POLYPHASE TECTONIC AND METAMORPHIC EVOLUT ION OF THE PALEOZOIC BASEMENT IN THE ZICAVO AREA (SOUTHERN CORSICA) - EVIDENCE FOR A LATE-OROGENIC COLLAPSE

In Corsica, a huge granitic batholith of Carboniferous-Permian age int ruded a previous metamorphic basement. Only few remnants of the baseme nt are still preserved as rafts enclosed within the granites. The pres ent study deals with two metamorphic septa exposed in Zicavo acid La V accia areas (southern Corsica). Evidence is provided for their polypha se tectonic and metamorphic history involving two main tectonic events D1 and D2. The D1 event, associated with Barrovian metamorphic condit ions, is related to the Variscan collisional stage. The D2 event corre sponds to late orogenic evolution which was controlled by continental crust attenuation. During the D2 event, Zicavo and La Vaccia areas wer e respectively affected by low angle ductile normal faults and by dext ral strike-slip shearing. Such a transtensional context, associated wi th LP-HT recrystallization, created a reduced metamorphic superpositio n involving greenschist facies down to cordierite-bearing anatectic ro cks. Field relationships suggest that intrusion of the surrounding cal c-alkaline granitoids took place during this extensional stage.