The deposition of gold and other metals: Pressure-induced fluid immiscibility and associated stable isotope signatures

摘要: Abstract It is often proposed that the onset of fluid immiscibility may be a direct cause ore deposition, with evidence cited from inclusions associated minerals. A reaction-path model used here to calculate speciation, including pH, and mineral precipitation or dissolution as function volatile loss undergoing phase separation. modified Redlich-Kwong equation state H2O-CO2 miscibility gap activity coefficients H2O CO2. This procedure incorporated into EQ3/6 chemical speciation mass transfer computer codes simulate response mineral-fluid system immiscibility. Calculations for systems Cu, Pb, Zn, Ag, Au show induce metal deposition under variety conditions, but simplistic assumptions regarding are not always correct because they ignore buffering capacity fluid-rock system.