Metallogenesis of the Quebrada del Diablo Lower deposit, Gualcamayo Mining District, Argentina

The Gualcamayo mining dictrict (68°38'26"O; 29°43'10"S) is located in the Precordillera of San Juan province, Argentina. It is hosted by carbonate rocks of the Cambro-Ordovician age which were intruded by Miocene magmatic rocks. The district includes a disseminated gold deposit in calcareous breccias (Quebrada del Diablo Main), a polymetallic skarn with Au mineralization (Amelia Inés- Magdalena) and a disseminated gold deposit in breccias called (Quebrada del Diablo Lower West). Quebrada del Diablo Lower West is is a blind body that lies between 500 and 600m deep that it is the result of two mineralizing stages. The first one, hosted mainly in tectonic breccias, consists of pyrite, marcasite, sphalerite and gold in calcite and quartz gangue. The second one cuts the first and conforms breccias or veinlets of realgar, orpiment and Au/Hg tellurides in calcite gangue. Fluid inclusion studies reveal that this second stage was produced by fluids of low to moderate temperatures and very low salinities.