GEOCHEMICAL AND ISOTOPIC CHARACTERISTICS OF DISSEMINATED SULFIDE MINERALIZATION OF OROGENIC GOLD DEPOSITS OF THE YANA-KOLYMA METALLOGENIC BELT (NORTH-EAST OF RUSSIA)

Abstract

The results of the study of the chemical composition and isotopic characteristics of the sulfur of disseminated pyrite and arsenopyrite from metasomatites of the Malo-Taryn, Badran, Khangalas, V’yun and Shumniy orogenic gold deposits of the Yana-Kolyma metallogenic belt are presented. Pyrites and arsenopyrites have a non-stoichiometric composition. Arsenopyrites are characterized by sulfur enrichment (As/S from 0.77 to 0.99), minor of Sb, Co, Ni and Cu with a total concentration of up to 0.15 wt %. Pyrites contain the same elements (total concentration up to 3.71%), less often Pb, depleted with S and enriched with As (up to 3.16 wt %). The ratio of Ni/Co in pyrite is 10.0 Ni/Co 0.1, it is characteristic of hydrothermal negatively charged pyrite with high conductivity (p-тип). It is assumed that the “invisible” Au+ is found in disseminated pyrite and arsenopyrite mainly in an isomorphic structurally related form. A range of values δ34S from –6.4 to +5.6‰ in sulfides, is characteristic of juvenile/magmatic sources of sulfur of the studied deposits.