The San Luis Metallogenic Belt (SLMB), Sierras Pampeanas: mineralization and geochronology in a regional metallogenic framework

Abstract

The San Luis Tertiary Metallogenic Belt located in the Sierras Pampeanas of San Luis is related with the subduction zone shallowing between 27º and 33º S. Several mineralizations of epithermal and porphyry typesare located along an 80 km WNW trending belt. They are closely related to thenormal to high-K calc-alkaline and shoshonitic volcanism, which began at ~ 12-13 Ma in the west and ended at 1.9 Ma in the east indicating a swift eastwardshift of the volcanic front. La Carolina and Cañada Honda are the most important metallogenic districts, including epithermal and porphyry deposits. The San Luis Metallogenic Belt reflects the extraordinary broadening of the magmatic arc at 33º S and resembles the situation of the Farallón Negrodistrict at 27º S. Both have similar geochemical signatures and were emplacedin the south and north transitions zones of the flat-slab segment where the subduction angle changes. The transversal attitude with regard to the Andean magmatic arc could be taken as strong evidence to suggest structural weakness zones along 27º and 33º S that led to the magma ascent and controlled the formation of hydrothermal mineralization.