P-T-t constraints on the metamorphic history of the Upper Gneiss Unit and of the Middle Allochthonous Unit. The Leptynite-Amphibolite Complex is characterized by HT eclogite facies metamorphism retrogressed into granulite facies by isothermal decompression and then into amphibolite facies by a decrease in temperature. Granulite facies to amphibolite facies metamorphism is also recorded in the migmatitic gneisses hosting the LAC. The PT path is depicted by the white arrows and numbers correspond to radiometric ages.