Pressure-temperature evolution of the late Hercynian Calabria continental crust: compatibility with post-collisional extensional tectonics

The late Hercynian tectonic evolution of the Calabria crust is characterized by peak metamorphic conditions up to 800 degrees C and 1000 MPa, and coeval mid-crustal granitoid emplacement at 304-300 Ma. To check if a post-collisional extensional framework, similar to that of other Hercynian massifs, can explain petrologic data, we model the pressure-temperature evolution of the crust during extension following granitoid emplacement. Model parameters are constrained by petrologic, geochemical and structural data. Computed P-T paths are characterized by nearly isothermal decompression followed by isobaric cooling, which show a good fit to petrologic P-T paths for duration of extension between 5 and 10 Ma. The model results, therefore, support an interpretation of the magmatic and metamorphic evolution of the Calabria crust in terms of the late Hercynian extension. In this framework, slab break-off is a reasonable explanation for the common evolution of the southern European Hercynian massifs.