Geochemia warstw cieszyńskich Śląska Cieszyńskiego

Irena Gucwa, Aurelia Pelczar




Geochemical research has been made of the Lower Cretaceous deposits that begin the flysch cycle in the Carpathian geosyncline, i.e. the Lower Cieszyn Shales, the Cieszyn Limestones, and the Upper Cieszyn Shales. Main macroelements (Tabs. 1–3) and microelements (Tabs. 4–6) have been determined, and thermal-differential analyses (Fig. 3) have been made. The results of the analyses prove the existence of some differences in chemical nature of the Lower and Upper Cieszyn Shales here. The Lawer Cieszyn Shales correspond, in their composition to the horizon of the Cieszyn Limestones, whereas the Upper Cieszyn Shales are referred to the marly-silty claystones. As far as microelements are concerned, some impoverishment has been observed, particularly in the Lower Cieszyn Shales and the Cieszyn Limestones. This is due to the sedimentary character of the rocks, which were a source for sedimentary processes. It should also been emphasized here that no enrichment may be observed in biogenic rare metals, except for the local Mo-concentrations, up to 88 ppm, mainly in the Upper Cieszyn Shales. This enrichment took place in a biochemical way, as proved by the directly proportional dependence of Mo upon bitumens. Due to an. impoverishment in microelements, the Cieszyn Beds do not find any equivalents among the Carpathian deposits in study. In the Upper Cretaceous deposits considerably higher concentrations, locally even fairly evident enrichments, have been discovered. This is due to a weak inflow of the materials eroded into the Carpathian geosyncline during the sedimentation of the Cieszyn Beds. The alimentation area was partly base-leveled and considerable weathering affected the cover built here mainly of sedimentary rocks.


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