Mineral paragenesis and ore fluids at the Turquoise Ridge gold deposit, Nevada
In this study, mineral assemblages and related fluid inclusions at the Turquoise Ridge Carlin-type gold deposit were examined to answer the following questions: (1) What is the ore-stage mineral paragenesis? (2) At what pressures and temperatures did the deposits form? (3) What are the sources of ore fluids?;Pyrite with gold, jasperoid quartz, stibnite, orpiment, realgar, and calcite were successively deposited at Turquoise Ridge. Microthermometric data and isotopic ratios of inclusion fluids in ore-related minerals indicate entrapment of multiple generations of fluids in pre-ore, ore-, and late-ore stage minerals. Primary fluid inclusions in an ore-stage jasperoid quartz crystal have salinities of 12.6 to 19 wt.% NaCl equivalent, and most inclusions homogenized between 130Ã‚Â° and 193Ã‚Â°C Isotopic signatures of inclusion fluids in ore-state jasperoid quartz, deltaD = -33Ã¢â‚¬Â° and delta 18O = +7.1 to +12.2Ã¢â‚¬Â° and deltaD = -46Ã¢â‚¬Â° and delta 18O = +5.4 to +10.5Ã¢â‚¬Â°, are consistent with a magmatic or metamorphic source, or both, while inclusion fluids in late-ore stage calcite yielded delta 18O = 10 to 14.5Ã¢â‚¬Â° and deltaD = -110Ã¢â‚¬Â°, indicating trapping of an evolved meteoric fluid.