金川含矿超镁铁岩侵入体侵位序列  

Emplacement sequence in the Jinchuan sulfide ore-bearing ultramafic intrusion,western China.

作　　者：苏尚国[1] 汤中立[1,2] 周岱[1] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]长安大学地球科学与资源学院,陕西西安710064

出　　处：《地学前缘》2010年第2期118-126,共9页Earth Science Frontiers

基　　金：大陆科学钻探选址与钻探试验项目(Sinoprobe-05-01);国家自然科学基金项目(40472051;40534020);高等学校学科创新引智计划(B7011)

摘　　要：金川铜镍硫化物矿床是世界第三大镍矿床,但其成岩成矿过程及侵位机制一直存在较大争论。根据金川含矿超镁铁岩岩石学特征、穿插关系、矿物成分及地球化学特征,提出了金川含矿岩体5阶段的成岩、成矿侵位序列,它们分别是:(1)超镁铁质岩浆侵位;(2)浸染状硫化物矿浆侵位;(3)网状硫化物矿浆侵位;(4)块状硫化物矿浆侵位;(5)铂钯富集体侵位。金川铜镍(铂)矿床中Ni,Cu,Pt,Pd,Rh,Ir,Ru,及Co与S呈正相关关系;当ω(S)=5%～15%时,铂族元素发生明显的分离作用,铂族金属主要富集在铂钯富集体中。铂钯富集体是硫化物矿浆经单硫化物固溶体结晶后的残余熔浆;块状矿石是单硫化物固溶体堆积而成的产物。金川铜镍硫化物矿床的侵位机制为岩墙型岩浆通道。The Jinchuan ultramafic intrusion in western China hosts the third largest magmatic Cu-Ni deposit in the world,but the emplacement history of the magma and sulfide liquid in the intrusion remains poorly under-stood. Based on the lithological structure,cross-cutting relationships and compositional variations in the intrusion, we propose a five-stage emplacement model：（1）formation of sulfide-poor ultramafic lithology by injection of an olivine-rich magma;（2）formation of disseminated sulfide zones by injection of olivine-rich magma containing small amounts of suspended sulfide droplets;（3）formation of net-textured sulfide ore zones by injection of sulfide olivine-rich magma;（4）formation of massive sulfides zones ore body by injection of sulfide liquid;and（5）formation of Cu-Pt-Pd-rich sulfide veins by injection of fractionated sulfide liquids derived by fractional crystallization from nearby sulfide zones and emplaced into fractures in the intrusion and footwall rocks.Ni,Cu,Pt,Pd,Rh,Ir,Ru,and Co correlate positively with S indicating that they were hosted primarily in sulfides.Pt-Pd enrichment zones are the relic liquid of monosulfide solid solution segregation,and massive ore may represent the accumulation of monosulfide solid solution.The magma conduit of Jinchuan Cu-Ni （PGE）sulfide deposit belongs to dike magma conduit.

关 键 词：侵位序列 含矿超镁铁岩侵入体 金川 

分 类 号：P597[天文地球—地球化学]