The candelaria copper-gold deposit, region III, Chile: paragenesis, geochronology and fluid composition

摘要

An early, barren, period of potassium- and iron-metasomatism (114.2 +- 0.8 Ma) of previously-spilitized earliest-Cretaceous andesitic strata preceded calcium metasomatism and accompanying copper-gold mineralization (111.7+-0.8 Ma) at Candelaria. Mineralization was sensibly contemporaneous with uplift and development of a mid-Cretaceous unconformity. Cu and Au were deposited from hypersaline, CO_2-rich and thermally retrograde fluids, which have S-isotopic compositions indicative of an evolution from a magmatic to an evaporitic sulphur source.