西北地质2012，Vol.45Issue(4)：321-333,13.
金川铜镍硫化物矿床成矿物质深部预富集过程探讨
The Preconcentration Process of Metal Mineral in the Deep Mgama Chamber of Jinchuan Ni-Cu Suphide Deposit
摘要
Abstract
The Jinchuan Ni-Cu deposit is one of the three largest magmatic sulfide deposits in the world. Jinchuan deposit have some unusual typical geological characteristics, such as the small size of the host intrusion, mainly consist of ultramafic rocks, high sulfide/silicate ration. , different rocks and ores showed the mutation contact relationship. These typical characteristics implied the the metal had precon-centrated in the deep stage magma chamber. The preconcentration process mainly involved three aspects; The mechanism of sulfide segregation; The relative time of sulfide segregation and the amount of sulfide segregated from the magma; The migration and fractional crystallization process of the sulfide. The Fo of olivine in different rocks have a narrow range (Fo= 80. 11-85. 68), which suggest that the deep magma chamber is an open system, the penetration of fresh magma make the Fe/Mg ration of the magma constant. Follow the olivine-liquid equilibrium principle, the MgO content of Jinchuan intrusion parental magma calculated from 10. 8%-12. 6%, which indicated that the source have a high degree of partial melting. The Sr-Nd-Os isotope and trace element geochemical features implied that the jinchuan intrusion parental magma suffered apparent crustal materials, the extent fo the contamination is about 5%-l0%. The Th-Ta, Th-Nb, (Th/Ta)PM- (La/Nb)PM diagram showed that part of the contaminated material is a component of the lower crust. The lower crustal material contamination may be the major pechanism of sulfide segregation in the deep magma chamber. The main ore-bearing rock types are lherzolite and dunite, The "Melts" software simulation calculation show that the sulfide segregation occurred in the early stage of magmatic evolution. After the sulfide segregation, as the gravity, it sink to the bottom or the lower part of the chamber. The massive ores of jinchuan deposit have the relative enrichment IPGE, and the rich copper ore body is relatively enriched in Cu and PPGE. The diffrerntiation of metal elements show that the sulfide had undergone significant fractional crystallization in the deep magma chamber.关键词
金川/铜镍硫化物矿床/原生岩浆/深部预富集/岩浆演化/硫化物熔离Key words
Jinchuan/ Ni-Cu sulfide deposit/ parental magma/ preconcentration in the deep chamber/ magma evolution/ sulfide segration分类
天文与地球科学引用本文复制引用
王亚磊,李文渊,张照伟,张江伟,高永宝,郭周平,李侃,钱兵..金川铜镍硫化物矿床成矿物质深部预富集过程探讨[J].西北地质,2012,45(4):321-333,13.基金项目
国家自然科学基金(41102050)和中国地质调查局地质大调查项目(1212010911032、1212011220897、121201112088、1212011120183和1212011121092)联合资助 （41102050）
