Caracterización Petrográfica y Geoquímica de un cuerpo intrusivo subvolcánico en el área del Proyecto san Roque ( Provincia de Río Negro, Argentina).

GRECCO, L.E; BONUCELLI, R.; GONZALEZ M.V.; GARRIDO M.M; LUNA L.

Córdoba

Congreso; XIII CONGRESO DE MINERALOGÍA, PETROLOGÍA ÍGNEA Y METAMÓRFICA, Y METALOGÉNESIS (XIII MINMET ? IV PIMMA).; 2019

XIII CONGRESO DE MINERALOGÍA, PETROLOGÍA ÍGNEA Y METAMÓRFICA, Y METALOGÉNESIS (XIII MINMET ? IV PIMMA).

Petrographic and geochemical characterization from a subvolcanic intrusive body at SanRoque Project (Provincia de Río Negro, Argentina). The San Roque Project is located in thenortheastern sector of NorthPatagonian Massif, at 60 km southwest from San Antonio Oesteand at 8 km from Aguada Cecilio, Valcheta Department. In this area a porphyry subvolcanicintrusive body crops out as part of Marifil Volcanic Complex (Lower-Medium Jurassic) andis associated with an In-bearing polymetallic mineralization (Zn-Cu-Pb-Au-Ag). By modalpetrography, this body is integrated by quartz monzonites. By geochemistry studies theycorrespond to granodiorites. Petrographic studies show phenocrystals/ groundmass relationsranging from 15/85 % to 30/70 %. They are integrated by plagioclase (oligoclase), Kfeldspar(ortoclase), biotite, amphibole (hornblende), clinopyroxene (augite). Accessory minerals areapatite, sphene, zircón and mostly pyrite. They are overprinted by a propylitic alteration offeldspar phenocrystals (plagioclase, Kfeldspar) and mafites that is integrated by calcite,chlorite and epidote; phyllic alteration with quartz and sericite. At the end, a potassicalteration is observed (biotite + Kfeldspar). Piritization is observed in groundmass andphenocrystals. Spider diagram show Nb and Ta negative anomaly indicative of a continentalmargin zone magmatism according to Pearce (1984). The Ta vs Nb tectonic diagram enablesthe discrimination between arc, within-plate, collisional and orogenic granites (Pearce et al.1984). The studied samples plot mainly between volcanic arc granites. In San Roque, indiumepithermal mineralization is characterized by a wide range of metallic elements (Zn-Cu-Pb-Au-Ag) of intermediate sulphidation associated to the subvolcanic porphyries