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Pleistocene glaciations of the SE Altai, Russia, based on geomorphological data and absolute dating of glacial deposits in Chagan reference section

Anna R Agatova
Anna R Agatova
 and 
Roman K Nepop
Roman K Nepop
   | Mar 30, 2017
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Published Online: Mar 30, 2017
Page range: 49 - 65
Received: Jun 25, 2016
Accepted: Feb 09, 2017
DOI: https://doi.org/10.1515/geochr-2015-0059
Keywords
© 2016 A. R. Agatova and R. K. Nepop
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig 1

Location of the Altai Mountains.
Location of the Altai Mountains.

Fig 2

Neotectonic profile across Altai Mountains (See Fig.3 for profile location) and trends of average summer temperature and annual precipitation.
Neotectonic profile across Altai Mountains (See Fig.3 for profile location) and trends of average summer temperature and annual precipitation.

Fig 3

Location of the Russian Altai within the Altai Mountains. Star shows the location of the Chagan section.
Location of the Russian Altai within the Altai Mountains. Star shows the location of the Chagan section.

Fig 4

Spatial distribution of glacial landforms and sediments of different states of preservation within the Chagan-Uzun massif. The cross-section across the Taldura-Chagan watershed (A-B) is shown below. Deposits of Miocene and Pliocene epochs are indexed as N11-3 and N21-2 correspondingly, and Pleistocene – as Q1-3 according to Stratigraphic Code of Russia (Zhamoida, 2006). Taking into account the lack of reliable absolute dates we follow the traditional Russian scheme of relative ages of ancient glaciations within the Russian Altai (Devyatkin, 1965; Okishev, 1982), where Q4 indicates the Holocene glacier advances, Q3 is associated with the late Pleistocene (Würm according Alpine scheme) including Q32 and Q34 – Zyryanka and Sartan stages according Siberian stratigraphic scheme correspondingly, and Q2 – middle Pleistocene (Riss according Alpine scheme). 1 – flattened and washed moraines, partly covered by sub-aerial cryogenic loams (Q2 ?); 2 – distal complex of well-preserved terminal and side moraines within Chuya depression, (Q32 ?); 3 – proximal complex of well-preserved terminal and side moraines, (Q34 ?); 4 – late Pleistocene – Holocene moraine ramparts of different glacial stages within river valleys, (Q34); 5 – LIA moraines, (Q4); 6 – glacial-lacustrine sediments of different ages; 7 – alluvial deposits; 8 – lakes and rivers; 9 – glaciers; 10 – altitudes (m a.s.l.); 11 – Chagan section; 12 – Chagan-Uzun River bounders. A-B – location of the cross-section across the Taldura-Chagan watershed.Photos demonstrate moraines of different state of preservation and their locations (number in rectangle) within the basin.
Spatial distribution of glacial landforms and sediments of different states of preservation within the Chagan-Uzun massif. The cross-section across the Taldura-Chagan watershed (A-B) is shown below. Deposits of Miocene and Pliocene epochs are indexed as N11-3 and N21-2 correspondingly, and Pleistocene – as Q1-3 according to Stratigraphic Code of Russia (Zhamoida, 2006). Taking into account the lack of reliable absolute dates we follow the traditional Russian scheme of relative ages of ancient glaciations within the Russian Altai (Devyatkin, 1965; Okishev, 1982), where Q4 indicates the Holocene glacier advances, Q3 is associated with the late Pleistocene (Würm according Alpine scheme) including Q32 and Q34 – Zyryanka and Sartan stages according Siberian stratigraphic scheme correspondingly, and Q2 – middle Pleistocene (Riss according Alpine scheme). 1 – flattened and washed moraines, partly covered by sub-aerial cryogenic loams (Q2 ?); 2 – distal complex of well-preserved terminal and side moraines within Chuya depression, (Q32 ?); 3 – proximal complex of well-preserved terminal and side moraines, (Q34 ?); 4 – late Pleistocene – Holocene moraine ramparts of different glacial stages within river valleys, (Q34); 5 – LIA moraines, (Q4); 6 – glacial-lacustrine sediments of different ages; 7 – alluvial deposits; 8 – lakes and rivers; 9 – glaciers; 10 – altitudes (m a.s.l.); 11 – Chagan section; 12 – Chagan-Uzun River bounders. A-B – location of the cross-section across the Taldura-Chagan watershed.Photos demonstrate moraines of different state of preservation and their locations (number in rectangle) within the basin.

