meters and consist mainly of explosive breccias, which have erupted in two or three stages. Basalts were emplaced at the final stage of the pipe formation.

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They break through the breccias, forming sickle-shaped bodies and veins of irregular shape. Breccias consist of a large number of angular fragments of host rocks: sandstones, mudstones, and mudstones. Various mantle and crustal xenoliths are also present. Breccia is cemented by a heavily modified brown fine-grained basic mass. The basalts also contain mantle xenoliths (pyroxenites and lherzolites), which are completely fresh as opposed to highly weathered inclusions in breccia. The size of the nodules of ultramafic rocks varies from a few millimeters to 5–10 cm, and less often there are inclusions with a diameter of up to 20–30 cm. The shape of the inclusions is usually rounded.

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Geological Structure of Diatremes

Note that some well-studied pipes, will not be visited by the participants of the excursion because of their remoteness and lack of time. The Barajulskaya pipe, confined to the flexure of the same name, has clear and relatively even contacts (Deep 1975; Vladimirov et al. 1976; Sobolev et al. 1988; Ovchinnikov 1989; Malkovets 2001). Contact metamorphism is weak, but there are signs of a mechanical effect on the horizontal lying sandstones of the Saragash Formation. The eruptive breccias form the outer ring of the pipe, and the basalts form a dike with a thickness of 10 m and a length of about 300 m. One end of the dyke is in the effusive rocks of the Kopievsky series (D1), and the other end is among the eruptive breccia of the pipe. The Kongarovskaya pipe is located on a two-headed hill with a height of 380.6 m (Shelkovnikov and Makarov 1963; Kryukov 1964c). The enclosing rocks are red-colored rocks of the Aidanovskaya series (D3) and coal-bearing deposits of the Khakass series (C2–3). They have a subhorizontal occurrence. The areal dimensions of the pipe is of 260  140 m. The pipe is mainly (70–80%) composed of two-generation eruptive breccias. The debris in the breccia of the first phase consists mainly of mudstone, sandstone, tuffstone, limestone, marl, and effusive. Among them are xenoliths of peridotites, pyroxenites, megacrysts of titanaugite, sanidine, and titanomagnetite. Breccia cement is intensely carbonated and enriched in iron, so the breccias are brown in color. Breccias of the second phase have a black color. They form the central part of the pipe. Carbonaceous mudstones, siltstones and coals predominate in the debris composition. Basalts compose several necks and dikes. The Trii Brata (the Three Brothers) basaltic neck is located in its close proximity. It is represented by three separate bodies, eroded in the form of a three-headed peak. Basalts contain small (up to 5–8 mm) peridotite nodules.

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Fig. 2 The Belyo pipe (north-western shore of Lake Belyo). Photo by V. Lukoshkina

In the Beleu pipe, weathered and ferruginous breccias practically contain no inclusions of deep rocks. The xenoliths are concentrated in basalts, exposed on the top of a 100-m hill (Fig. 2). The basalts contain a large amount of various crustal and mantle xenoliths ranging in size from 1 to 20 cm, as well as monomineral inclusions—megacrystals. The accompanying basalt dike is characterized by a columnar jointing. Xenoliths are represented by fragments of crustal (gabbro, granite, and granulite) and mantle (lherzolite and pyroxenite) rocks. Unlike other pipes of Khakassia, among the xenoliths of the Beleu pipe, pyroxenites prevail over lherzolites. Pyrope peridotites and eclogites were also found in this diatreme. The “black” series of pyroxenites is represented by spinel augitites and wehrlites. In the “green” pyroxenite series, most are garnet websterites and spinel clinopyroxenites. The formation temperatures of garnet- and spinel-containing parageneses for the Beleo pipe are estimated to be 900 to 1020 °C, and pressures are 13–16 kbar (Sobolev et al. 1988). According to the structural features, two types are distinguished among the Khakassian pipes—complex and simple. Pipes of a complex type are more common. They have been formed in two stages and are characterized by a variety of mineral parageneses in mantle xenoliths. This type includes Beleo, Barajulskaya, Kongarovskaya and Tergesh pipes (Stop 11). All of them form oval bodies of size ranging from 150 to 250 m along the long axis and stand out in relief in the form of peaked hills 40–50 m or more in height. The formation of the pipes took place in two stages: first, eruptive breccias were formed, and then basalts. The basalts form

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necks and dikes, which are located either among the breccias or form independent bodies in the enclosing strata. Basalts are characterized by increased alkalinity (up to 5–6 wt% of Na2O + K2O) and magnesia (up to 12 wt% of MgO) (Table 1). In some places variolitic structures are developed in them. Phenocrysts are represented by ferruginous olivine, titanaugite and titanomagnetite. The matrix is composed of plagioclase, titanaugite and titanomagnetite. In the interstices, nepheline is diagnosed, that allows classifying these rocks as basanites (olivine tephrites). In some pipes, pyrope megacrysts (up to 0.5 cm) and sanidine megacrysts (up to 6 cm) are also found.

Table 1 Major oxides (wt. %) и rare element (ppm) contents in mafic units from the Tergesh pipe Sample SiO2 TiO2 Cr2O3 Al2O3 FeO MnO MgO CaO Na2O K2O P2O5 Cl LOI H2O F Sum Li Be B Sc V Cr Co

Tsh-2 43.96 2.45 – 14.22 11.50 0.17 8.54 10.05 3.50 1.38 0.77 – 2.06 – – 99.90 11 2.5 – 19 169 170 47

Tsh-ssv 43.95 2.49 – 14.32 12.51 0.18 8.90 9.82 3.18 1.88 0.78 – 0.98 – – 99.97 10 2.7 – 17 167 181 47

Tsh-65 46.24 1.80 – 13.52 10.29 0.16 10.65 8.15 2.12 1.53 0.57 0.35 2.93 – – 100.10 – – – – 186 488 –

Tsh-66 45.73 1.89 – 13.70 10.85 0.17 10.16 8.53 2.99 1.57 0.59 0.05 2.78 – – 100.15 – – – – 165 516 –

Tsh-77 44.89 2.35 – 14.90 11.25 0.17 8.28 8.1 3.40 1.15 0.770 0.05 2.58 – – 100.12 – – – – 245 279 –

Tsh-78 44.29 2.33 – 14.62 11.24 0.17 8.12 9.34 3.25 1.41 0.69 0.24 3.41 – – 100.10 – – – – 174 138 –

Tsh-77* 54.14 1.17 0.01 22.44 6.06 0.11 0.92 1.65 3.28 3.48 0.73 0.19 – 6.04 0.12 100.34 21 5.2 8.7 0.4 32 10 – (continued)

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Table 1 (continued) Ni 143 148 145 171 68 65 – Cu 67 65 44 58 44 42 – Zn – – 62 84 85 76 – Ga 20 20 6.9 14 14 11 – Rb 23 26 14 18 18 17 71 Sr 1170 1090 602 803 984 945 537 Y 24 23 16 17 17 15 21 Zr 207 207 132 1658 388 525 278 Nb 95 97 59 67 79 74 232 Mo 5.5 6.8 1.7 3.9 4.2 5.4 – Sn – – 1.9 2.1 3 2.3 – Cs 0.4 0.4