Utwory tufogeniczne warstw porębskich z rejonu Chorzowa

Abstract

TUFFOGENIC DEPOSITS OF THE PORĘBA BEDS IN THE REGION OF CHORZÓW Summary In the Namurian A deposits of the Upper Silesian Coal Basin, Chorzów region, claystone-siltstone rocks, arenaceous at places, green-grey in colour, easily collapsing and swelling in water, have been encountered in a series known here as the Poręba beds. Stratigraphical position of these rocks is identical with that of the montmorillonite clays from the Radzionków region (Z. Stopa, A. Bolewski, Z. Michałek). Microscope, X-ray structural, DTA and chemical examination enabled to refer the rocks considered to the bentonitized tuff of the following mineral composition: montmorillonite, illite, potash and soda feldspars, biotite, quartz and other admixtures. A considerable change in thickness of this deposit and structural features of the rock suggest an accumulation of almost pure tuffogenic material laid down under the fresh-water conditions. Mineral composition of the bentonitized tuff from the Chorzów region proves the granite-syenite and syenodiorite type of the magma. A considerable thickness of the deposit, revealing a great concentration of montmorillonite material in the region of Chorzów, stresses a possibility of its economical utilization in the future.