Mid-Miocene epithermal Au-Ag ores of the northern Great Basin USA are related to magmatism associated with the inception of the Yellowstone hotspot. The geochemical chemical connection between these ores and spatially and temporally related volcanism is not well understood, but has been suggested (Kamenov, 2007;Saunders et al., 2015). These Cu-and Pbisotope studies show that the ore and associated gangue minerals have different sources of Pb, which supports evidence that the metal(loids) originate from a deep magmatic source (Saunders et al., 2008). Cu isotopes as a tool for exploring linkages between ore deposits and related Moeller et al., 2012;Liu et al., 2014Liu et al., , 2015 suggesting that aquaregia leach may not be a preferable technique when analyzing volcanic rocks.iii