Polymetallic Vein Deposits and Occurrences, Central Chubut Province, Argentina

Fil: Sangster, Alan L. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; Argentina.The project area of central Chubut Province consists mainly of andesitic and basaltic rocks of Jurassic age that have undergone only very minor penetrative and/or thermal metamorphism. The andesites are underlain by a late Precambrian basement that is intruded by 200 Ma. granites that are not well exposed. The andesites are locally overlain by the Cretaceous Chubut Group molasse deposits (oil producer), Miocene rhyolites, and locally by plateau basalts that are younger than Miocene. The Jurassic volcanic rocks form 90 percent of the bedrock in the area. Three types of deposits were selected for investigation by SEGEMAR; 1) Polymetallic Zn-Pb- Cu-Ag-+/- Au veins (Mina Angela area); 2) monomineralic barite and polymetallic Ba-Zn-Pb veins mainly occurring in widespread groups in the central part of the project area; and 3) quartz veins along the southern part of the project area near the highway from Paso de los Indios to Esquel (Figure 1)