Tellurium-bearing minerals in clastic ores of Ybileynoe massive sulfide deposit (South Urals)

Abstract

At the well preserved Yubileynoe VMS deposit (South Urals), sulfide breccias and turbidites contain abundant tellurides represented by hessite, coloradoite, altaite, volynskite, stutzite, petzite, calaverite as well as phases of intermediate solid solution tellurobismuthite – rucklidgeite. There is three generation of tellurides were highlighted: 1) primary hydrothermal tellurides in the fragments of chalcopyrite and sphalerite of chalcopyrite-rich black smoker chimneys; 2) authigenic tellurides in pseudomorphic chalcopyrite and veins of chalcopyrite after fragments of colloform and granular pyrite; 3) authigenic tellurides in pyrite nodules. Authigenic tellurides are widespread in pyrite-chalcopyrite turbidites. In sulfide turbidites and gravelites with fragments of sphalerite-pyrite, pyrite-sphalerite paleosmoker chimneys and clasts of colloform and fine-grained seafloor hydrothermal crusts, primary hydrothermal and authigenic tellurides are less common. Siliceous siltstones intercalated with sulfide turbidites contain pyrite nodules, which peripheral parts contain inclusions of epigenetic tellurides. It is assumed that the source of tellurium for authigenic tellurides were fragments of colloform pyrite and hydrothermal chalcopyrite of pyrite-chalcopyrite chimneys, which dissolved during post-sedimentation processes. The main concentrators of tellurium in clastic ores are pseudomorphic chalcopyrite, which inherits high contents of Te, Bi, Au, Ag, Co, Ni, As from the substituted colloform pyrite, and varieties of granular pyrite, containing microinclusions of tellurobismuthite (Bi, Te), petzite (Au, Ag, Te), altaite (Pb, Te), coloradoite and hessite (Ag, Te).