Ewolucja paleogeografiezna i palectektoniczna w wendzie górnym w Polsce (obszar starej platformy)

Abstract

PALEOGEOGRAPHIC AND PALEOTECTONIC EVOLUTION IN THE UPPER VENDIAN OF POLAND Summary In the Polish part of the East-European Platform, the Upper Vendian is represented by clastic rocks resting on Lower Vendian volcanogenic ones (or locally directly on crystalline basement) and overlain by the Lower Cambrian. Sedimentation of the Upper Vendian was related to processes affecting mobile western marginal zone of the platform, which is reflected by variability in type of sediments and rates of subsidence. Coarse-grained and arkosic sandstones were deposited in northern part of the studied area, and mudstones and claystones - in south-western part, characterized by increase of rates of subsidence in connection with lowering of the shelf. Rocks of lower part of the Upper Vendian (V12) are assigned to three formations (see Fig. l): Kruszyniany, Siemiatycze, and Białopole, and those of the upper part (V22 - to two formations (Fig. 2): Lublin and Żarnowiec. The lithofacies maps (Figs l and 2) show development of the Upper Vendian and form the basis for compilation of paleotectonic and palecgeologic reconstructions (Figs 3 and 4). The paleotectonics reconstructions are supplemented by paleotectonic cross-sections (Figs 5 and 6). Paleogeographic evolution of the Upper Vendian in the studied area was connected with changes in type of sedimentation and tectonic movements affecting marginal part of the East-European Platform. The available data on the Upper Vendian of eastern Poland are briefly discussed and the necessity to carry out further studies on the Vendian in other parts of the country, that is in foreland of the platform, is emphasized.