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.