准噶尔盆地周缘蛇绿混杂岩中洋岛玄武岩的识别:地幔柱的产物?  

Recognition of Oceanic Island Basalts in Ophiolitic Melange around the Junggar Basin:Product of Mantle Plume?

作　　者：杨高学[1,2] 李永军[1,2] 佟丽莉[1,2] 司国辉 杨宝凯 李甘雨[1] 沈锐[1] 晁文迪 

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]国土资源部岩浆作用成矿与找矿重点实验室,西安710054 [3]陕西省地质矿产勘查开发局西安地质矿产勘查开发院,西安710100 [4]青岛地质工程勘察院,山东青岛266071

出　　处：《地质论评》2015年第5期1021-1031,共11页Geological Review

基　　金：国家自然科学基金资助项目(编号41303027);中央高校基本科研业务费专项资金资助项目(编号310827153506;310827153407;2014G1271058)的成果

摘　　要：地处中亚造山带西南缘的准噶尔盆地周缘发育多条蛇绿混杂岩带。初步研究表明,在西准噶尔克拉玛依,东准噶尔卡拉麦里及北天山巴音沟蛇绿混杂岩中除典型蛇绿岩组合之外,还存在海山或大洋岛屿岩石组合,即玄武岩、灰岩、泥岩和硅质岩。这些玄武岩属于碱性玄武岩系列,具有高TiO_2和TFeO,低MgO,强烈富集轻稀土元素特征,无明显Nb、Ta负异常,与日喀则及夏威夷洋岛玄武岩地球化学特征极为相似,可能形成于大洋板内的海山或洋底高原,认为其成因与地幔柱相关,表明在古亚洲洋演化过程中,不仅是洋内俯冲系统,还伴有地幔柱活动。The Junggar terran is located in the southwestern part of the Central Asian Orogenic Belt （CAOB）,which is characterized by widespread ophiolitic mélange belts.Preliminary studies indicate that seamount or oceanic island assemblages,including basalt,limestone,mudstone and chert,exist in the Karamay （west Junggar）,Kalamaili （east Junggar） and Bayingou （northern Tianshan Mountains） ophiolitic mélanges,except typical ophiolitic rock assemblages.The basalts are alkaline basalt series,characterized by high TiO2 and TFeO,low MgO,strongly LREE enrichment,and no obvious Nb,Ta negative anomalies.This is very similar to oceanic island basalts from Xigaze and Hawaii,probably formed in the ocean seamount and/or oceanic plateaus in oceanic plate.The alkaline basalts were derived from mantle plume-related source,indicating that not only the intra-oceanic subduction system but also mantle plume activity in the Paleo-Asian Ocean evolution.

关 键 词：碱性玄武岩 洋内俯冲系统 地球化学 准噶尔 中亚造山带 

分 类 号：P588.1[天文地球—岩石学]