Tektonika obszaru częstochowskiego

Abstract

TECTONIC OF THE CZĘSTOCHOWA REGION Summary There are two structural complexes in the tectonic building of the Częstochowa Region; the substratum composed mainly of young Palaeozoic rocks, and the sedimentary cover built of Caenozoic and Mesozoic excluding Permian and Lower Triassic. Previous tectonic conceptions were based on the rather scarce knowledge of substratum, because only Devonian in outcrops and Culm and boreholes was known. Recently well developed and partly metamorphosed Hercynian is discovered in many boreholes N and NE from Cracow. Hercynian is arranged around the W, N and NE border of Upper Silesian Coal Basin. Direction of folds is changed according to the changes of the border direction. Hercynian lies close to Caledonian in S-part of Świętokrzyskie Mts, and is prolonged to the west and middle part of the Sudety Mts. Caledonian is emplaced between the Hercynian of Silesia-Cracow and that of Łysogóry. The last Hercynian Block forms the E continuation of the Subvarisc Zone. Some anticlines with Carboniferous limbs and Devonian cores area were investigated, also in Carboniferous some sharp folds were observed. The folding take place after Westphalian “A”; the main period was finished probably before Westphalian “B” and “B” and “C”. A great disconformity with the fragment absence of Permian and Lower Triassic is observed between the folded Hercynian substratum and the sedimentary cover. The Cracow-Częstochowa Jura Chain is an element of the W-slope of Miechów Synclinorium. The different structure pattern of the substratum and the cover is distinctly visible of the respective maps. The sedimentary cover is not folded. These are only broad, competent uparchings and faults. The tectonic pattern of the cover is frequently connected with the Hercynian directions. In the S-part of the Region faults are oblique to the escarpment of Jurassic Cuesta, so its directions are transional between Hercynian and Mesozoic ones. In the N-part faults are vertical to the escarpment (the Hercynian substratum is deeper), so the influence of rigid substratum was weaker. The strike of sedimentary cover is NW and its dip is no more than 2° at the NE. The especially intensive faulting of the sedimentary cover is noticed in the Wieluń vicinity, where some horsts with amplitude till 250 m area known. The Wieluń-Siemkowice Fault, and the Kodrąb Fault are probably the prolongation of Łysogóra Overthrust (Świętokrzyskie Mts.).