PLATINUM GROUP MINERALS IN DUNITES OF GALMOANAN MASSIF (KORYAK UPLAND)

摘要

Galmoanan consentrically-zoned massif is situated within Koryak upland, the North-Eastern part of Russia. Size of aggregates of PGM ranges from 0.01mm to 2-3cm. The numerous platinum group minerals (PGM) manifestations often associated with disseminated, brecciated and veined chromitites were detected in dunities of the South part of Galmoanan massif. The platinum group element mineralization is represented by following classes of minerals: intermetallides-isoferroplatinum, tetraferroplatinum, tulameenite, osmium and pt-bearing native copper; sulfides-laurite, cooperite; arsenides-sperrylite; sulfoarsenides-irarsite, hollingworthite. Isoferroplatinum is the most widespread of PGM; tetraferroplatinum, sperrylite and tulameenite-secondary minerals; osmium, laurite, cooperite and Pt-bearing native copper-rare minerals. Tentatively three paragenetic mineral associations were determined: 1) early-laurite and osmium; 2) middle-isoferroplatinum; 3) late-tetraferroplatinum, sperrylite, tulameenite and Pt-bearing native copper. The significance part of PGM were located to late magmatic or postmagmatic deformations in chromite grains.