Ore Fluids at the Getchell, Carlin-Type Gold Deposit, North-Central Nevada
Jean S. Cline, Albert Hofstra, Gary Landis, Robert Rye, 1997. "Ore Fluids at the Getchell, Carlin-Type Gold Deposit, North-Central Nevada", Carlin-Type Gold Deposits Field Conference, Peter Vikre, Tommy B. Thompson, Keith Bettles, Odin Christensen, Ron Parratt
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The Getchell gold deposit is one of several Carlin-type gold systems located along the Getchell Trend in north-central Nevada. Deposits located along this trend exhibit all of the characteristics typical of Carlin-type systems including the presence of submicron-sized gold particles in arsenic-rich pyrite. Although Carlin-type deposits have been mined for thirty years and are currently responsible for Nevada being one of the leading gold pr~ducers in the world, there is little consensus concerning the geological processes that concentrated gold in these deposits.
The lack of understanding of formation conditions stems from the submicron size of the gold particles, a paucity of ore stage fluid inclusions in most systems, and a lack of readily datable minerals that are unequivocally related to gold mineralization. The lack of visible gold, even under the microscope, has made it difficult to identify minerals and textures associated with gold precipitation, complicating determination of gold precipitation mechanisms. Fluid inclusions are sparse or absent in the fine-grained replacement ore present in most systems, making it difficult to determine system pressure and temperature, and ore fluid chemistry. The lack of datable minerals has prevented identification of key geological events responsible for gold concentration.
The Getchell deposit is somewhat unusual in that a significant amount of open-space-filling mineralization is hosted within the Getchell fault zone. This mineralization exhibits cross-cutting and textural relationships that provide constraints for the ore paragenesis. Additionally, these slightly more coarse-grained minerals trapped several populations of fluid inclusions, including primary inclusions contained within growth zones. Examination of