Geotectonic significance of Carboniferous deposits NW of the Holy Cross Mts. (central Poland)

Abstract

Carboniferous sandstones and shales encountered in deep boreholes drilled in central Poland, NW of the Holy Cross Mts., represent a pseudoflysch i.e. they show facies features of flysch and, simultaneously, are of cratonic provenance. Clastic sediments were derived from a peripheral bulge formed within the East European Craton as a result of stresses exerted by the accretion/thrust wedge advancing up the marginal part of the craton. In central Poland, NW of the Holy Cross Mts., a Variscan foredeep existed. The foredeep was the depositional site of interfingering exo- and pseudoflysch which, from a geodynamic point of view, are equivalent to an outer molasse. Huge masses of Carboniferous deposits (generally corresponding to flysch) from southwestern and central Poland successively represent, moving from SW to NE, Variscan ortho-, exo- and pseudoflysch.