Extent of the Odranian Glaciation in the Silesian-Kraków Upland

Abstract

The scarcity of Scandinavian rock fragments in glaciogenic deposits and lack of well-preserved glacial accumulation forms make it difficult to determine the maximum extent of the Odranian ice sheet in the area of the Częstochowa Upland, the Woźniki-Wieluń Upland and the Silesian Upland. While the glaciogenic deposits only contain a small admixture of Scandinavian rocks, they have been enriched with local flints and gravels that are undoubtedly related to glacial transport. The distribution of flint debris suggests that within these areas, the Odranian ice sheet reached farther south than previously assumed. This question has been analysed again on the basis of archival materials, new publications and the results of field research (studies of the distribution of flints, the Połomia gravels, siderite clasts and roches moutonnées. The use of methods based on 3D visualizations via digital terrain models (DTMs) has proven very useful. Moreover, the use of computer methods (GIS) in conjunction with field surveys made it possible to delineate the Odranian Glaciation boundary more precisely in the study area. The study indicated the important role of local material for inferring the maximum extent of Pleistocene glaciations. This is particularly important in areas where typical forms of glacial accumulation have not been preserved.