PTd evolution of greenschist facies metapelites from the Variscan middle crust of the Peloritani Mountains (North Eastern Sicily)

Thermodynamic modeling of medium grade porphyroblastic metapelites assisted by statistical data handling of X-ray maps provided new and more reliable PT constraints for a remnant of the southern European Variscan chain, now incorporated in the southernmost termination (i.e. Peloritani Mountains) of the Calabria-Peloritani Orogen (CPO) as the result of Apennine nappe-pile stacking during the latest stages of the Alpine tectono-metamorphic evolution (Fig. 1a). In the Peloritani Mountains the effects of the Alpine evolution have obliterated only locally the Variscan structural features and metamorphic assemblages, allowing the pre-Alpine tectono-metamorphic history of this polyorogenic segment to be investigated (Fig. 1b). Nevertheless, a few PT paths have been up to now elaborated for the upper-middle crustal rocks of this sector of the Variscan chain. New integrated micro-structural and petrological techniques have been here implemented with the aim of reconstructing the tectono-metamorphic evolution of a segment of upper-middle Variscan crust which is currently represented, in the Peloritani Mountains, by the Mandanici Unit (e.g., Ferla and Meli, 2007; and references therein) (Fig. 1c). In this view, medium grade metapelites, outcropping in three different areas (Savoca, Montagna di Vernà, Briga) and representative of the highest metamorphic grade levels of the Mandanici Unit, have been studied (Fig. 1c). Selected samples show porphyroblastic texture, that permits to better infer deformation-blastesis relationships, and growth zoning in PT-sensitive porphyroblasts (e.g. garnet), useful to determine reliable thermobaric variations.