Deep seismic reflection profiles in SE Poland reveal a Variscan thin-skinned fold-and-thrust belt encroaching the East European Craton

20th EGU General Assembly, EGU2018, Proceedings from the conference held 4-13 April, 2018 in Vienna, AustriaRecent years have brought a significant progress in understanding of the external Variscides in Poland. Combined POLCRUST-01 and PolandSPAN deep seismic surveys imaged for the first time a Variscan thin-skinned fold-and-thrust belt that encroaches onto a little deformed basement slope of the East European Craton (EEC) much farther eastward than the previously postulated position of the Variscan deformation front. This deformed belt consists of several tectonic units, to a various degree overprinted by Variscan shortening and inversion (Fragment tekstu)

Late Carboniferous thin-skinned deformation in the Lublin Basin, SE Poland: Results of combined seismic data interpretation, structural restoration and subsidence analysis

The aim of this study was to investigate the factors, which controlled the lateral change of structural style in the southeastern part of the Lublin Basin (Poland). Five selected seismic reflection profiles were interpreted with a focus on structural interpretation. Along the representative seismic reflection profile, a geological cross-section was constructed and restored. The structural model was supplemented/refined with core analysis to characterize the deformation mode affecting Silurian strata at a sub-seismic scale (i.e. below the seismic vertical resolution). Published palaeothickness maps were used to estimate the pre-deformation thickness of partly eroded Carboniferous rocks. The results of cross-section restoration were then compared to the subsidence modelling carried out for one deep well. The study revealed that during Late Carboniferous shortening, a thick layer of Silurian shales played the role of detachment level, above which brittle Devonian-Carboniferous strata were folded and thrust. The lateral extent of thin-skinned deformation was controlled by the presence of a step in the basement and the pinching out of the Silurian strata. In the northwestern part of the Lublin Basin, the Kock Fault Zone acted as a region of strain concentration, where Silurian shales were tectonically thickened, and shows a ductile style of deformation resembling the mushwad structures of the Appalachian fold-and-thrust belt