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Petrographical analysis of Warthian fluvioglacial gravels as a tool to trace the source area – a case study from central Poland

Górska-Zabielska M., Wachecka-Kotkowska L.

Geologos

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2014

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Vol. 20, No. 3

183--199

EN

The petrographical features of the medium- and coarse-grained gravels (4-10 mm and 20-60 mm, respectively) of weathered and fresh (unweathered) deposits indicate, in combination with so-called indicator and statistical erratics, that two glacial lobes joined in the borderland of the Polish Lowlands and Uplands. Lower Palaeozoic limestones become less frequent in the finer gravel fraction, whereas crystalline rocks and flints become more frequent. The petrographical analysis of the coarser gravel fraction indicates that the ice sheet advanced from the NE to NNW (the Widawka lobe) and from the NE to ENE (the Rawka, Pilica and Luciąża lobes). The source areas of the gravel deposited by the Warthian ice sheet were magmatic and sedimentary areas of both the Baltic and the SE Sweden basins.

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Is the Charlottenthal fan (marginal zone of the Pomeranian phase, NE Germany) an end moraine?

Pisarska-Jamroży Małgorzata, Börner Andreas

Geologos

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2011

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Vol. 17, No. 1

17--28

EN

The maximum ice-sheet extent of a glaciation or glacial phase is in most cases indicated by the position of end moraines. In some cases, however, the maximum extent of the ice sheet is indicated by a fan which represents the transitional zone between the end moraine and the proximal outwash plain (sandur). Such a fan from the Pomeranian phase near Charlottenthal in NE Germany has been investigated for its lithofacies, and the depositional mechanisms of the two sedimentary environments (end moraine and outwash plain) are reconstructed. The Charlottenthal profile is not characteristic in a sedimentological sense of a typical marginal end moraine or a sandur. The deposits represent subaerial debris flows, sheet floods and channelized currents, which are typically processes for transitional fan. Gravel samples from the till complex show typical Weichselian till compositions. These till compositions indicate a general transport direction from North to South, which is consistent with the known movement of the ice sheet during the Pomeranian phase of the Weichselian.

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

Górska-Zabielska M., Pisarska-Jamroży M.

Przegląd Geologiczny

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2008

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Vol. 56, nr 4

317-321

EN

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 Smĺland. Other regions where the ice sheet could have been nourished were located in Dalarna and Ĺland Islands. The most numerous erratics found in the glacial sediments are: Smĺland granites and quartz porphyries, Ĺland rapakivi granites and quartz porphyries, Bredvad porphyries, Venjan and Grönklitt porphyrites.