G. D. Kamenov Albert H. Hofstra D. L. Unger R. A. Creaser F. Barra Roger Steininger Bill Pennell James A. Saunders 2011 <p><span>In order to better constrain genetic processes involved in forming mineral deposits </span><span>(and ultimately exploration models), it helps to know from where the metals of interest </span><span>are derived. How the metals arrived at their point of deposition, and why they </span><span>were deposited there, are separate issues. We are using three different techniques in an </span><span>attempt to better understand these processes for epithermal ores. All have some ambiguity </span><span>inherent to them, but we think that based on our preliminary investigations, together </span><span>they point to a new understanding of how some epithermal ores in the northern </span><span>Great Basin form. These techniques include: 1) plotting the relative abundances of Au, </span><span>Ag, Pb, As, Sb, Se, Te of the ores; 2) Pb-isotope abundances in Au-Ag minerals; and 3) </span><span>Re-Os isotope analyses of Au-Ag minerals in the ores. Results to date suggest: 1) the </span><span>“epithermal suite” geochemical association is likely related to the similar volatility of </span><span>these metal(loid)s, and thus we conclude they are derived from the mantle as opposed </span><span>to representing a shallow origin; and 2) Preliminary Pb and Re-Os isotopic analyses of </span><span>Au-Ag minerals indicate that they are derived from the mafic that were part of the bimodal </span><span>volcanic suite associated with the initial emergence of the Yellowstone Hotspot </span><span>(YHS) in the northern Great Basin at about 16-15 Ma. Epithermal ore formation associated </span><span>with the YHS which may suggest the source region of the mantle was rapidly depleted.</span></p> application/pdf en DEStech Publications, Inc. 'Forensic' geochemical approaches to constrain the source of Au-Ag in low-sulfidation epithermal ores text