西南暗色岩铜镍硫化物矿化岩体与峨眉山玄武岩的关系--以云南金宝山岩体为例

内容提要本文以金宝山为典型实例,根据元素地球化学特征探讨了西南暗色岩铜镍硫化物矿化岩体与峨眉山玄武岩的关系。分析表明,金宝山超镁铁岩与低钛峨眉山玄武岩在元素地球化学特征上具有一致的岩浆成因属性,两者在成岩机制上互补,低钛峨眉山玄武岩普遍经历了橄榄石结晶分异和硫化物熔离亏损作用,金宝山成矿岩体则与低钛峨眉山玄武岩同源岩浆深部分异的堆晶相相对应,由堆晶橄榄石及熔离硫化物和部分残余熔体构成的“晶-糊”侵位形成,因此认为铜镍硫化物矿床成矿岩体与低钛峨眉山玄武岩为同源异相产物。

The Relation between Emeishan Continental Flood Basalts and Cu-Ni-PGE Deposits of Southwestern China Trap--A Case Study on Jinbaoshan Mafic-Ultramafic Intrusion, Yunnan

Cu-Ni-PGE deposits bearing intrusions are contemporaneous with Emeishan continental flood basalts,crops out in western part of Yangtze craton, southwestern China. They as a whole are believed to be linked genetically with mantle plume activities in Permian-Triassic boundary. By a case study on Jinbaoshan ultramafic intrusion,Yunnan,it shows that the intrusion have genetical connection with lower Ti Emeishan basalt in litho-geochemistry. They are counterpart of parental magma evolution process. The original magma experienced about 12% fractionation of olivine crystallization and segregation of sulfide. The fractionated olivine and segregated sulfide accumulated in the lower part of magma chamber mixed with some residual melt, forming "crystal-liquid mush",intruded to be mafic-ultramafic intrusion. Most part of the residual melt erupted out to become the Lower Ti Emeishan continental flood basalts. They are cogenetic rocks in different occurrence.