Carboniferous-Permian tectono-metamorphic evolution of the Pelvoux Massif (External Crystalline Massif, Western Alps), with discussion on flow kinematics of the Eastern-Variscan Shear Zone

Based on new structural, petrological and U-Th-Pb geochronological data, a reappraisal of the Variscan tectono-metamorphic history Pelvoux Massif (External Crystalline Massif, French Alps) is proposed with aim to understand flow pattern kinematics partially molten crust Eastern Shear Zone. The consists high-grade metamorphic rocks middle lower crust, mostly migmatites, that record prominent syn-metamorphic deformation event (D 2 ) characterized by pervasive NE-SW striking, steeply dipping, S foliation, network anastomosed NS NW-SE trending shear zones, which indicates sinistral transpression. Relics an early 1 /M related crustal thickening top-to-the-east nappe stacking are also reported. Both D features interpreted as reflecting shortening event, firstly marked dominant stacking, secondly overprinted transpression started at peak metamorphism onset partial melting ca. 650 °C during late Visean (ca. 335–330 Ma). Ongoing in middle-lower involved strain partitioning between C C’ zones horizontal longitudinal range 330–300 Ma. Along anatectic front, vertical top-to-the-NW shearing 3 coeval argue for southeastward motion crust. contemporaneity directed transpressional supported our radiometric data attests suprastructure infrastructure under transpressive regime. exhumation deep-seated followed near isothermal 700 °C) evolution down pressure 0.5 GPa period 325–306 recorded might corresponds antithetic zone dextral East-Variscan Zone, this part orogen.