Contrasting thermomechanical evolutions in the Southalpine metamorphic basement of the Orobic Alps (Central Alps, Italy)

New petrological and partly new structural data have been obtained for two sectors of the Orobic Alps, traditionally attributed to different metamorphic zones. Thermo-barometric determinations, supported by microstructural analysis, indicate different pressure-retrograde paths in each sector. Reinterpretation of the available geochronological data indicates a diachronism for the two thermo-mechanical evolutions. In the light of these data, we interpret the retrograde P-T-t path of the VVB rocks as a pre-Permian post-thickening uplift and the retrograde P-T-t evolution of the LB rocks as a Permo-Mesozoic uplift related to the extensional tectonic regime of the Tethyan rifting. -from Author