A regional cross-section based on geophysical, borehole, and structural field data reveals the subsurface structure of the western Polish Outer Carpathians, a relatively understudied segment of the Carpathian thrustand- fold belt. A key feature is an antiformal stack, where the Dukla Unit underlies the central part of the Magura Unit. This structure probably was formed due to a thrust ramp within the Palaeozoic cover of the North European Platform. New apatite fission-track ages, along with a re-evaluation of published thermochronologic age data, indicate two exhumation phases. The first occurred in the Early Miocene (~20 Ma), affecting the Magura and Silesian units. The second, in the Late Miocene (~10 Ma), is confined to the Magura Unit and linked to an antiformal stack formation either through underthrusting of the Magura Unit by the Dukla Unit or large-scale normal faulting that drove arc-parallel extension. Both structures are supported by outcrop and seismic evidence. The present authors propose that the lateral termination of the antiformal stack triggered a normal fault system, forming a hanging-wall drop fault along a lateral culmination wall. The structural data of the present study do not support a Middle–Late Miocene arc-perpendicular extension, previously documented in the eastern Polish Outer Carpathians, as a viable explanation for the Late Miocene exhumation, recorded in the western sector.
