Revista de la Asociación Geológica Argentina, Vol. 78 Núm. 2 (2021)
The porphyry of Alcaparrosa, located in the Western Precordillera of San Juan (31 ° 17 '14 ”S and 69 ° 23' 43” W), constitutes a small hypabyssal body (approximately 0.8 km2) of andesitic to dacitic composition and Permian age, with disseminated and in veins Cu, Mo and base metals mineralization . Pervasive and in veins potassic, phyllic and propylitic alteration affecting the intrusive and the host rock confirms that the mineralization corresponds to a porphyry-type system. The new geochemical data of the hypabyssal body show that the magmatism precursor of mineralization has typical arc characteristics (magnesian, calc-alkaline and metaluminous) and was generated at relatively shallow depths. Comparison with magmatic rocks of similar age and geochemical characteristics allows to include the Alcaparrosa porphyry in the lower section of the Choiyoi magmatic province.
