Derived marine microfossils in loesses of the last glaciation and their significance in the reconstruction of loess-forming processes in central-eastern Europe

Abstract

Documented examples of type sections with Pleistocene deposits in southern Poland (Tłumaczów, Branice, Wożuczyn, Tyszowce, Hrubieszów) and southwestern Ukraine (Bojanice, Horokhov, Zhorniv) indicate that loesses of the last glaciation (Vistulian, Valdayan) contain derived marine microfossils of Cretaceous age. The microfossil assemblages studied are richly represented by foraminifers, which are mostly well-preserved, and derived mainly Cretaceous, forms. Suitable Late Cretaceous exposures are nearby, around data shows that these rocks and their debris, and the overlying Pleistocene tills and sands, which are older than the loesses, represent one of the main sources of the loess silt. This fact and the heavy mineral content are evidence of the participation of local material in loess-forming processes in central-eastern Europe. The spatial distribution of the sections studied in relation to the determined sources of loess material indicate that the accumulation of the loesses took place mainly in the presence of western and/or northwestern winds in the lower parts of the atmosphere.