The depositional conditions of the fluvio-aeolian succession during the last climate minimum based on the examples from Poland and NW Ukraine

The object of the study was the fluvio-aeolian sedimentary succession in eight sites located in the central part of the European Sand Belt, in Poland and NW Ukraine. Based on the lithofacies, pedological and morphoscopic analyses, the analyses of frost structures and grain size as well as the TL, IR-OSL and 14C dating, three lithofacies complexes deposited at the turn of the Weichselian and Holocene were documented. The fluvial complex was deposited in the Pleniglacial within a sandbed braided river, which in the final stage of deposition of the complex was transformed into an anastomosing river. These rivers functioned in continuous permafrost coverage.The fluvio-aeolian complex was the result of aeolian deposition and fluvial redeposition, resulting from the degradation of continuous permafrost at the turn of the Pleni- and Late Glacial. These processes operated in the areas abandoned by regular flow. The aeolian complex was accumulated following the development of aeolian sand forms – sandy and silt covers as well as parabolic and longitudinal dunes, after the complete degradation of permafrost at the end of the Late Glacial and Holocene. Improving climatic conditions were expressed by the presence of fossil levels of initial gley soil in the roof of the fluvio-aeolian complex as well as poorly developed podzolic and colluvial soils in the aeolian complex.