GEOCHEMICAL CHARACTERISTICS OF PLATINUM GROUP ELEMENTS IN JINCHUAN SUPER-LARGE SULFIDE COPPER-NICKEL DEPOSIT, JINCHANG CITY, GANSU PROVINCE, CHINA  

作　　者：WANG Ruiting MAO Jingwen HE Ying WANG Dongsheng TANG Zhongli 

机构地区：[1]Faculty of Geosciences and Resources, China University of Geosciences, Beoing 100083,China [2]Bureau of Geological Exploration for Nonferrous Metals in Northwest China, Xi＇an, SX710054, China, [3]Institute of Mineral Resources, Chinese Academy of Geological Sciences,Beifing 100037, China [4]Department of Geology, Northwest University, Xi＇an, SX 710069, China [5]Faculty of Geosciences and Resources, Chang＇an University, Xi＇an, SX 710054, China

出　　处：《Geotectonica et Metallogenia》2005年第2期152-163,共12页大地构造与成矿学（英文版）

摘　　要：The platinum-group element geochemistry of rocks and ores from Jinchuan super-large copper-nickel sulfide deposit is systemically studied in this paper. The Cu/Pd mean ratio of Jinchuan intrusion is lower than that of original mantle magma, which indicates that these ultrabasic rocks were crystallized from magma that lost Pd in the form of melting segregation of sulfides. The PGE of the rocks show trend of partial melting, similar to that of mantle peridotite, which shows that magma formation occurs during rock-forming and ore-forming processes. The chondrite normalized PGE patterns of the rocks and ores are well related to each other, which signifies the signatures of multi-episode magmatic intrusion, melting and differentiation in the formation processes of rocks and ores. In addition, analyses about the relation between PGE and S, and study on Re-Os isotopes indicate that few contamination of the crustal substances occurred during the magmatic intrusion and the formation of deposit. However, contamination by crustal substances helps to supply part of the S for the enrichment of PGE. Meanwhile, the hydrothermal process is also advantageous for the enrichment of PGE, especially lbr Pt and Pd, due to deep melting segregation. The characteristic parameters （such as Pt/（Pt＋Pd）, （Pt＋Pd）/（Ru＋Ir＋Os）, Pd/Ir, Cu/（Ni＋Cu）, and so on.） for platinum-group elements for Jinchuan sulfide copper-nickel deposit show the same features as those for sulfide copper-nickel deposit related to basic magma, which also illustrates its original magma property representative of Mg-high tholeiite. Therefore, it is the marie （not ultramafic） magma that resulted in the formation of the superlarge sulfide copper-nickel deposit enriched in Cu and PGE. To sum up, the geochemical characteristics of platinum-group elements in rocks and ores from Jinchuan copper-nickel sulfide deposit are constrained by the continental rift tectonic environment, the parent magma features, the enriched mantel magma source, the compThe platinum-group element geochemistry of rocks and ores from Jinchuan super-large copper-nickel sulfide deposit is systemically studied in this paper. The Cu/Pd mean ratio of Jinchuan intrusion is lower than that of original mantle magma, which indicates that these ultrabasic rocks were crystallized from magma that lost Pd in the form of melting segregation of sulfides. The PGE of the rocks show trend of partial melting, similar to that of mantle peridotite, which shows that magma formation occurs during rock-forming and ore-forming processes. The chondrite normalized PGE patterns of the rocks and ores are well related to each other, which signifies the signatures of multi-episode magmatic intrusion, melting and differentiation in the formation processes of rocks and ores. In addition, analyses about the relation between PGE and S, and study on Re-Os isotopes indicate that few contamination of the crustal substances occurred during the magmatic intrusion and the formation of deposit. However, contamination by crustal substances helps to supply part of the S for the enrichment of PGE. Meanwhile, the hydrothermal process is also advantageous for the enrichment of PGE, especially for Pt and Pd, due to deep melting segregation. The characteristic parameters (such as Pt/(Pt+Pd), (Pt+Pd)/(Ru+Ir+Os), Pd/Ir, Cu/(Ni+Cu), and so on.) for platinum-group elements for Jinchuan sulfide copper-nickel deposit show the same features as those for sulfide copper-nickel deposit related to basic magma, which also illustrates its original magma propertyrepresentative of Mg-high tholeiite. Therefore, it is the mafic (not ultramafic) magma that resulted in the formation of the superlarge sulfide copper-nickel deposit enriched in Cu and PGE. To sum up, the geochemical characteristics of platinum-group elements in rocks and ores from Jinchuan copper-nickel sulfide deposit are constrained by the continental rift tectonic environment, the parent magma features, the enriched mantel magma source, the complex metallogenesis and PGE geochemic

关 键 词：platinum group elements copper-nickel sulfide deposit geochemical feature Jinchuan 

分 类 号：P591[天文地球—地球化学] P611.1[天文地球—地质学]