CARACTERIZACION PETROGRAFICA Y GEOQUIMICA DE UN CUERPO INTRUSIVO SUBVOLCANICO EN EL AREA DEL PROYECTO SAN ROQUE (PROVINCIA DE RIO NEGRO, ARGENTINA).

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

XIII Congreso de Mineralogía, Petrología Ígnea y Metamórfica, y Metalogénesis

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

Lugar: Córdoba; Año: 2019; p. 87 - 94

Petrographic and geochemistry characterization from a subvolcanic intrusive body at SanRoque Project (Provincia de Rio Negro, Argentina). The San Roque Project is located in thenortheastern sector of NorthPatagonian Massif, at 60 km southwest from San Antonio Oeste andat 8 km from Aguada Cecilio, Valcheta Department. In this area a porphyry subvolcanicintrusive body outcrops as part of Marifil Volcanic Complex (Lower-Medium Jurassic) and isassociated 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), clynopiroxene ( augite). Accesory minerals areapatite, sphene, zircón and mostly pyrite. They are overprinted by a propylitic alteration offeldspar phenocristals (plagioclase, Kfeldspar) and mafites that is integrated by calcite, chloriteand epidote; phyllic alteration with quartz and sericite. At the end, a potassic alteration isobserved (biotite + Kfeldspar). Piritization is observed in groundmass and phenocrystals. Spiderdiagram show Nb and Ta negative anomaly indicative of a continental margin zone magmatismaccording to Pearce (1984). The Ta vs Nb tectonic diagram enables the discrimination betweenarc,within-plate, collisional and orogenic granites (Pearce et al. 1984). The studied samples plotmainly between volcanic arc granites. In San Roque, indium epithermal mineralization ischaracterized by a wide range of metallic elements (Zn- Cu- Pb- Au- Ag) of intermediatesulphidation associated to the subvolcanic porphyries.