Zróżnicowanie petrograficzne plejstoceńskich osadów Pojezierza Myśliborskiego na przykładzie żwirów z Chełma Górnego i Cedyni

Abstract

Petrographical differentiation of Pleistocene deposits of Myoelibórz Lakeland (Western Pomerania) based on gravels from Chełm Górny and Cedynia.A b s t r a c t. Petrographical content of Pleistocene gravels (4–10 mm) derived from till and glaciofluvial deposits of Western Pomerania was studied. The coarse-grained gravels (20–60 mm) have been additionally investigated for indicator erratics. There are three dominant petrographical groups within the gravels regardless of genetic type of sediments: crystalline rocks, Lower Paleozoic limestones and sandstones. Indicator erratics indicate the most effective glacial erosion in south-eastern Sweden. Theoretical stone center is located at 57.7°N and 16°E, that is in Småland. Other regions where the ice sheet could have been nourished were located in Dalarna and Åland Islands. The most numerous erratics found in the glacial sediments are: Småland granites and quartz porphyries, Åland rapakivi granites and quartz porphyries, Bredvad porphyries, Venjan and Grönklitt porphyrites.