Pedosedimentary archive of the Kostenki 21 (Gmelin) site as a memory of the dynamics of periglacial geosystems in the extreme conditions of the Last Glacial Maximum

Data on the structure of pedosedimentary archive (PSA) of the Upper Paleolithic Kostenki 21 (Gmelin) site on the first terrace of the Don River are discussed. The site consists of a series of eolian, colluvial, and alluvial loamy and sandy loamy sediments and includes cultural layers, pedosediments, and layers of initial pedogenesis with clear features of cryogenic disturbance. The complex structure of this soil–sediment sequence reflects the transition of the landscape from the subaqueous regime of the disappearing oxbow lake on the Don floodplain to the subaerial regime of slope, as well as the dynamics of local paleogeosystems in the most extreme phase of the last (Valdai) glaciations (MIS 2.2), reflected in three pedocryocycliths. The general trend and cycles of environmental events in the periglacial zone are reconstructed, and the adaptation capabilities of ancient humans in harsh climatic conditions are shown.