A physicochemical model for the volcanic hydrothermal ore-forming system of epithermal gold-silver deposits, Northeastern Russia

For research on physicochemical processes of dissolution, transportation, a nd deposition of Au and Ag in epithermal deposits, a model containing 12 re servoirs was devised. The composition of deep-seated sub-ore solutions resu lting from the "solution-andesite'' and "solution-rhyolite'' interaction wa s determined, showing that Au and Ag may be mobilized through the ore-beari ng fluids, even from rocks with Clark concentration. Simulations allowed fo r the inference that the main source of reserves of Au and Ag in the Cretac eous Okhotsk-Chukotka volcanic plutonic belt (Russia's part of the Circum-P acific belt) is magmatic chambers derived from the initial andesite magma. (C) 2000 Elsevier Science B.V. All rights reserved.