Osmium isotopes fingerprint mantle controls on the genesis of an epithermal gold province

Abstract The formation of crustal blocks enriched with gold (Au) deposits above subduction zones is intimately bound to the genesis and evolution magmatic-hydrothermal systems. A long-standing question, however, whether metal fertility these systems stems from distinct sources that are anomalously in Au or subsequent processes occurring during magma emplacement hydrothermal activity. Deseado Massif auriferous province southern Patagonia (Argentina) a unique place test contrasting hypotheses because Au-bearing mantle xenoliths indicate presence an underlying Au-rich lithospheric reservoir. However, direct geochemical links between source overlying crust remain be established. To address this prominent gap knowledge, we used sulfide Re-Os geochronology identify at Cerro Vanguardia, largest low-sulfidation epithermal Au-Ag deposit Massif. Pyrite high-grade quartz veins yielded isochron age 147.4 ± 2.9 Ma (mean square weighted deviates = 1.04, n 8) initial 187Os/188Os ratio 0.26 0.01, fingerprinting dominant control for Os and, by inference, Au. Our data provide linkage subcontinental deposits, supporting hypothesis pre-enriched domains may critical factor underpinning global-scale localization provinces.