Dysharmonijność budowy fałdowej karbonu produktywnego w rejonie ostrawsko-karwińskim

Vlastimil Svoboda, Jaroslav Zeman

Abstract


DISHARMONY OF THE FOLD STRUCTURE OF THE PRODUCTIVE CARBONIFEROUS IN THE OSTRAVA-KARVINA REGIQN

While preparing tectonic maps of the Ostrava-Karvina region, the authors studied folding deformations, as well as intensity and character of these latter.

A structural disharmony comprises here beds lying in the western marginal area of basin, where three asymmetrical folds of flexure type, overturned in places occur. In the deeper parts the fold-like structure is simpler, while simultaneously the axial planes are straightened there. A sudden change exists between both zone of foldings and that of brachystructures. The beds disclosing greater share of argillaceous rocks and lesser thicknesses of cyclothems are much feebly folded, than the sandstone beds.

The structural disharmony should be first of all, ascribed to the changing intensity of pressures exerted here. The lithological character of beds, appearing, however, rather locally there, is of some influence, too.

As concerns structure of the deeper-lying, beds, one anticipates a tectonics of blocks and faults. As a cause of the folding processes there are regarded vertically acting forces connected with the uplifting process of blocks of deep .structure. The influence of the horizontal forces has revealed most intensively in the upper parts, where not only a greater overturning of beds took place, but also separation of the upper part from the lower one appeared. With the depth, also the influence of the horizontal forces decreases. Inclination of folds in the west and difference between both the western and the eastern parts can only be explained by the existence of the deep fauIts. An influence of blocks of substratum existed not only during the sedimentation but it took place also during the ultimate formation of the tectonic structure.


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