New data on Quaternary morpholithogenesis in the Chuya basin (Gorny Altai)

Abstract

New data have been obtained on the paleogeographic and stratigraphic assignment of Neopleistocene morpholithogenesis in the Chuya basin. They were derived from analysis of topographical maps, digital elevation models, and medium- and high-resolution satellite images as well as a textural and facies description of Quaternary sections. Near the basin side, a paragenetic association of sediments is widespread. These sediments, laid down by fluid debris flows and mudflows, formed a ridged terrain during the emptying of a Late Quaternary paleolake. A diluvial–erosional origin of a series of small parallel scarps has been suggested. They are usually interpreted as wave-cut benches, which mark temporary levels of a glacier-dammed lake. We have examined geological evidence for a high glacial dam with an age of maximum glaciation inside the Chuya basin. Because of the dam, glacier floods during the Middle Neopleistocene were larger than those during the Late Neopleistocene.

Palaeoshorelines of glacial Lake Kuray–Chuja, south-central Siberia: form, sediments and process

“…The tilted shorelines are largely due to tectonic motion and are believed to be Middle Pleistocene (Zol'nikov et al 2010). However, it is evident from the modelling studies that the effect of alongshore drift of sediment on pocket beach crest height will also need to be considered in many cases where tectonic tilting is suspected.…”

“…Cenozoic deposits infilling the Chuja and Kuray basins include Quaternary glacial moraine and glaciolacustrine deposits at the margins (Zol'nikov et al 2010). Within the Chagun-Uzun River valley (Fig.…”

“…2a) where glaciological studies indicate that three large glaciers converged and impounded the sole drainage outlet from the basin (Herget 2005;Carling et al 2009). Strandlines are also absent from other locations within the basins, where it is known that Pleistocene glaciers extended into the lake waters (Herget 2005;Zol'nikov et al 2010) including during the Late Glacial, but otherwise the basins were not glaciated at this latter time. At times of high water level there was one conjoined lake in the Kuray and Chuja basins.…”

“…At the extreme, one of these pocket beaches rises 55 m in a distance of 700 m (0.078) but is otherwise undistorted; it would be perfectly horizontal if the regional trend was subtracted. It therefore appears that this generation of strandlines has been affected by regional uplift of tectonic blocks in the SE of the region (Zol'nikov et al 2010).…”

Dynamic simulation of catastrophic late Pleistocene glacial-lake drainage, Altai Mountains, central Asia

“…The enclosing mountain ranges rise to 4000 m in height and sustain icecaps and valley glaciers today. The basins contained large ice-dammed lakes in the middle Pleistocene, which might have emptied catastrophically, but little is known of these lakes (Zol'nikov et al 2010;Deev et al 2012) and so these waterbodies are not considered herein. During the late Pleistocene glacial ice was extensive and, although ice did not extend into the lake basins significantly, ice lobes did block the drainage outlet from the basins to the northwest, in the vicinity of the town of Aktash (Herget 2005).…”