Minerały ciężkie jako wskaźniki źródła materiału detrytycznego w formacji dębowieckiej (miocen, zachodnia część zapadliska przedkarpackiego)

Abstract

Heavy minerals as indicators of source of detrital material in the Dębowiec Formation (Miocene, western part of Carpathian Foredeep) The composition of heavy fraction has been analysed for the clastic deposits of the lower part of Tertiary strata in the western part of the Carpathian Foredcep. Three assemblages of heavy minerals were obtained. Assemblage A, typical of the bottom breccias, indicates provenance of these deposits from the underlying Upper Carboniferous rocks and from the Carpathian flysch. In light of the heavy mineral data, the Dębowiec Formation consists of two parts. The lower one, preserved in the deepest palaeovalleys cut into the Upper Carboniferous basement, is characterized by assemblage B. The source of the clastic material for this assemblage was the flysch of the Subsilesian unit, which built the margin of Carpathians at time of The Dębowiec Formation deposition. The monomineral assemblage C consists of garnets (more than 90 %) and has the widest lateral extension. It might be supplied by the flysch of the Subsilesian unit and the Middle Godula Beds and Upper Istebna Beds belonging to the Silesian unit. It is also possible that the Culm rocks from the western fringe of the Upper Silesian Coal Basin and the Upper Carboniferous Krakowska Sandstone Scries of the eastern part of the Upper Silesian Coal Basin were also sources of the clastic material. The final identification of the sources of clastic material to the Tertiary deposits requires further studies on heavy fraction in the flysch of the Western Carpathians.