THE ROLE OF AU IN METAMORPHIC PROCESSES OF SEDIMENTARY-VOLCANOGENIC ROCKS

General model of Au behavior in regional metamorphic, ultrametamorphic, and hydrothermal processes was developed based on the study of distributions of Au in metamorphic complexes and the data on experimental study of recrystallization of gold-bearing pyrite. Regional metamorphic processes do not lead to substantial extracting or concentrating of Au in metamorphites under isochemical conditions. Only local Au redistribution with negligible concentration on isograde boundaries of chlorite and biotite takes place under active participation of pore solutions. Metasomatic processes developing in zones of metamorphism were accompanied with redistribution and concentration of Au (K(H)Au from 0.3 to 320) providing the first step of Au concentration.