Geochronology of the Late Pleistocene Catastrophic Biya Debris Flow And
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This article was downloaded by: [95.215.86.12] On: 07 July 2015, At: 05:32 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: 5 Howick Place, London, SW1P 1WG International Geology Review Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tigr20 Geochronology of the late Pleistocene catastrophic Biya debris flow and the Lake Teletskoye formation, Altai Region, Southern Siberia Gennady Baryshnikova, Andrei Paninb & Grzegorz Adamiecc a Geography Faculty, Altai State University, Barnaul, Russia b Geography Faculty, Lomonosov Moscow State University, Moscow, Russia c GADAM Centre, Institute of Physics, Silesian University of Technology, Gliwice, Poland Published online: 06 Jul 2015. Click for updates To cite this article: Gennady Baryshnikov, Andrei Panin & Grzegorz Adamiec (2015): Geochronology of the late Pleistocene catastrophic Biya debris flow and the Lake Teletskoye formation, Altai Region, Southern Siberia, International Geology Review, DOI: 10.1080/00206814.2015.1062733 To link to this article: http://dx.doi.org/10.1080/00206814.2015.1062733 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. 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Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions INTERNATIONAL GEOLOGY REVIEW, 2015 http://dx.doi.org/10.1080/00206814.2015.1062733 Geochronology of the late Pleistocene catastrophic Biya debris flow and the Lake Teletskoye formation, Altai Region, Southern Siberia Gennady Baryshnikova, Andrei Paninb and Grzegorz Adamiecc aGeography Faculty, Altai State University, Barnaul, Russia; bGeography Faculty, Lomonosov Moscow State University, Moscow, Russia; cGADAM Centre, Institute of Physics, Silesian University of Technology, Gliwice, Poland ABSTRACT ARTICLE HISTORY In the Biya River valley flowing from Lake Teletskoye, geomorphic and sedimentological evidence Received 1 March 2015 of a catastrophic debris flow has been found and assigned to glacier retreat after the last glacial Accepted 11 June 2015 maximum. Here, we report the results of lithological analysis of three sedimentary sections along KEYWORDS – Lake Teletskoye the Biya River valley system and optically stimulated luminescence dating of key megaflood; outburst stratigraphic units that led to a revised model for the geomorphic history of the region. Maximal flood; debris flow; glacier advance is suggested to have occurred during MIS 4–early MIS 3. It was accompanied by moraine-dammed lake; OSL the damming of tributary valleys by ice, by terminal and side moraines, and by the accelerated dating; valley incision and aggradation of the trunk valley below the glacier front. Formation of Lake Teletskoye, which aggradation; deglaciation followed the glacier retreat, occurred between 35 and 40 ka BP, most probably around 37.5 ka BP. Lake formation was shortly followed by a break in the moraine dam, catastrophic debris flow, rapid valley incision, and reduction in the lake level by ~100 m. Subsequently, incision has proceeded at a much lower rate and produced valley deepening and lake lowering of 30–35 m in the last 35–40 ka, or 0.8–0.9 m per thousand years on average. Introduction Numerous studies of megafloods in the Altai have focused on outflows from ancient lakes dammed in the In the Russian Altai, evidence has been recognized of Chuya and Kurai basins in southeast Altai, through the past megafloods – massive freshwater floods with dis- ‒ Chuya and Katun river valleys (Baker et al. 1993; Rudoy, charges that exceeded 1 million m3 s 1,or1Sv(Baker, Baker, 1993; Rudoy 2002; Herget 2005; Carling et al. 2013). More than three decades ago, giant current 2009; Carling 2013; etc.; see review of publications ear- ripples were found in Altai in the valleys of the lier 1991 in Baryshnikov (1992)). Much less attention has Bashkaus, Chuya, and Katun rivers and in the Kurai been paid to the development of the other headwater Basin (Butvilovskiy 1982, 1985;Okishev1982;Rudoy of the Ob River system – the Biya River valley. Downloaded by [95.215.86.12] at 05:32 07 July 2015 1984), as well as in the Biya River valley (Baryshnikov Baryshnikov (1992) proposed that outburst floods in 1976, Baryshnikov, 1992). A number of workers the Biya valley had a different mechanism to that in hypothesized that these features are glacial till the Katun–Chuya system, where megafloods originated (Borisov and Minina 1979;Okishev1982, 2011). from breaks in dams formed by glaciers descending However, the majority of scholars interpret them as from tributary valleys. In the Biya valley, glaciers occu- evidence of catastrophic outburst floods that resulted pied the main valley itself and a large lake formed after from water flowing from big lakes formed due to glacier retreat due to damming by terminal moraines. blockage of rivers by glaciers. Later, other evidence of Destruction of the moraine dam was followed by a huge outbursts from glacial lakes was recognized, such as debris flow that spread for many tens of kilometres spillways and distant transportation of giant rocks torn downstream and probably extended out to the lowland from valley sides. Palaeohydraulic assessments (Baker section of the valley and to the Ob River. This event was et al. 1993;Herget2005;Carlinget al. 2010) indicate attributed to the late Pleniglacial shortly after the Last that the Altai outburst floods were up to 400 m deep, Glacial Maximum (LGM) (Baryshnikov 1992). The release flowed at 20–25 m s‒1, and discharged 10–20 million ‒ of a large amount of water initiated the Biya River m3 s 1, similar to the well-known Missoula flooding in incision and the formation of a series of fluvial terraces. the western USA (Baker 2009). CONTACT Andrei Panin [email protected] © 2015 Taylor & Francis 2 G. BARYSHNIKOV ET AL. The post-LGM age estimate for the drainage of the Regional settings: northeast Altai and the moraine-dammed lake in the Biya valley gave rise to the upper Biya valley late Pleniglacial dating of the maximal glacier advance Altai is a mountain terrain in southern Siberia, at the and to post-LGM dating of Lake Teletskoye. However, Russian political boundary with Mongolia, China, and this timing is still not completely clear because it is Kazakhstan (Figure 1). The modern basin-and-range based on indirect data – relatively few radiocarbon dates structure was developed during the late Cenozoic, in the range 15–16 ka (uncal) derived from fine-grained mostly during the late Pliocene–early Quaternary. At sediments in tributary valleys that were interpreted as that time, the Teletsky rift valley was formed and filled deposits of lakes dammed by side levees produced by by the ancient Lake Teletskoye. Tectonic restructuring the giant mudflow in the main valley (Baryshnikov 1992). led to large-scale transformation of the drainage net- Previously, no data were collected on the absolute geo- work, which is evident in the finds of alluvial gravels on chronology of the Biya River and tributary valley terraces watersheds far from the trunk river valleys. According to that could give direct estimation of the timing of the Baryshnikov (1984), in the early middle Pleistocene the outburst flood and subsequent valley deepening. Our ancient Biya was a small river whose upper course did goal in this study was to obtain numerical ages for the not reach Turachak village (Figure 2(a)). In this manner it alluvial fills in the Biya River–Lake Teletskoye system and is distinguished from the Katun, which totally inherited to use these as time constraints for the catastrophic drai- its valley from initial fluvial systems. In the late middle nage of the dammed lake and formation of the modern Pleistocene, outflow from Lake Teletskoye began and Lake Teletskoye. Downloaded by [95.215.86.12] at 05:32 07 July 2015 Figure 1. Location map. (a) Russian Altai; (b) Lake Teletskoye region. Open squares with numerals denote study sites: (1) Chechenek River at Yaylyu; (2) Yogach River at Artybash; 3: Turochak River at Kebezen’. INTERNATIONAL GEOLOGY REVIEW 3 Figure 2. Evolution of the drainage net in northeast Altai (after Baryshnikov 1992). the Biya valley reach between the lake and Turachak At the source of the Biya the described lacustrine/ village was formed (Figure 2(c)). Therefore, the modern alluvial sequence is buried under glacial till (Figure 3). Biya valley is a combination