Model of the Late Quaternary deposits formation at the geoarchaeological ensemble of Kovrizhka and adaptation of ancient man to the hydrological regime of the Vitim River and the restructuring of the landscape

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As a result of geomorphological research and the analysis of calibrated radiocarbon dates of the archaeo-logical sites of Kovrizhka I–VI (Baikal-Patom Uplands), a model of formation of the Late Quaternary deposits of the Vitim valley within the area of the Kovrizhka ensemble has been developed. Based on this, and according to the archaeological data, the history of human habitation during the late Upper Paleolithic — Early Neolithic (19–6 ka BP) has been reconstructed for different levels of the valley depending on general landscape features, flood regime of the river, and the dynamics of the relief formation. This adaptation is manifested in the choice of locations for long-term and short-term settlements, and characteristics of exploitation of stone (mineral) and food resources. People settled along the shoreline throughout the entire timeline of the formation of the floodplain and the terrace, with seasonal flood threats being the limiting factor. High floods of the end of the Pleistocene — early Holocene, caused by intensive melting of glaciers, resulted in relocation of human settlements to the levels of modern 2nd and 3rd floodplains, and higher up the slope. An important point in the study was the idea of the last megaflood, which manifested itself with the discharge of the Muya (Vitim) glacier-dammed paleolake, whose existence on the geological timescale corresponds to the third and partially second marine isotope stages (MIS 3–2). In particular, the issues of the presence of traces (deposits and landscape) of such flood in the Vitim River valley at the Kov-rizhka archaeological site and its possible impact on the settlements of ancient people have been raised. The OSL date (39.4 ± 4.1 ka BP) has been obtained for the gravel underlying the normal occurrence of unwashed culture-bearing deposits with settlement structures, hearths, and remains of dwellings. This indicates that the last megaflood could not have happened later than the earliest time of human settlement on Kovrizhka IV (level of the first terrace) about 19 thousand years ago. At the same time, flooding activity has been recorded at all stages, especially the increased role of floods at the turn of the Pleistocene — Early Holocene.