西天山塔尔得套地区乌郎组地球化学特征和构造环境  

Tectonic Setting and Geochemistry of the Wulang Formation in Taerdetao,West Tianshan

作　　者：吴明仁[1] 楼法生[1] 宋志瑞[1] 肖晓林[1] 凌联海[1] 程春华[1] 

机构地区：[1]江西省地质调查研究院,江西南昌330201

出　　处：《东华理工学院学报》2006年第3期217-224,共8页Journal of East China Institute of Technology

基　　金：新疆维吾尔自治区克令一带1:5万区域地质矿产调查(XJQDZ2003-07)

摘　　要：新疆尼勒克县塔尔得套地区二叠纪火山岩产于伊犁微板块中。为陆相火山岩，主要岩性为玄武岩和流纹岩。具双峰式火山岩系组合特征。基性火山岩属高钾钙碱系列，轻微富集LREE，HREE分馏较明显（（Gd／Yb）N：1．52～2．68），富集大离子亲石元素（LILE），亏损高场强元素（HFSE）。流纹岩的Eu负异常明显（δEu：0．33），在微量元素蛛网图上，流纹岩除了具LILE富集和HFSE亏损特征外。Sr，P，Ti等元素的强烈亏损。稀土元素和微量元素特征表明火山岩形成于大陆拉张环境，处于裂谷演化的早期阶段。The Permian volcanic rocks were continental volcanic rocks from Taerdetao area in Nileke County,which occurred in Yili Microplate that were dominated by basalt and rhyolites and exhibited a bimodal feature. The basalts belong to the high-K calc-alkaline series demonstrating slight REE enrichment and apparently fractionation within HREE contents and （ （Gd/Yb） N = 1.52 - 2.68）. The primitive mantle （PM） -normalized spidergrams are characterized by LILE enrichment and HFSE depletion. Apparently negative Eu anomalies for rhyolites （δEu = 0. 33 ） , the PM-normalized spidergrams while the rhyolites are significantly depleted in Sr, P and Ti as well as the LILE enrichment and HFSE depletion. The REE element and trace element characteristic expresses the volcanic rocks formation to an pull-aparting continental environment, being at the earlier stage in rift valley evolution.

关 键 词：西天山 乌郎组 元素地球化学 构造环境 

分 类 号：P591.2[天文地球—地球化学]