Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy;Vol.XXIII, No.2

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Chemical Compositions and Paragenesis of the Platinum-group Element Minerals in the Jinchuan Sulfide Deposit, Gansu Province, China

Yang, Xuan-Zhu;Matsueda, Hiroharu;Yui, Shunzo;Dong, Xian-Yang

Permalink : http://hdl.handle.net/2115/36784

Abstract

A variety of platinum group minerals (PGM) occurs in the Jinchuan deposit, China. Four different PGM assemblages have been distinguished as follows: The first group, mainly sperrylite, occurs within altered olivines. The second occurs within sulfide mineral grains and is composed of platinum- and palladium-dominated tellurides, bismuth tellurides. The third occurs at the margin of sulfide minerals, and includes platinum- and palladium-dominated bismuth tellurides, tellurobismuthides and sperrylites. The fourth group is composed of platinum- and palladium-dominated tellurobismuthides and bismuthides, and occurs in the fractures of sulfide minerals. Their chemistry and mineral paragenesis indicate different origins for the four PGM groups. The first and fourth PGM groups clearly display secondary alteration products as a result of serpentinization of the host rocks. The second group represents primitive PGM formed during the sulfide crystallization stage. The third group could have been formed during the last crystallization stage of the sulfide melt. Based on these facts, a model for the remobilization and deposition of PGE is proposed for this deposit.

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