大别造山带祝家铺辉长岩的铂族元素特征  

The distribution of platinum-group elements in gabbros from Zhujiapu, Dabie orogen

作　　者：刘庆[1] 侯泉林[1] 周新华[1] 谢烈文[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩石学报》2005年第1期227-239,共13页Acta Petrologica Sinica

基　　金：中国科学院知识创新工程重大项目(KZCX1-07)资助

摘　　要：采用镍锍火试金法结合ICP-MS分析了祝家铺14个辉长岩样品中的Ir,Ru,Rh,Pt和Pd的含量。结果显示其PGE的含量较低,原始地幔标准化后的PGE分布模式呈正斜率型,PPGE相对原始地幔略微亏损,而IPGE强烈亏损,Pd/Ir值(22-138)远高于相应的地幔比值,表明铂族元素发生了分异。对祝家铺辉长岩的铂族元素研究表明,在其源区发生过硫化物的分异作用,地壳的混入可能促进了硫化物的饱和祝家铺辉长岩中铂族元素的分异是因为在地幔部分熔融和岩浆演化过程中,PPGE主要受硫化物控制,而Ir则存在于非硫化物相如尖晶石。The contents of platinum group elements (PGEs: Ir, Ru, Rh, Pt, Pd) in Zhujiapu gabbros have been determined using ICP-MS after a nickel sulphide fire assay preconcentration. The absolute PGE abundances for all of the fourteen samples are extremely low. They display pronounced positively-sloping in mantle-normalized pattern that highlight their slightly depleted in PPGEs and strongly depleted in IPGEs. Pd/Ir ratios (22 similar to 138) are higher than that of primitive mantle. These characters suggest the fractionation of PGE in the gabbros of Zhujiapu. Sulphide segregation has happened in the original magma. S-saturation of the magma can be promoted by crust contamination. PGE fractionation in the gabbros is controlled by the phase that can potentially fractionate IPGEs is spinel, sometimes maybe Os-Ir alloy,but the PPGEs reside in sulfide.

关 键 词：铂族元素 辉长岩 分异作用 部分熔融 

分 类 号：P588.125[天文地球—岩石学] P594.1[天文地球—地质学]