Geochemical features of pyrite types of the Kumtor gold deposit, Kyrgyzstan
A.G. Shevkunov, V.V. Maslennikov, R.R. Large, S.P. Maslennikova, L.V. Danyushevsky
Successively forming sedimentary-diagenetic (Py1), metamorphic (Py2) and hydrothermal (Py3) pyrite types are recognized in black shales of the Kumtor gold deposit (Central Tien Shan). According to LA-ICP-MS analysis, each type exhibits specifc geochemical features. Sedimentary-diagenetic pyrite is characterized by higher median Mn, Tl, Co, Ni, As, Sb, Pb and Mo contents. The contents of these elements, as well as Au, Ag, Te and W, gradually decrease from framboidal to crystalline-grained pyrite. The minimum contents of most trace elements are typical of metamorphic pyrite and pyrrhotite. Hydrothermal pyrite is characterized by strongly variable Cu, Se, Zn, Pb, Sb, Au, Ag, Te, Ti, W contents due to microinclusions of chalcopyrite, sphalerite, tetrahedrite, native gold, galena, altaite, Au-Ag tellurides, rutile and scheelite. The correlation between Au, W and Ti contents is established. Our data are in line with a multistage model of (Large et al., 2011), who considers sedimentary-diagenetic sources of most chemical elements, which are mobilized to the fuid during formation of pyrrhotite and form their minerals during hydrothermal stage.
Figures 10. Tables 2. References 25.
Key words: gold, trace elements, LA-ICP-MS, pyrite, Kumtor
MINERALOGY № 4 2018