Phylogenesis of gold in polymetallic volcanogenic-sedimentary massive sulfide ores

The Au concentrational level of the ores of polymetallic volcanogenic-sedimentary massive sulfide deposits is predetermined by the geodynamic setting of their formation. The ores formed in a mid-ocean ridge setting are characterized by low Au grades. The ores formed under the island arc conditions possess higher Au contents. In the course of the further existence of the ore deposit, its ores experience repeated external influences: underwater halmyrolysis, thermal and dynamic metamorphism, hydrothermal-metasomatic transformations, and exogenous oxidation. These processes lead to the transfer of gold from a micro- or nano-sized form in the sulfides to the free form and to redistribution of Au over the ore field of the deposit. The heterogeneity of the ores in terms of the Au content and existence forms must be taken into account when preparing a feasibility study. The work is intended for geologists conducting mining and geological modeling, designing techniques for the ore extraction, and proposing ore processing technologies.