METALOGÉNESIS DE LA VETA FARALLÓN NEGRO RAMA NORTE, FARALLÓN NEGRO, PROVINCIA DE CATAMARCA

The Rama Norte vein in Farallon Negro deposit is located in Hualfin, Belen Department, Catamarca. This deposit belongs to the Tertiary Farallon Negro Volcanic Complex, the wall rock of the gold rich vein system. The Farallon Negro Rama Norte vein strikes N40°W, dips 65° NE, has 600 m length extends from the surface to a depth of about 400 meters. The wall rock is a monzonite with different types of hydrothermal alteration: intermediate argillic, silicic, phyllic and propylitic. The vein is composed of quartz, carbonates and Mn-oxides with banded, colloform and massive textures. The geochemical analyses indicate that gold-bearing vein samples are generally Ag- and base-metal poor. Gold also displays a positive correlation with Sb, but a negative correlation with Mn. High trace element contents (As, Cu, Mo, Pb, V and Zn) of polymineralic Mn-oxides suggest a hydrothermal origin. The values of carbon and oxygen isotopes in carbonates indicate magmatic and meteoric fluids participation in the hydrothermal system.