The main elements of Upper Pleistocene paleogeography in Central Poland

Abstract

The processes that took place during the last cold period were based on a landform system shaped during the Wartanian stadial and the Eemian interglacial. A characteristic feature of the deposits and landforms developed in the studied region during the Wartanian stadial are glacial tectonic structures, among which two types are distinguished: monoclinal and folded. Plastic, folded structures were formed in loose material, whereas the "rigid" monoclinal structures were detached from the permafrost substratum. Landforms and deposits of the ablation and ice-contact types indicate that the deglaciation of the Wartanian ice sheet did not proceed frontally, but occurred simultaneously over a wide area, accompanied by the disintegration of the ice cover into separate blocks. The Eemian interglacial was identified on the basis of organic deposits – mainly peat and carbonate – and also through the analysis of fossil soils, primarily podzolic soils. The main lithological units of the "cold" mineral deposits include stone pavements, solifluction deposits, and slope deposits with rhythmic layering. Among the fossil structures, special attention was paid to polygonal frost cracks, injection structures – especially cryolaccoliths, structures of thermal karst, frost-induced stone heave, and permafrost blocks. The stratigraphic position of the lithological units, determined based on their formation dynamics and environmental conditions, provided the basis for palaeoclimatic and morphoclimatic reconstructions of the region. 
Three phases were distinguished within the Würm cold period: the growth phase, the climax phase and the decline phase. It is important to emphasise that the term "climax phase" does not correspond to the maximum extent of the last glaciation.