柴北缘尕秀雅平东含铜镍硫化物镁铁-超镁铁质岩体铂族元素地球化学特征研究  

Geochemical Characters of Platinum-Group Elements of the Gaxiuyapingdong Cu-Ni Sulfide-Bearing Mafic-Ultramafic Intrusion in the Northern Margin of the Qaidam Basin

作　　者：杜玮[1] 周伟[1] 伍学恒[2] 宋艳芳[3] 王子玺[1] 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]湖南省地质矿产勘查开发局四一七队,湖南衡阳421001 [3]湖南工学院,湖南衡阳421002

出　　处：《地质与勘探》2015年第2期203-211,共9页Geology and Exploration

基　　金：国家自然科学基金项目(编号41302070);青海省地质勘查基金项目(编号2012209)资助

摘　　要：尕秀雅平东含铜镍硫化物镁铁-超镁铁质岩体位于柴达木地块北缘,主要由蛇纹石化纯橄岩、单辉橄榄岩、橄榄辉石岩、辉石岩、辉长岩及斜长岩组成,侵位于古元古代达肯大坂岩群。本文对组成岩体的4件橄榄辉石岩样品和3件含矿岩石样品进行铂族元素分析,其∑PGE=8.82×10-9~84.8×10-9,原始地幔标准化配分曲线均呈左倾型式。利用Ni/Cu、Pd/Ir等相关参数确定原生岩浆为高镁玄武质岩浆,而低程度的地幔部分熔融作用是导致PPGE与IPGE强烈分异及Ru亏损的主要原因。岩体在形成过程中有一定程度地壳物质的混染作用,但早期硫化物的熔离作用不明显。同时,PGE元素间的协变关系显示热液蚀变作用对全岩PGE丰度影响不大。Located in the northern margin of the Qaidam basin,the Gaxiuyapingdong Cu- Ni sulfide-bearing mafic-ultramafic intrusion is composed of serpentinized-dunite,clinopyroxene peridotite,olivine pyroxenite,pyroxenite,gabbro and anorthosite,which intrude into the Dakendaban Group of Palaeoproterozoic. In this work,4 pieces of olivine pyroxenite samples and 3 pieces of ore bearing rock samples are analyzed for platinum-group elements.The results show ∑PGE = 8. 82 × 10- 9~ 84. 8 × 10- 9,and primitive mantle normalized PGE partition curve exhibits a left leaning style. Its parental magma was high Mg basalt magma based on related parameters like Ni / Cu,Pd / Ir. Low-degree partial melting of mantle is responsible for strong differentiation of PPGE and IPGE,and depletion of Ru. The formation process of this intrusion has undergone some degree of assimilation and contamination from crust material,but the early segregation of sulfide was not significant. Meanwhile,the covariant relation of PGE shows that hydrothermal alteration has little effect on the PGE abundance of the whole rock.

关 键 词：镁铁-超镁铁质岩体 尕秀雅平东 铂族元素 柴达木盆地北缘 

分 类 号：P595[天文地球—地球化学] P612[天文地球—地质学]