Hercynian tectonics in the Pyrenees: a new view based on structural observations around the Bassie`s granite pluton

The structural study of the metasedimentary rocks surrounding the Bassie`s granite pluton allows definition of the succession and kinematics of the Hercynian tectonic events in this part of the Pyrenees, and supports a model of syntectonic emplacement of the pluton. The following sequence of events has been identified: (i) an early phase of N-S compression, essentially resulting in southwards thrusting; (ii) emplacement of the granite body along a NE-SW sinistral strike-slip shear zone which could be a late effect of the first phase; (iii) a major dextral and transpressive phase, responsible for themain fold structures trending, on average, N100 °, and following a sigmoidal pattern around the granite body. This succession of events and their kinematics could be extended to the whole Hercynian basement of the Pyrenees.