Le passage des granulites aux éclogites dans les métapélites de l'unité de la Punta Muret (Massif Dora-Maira, Alpes occidentales)

In the Punta Muret area, North Dora-Maira, a pre-alpine biotite-sillimanite-garnet assemblage has been identifed. A petrogenetic and thermobarometric study indicates P-T conditions of 4-7 kbar and 650-700 o C for this early metamorphism. The transition between the high-temperature and the high pressure-low temperature assemblages is discussed. An indirect path between the low pressure granulite facies and the eclogitic facies is preferred. It is characterized by an eoalpine prograde evolution with a strong increase in pressure and a moderate increase in temperature, which is in agreement with a subduction process of continental crust