Large, exposed mineral resources have sustained economies and stabilized social order worldwide for centuries. Future mineral supplies will be obtained from concealed resources, which must be higher grade for unsubsidized extraction. Lithospheric-scale (crust and upper mantle) investigations of large, high-grade metal deposits are fundamental to identifying concealed resources with sufficient unit value to mine with existing technology. Determination of sources of igneous host rocks and components of hydrothermal minerals in such world-class gold-silver-copper (Au-Ag-Cu) deposits as Tonopah, Goldfield and Comstock Lode, Nevada, is a basic requirement for understanding the magmatic and hydrothermal processes that form these deposits, and for predicting the location of similar, concealed deposits.
During previous research in the Southern Walker Lane, a systematic investigation was begun of the sources of igneous and hydrothermal mineral components in three significant, subduction-related, Au-Ag-Cu districts in Miocene volcanic fields in western Nevada and eastern California (Goldfield and Tonopah, NV, Bodie Hills, CA-NV). This investigation employed multiple methods including mapping of volcanic stratigraphy, geochronology, and geochemical and isotopic analyses. Although studies were completed in the Bodie Hills, they were not completed in the Goldfield and Tonopah districts. The Comstock Lode Au-Ag district was added to the current investigation because of its world-class size and grade, and the existence of significant legacy data. Our objectives are refinement of stratigraphy, structure, and magmatic-hydrothermal evolution of the Tonopah, Goldfield, and Comstock Lode districts, and determination of the sources of hydrothermal mineral components.
Project results are expected to include refined geologic and tectonic maps of important districts in the Walker Lane, reduced uncertainty in sources of elements in ore deposits, improved precious metal deposit models, and refined provincial and local scale exploration concepts for concealed, high-grade, gold-silver deposits.
Manning, A.H., and Hofstra, A.H., 2017, Noble gas data from Goldfield and Tonopah epithermal Au-Ag deposits, ancestral Cascades Arc, USA: Evidence for a primitive mantle volatile source: Ore Geology Reviews, 89, p. 683-700, doi:10.1016/j.oregeorev.2017.06.023.
Manning, A.H. and Hofstra, A.H., 2017, Fluid Inclusion Noble Gas Data from Goldfield and Tonopah Epithermal Au-Ag Deposits, v2: U.S. Geological Survey data release, https://doi.org/10.5066/F7ST7N2F.
Balogh, C., Holm-Denoma, C., and Vikre, P.G., 2016, Volcanic stratigraphy, hydrothermal alteration and telluride-bearing epithermal deposits of the Patterson mining district, Sweetwater Mountains, CA-NV: Geological Society of America Abstracts with Programs, Vol. 48, No. 7, doi:10.1130/abs/2016AM-285486.
John, D.A., Colgan, J.P., Cosca, M.A., du Bray E.A., and Vikre, P.G., 2016, Magmatic-hydrothermal histories of the Miocene epithermal gold-silver deposits in the Tonopah and Divide districts, western Nevada: Geological Society of America Abstracts with Programs, Vol. 48, No. 7, doi:10.1130/abs/2016AM-281757.
Vikre, P.G., Colgan, J.P., Cosca, M.A., du Bray, E.A., Hayden, L.A., John, D.A., Koenig, A.E., Premo, W.R., and Pribil, M.R., 2016, Sulfide saturation in magmas associated with precious metal deposition and quartz-alunite alteration at Goldfield and other districts in the ancestral Cascades magmatic arc, CA-NV: Geological Society of America Abstracts with Programs, Vol. 48, No. 7, doi:10.1130/abs/2016AM-282776.
Vikre, P.G., Premo, W.R., and Cosca, M.A., 2014, Linkages between crustal stratigraphy, magmatic-hydrothermal evolution and sources of components of gold-silver deposits in the adjoining Goldfield and Tonopah Districts, Nevada: Geological Society of America Abstracts with Programs, Vol. 46, No. 6, p. 249. View Vikre 2014 GSA abstract.
Vikre, P.G., Premo, W.R., Hayden, L.A., Koenig, A.E., and Pribil, M.J., 2013, Sources of host rocks and hydrothermal mineral components in the Miocene Goldfield, Tonopah, and Comstock Lode Au-Ag-(Cu) districts, NV: Geological Society of America Abstracts with Programs, Vol. 45, No. 7, p. 536. View Vikre 2013 GSA abstract.
Vikre, P.G., Pribil, M.J., Poulson, S., Premo, W.R., and Hayden, L.A., 2017, Transfer of sulfur in the Miocene Comstock Lode Au-Ag system (Nevada, USA) from mantle to meteoric water: Geological Society of America Abstracts with Programs, Vol. 49, No. 6, doi:10.1130/abs/2017AM-303589.
Geology, Minerals, Energy, and Geophysics Science Center