Wody podziemne Górnośląskiego Zagłębia Węglowego

Abstract

GROUNDWATERS IN THE UPPER SILESIA COAL BASIN Summary Taking into account the occurrence of waters in coal-bearing Carboniferous, two basic hydrogeological regions were differentiated within the boundaries of the Upper Silesia Coal Basin (Fig. 1). One region, situated in the area of the Silesia-Cracow monocline is hydrogeologically exposed which makes possible penetration of precipitation waters into the substratum. Highly mineralized brines were found in buried structures at large depths in this region. The other hydrogeological region, situated within the boundaries of the Carpathian Foredeep, is hydrogeologically covered. Carboniferous rocks are here covered by impervious complex of clay Tertiary deposits. Strongly mineralized waters occur at depths so small as about 100 m in this region. The water-bearing stages occurring in the hydrogeolocical profile of the Upper Silesia Coal Basin include: Quaternary, Tertiary, Jurassic, Triassic, Permian, Carboniferous, Devonian, and Cambrian. The Jurassic and Permian water-bearing stages are without any greater importance for water relations in this area because of their very limited distribution. An increased water-bearing capacity of the Quaternary water-bearing stage is confined to river valleys and buried valleys only but these valleys form important reservoirs o consumption groundwater. The Tertiary water-bearing stage is characterized by low water-bearing capacity and contains water mineralized and unusable for consumption. The exceptions are here Pliocene and Sarmatian aquifers but their extent is rather highly limited. The Triassic water-bearing stage is characterized by optimum hydrogeological parameters and it forms the greatest groundwater reservoirs in the Basin. Fissure-karst Triassic aquifers are intensively drained by wells and zinc and lead and coal mines. In the hydrogeological profile of the coal-bearing Carboniferous water-bearing stage occur 4 aquifer complexes differing in permeability. The complexes related to the Cracow and Upper Silesia sandstone series are characterized by higher water-bearing capacity than those of the siltstone and paralic series. Fissure-layer aquifers are related to sandst.one and siltstone layers isolated by claystone packets. Hydrogeological properties of sandstones decrease along with depth. Draining connected with mining resulted in origin of deep and wide depressional cones (Fig. 1). Lower Carboniferous and older Paleozoic water-bearing stages are characterized by low hydrogeological properties and negligible water-bearing capacity. In the Upper Silesia Coal Basin, there is found normal hydrochemical zonality reflected by changes in mineralization and chemistry of water along circulation routes.