The Disappearance of Coal Seams Recorded in Associated Gangue Rocks in the SW Part of the Upper Silesian Coal Basin, Poland

Coal seams in the Upper Silesian Basin vanish within Carboniferous Sandstone Series and below an unconformity marking top surface. Changes geochemical, mineralogical, petrological palynological characteristics of gangue rocks associated with vanished record what happened. The observed changes could have been caused by (1) coal-seam paleofire, (2) peat combustion, (3) igneous intrusion, (4) metasomatism and/or (5) weathering. Multifaceted research on samples collected at Jas-Mos mining area, a part operating Jastrzębie-Bzie Mine that are representative different geological settings northern southern parts point to intra-deposit paleofire as most plausible reason for disappearance. Biomarkers enabled recognition differences heating duration oxygen access. south burned quickly abundant supply. Seams north pyrolyzed extended time under conditions limited oxygen. Though other methods used proved less sensitive, all confirmed low (100–150 °C) paleotemperature heating. Overall, local disappearance coal seams, making their exploitation difficult unprofitable, can be assigned variety processes complex overlapping history variable weathering, due endogenic fires and, probably, earlier combustion.