PGE mineralization in the Vuruchuaivench gabbronorite massif, Monchegorsk pluton (Kola Peninsula, Russia)

The article presents some of the first data on the platinum-bearing potenti al of the Vuruchuaivench massif. According to recent opinions, the massif i s a marginal part of the Monchegorsk pluton. Ore mineralization of the Vuru chuaivench massif belongs to the low-sulfide PGE type with a higher concent ration of PGE relative to that of Ni and Cu. This type of ore mineralizatio n is new to the Monchegorsk pluton. Elements of the platinum group at the V uruchuaivench occurrence are distributed very unevenly in ore bodies, with content variations from 1 to 7 g/t of the PGE sum. Impregnated sulfide mine ralization is localized in an extended 1-3 m-thick horizon, which is made u p of medium- and coarse-grained, often taxite, leucocratic gabbronorites an d anorthosites that conform to the host gabbronorites. PGE form their own m inerals and solid solutions in sulfides and sulfoarsenides. Minerals of pla tinum metals (PGM) associate with postmagmatic sulfide paragenesis. They ar e represented by Pd arsenides and bismuth tellurides. Mayakite, sperrylite, hollingworthite, irarsite, Pd3Ni2As3, and (Ni,Pt)AsS are subordinate miner als. Native gold, electrum, kustelite, naumanite, hessite, minerals of the galena sequence: clausthalite, POE-containing cobaltite, and gersdorffite a re associated with MPM. The abundance of fine (micron and submicron) inclus ions of noble metal mineral phases in sulfides, sulfoarsenides, and rock-fo rming minerals is a typical feature of this mineralization. Platinum minera lization was formed in the process of a metasomatic alteration of primary s ulfide and silicate parageneses by magmatic fluids at the final stages of t he massif formation. This is confirmed by the following features: by the pa rticulars of the PGM composition, their paragenesis with low-temperature su lfide assemblages, and the confinement of ore horizons to autometasomatical ly altered gabbronorites and anorthosites.