Low-T thermochronometric evidence for post-thrusting (< 11 Ma) exhumation in the Western Outer Carpathians, Poland

Thermal indicators record exhumation of sedimentary units from depths in excess of 6 km over most of the Outer Carpathian fold and thrust belt in Poland. Apatite fission track data, showing cooling ages ranging between 32.1±4.8 and 7.0±0.8 Ma, indicate that exhumation was partially coeval with shortening. However, new hermochronometric information obtained as part of this study allowed us to unravel a previously undetected, postthrusting exhumation stage. The integration of new field data and structural analysis with low-T thermochronometry suggests that termination of thrusting at ca. 11 Ma in the area of the present study was followed by gravity disequilibria within the orogenic wedge. The related extension and denudation phenomena appear to have played a primary role in the recent (< 10 Ma) tectonic evolution of the Western Outer Carpathians, exerting a major control on exhumation processes in this key area of the Alpine–Carpathian mountain system.