新疆库鲁克塔格西段三叠纪辉绿岩墙的发现及地质意义  

The Discovery of the Triassic Mafic Dykes in Western Quruqtag and Its Geological Implications

作　　者：吕彪[1] 郭瑞清[1] 王克卓 魏震[1] 郭羽[1] 何海伦[1] 胡雪原[1] 

机构地区：[1]新疆大学地质与矿业工程学院,新疆乌鲁木齐830046 [2]新疆地质调查院,新疆乌鲁木齐830011

出　　处：《新疆地质》2016年第3期317-324,共8页Xinjiang Geology

基　　金：中国地质调查局新疆兴地塔阿匍口地区1:5万(K45E014010;K45E014011;K45E015010;K45E015011;K45E016011)等5幅区调项目(1212011120477)资助

摘　　要：对新疆库鲁克塔格西段辉绿岩墙进行LA-ICP-MS测年、岩石学和岩石地球化学分析,结果表明,该岩墙为碱性系列,在稀土元素球粒陨石标准化图解中显示弱Eu正异常的向右陡倾特征,微量元素标准化图解显示其富集Rb,Ba,Sr等大离子亲石元素,高场强元素Nb,Ta,Ti等弱富集,与板内洋岛玄武岩特征相似;辉绿岩墙起源于具OIB性质的富集地幔,原始岩浆在侵位过程中发生了分离结晶作用,还受到地壳混染作用影响;辉绿岩墙的锆石UPb加权平均年龄为(233.0±2.4)Ma(MSWD=1.17),岩墙显示板内岩浆特征,指示其为板内伸展作用产物。Systematically LA-ICP-MS dating technique,petrography and geochemical analyses were used to the mafic dykes located in the Western Quruqtag,Xinjiang.Geochemistry ofmafic dykes shows that they are belongs to alkaline se- ries.The chondrite-normalized REE patterns of mafic dykes are characterized by high dip REE right-deviation and slight- ly positive Eu anomaly.The primitive mantle-normalized spidergrams are similar to OIB which characterized by enrich- ment of LILE （Rb,Ba and Sr） and Weak enrichment of HFSE （Nb,Ta and Ti）.Analysis shows that magma of these mafic dykes was derived from OIB-type enriched mantle and experienced crustal contamination and fractional crystallization in the emplacement process. The zircon SHRIMP U-Pb age of the mafic dykes is （233.0±2.4） Ma （MSWD=1. 17）, these dykes showing the within plate basalt characteristics,integrating with regional geology, it can be concluded that the maf- ic dykes formed in a intraplate extension tectonic setting.

关 键 词：库鲁克塔格西段 三叠纪 辉绿岩墙 

分 类 号：P534.51[天文地球—古生物学与地层学] P619.224[天文地球—地质学]