西昆仑团结峰地区E-MORB残片的发现、地球化学特征及构造意义  

The Discovery of E-MORB in Tuanjiefeng Area of West Kunlun Mountain,its geochemical characteristics and tectonic significance

作　　者：魏永峰[1] 赵志强[1] 林美英[1] 罗巍[1] 徐刚[1] 邓泽锦[1] 

机构地区：[1]四川省地质矿产勘查开发局区域地质调查队,四川双流610213

出　　处：《新疆地质》2016年第3期312-316,共5页Xinjiang Geology

基　　金：昆仑-阿尔金成矿带地质矿产调查(1212011220646)项目资助

摘　　要：团结峰地区玄武岩呈残片状产于上河尾滩组复理石中,为碱性系列岩石。稀土元素球粒陨石分布模式呈LREE略富集-富集的右倾型,轻重稀土分异明显,（La/Sm）_N=1.02~2.71、（La/Ce）_N=1.02~1.38,为典型E-MORB,Rb,Ba,Sr等大离子亲石元素富集,蛛网图特征与碱性E-MORB相似,表明岩石可能形成于陆间裂谷-初始洋盆环境。在团结峰地区已发现与E-MORB岩片相伴生的超基性岩、基性岩及硅质岩岩片,共同构成了蛇绿岩残片。其中,基性岩及玄武岩U-Pb年龄为229~254 Ma,为蛇绿岩形成时间。从形成时代、物质组分和分布位置分析,该蛇绿岩残片可与西兰乌金蛇绿混杂岩带对比。The basalts in Tuanjiefeng area is produced in pieces in the flysch formation of Shangheweitan Group,be- longs to alkaline series.The Chondrite-normalized REE patterns are LREE enrichment to slight enrichment, incline to the right,show obvious fractionation between LREE and HREE.The （La/Sm）N is 1.02 to 2.71,the （La/Ce）N is 1.02 to 1.38, is a typical E-MORB,and rich in the contents of big ion lithophile element Rb, Ba, Sr, etc. Cobweb graph is similar to alkaline E-MORB which formed in the intercontinental rift-initial ocean basin environment.The ultrabasic rock,basic rock and rock slices of siliceous had been found associated with the slices of E-MORB which already had been found in Tuan- jiefeng area, constitute the ophiolite pieces.The U-Pb age of basic rock and basalt in ophiolite pieces is 229-254 Ma,the time which the ophiolite formed.It can be compared with the migmatite of Xilan Wujin ophiolite melange zone.

关 键 词：西昆仑 团结峰地区 E-MORB 地球化学 构造环境 

分 类 号：P587[天文地球—岩石学]