Oscillatory zoning in goldfieldites from epithermal gold deposits

Goldfieldites from three acid-sulfate type epithermal gold deposits (Paleogene, Neogene and Paleozoic) were investigated. All three deposits are confined to volcanic structures and had developed within porphyric-epithermal ore-forming systems. Mineral oscillatory zoning in the crystals was analyzed in terms of variation of mineral-forming element concentrations (Te, Sb and As). It is shown that self-organization processes in the reaction zones of growing goldfieldite crystals control the forms of Te, Ag and Au occurrence in ores. Moreover, in the conversion of these components from bounded form to free form, self-organization processes play the role not less important than the changing of physicochemical mineral formation conditions.