Durham Research Online Deposited in DRO: 30 May 2018 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Paxman, G. J. G. and Gregory, B. S. and Payne, S. J. and Forshaw, J. B. and Brady, M. P. and Khan, M. D. and Avadanii, D. and Wardle, G. and Wills, J. J. and Kovin, O. N. and Naumova, O. B. and Osovetskiy, B. M. and Naumov, V. A. (2015) 'Placer gold composition and provenance studies in the Kuznetskiy Alatau and Western Sayan, South-East Siberia : results of eld trip, Summer 2014.', Bulletin of Perm State University : geology., 1 (26). pp. 44-59. Further information on publisher's website: https://doi.org/10.17072/psu.geol.26.44 Publisher's copyright statement: The publication in this journal is licensed under a Creative Commons Attribution (CC BY) license. 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Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk ВЕСТНИК ПЕРМСКОГО УНИВЕРСИТЕТА 2015 ГЕОЛОГИЯ Вып. 1 (26) ГЕОЛОГИЯ, ПОИСКИ И РАЗВЕДКА ТВЁРДЫХ ПОЛЕЗНЫХ ИСКОПАЕМЫХ, МИНЕРАГЕНИЯ УДК 553.08 Placer Gold Composition and Provenance Studies in the Kuznetskiy Alatau and Western Sayan, South- East Siberia: Results of Field Trip, Summer 2014 G. J. G. Paxmana, B. S. Gregorya, S. J. Paynea, J. B. Forshawа, M. P. Bradyа, M. D. Khana, D. Avadaniia, G. Wardlea, J. J. Willsb, O. N. Kovinc, O. B. Naumovac, B. M. Osovetskiyc, and V. A. Naumovd aDepartment of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK. E-mail: [email protected] bClarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK cGeological Faculty, Perm State University, 15 Bukireva Str., Perm 614990, Russia dNatural Sciences Institute of Perm State University, 4 Genkelya Str., Perm 614990, Russia This article presents the results of a study of gold samples obtained by students during a practical field trip in the summer of 2014. Placer gold samples retrieved from four rivers in southeast Siberia (Khakassia and Tyva territories) by panning and sluicing were de- scribed and analyzed compositionally by Scanning Electron Microscopy. There is evi- dence from grain flattening and morphology for significant variations in gold transport distance, both within and between sample locations. The composition and texture of gold is compared to similar studies in the Yukon, and it is inferred that most of the placer gold in the region originated from orogenic lode sources. This orogenic gold is of Devonian to Carboniferous age. There is also evidence for a contribution from igneous intrusion- related bedrock gold, which is supported by the presence of granite, granodiorite and sienite intrusions of Devonian age. There is scope for further study, since relatively few grains were analyzed here. In addition, if compositional data of the prospective primary gold deposits can be obtained, there would be potential for more precise determination of provenance. Keywords: placer gold; Kuznetskiy Alatau; West Sayan; Siberia; sampling; panning; composition; grain morphology. DOI: 10.17072/psu.geol.26.44 © Paxman G.J.G., Gregory B.S., Payne S. J., Forshaw J. B., Brady M. P., Khan M. D. et al., 2015 Placer Gold Composition and Provenance Studies in the Kuznetskiy Alatau … 45 Introduction Geographical settings Previous studies of the texture and com- The area of study is located within the position of placer gold samples from the southern part of Siberia and encompasses Western Yukon [3]; [7] have allowed the au- territories of the Khakassia, and Tyva (Tuva) thors to draw preliminary conclusions regard- Republics (figure 1). The Republic of Kha- ing the origin and depositional history of the kassia, whose capital city is Abakan, is locat- grains. In this study, we employ the same ed northwest from Tyva Republic. Krasno- methods on four river locations in southeast yarsk Kray, Kemerovskaya Oblast, Tyva Re- Siberia. The study was carried out in order to public, and Altay Republic border Khakassia. develop an understanding of the evolution of The Kuznetskiy Alatau Mountains serve as the gold deposits that are found in the alluvi- the geographical border to the west, with the um of these rivers. After recovering the plac- Western Sayan ranges stretching along the er gold from the locations, the samples were southern border. Eastern boundary of Kha- taken to Perm State University, Russia. Here, kassia is formed by the Dzhebashsky Range the gold grains were separated from the con- and Yenisey River [11]. centrate, and their chemical composition was In Khakassia, there are two rivers of in- analyzed. In addition, the morphology of the terest, at which samples were collected - the gold was