Minerals of precious metals in the Oleninskoe gold occurrence, Kolmozero-Voronye belt (Kola Peninsula)
Kalinin A. A., Savchenko Ye. E., Selivanova E. A.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2017. V. 146. N 1. P. 43-58
Distribution of the Au-Ag mineralization in the Oleninskoe occurence in the Kolmozero-Voronya greenstone belt is controlled by zones of quartz and quartz-tourmaline alteration of quartz porphyry and amphibolite with intensive arsenopyrite-pyrrhotite dissemination. Gold and silver form alloys, sulfide minerals and sulfosalts, tellurides and antimonides. Four stages are defined in development of precious metal mineralization. At the early stage silver-gold (25.5—31.3 wt % Au) inclusions formed in arsenopyrite, these inclusions are often situated at löllingite-arsenopyrite boundaries. At the second stage electrum with 33—77 % Au, Ag-sulfosalts, dyscrasite, hessite and cervelleite formed together with galena, sphalerite, gudmundite, second generation of arsenopyrite. At the third stage native gold (87—95 % Au) was recrystallized and redeposited in fractures in quartz and silicate minerals in amphibolite. And, finally, at the fourth stage, Ag sulfides, mainly acanthite, formed rims around grains of galena, pyrrhotite, and sulfosalts. Uchucchacuaite, ramdohrite, mckinstryite, ugtenbogardtite, cervelleite, semseyite are the first finds in the Kola region. Uchucchacuaite has an unusual chemical composition, rich in Fe.
Key words: Kolmozero-Voronya greenstone belt, Oleninskoe occurrence, native gold, silver, sulfosalts, uchucchacuaite, ramdohrite, dyscrasite, acanthite.