Waryscydy południowej Wielkopolski

Wojciech Grocholski



A burried Variscan belt, recently found in the substratum of Laramie structural stage rocks of the southern Wielkopolska is described. The Variscides of the souther Wielkapolska represent northern mountain belt from the Late Carboniferous times in northern Poland. They are formed of epimetamorphic rocks of the Early Paleozoic age, folded Carboniferous rocks, and Late Variscan extrusives. The principal parts of this burried belt are situated at depths over 1250 m below the surface. Top parts of epimetamorphic rocks were penetrated by boreholes in the area between Krotoszyn and Babimost at the depth over 2000 m. Longitudinal section through the Variscan structures occurring between the Sudety Mts and Poznań (Figs. 1-2) shows five, SE-NW oriented parallel blocks: I - large Sudetic horst, Il - Fore-Sudetic block, III – substratum of Fore-Sudetic depression, IV - southern Wielkopolska block, and V - crystalline substratum of Variscan fore deep. Paleogeography of burried structures of the blocks III, IV and V (substratum of Fore-Sudetic monocline) is reconstructed; moreover, their present location and hypothetized mutual configuration at the onset of Variscan movements are given (Fig. 3a-b). General characteristics of dislocations from this area is given. Moreover, the effects of the Variscan structures on sedimentation of oil- and gas-bearing Permian rocks is discussed.

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