GEOCHEMICAL ZONATION AND SPECIFIC DISTRIB UTION OF THE MAIN INDICATORELEMENTS OF AU-AG-BEARING HYDROTHERMAL SYSTEMS IN NORTHEASTERN RUSSIA

Specific features in the distribution of the main ore- and aureole-for ming elements (Au, Ag, Sb, As, Pb, and Zn) are examined at two hierarc hical levels of Au-Ag hydrothermal systems: local (mineral, orebody, a nd mineral deposits) and regional (ore center and mining area). The el ement distribution apparently shows the following zoned pattern: Zn-Pb -Au-Ag-As-Sb (along the flow course of mineralizing solutions). Both t he geochemical zonation and the pervasive occurrence and preservation of its principal features are independent of the hierarchical level of geologic objects and are a general feature (collective effect), which characterizes self-organizing processes in Au-Ag-bearing hydrothermal systems and, possibly, in all mineralizing hydrothermal systems as we ll. Correlation links were established for the Au-As and Ag-Sb element pairs. The correlations are accounted for by the fact that the elemen ts are transported in the form of the same species in hydrothermal sol utions: thiosulfate and hydrosulfide complexes. Presumably, the chemis try of the ascending mineralizing fluids evolved from weakly alkaline, to nearly neutral, and finally to acid.