Low-sulfidation Au-Ag deposits associated with mantle plume volcanic rocks form under relatively low oxygen and sulfur fugacities, and have low base metal contents and high Au/Ag ratios and selenium contents. Low-sulfidation deposits also occur along extensional fault zones that are not associated with proximal, coeval magmatic activity.
John, D.A., and Henry, C.H., 2020, Magmatic-tectonic settings of Cenozoic epithermal gold-silver deposits of the Great Basin, Western United States, in Geological Society of Nevada Symposium, 2020, Sparks, Nev., May 18-21, 2020, Proceedings: Reno, Nev., Geological Society of Nevada, p. 765-796.