Petrological and metallogenic evolution of the Cerro Áspero Batholith, Sierras Pampeanas, Argentina: an example of long-lived hydrothermal history related to high-K, F-rich granites

CONIGLIO, J., DERAMO, F.J., PINOTTI, L.P., DEMARTIS, M., PETRELLI, H.A., AGULLEIRO INSÚA, L.A., DE LA HOZ, M.

Antofagasta

Encuentro; 11th Biennial Meeting of the Society of Geology Applied to Mineral Deposits; 2011

Society of Geology Applied to Mineral Deposits

Several significant W-Mo-F-U bearing hydrothermal deposits occur in the south of Sierras de Córdoba, central Argentina. These deposits are spatially related to a group of three subcircular, high-level monzogranite plutons of the Cerro Áspero batholith (CAB) of Upper Devonian age. Two mineralization stages were recognized: 1) a syn-batholith W-Mo-F-rich stage related to the CAB emplacement (formed between 1.75 and 1.25 Kb), and 2) a post-batholith stage (Cretaceous to Tertiary age), responsible for the formation of epithermal fluorite and uranium deposits. The geochemical evolution of the CAB was the result of differentiation from high-K, F-rich granitic magmatism in which the changes in the geochemical behavior of F and P in the magma, from compatible to incomplatible, influenced strongly on the genesis and spatial distribution of the syn-batholith mineralizations. The leaching of the monzogranites by highly exchanged mesozoic meteoric water into the hydrothermal alteration fracture zones, is the most plausible source of fluorine for the epithermal veins. Metallogenic evolution of the CAB was the product of multiple hydrothermal events, that probably occurred over more than 300 Ma. This postulated long-lived thermal history is similar to that displayed in granites with high contents of radiogenic heat-producing elements such as U, Th and K.