The structure of the silesian and magura units in the westernmost polish outer carpathians

Abstract

Based on the recent geological mapping campaign, 2D seismic profiles, well data and regional correlations, a structural framework of the western part of the Polish Outer Carpathians have been established. The proposed structural model differs from the ones that so far have been accepted in the literature. Our interpretation of available seismic data as well as regional outlook suggests that Cretaceous to Oligocene deposits of the Silesian Unit terminates abruptly to the south and does not continue beneath the Magura Unit cover. Pinching-out of the Silesian Unit formations from a few thousand meters to zero meters at a distance of about 7 km can be explained by the basin morphology, intrabasinal ridge dynamics as well as depositional environment of these formations. Whereas, deeper segment of the Carpathian orogen below the Magura Unit is built of the Oligocene Krosno Beds and Cretaceous rocks, probably of the Inoceramian type. They can be correlated with the Fore-Magura/Dukla Unit. Moreover, seismic images and magnetic signature reveal that basement is involved in deformations thus the Carpathians in their western part display rather a thick than thin skinned tectonic style.