Tellurium and Selenium Mineralogy of Gold Deposits in Northern Fennoscandia

Mineralization of Te and Se was found in gold deposits uranium occurrences, located the Paleoproterozoic greenstone belts Northern Fennoscandia. These are different genesis, but all them formed at late stages Svecofennian orogeny, they have common geochemical association metals Au, Cu, Co, U, Bi, Te, Se. The prevalent minerals Ni Fe tellurides melonite frohbergite, Pb telluride altaite. Bismuth were detected many region, usually not more than two–three grains. main selenide studied is clausthalite. most diversified selenium mineralization (clausthalite, klockmannite, kawazulite, skippenite, poubaite) discovered deposits, Russian part Salla-Kuolajarvi belt. Consecutive change sulfides by tellurides, then selenotellurides later selenides, indicates increase fugacity, fSe2, relation to fTe2 fS2in mineralizing fluids. Gold-, selenium-, tellutium-rich fluids potentially linked with post-Svecofennian thermal event intrusion post-orogenic granites (1.79–1.75 Ga) Perapohja belts. Study fluid inclusions quartz from belt showed that high-temperature (240–300 °C) high salinity (up 26% NaCl-eq.). Composition selenotellurides, kawazulite-skippenite, poubaite varies significantly Se/Te ratio content. Skippenite kawazulite show full range Se-Te isomorphism. Ni-Co Co-Fe substitution plays an important role mattagamite: cobalt nickel Juomasuo Konttiaho, mattagamites Ozernoe contain significant Fe. In occurrence, mineral-concentrator molybdenite, which contains up 16 wt.% marginal parts molybdenite rich Re 1.2 wt.%), impurity irregularly distributed flakes spherulites.