Génesis común de los yacimientos estratoligados y vetiformes de cobre del Jurásico Medio a Superior en la Cordillera de la Costa, Región de Antofagasta, Chile

Unraveling the origin of the Andean IOCG clan: A Re-Os isotope approach

“…In this model, hypersaline fluid bubbles attach to the surface of magmatic magnetite microlites owing to the preferred wetting angles The origin of stratabound Cu(-Ag) deposits is also a matter of debate. Although several models have been presented (e.g., Ruíz et al, 1971;Losert, 1973;Sato, 1984;Klohn et al, 1990;Vivallo and Henríquez, 1998;Kojima et al, 2003;) the two prevailing hypotheses are: (1) formation by hydrothermal fluids of magmatic derivation, and (2) formed by fluids of mixed origin mobilized by cooling batholiths (Maksaev and Zentilli, 2002). In the latter, the fluids can be of metamorphic or meteoric origin, or a mix of both.…”

Mineral Paragenesis and Fluid Inclusions of Some Pluton‐hosted Vein‐type Copper Deposits in the Coastal Cordillera, Northern Chile

“…Kojima et al (2002) have suggested, based on carbon and oxygen isotope data of calcite combined with fluid inclusion data, that the hydrothermal fluid responsible for the formation of the manto-type deposits was generated by mixing of high-temperature meteoric fluid with cooler basinal brine in the La Negra Formation. Vivallo and Henríquez (1998) also implied some contribution of a meteoric water with a high 87 Sr/ 86 Sr isotope value in the formation of the vein-type and manto-type deposits, because calcites from both types of deposits show a similar 87 Sr/ 86 Sr value (~0.70435), which is slightly higher than that of the related igneous rocks (0.7033~0.7039). Nevertheless, the above discussion on the sources of sulfide sulfur and mineralizing fluid related to the two types of copper deposits still remains in speculation, and thus the authors will pursue isotopic studies to solve these metallogenic problems.…”

“…The vein-type and manto-type deposits are distinct in their geologic setting and formation conditions, and also in δ 34 S compositions of sulfide sulfur: the former and the latter show mostly positive values (-0.9 ~ 5.5 ‰) and negative values (-6.6 ~ -1.5 ‰), respectively (Vivallo and Henríquez, 1998 Rau (1967Rau ( , 1974, Barton (1973) and Barton and Skinner (1979). Abbreviations: S(L) sulfur liquid; S(V) sulfur vapor; Bn bornite; Py pyrite; Cp chalcopyrite; Po pyrrhotite.…”

“…Main geological characteristics of the veintype and manto-type deposits in the Coastal Cordillera are compared (Table 3), based on the data of the present study and those of Vivallo and Henríquez (1998) and Kojima et al (2002). The vein-type and manto-type deposits are distinct in their geologic setting and formation conditions, and also in δ 34 S compositions of sulfide sulfur: the former and the latter show mostly positive values (-0.9 ~ 5.5 ‰) and negative values (-6.6 ~ -1.5 ‰), respectively (Vivallo and Henríquez, 1998 Rau (1967Rau ( , 1974, Barton (1973) and Barton and Skinner (1979).…”

“…Ohmoto, 1974), Vivallo and Henríquez (1998) suggested that this variation would be attributed to a certain difference in proportion of oxidized and reduced sulfur species in the mineralizing fluids. Namely, they consider that the sulfide sulfurs of both deposit types are of a similar igneous source and that the vein-type sulfide formed in reduced sulfur species-dominant region.…”