Petrology and geochemistry of late-Hercynian granites from the Western Central System of the Iberian Massif

The granites in this area are mainly porphyritic biotite monzogranites-granodiorites (BG), with minor muscovite +- cordierite-bearing types (MCG) intruded at high level into a thick sedimentary sequence metamorphosed at greenschist facies, and into cordierite + K-feldspar-rich migmatites. Magmatic mafic microgranular enclaves commonly occur in the BG, but both types are ilmenite-bearing. The textural and compositional data suggest at least a partly magmatic origin for muscovite; cordierite could be primary and partly exogenic in origin. The field, petrographic and chemical data suggest an origin via mantle-crust mixing processes. Further data are necessary to constrain the granite genesis and to choose between a pure intracrustal melting process triggered by basic intrusions and, mainly for the BG, a model involving mantle derivatives.