Lessy w strefie glacjalnej zlodowacenia północnopolskiego

Abstract

LOESSES IN THE GLACIAL ZONE OF THE NORTH POLISH GLACIATIONSummaryIn the zone of glacial deposits of the North Polish Glaciation, within the Lower Vistula region, loesses and loess-like deposits have been encountered (Fig. 1). The loesses are found at exposures in the upland edge at Nowe (Fig. 2) and at Aplinki (Fig. 3), as well as in the region of Widlice (Fig. 4), where they are known from drill samples. These are loesses of subaeral type, blown on the surface of river terraces (Nowe); or alluvial loesses laid down in a water environmmt (Aplinki, Widlice). The analysis of mechanical composition and of lime content (Table 1) shows that these are deposits characterized by the prodominance of grains, 0,05-0,01 mm in diameter (70-74,8%), of similar composition in all the cases examined, resembling also the loesses of the extraglacial zone; apart from the overlying series they reveal also a considerable prosity (Table 2). At the remaining sites there occur mainly loess-like deposits (Fig. 5), i.e. "loessial" silty deposits, banded horizontally, related to ice-dammed lake deposits. These formations occur in three different stratigraphical horizons, and in all the cases are related to the glacial or extraglacial deposits of the North Polish Glaciation, which rest above the marine marls with Eemian fauna (Tyochnowy - Fig. 6). The lower glacial horizons (Fig. 6, horizons BI, BII), are for the first time distinguished in the present paper as the deposits of this glaciation. A more detailed determination of their stratigraphical rank requires further research work. The results of this research work will, among others, be of a considerable importance for the correlation of loesses from the glacial zone, with those from the extraglacial one.