Exploration potential for sulfide-rich vein deposits in the Deseado Massif,

JOVIC, SEBASTIÁN; GUIDO, DIEGO; SCHALAMUK, ISIDORO

Keystone, Colorado, USA

Conferencia; SEG 2006 Biennial Conference; 2006

Society of Economic Geologists

The Deseado Massif is characterized by the presence of LS epithermal deposits; it has two Ag-Au active mines (Cerro Vanguardia and Martha mine) and it is subject of intense exploration activities. Cerro León deposit is located in the center of the geological province and is composed of eleven quartz veins with atypical mineralization that presents an extraordinary concentration of sulphides, which reach up to 90 % in volume in some veins, with a complex mineralogy represented by Sn, Cd, In, Pb, Zn, Ag, Bi, W and Au minerals. The sulphide-rich veins are poorly exposed in surface and are characterized by the presence of grey quartz with cavities filled with limonite and minor sulphides, quartz-limonite veinlets, ferruginous silica breccias and Fe-Mn oxide breccias. Some parts of the veins are represented by a high concentration of limonite, an important pyritization, red clays and oxidation and alteration zones, forming a Fe-rich gossan with supergenic enriched values up to 1.34 g/t Au, 150.5 g/t Ag, 11,983 g/t Pb and 1106.72 g/t Zn, that relates to Au-Ag-sulphide-rich veins in depth. These characteristics represent another surface target to explore in the Deseado Massif province. Detailed satellite image geoprocessing, chargability geoelectric surveys and sampling of soils and Fe-rich gossans could detect this type of Au-Ag-sulphide-rich mineralization. This new type of deposit for the Deseado Massif province increase the mining potential of the region and must be considered during future exploration activities in the region.