Synthetic P-T-t paths of the Upper Gneiss Unit, Middle Allochthonous Unit, and of the Lower Gneiss Unit. The Upper Gneiss Unit is made of granulitic migmatites enclosing mafic and ultramafic enclaves of the Leptynite-Amphibolite Complex, whereas the Middle Allochthonous is not migmatitic. A. The Leptynite-Amphibolite Complex contains UHP and eclogitic relics dated at the transition from late Silurian to late Devonian as indicated by the numbers in the circles (c. 432 to c. 377 Ma). B. These rocks are retrogressed into the granulite facies dated from the middle to the late Devonian (c. 384 to c. 360 Ma) in the migmatitic gneisses of the Upper Gneiss Unit. C. The Lower Gneiss Unit comprises rare HP/LT rocks in the Limousin dated at c. 376 Ma. Rocks of the Lower Gneiss Unit have also recorded early Carboniferous (348–320 Ma) and late Carboniferous (304–302 Ma) LP amphibolite facies metamorphism.