Neogene activity of the Outer Carpathians recorded by thrust-top basin deposits – an example from the Rzeszów area, Poland

Abstract

The Rzeszow thrust-top basin was formed on the active Skole thrust sheet of the Outer Carpathian fold-and-thrust  belt and filled with Miocene syntectonic sediments. New seismic 3D, well and field data were used to define the relationship between sedimentation and tectonic activity and to establish the synkinematic context of the Rzeszow basin-fill architecture. The basin evolution was controlled by the activity of the Carpathian frontal thrust and hinterland thrusts developed in the forelimbs of folds in the Skole thrust sheet, bounding the basin from the north and south, respectively. The activity of the frontal thrust resulted in hinterland-directed depocentre migration and tilting of the syntectonic stratigraphic sequence. Balanced cross-sections have indicated that during the last compressive stage of deformation, the syntectonic deposits filling the basin were shortened by c. 5%, which resulted in the formation of folds and contractional faults. The architecture of the syntectonic deposits and the development of contractional structures reflect the activity of thrusts bounding the basin during compressive deformation of the Carpathian orogenic belt.