新疆塔克札勒蛇绿混杂岩中玄武质熔岩地球化学特征及其成因讨论  

GEOCHEMICAL CHARACTERISTICS AND TECTONIC SETTINGS FOR BASALTS IN TAKEZHALE OPHIOLITE IN EAST JUNGGAR, XINJIANG

作　　者：卜国民[1] 李华启[1] 李文铅[1] 俞亨祥[2] 金辉 

机构地区：[1]中国科学院广州地球化学研究所与南海海洋研究所边缘海地质重点实验室,广东广州510640 [2]桂林工学院,广西桂林510004 [3]河南省地质矿产勘查与开发局第二地质勘查院,河南许昌416000

出　　处：《大地构造与成矿学》2005年第2期252-261,共10页Geotectonica et Metallogenia

基　　金：国家重点基础研究发展规划项目(2001CB409805);中科院创新重要方向性项目(KZCX3-SW-137)共同资助.

摘　　要：塔克札勒蛇绿混杂岩玄武岩的SiO2 和MgO高,同时较富集Cr、Ni及Co等过渡族元素,具有玻安岩特征;微量元素以富集LILE(Ba,Rb,Sr等)而亏损HFSE(Nb、Ta、Zr、Hf等)为特征;该玄武岩具LREE平坦或弱亏损、HREE亏损的分配型式;构造环境判别图解指示该玄武岩形成于弧前环境。地球化学特征与其它地质特征表明该蛇绿岩代表了古亚洲洋消亡过程中的洋壳残片。The basalts in Takezhale ophiolitic mélange show the characteristics of boninite, i.e., being characterized by high SiO_2, MgO and enrichment in transition elements such as Cr, Ni and Co etc. The spider diagram for trace elements indicates that they are enriched in LILE (Ba, Rb, Sr etc.) but are depleted in HFSE (Nb, Ta, Zr, Hf etc.). The REE distributions show flat LREE trends but HREE-depleted patterns. Discrimination diagrams demonstrate that the basalts were formed in forearc in terms of tectono-environment. Geochemical and other geological features suggest that the ophiolitic mélange represents the ocean crust tags resulted from the withering away of the Palaeo-Asian ocean.

关 键 词：蛇绿混杂岩 地球化学 弧前环境 塔克札勒 

分 类 号：P595[天文地球—地球化学] P588.14[天文地球—地质学]