Geneza otoczaków węgla kamiennego w piaskowcach formacji dębowieckiej miocenu

Sonia Jachowicz, Dominik Jura

Abstract


Na Śląsku Cieszyńskim w piaskowcach miocenu rowu przedgórskiego Karpat występują okruchy karbońskich węgli kamiennych, należąIcych do westfalu AB. Obszar alimentacyjny z wychodniami utworów węglonośnych, położony jest kilka km od miejsca depozycji klastów. Transport otoczaków węgli, o średnicy do 5 cm, razem z polimiktycznym materiałem grubopiaszczystym odbywał się grawitacyjnymi spływami z udziałem prądów zawiesinowych. a sedymentacją na stożkach podmorskich wypełniających paleodoliny w rowie przedkarpackim.

GENESIS OF HARD COAL BOULDERS IN SANDSTONES OF THE MIOCENE DĘBOWIEC FORMATION

In Cieszyn - Silesia the Carpathians foredeep is filled with the Miocene macroclastic molasse - the Dębowiec formation composed of four lithofacies. There are (from the Carpathian edge) and from the bottom - olistostromes, boulder - gatherings, conglomerates and sandstones.

Polymiktic material were transported from the Carpathians and partly from the coal bearing rock basement of the Upper Silesia Coal Basin (Fig. 1, 3). Coarse-grained sandy lithofacies contains hard coal chippings and boulders in the form of insents (Figs 2. 4). These clasts range to maximum 50 mm, 15 mm on the average. They are found in beds of coarse-grained and vari-grained polymiktic - limy sandstones with the characteristic fractional normal gradation graining, the Ta and Th sequence. Sediments of this lithosome compase a submarine internal cone. The coal boulders could be transported directly from the origin areas through the channel in the cone. Based on palynologic investigations of coal boulders taken from sandstones (the Dębowiec formation) in the Chybie IG 1 borehole (Fig. 4, Tabls I - X) in has been concluded that they originated from hard-coal beds of the Westfalian AB mud-stone series. Outcross of these rocks are situated on a slope of the Pawłowice palaeoridge within 6 km distance from deposition site in the Strumień palaeovalley (Figs 3, 4).

From the wide spreas of two inserts with the coal boulders in the coarse-grained sandy lithofacies result that the material were accumulated by suspension currents. The boulders originated from the falls on subsea hard coal outcrops, occurring in the slope of the Pawłowice and Kaczyce palaecoridges (Figs 3, 4). The falls of these fragile rocks were initiated by tectonic shocks along the Miocene activity fault zones (the Ruptawa zone at the foothill of the Pawłowice palaeoridge - Fig. 3 - among others).


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