The western border of the Bohemian Massif is characterized by a complex pattern of major NW-SE striking fault zones which form the tectonic boundary to younger sedimentary rocks to the west. To date, data about orientations, kinematics and the spatial distribution of brittle faults across the Moldanubian basement is scarce.
In 2023, geological field mapping focusing on structural features was carried out in the Bavarian Forest between the Pfahl fault zone and the Czech-German border. A total of 1070 fault planes were measured in outcrops of late to post-Variscan magmatic rocks, metamorphic rocks of the Moldanubian sensu stricto as well as in metabasites of the Teplá-Barrandian unit. After reconstructing their hypothetical paleo-stress fields, a total of six different main stress regimes were derived, representing the plate tectonic evolution in central Europe from Carboniferous-Permian to recent times: (1) Late-Variscan NNW-SSE compression is characterized by a conjugate fault set (WNW-ESE, N-S) with abundant muscovite on slickensides. Most noteworthy, partial reactivation under today’s similar stress field is likely. (2) N-S trending normal faults represent E-W extension presumably during the Permian. (3) Sinistral reactivation of NW-SE striking faults and dextral activity on WSW-ENE faults can probably be assigned to a Permian event with E-W shortening. (4) Presumably Late Jurassic to Early Cretaceous NE-SW Extension activated NW-SE trending normal faults. (5) Late Cretaceous to Paleogene NE-SW compression led to extensive dextral reactivation of N-S to NNE-SSW striking faults and sinistral motion on ENE-WSW trending structures. (6) Cenozoic rifting caused normal motion along NE-SW striking faults.