Genesis of Au-Ag sulfides at the Ulakhan deposit (Russia)

摘要

Analysis of mineralogical and geochemical features shows evidence that uytenbogaardtite genesis is hypergenic at the Ulakhan epithermal gold-silver deposit (Russia). Thermodynamic modeling demonstrates the possibility of forming uytenbogaardtite from the interaction of native gold, acanthite or Au(Ag)-bearing pyrite with surface waters at 25 °C and l bar. The features of Au-Ag sulfide compositions at gold-silver deposits are revealed. Conditions under which uytenbogaardtite and petrovskaite may form in hypergene and low temperature hydrothermal processes are considered.