新疆科克森套蛇绿岩套玄武岩的地质地球化学  

Geology and Geochemistry of Basalt in the Kekesentao Ophiolite,Xinjiang

作　　者：王玉往[1,2] 王京彬[1,2] 唐萍芝[1] 赵路通[2] 石煜[3] 陈言飞[3] 

机构地区：[1]北京矿产地质研究院,北京100012 [2]昆明理工大学国土资源工程学院,云南昆明650093 [3]中国地质大学,北京100083

出　　处：《地球科学进展》2012年第10期1100-1107,共8页Advances in Earth Science

基　　金：国家重点基础研究发展计划项目“后碰撞过程壳幔物质交换与成矿”(编号:2007CB411304);全国危机矿山找矿专项“危机矿山勘查理论、方法与总结项目”(编号:200699105)资助

摘　　要：新疆北部科克森套地区玄武岩出露于超镁铁质岩体的北侧,与玄武质凝灰岩共生,厚度达50～80 m;玄武岩普遍具有片理化、斑状结构;岩石地球化学特征表明,该玄武岩属低碱(Na2O+K2O均<3%,σ值在0.60～1.19)、低钛(TiO2在0.73%～1.22%)、富镁(MgO在7.43%～9.72%)的拉斑玄武岩系列,具有原始岩浆特征(其Mg#值在0.65～0.71),稀土总量较低(ΣREE在29.68×10-6～44.91×10-6),稀土及微量元素配分曲线平缓,可能形成于洋中脊构造环境。该区玄武岩的发现和岩石地球化学研究,佐证了科克森套蛇绿岩套的存在。The newly-found Kekesentao basalt occures in the north of the Kekesentao ultramafic complex,north Xinjiang.It is composed of basalt and basaltic tuff with thickness of 50 to 80 meters.The basalt generally undergoes schistosition,but porphyritic structure still remained.The geochemistry of rocks shows that the basalt is low alkali（Na2O＋K2O3%,σ=0.60-1.19）,low titanium（TiO2=0.73%-1.22%） and magnesium-rich（MgO=7.43%-9.72%） tholeiitic rock series,and might be generated from primary magma characterized by Mg# value of 0.65 to 0.71.The characteristics of low REE contents（ΣREE=29.68×10-6-44.91×10-6）,and flat REE and trace elements normalized pattern of the basalt suggest that it form in middle-ocean ridge tectonic setting.The discovery and geochemical research of the basalt proves the existence of Kekesentao ophiolite suite.

关 键 词：蛇绿岩 地球化学 缝合带 科克森套 新疆北部 

分 类 号：P588.34[天文地球—岩石学]