Fig 5

Chagan section – the regional reference sections of the Pleistocene glacial, glacio-fluvial, and glacio-lacustrine deposits. Aerial photograph A) and common view of the section B). Arrow shows the location of the studied section (Fig. 7). Regional suites and types of deposits are described in Fig.4.
Chagan section – the regional reference sections of the Pleistocene glacial, glacio-fluvial, and glacio-lacustrine deposits. Aerial photograph A) and common view of the section B). Arrow shows the location of the studied section (Fig. 7). Regional suites and types of deposits are described in Fig.4.

Fig 6

Correlation scheme of absolute dates for glacial sediments from Chagan section obtained by different authors. Designation of deposition units is given in Fig. 7.* No information about both the dating laboratory and sample codes was presented by the author. First mention about these dates was given in 90th of the last century (Sheinkman, 1990, P. 81). Twelve years later these dates were recalculated (Sheinkman, 2002, P. 45, 46) (without any explanations of methodology or the reasons) and their position in the section was specified (underlined dates). This could not allow utilising these data as the “new generation dates”, as they were presented in (Zol’nikov and Mistrukov, 2008 and Rusanov, 2011)
Correlation scheme of absolute dates for glacial sediments from Chagan section obtained by different authors. Designation of deposition units is given in Fig. 7.* No information about both the dating laboratory and sample codes was presented by the author. First mention about these dates was given in 90th of the last century (Sheinkman, 1990, P. 81). Twelve years later these dates were recalculated (Sheinkman, 2002, P. 45, 46) (without any explanations of methodology or the reasons) and their position in the section was specified (underlined dates). This could not allow utilising these data as the “new generation dates”, as they were presented in (Zol’nikov and Mistrukov, 2008 and Rusanov, 2011)

Fig 7

New absolute dates of glacial and associated sediments from the Chagan section.
New absolute dates of glacial and associated sediments from the Chagan section.

Obtained absolute dates.Applied techniques: RTL – radiotermoluminescence; IRSL – Infra Red stimulated luminescence; 14C – scintillation radiocarbon analysis (both calibrated (2σ) and radiocarbon (in brackets) ages are given).

NSampleLab. codeTechniqueAge (ka)
12001/04BuGIN 504RTL60±11
MSU NS-4RTL106 ± 27
22001/05BuGIN 498RTL25 ± 4
MSU NS-5RTL127 ± 32
32001/06MSU NS-6RTL260 ± 65
42001/07BuGIN 503RTL140 ± 17
MSU NS-7RTL336 ± 84
52001/10BuGIN 501RTL124 ± 15
62001/13MSU NS-13RTL251 ± 63
72001/18MSU NS-18RTL151 ± 38
BuGIN 506RTL190 ± 23
82001/19BuGIN 513RTL41 ± 6
MSU NS-19RTL290 ± 73
92003/02BuGIN 664RTL380 ± 51
102003/03BuGIN 665RTL310 ± 50
112003/05MSU NS-305RTL480 ± 20
122003/08BuGIN 669RTL253 ± 26
132003/10BuGIN 670RTL340 ± 46
MSU NS-310RTL505 ± 20
142003/11BuGIN 671RTL330 ± 57
15CHM1IRSL236 ± 52
16CHM5IRSL≥360
17CHM8IRSL≥220
18SOAN 854814C30.189 ± 0.548
(25.470 ± 0.195)
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