aLaboratoire de Géochimie et Cosmochimie (LA CNRS 196), Département des Sciences de la Terre, Université de Paris 7, 75230 Paris 05 France
bInstitut de Physique du Globe, Université de Paris 6, 75230 Paris 05 France
Abstract:
39Ar-40Ar and 87Rb-87Sr studies of some metamorphic minerals from the North Pyrenean zone indicate that they crystallized about 92–104 m.y. ago on the east, 85 m.y. or older on the west. An amphibole from a lherzolite in the eastern area gives a plateau age at 103 m.y. The North Pyrenean metamorphism is shown to be a thermal effect of forcible lherzolite emplacement along the North Pyrenean zone. This latter process is related to the early breakup of the Europe-Iberia plate during the middle Cretaceous time.