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

Abstract

Geomorphological evidence of at least two Pleistocene glacial epochsis noted within the Chagan-Uzun river basin, SE Altai. A review and analysis of all available absolute dates for reference Chagan section is presented. The highest correlation amongst all TL dates is observed for the lens of glacio-lacustrine sediments -the most suitable among glacial deposits for luminescence dating, and indicates its possible Middle Pleistocene age. IRSL dates obtained from feldspar indicate a Middle Pleistocene age of moraines already in the upper part of the section. The small number of obtained IRSL dates does not allow making geochronological reconstructions of the Pleistocene glaciations, but gives the possibility for further experiments with different variation of OSL (IRSL) techniques. Strong low temperature peak in TL signal and strong response to IR stimulation are specific regional quartz features, which could be explained by combination of short transportation distance and low number of depositional cycles for mineral grains. Available radiocarbon dates of carbonate concretions from this section are not related to the age of moraine sedimentation and most likely indicate the period of the Chagan river incision into the ancient glacial deposits. This study has shown that TL method is not valid for dating glacial sediments and TL dates cannot be utilized as chronostratigraphic markers. Generally, the Chagan section could hardly serve as a reference section for the Altai stratigraphy; available depositional correlation schemes for the Russian Altai and Siberia which are based on several TL dates obtained in the last century needs to be improved.

Application of Rock Weathering and Colonization by Biota for the Relative Dating of Moraines from the Arid Part of the Russian Altai Mountains

“…Later, the use of a TL technique based on applying naturally saturated etalons [94] showed that the formation of the entire gray-colored strata of the Chagan moraines in this section occurred in the interval from 135 ± 15 to 58 ± 7 ka BP. Later research led the authors of [27] to the conclusion that the use of modern TL technologies for dating moraines is inappropriate.…”

“…al. [27] studied the applicability of the TL method for the dating of glacial sediments in Chagan-Uzun. It was found out that the dating results of the same sample, performed in different laboratories, were very different, and both had poor agreement with the stratigraphic position of the samples in the section.…”

Potentiality of Charcoal as a Dendrochronological and Paleoclimatic Archive: Case Study of Archaeological Charcoal from Southeastern Altai, Russia

“…and are high enough for the formation of glaciers. The number and extent of Pleistocene glaciations remains a subject of discussion [24], and the middle-late Holocene glacier advance was inferred to have occurred in three events [2,25].…”

Climatically Driven Holocene Glacier Advances in the Russian Altai Based on Radiocarbon and OSL Dating and Tree Ring Analysis

“…The high-mountain, south-eastern part of the Russian Altai (SE Altai, Figure 1), which is examined in this paper, is characterized by strongly dissected topography-the result of Cenozoic orogenesis [5,32,33]. Summits rise above the floors of intermountain depressions and major valleys up to 2600-3000 m, which is one of the largest values for the whole Altai Mountains system [33].…”