described. The data were integrat- Abakan and Beliy Ius (figure 2). The Abakan ed, and some conclusions regarding the prov- River rises in the Altay Mountains and flows enance of the grains are presented here. From northeast through the Minusinsk Depression, the compositional data, we attempt to match joining the Yenisey River at the confluence placer gold particles to possible sources, in Abakan. The Beliy Ius, a tributary of the while the textural information provides an Chulym River, has its sources in the Kuz- insight into the transportation history of the netskiy Alatau. gold. Figure 1. Location of the study area Khakassia is rich in mineral resources Kyzyl, is located near the geographic centre (e.g. coal, iron ore, and nonferrous metal ore, of Asia. including gold). Two major rivers of Tyva, Bia Khem and The Tyva Republic is situated in the far Kaa Khem (with its tributary Bai Syut), are south of Siberia (figure 1). It borders Kha- tributaries of the Yenisey River (Ulug- kassia to the northwest, Krasnoyarsk Krai to Khem), which flows west through Tyva and the north, Altay to the southwest, Irkutskaya then passes through the Western Sayan Oblast to the northeast, Buryatia to the east, Mountains in a gorge containing the Sayano- and Mongolia to the south. Its capital city, Shushenskaya Dam. 46 G.J.G. Paxman, B.S. Gregory, S.J. Payne, J.B. Forshaw, M.P. Brady et al. The river then flows through the Mi- clude iron ore, gold, cobalt, coal and asbestos. nusinsk Hollow to the east of the Kuznetskiy Gold samples were taken from two localities Alatau. The Minusinsk Hollow also contains a in Tyva: Bia (Bii, Biy) Khem (Upper Yenisey famous deposit of coal: The Minusinsk Coal River) and Bai Syut (figure 2). Basin. Natural mineral resources of Tyva in- Figure 2. Sampling sites location. The yellow pins accompanied by white labels mark the four geo- graphic locations (rivers) at which gold samples were collected (modified from Google [5]) A wide range of lithologies outcrops within the Khakassia and Tyva Republics. In Geology and tectonics of the area general, a bimodal distribution of the geology is reflected in the landscape (figure 3). Precambrian to Upper Palaeozoic sedi- mentary and igneous rocks form the elevated regions of the Kuznetskiy Alatau and West- ern Sayan Mountains [10]. These rocks are juxtaposed against Devonian–Permian sedi- ments, which comprise the Minusinsk De- pression [14]. The action of approximately north–south-trending normal faults caused subsidence of the South Minusinsk Depres- sion in the Devonian while the regions to the north (Kuznetskiy Alatau) and south (West- ern Sayan Mountains) were contemporane- Figure 3. Geography of the south-central Siberia ously uplifted. Denudation of these uplifted area (modified from Wikipedia [17]). The area of Precambrian–Silurian rocks provided a sedi- study is shown by the orange box ment supply, which filled the accommoda- tion space. Sedimentation also occurred in Placer Gold Composition and Provenance Studies in the Kuznetskiy Alatau … 47 the North Minusinsk Depression to the ty was responsible for mineralization, includ- northeast of the Kuznetskiy Alatau. ing formation of intrusion-related gold de- The basement rocks are Rifean (Neopro- posits. These bedrock gold formations are a terozoic) to Cambrian in age [9]. They com- source of placer gold found in the present- prise a large sequence of meta-sedimentary day and paleo-rivers in the region. rocks metamorphosed during the Salair The tectonic processes of this region in (Kuznetskiy Alatau) and Caledonian Oroge- simple terms can be linked to the disintegra- nies (Western Sayan). An ophiolite sequence tion of Rodinia and formation of Pangaea is exposed, with ultramafic and gabbroic [13]. rocks at the base. The overlying pillow bas- There are four significant orogenic events alts are succeeded by metapelites, black in this region. The first occurred during the quartzites, and marbles. Typical metamor- Early Palaeozoic; its products are commonly phic conditions peaked in the amphibolite referred to as the Salairides. The event led to facies, although retrogression to greenschist the formation of the basement of the Mi- facies is common. Chlorite schists are ex- nusinsk Depression, and the Eastern Sayan posed in the Western Sayan Mountains. mountain range, which strikes southeast– These rocks are folded into large-scale anti- northwest for 1000 km from Lake Baikal to clinal and synclinal structures, which make the Yenisey River. up the Kuznetskiy Alatau and Western Sayan The next event, the Caledonian Orogeny, Mountains.