Osady deglacjacyjne zlodowacenia warty we wschodniej części regionu łódzkiego

Abstract

The author attempts at formulating a synthetic description of geological and geomorphological effects of the Wartanian ice-sheet deglaciation in the eastern part of the Łódź region, taking their spatial variability into consideration. Characteristic features of Wartanian Glaciation sediments occur in this area, and their lithofacial diversity and spatial distribution needed interpretation. The deposits document the complex processes of deglaciation, which developed here across an unusually broad area in the scale of the Polish Lowland. The best developed deglaciation sediments occur in the eastern part of the Łódż Heights, between the Mroga and Rawka rivers, as structural components of different types of kames and glaciofluvial covers. In locations where glacial till is elevated they include mainly sediments of braided rivers and alluvial cones, whereas in areas of wide depressions of till and, thus, of the ice-sheet bedrock — glaciolimnic sediments prevail. The highest and most diverse western part of the Łódź Heights is characterised by the occurrence of thin and discontinuous deglaciation sediments, because this area was shaped mainly during the ice-sheet transgression. During deglaciation, ablation waters left mainly traces of erosion, whereas the glaciofluvial accumulation series are not well developed. In the Rawa Interfluve, deglaciation sediments accumulated predominantly at the early deglaciation stage in sparesely distributed broad basins of kame sedimentation. In the Piotrków Plain, deglaciation deposits are thin; ice-sheet disintegration proceeded without major blockages of ablation waters, resulting in a less diverse interfluvial landscape.