Gold-arsenic sulfide mineralization of the Kayancha area, Gorny Altai

Gold-arsenic sulfide type mineralization has first been revealed for the Gorny Altai region. The mineralized zones associate with lamprophyre dikes and are controlled by steeply dipping faults transecting the Vendian-Cambrian terrigenous-carbonate-volcanogenic sequence. The ore bodies are localized in horizons of basic metavolcanic rocks, enclosed between limestone layers. The near-ore metasomatites are composed of the paragenesis of albite, magnesiosiderite, and sericite. The gold content is related to fine dissemination of arsenic pyrite and arsenopyrite. Gold in the primary and oxidized ores is submicroscopic and finely dispersed. The sulfur isotopic composition of the sulfides (δ34SCDT = 0 ‰) indicates an association of the mineralization with a deep-seated magmatic source. The Kokpatas gold deposit in western Uzbekistan is considered as an analogue.