Genetic and exploration models for the Florida Canyon gold deposit, Nevada: Integrating geological, geochemical, GIS, remote sensing, geostatistical and statistical data analysis

The Florida Canyon gold deposit is a large, low-sulfidation (LS), epithermal deposit with low-grade, disseminated mineralization in Pershing County, Nevada. Unlike most other LS deposits in the region, mineralization at Florida Canyon is hosted by sedimentary rocks and lacks an association with coeval igneous intrusives. An investigation of the origin of the deposit revealed that the deposit formed in three main stages. Early quartz-adularia-sulfide-gold stockwork bodies formed at 5.0 to 4.5 Ma from meteoric water that had isotopically exchanged with and leached metals and sulfur from a package of sedimentary and volcanic rocks hosting the deposit. Mineral deposition likely happened at 150 to 200°C from episodically boiling fluids. Oxidizing, acid-sulfate steam-heated alteration developed between 3.4 and 1.8 Ma overprinted the stockwork bodies but did not result in detectable gold enrichment. Within the last ∼1 Ma weathering overprinted the deposit producing widespread hematite-goethite alteration.; The origin of the deposit is closely related to the kinematic history of the range front fault system along which the deposit is located and possibly to changes in the paleoclimate regime. Moreover, it represents an older expression of a long-lived (∼5 Ma) hydrothermal system that is presently manifested by the Humboldt House geothermal field located adjacent to this deposit.; A second phase of this study used contour maps of gold (Au) concentration developed with a geographic information system (GIS), and variogram maps to identify and map linear trends of high gold values in the Florida Canyon gold deposit. These linear trends are interpreted to represent fault zones that exerted a strong control on gold mineralization and therefore imparted a spatial anisotropy to gold concentrations. The results suggest linear trends of northeast, northwest and, less prominently, north-south orientations.; A third aspect of the study used a multivariate regression-based statistical modeling technique to develop a quadratic model to quantitatively predict Au concentration from the known concentrations of pathfinder elements. The proposed statistical approach may be utilized in mineral exploration programs to predict gold concentrations in under-sampled areas of a deposit, optimize the number of pathfinder elements required for the efficient detection of the element of interest, and evaluate geochemical data sets generated by different laboratories or analytical techniques.