CARACTERIZACIÓN GEOQUÍMICA DEL MAGMATISMO DE ARCO DEVÓNICO Y CARBONÍFERO-PÉRMICO EN EL NOROESTE DE PATAGONIA, ARGENTINA

Based on 23 whole rock chemical analyses of the igneous basement rocks from the Northwest Patagonia, Neuquen, Rio Negro and Chubut provinces, we characterize the magmatism and tectonic setting for the region between 40o and 42o S, further west of 70o W. The analysed rocks are mainly granitoids (with one migmatite and another meta-basite), with ductile deformation. Previously, all these rocks have been isotopically dated by U-Pb, K-Ar and Sm-Nd methods, and then the crystallization and metamorphism-deformation ages, and extraction time from the mantle are known. According to their geological ages, they have been separated into Chanic (Devonian) and Gondwanic Groups (Carboniferous-Permian). In both cases, the granitoids are subalkaline, normal calc-alkaline, I- type, peraluminous, and related to their respective magmatic arcs, developed on continental margin. The Gondwanic granitoids were also compared with the granitoids of the same age ranging from Northpatagonian Massif, Cordillera Norpatagonica, and Cordillera Frontal from Mendoza (Argentina) and Chile.