High temperature-low pressure Cretaceous metamorphism related to crustal thinning (Eastern North Pyrenean Zone,France)

The Mesozoïc sediments in the Eastern North Pyrenean Zone have suffered a high temperature-low pressure metamorphism which reached its climax before the major deformation event. The mineral associations in pelitic rocks are consistent with temperatures of 500°–600°C and a maximum pressure of 3–4 kb. Post-metamorphic brittle deformation has disturbed the initial thermal pattern. The Albo-Cenomanian (98–87 Ma) metamorphism is related to thermal anomalies contemporaneous with the crustal thinning in the North Pyrenean Zone. The distribution of paleotemperatures suggests that the intensity of metamorphism may have been related to the magnitude of crustal attenuation. High-grade rocks are associated with lherzolites and granulites, whereas low-grade rocks are associated with higher-level crustal material (gneisses and micaschists). Crustal thinning and metamorphism developed during sinistral transcurrent displacement of Iberia with respect to Europe.