Edad de enfriamiento U/Pb en rútilos del Gneis de Chímparra (Cabo Ortegal, NO De España)

Abstract

The Chfmparra gneisses are characterized by a HP-HT (800°C, ISOO MPa) mylonitic fabric reequilibrated under amphibolite facies (600°C, 900 MPa). This fabric is formed by Qtz+Plag+Bt+white mica + Grt+Ky. Rutiles are preserved as inclusions whithin garnet. These rutiles have been dated at 382+1-3 Ma C0GPb 123SU age). This cooling age is consistent with a reported age of peak melamorphism in the same unit (392+1-27 Ma, Ordonez-Casado et al., 1995) suggesting a fast cooling rate during the exhumation process responsible for the mylonitic foliation