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Shangguo Su, China University of Geosciences (Beijing) (China)
Chusi Li, Indiana University (United States)
Mei-Fu Zhou, University of Hong Kong (China)
Edward M. Ripley, Indiana University (United States)
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The Jinchuan Ni-Cu-PGE (Platinum group element) deposit in northwestern China is one of the largest magmatic sulfide deposits in the world. The PGE of Jinchuan deposit mainly occur in the Pt-Pd enriched zones, which are discordant lenses in the sulfide-bearing peridotite. Chalcopyrite, pyrrhotite, and pentlandite occur in both Pt-Pd enriched zones and normal ores, but Cu-bearing minerals such as cubanite and Bi-, Te-, and As-bearing minerals are more abundant in the Pt-Pd enriched zones. Sperrylite is the major Pt-host minerals in the Pt-Pd enriched zones of the Jinchuan deposit and occurs mainly as euhedral grains within base-metal sulfides which distribute among the cumulates of olivine. PGE-enrichment is found only in sulfide-bearing samples. In orebody 1 and orebody 24, Rh, Ru, and Ir are positively correlated, but Pt and Pd have negative correlation with Ir. However in orebody 2 Rh, Ru, Pt, Pd and Ir are positively correlated. Taken together, the elemental correlations and mineralogical data support the origin of Pt-Pd rich ores in Orebody 1 and Orebody 24 by fractional crystallization of monosulfide solid solution from sulfide liquids on cooling. The origin of Orebody 2 involves variable magma/sulfide liquid mass ratios (R-factors).
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