Age of mineralization by basinal fluids at the El Soldado manto-type copper deposit, Chile: 40Ar/39Ar geochronology of K-feldspar

Geochronology of the giant Beiya gold-polymetallic deposit in Yunnan Province, Southwest China and its relationship with the petrogenesis of alkaline porphyry

“…Furthermore, the high oxygen fugacity of magma and the addition of mantle materials provided favorable conditions for the concentration of Au and Cu in the Beiya deposit. The rapid cooling of the deposit to~100°C within a few million years is consistent with other high-grade porphyry Cu-Au magmatic systems spatially and temporally associated with crustal faulting and exhumation (Wilson et al, 2003;Mclnnes et al, 2005aMclnnes et al, ,2005b. …”

Geochronology of very low-grade Mesozoic Andean metabasites; an approach through the K–Ar, 40 Ar/ 39 Ar and U–Pb LA-MC-ICP-MS methods

“…1). An interval of c. 20-25 Ma exists between the volcanism and subsequent metamorphism (Aguirre et al 1999;Wilson et al 2003;Fuentes et al 2005).…”

Extremely negative and inhomogeneous sulfur isotope signatures in Cretaceous Chilean manto-type Cu–(Ag) deposits, Coastal Range of central Chile

“…framboidal pyrite) were provided. This hydrothermal event occurred after peak very low-grade metamorphism and has been argued to be coincident with batholith intrusion (Wilson et al, 2003a), occurring in an extensional geological context (Vergara et al, 1995). Previous sulfur isotope studies on these Lower Cretaceous CMT deposits show a relatively large variation in …”

“…This process was possible due to relatively slow cooling rates, incompatible with typical dramatic hydrothermal temperature drops in shallow hydrothermal systems, but in accordance with a waning stage of a very low-grade metamorphic event. In fact, at El Soldado CMT deposit it is shown by fission track thermochronology in apatite that temperatures going down of 100º C, more than 10 Ma after metamorphic peak (Wilson et al, 2003a). The dominance of this texture in MelipillaNaltahua with respect to La Serena could be supported by the higher temperature regime deduced in the former, according to calc-silicate mineral assemblage (i.e.…”

“…up to 200Mt with 1.34% Cu at the El Soldado mine (Boric et al, 2002), with variable amounts of Ag as a by-product. Their origin is controversial (Maksaev and Zentilli, 2002), and while syngenetic models have been proposed (Ruiz and Peebles, 1988;Ruiz et al, 1965), local discordant structures have been observed, and geochronological data indicates that the orebodies were emplaced after the deposition of host rocks (~1 Ma at the Michilla, Jurassic CMT deposit, Oliveros et al, 2008; 10 Ma at El Soldado Cretaceous CMT deposit, Wilson et al, 2003a). Therefore, epigenetic models appear more realistic (Saric et al, 2003;Tassinari et al, 1993;Vivallo and Henriquez, 1998;Wilson et al, 2003b).…”