中文摘要：

盆地基底是制约盆地形成演化与构造变形的关键因素之一,研究盆地基底是剖析盆地构造特征的重要途径。塔里木盆地北部处于负磁异常区,推测其基底为变质沉积岩。本文对这一推断利用塔里木盆地北部库车坳陷吐格尔明背斜核部出露的元古宙片岩进行了锆石U-Pb年代学和岩石地球化学研究。研究表明,片岩中锆石的206Pb/238U年龄集中在（775.3±5.8）Ma～（787.1±6.8）Ma,表明它们形成于新元古代早期,代表约800 Ma发生的晋宁运动,这一构造事件形成了塔里木盆地北部的基底。片岩SiO2含量大于70%,长英质组分含量高,Al2O3、K2O富集;稀土元素总量（ΣREE）平均为166×10-6,稀土元素配分曲线呈微右倾型,具有弱的负Eu异常;高场强元素Ta、Nb、Ti等具有负异常,大离子亲石元素Rb、Ba等具有正异常。通过原岩恢复,判断该变质岩是一套由石英砂岩类变质形成的副变质岩。这与塔北航磁负异常特征吻合,这种性质的基底强度较小,在后期表现出构造沉降幅度大与构造变形强烈。

英文摘要：

Basin basement is one of the key factors to control basin evolution and its structural deformation.The study of basement is an important way to analyze the basin＇s tectonics and structures.The northern part of Tarim basin is in the negative magnetic anomaly,suggesting that the basement is composed of meta-sedimentary rocks.Utilizing the data of zircon U-Pb chronology and geochemistry of Proterozoic schist at the core of Tugerming anticline in Kuqa depression in the north of Tarim Basin,this paper conducted the studies.The results show that zircon 206Pb/238U dating ages are concentrated on 775.3± 5.8 Ma～787.1± 6.8 Ma,which demonstrates that the schist was formed in the early Neoproterozoic,and the basement of northern Tarim basin was formed during Jinning movement.SiO2 content of schist is more than 70%,with high felsic constituents and enriched Al2O3 and K2O;the average value of ΣREE is160 ppm.Chondrite-normalized REE patterns are rightly-oblique,the rocks possess weak Eu anomalies;primitive mantle standardized trace elements characterized by LILE（Rb,Ba etc.）are relatively enriched,while HFSE（Ta,Nb,Ti etc.）are depleted.Through the restoration of the proto-rock,it can be determined that the metamorphic rock is parametamorphic rock formed from a quartz sandstone,which is in good agreement with the negative aeromagnetic anomalies in the north of Tarim Basin.The basement had low rigidity,which resulted in large-scale tectonic subsidence and intense structural deformation in the subsequent evolution of the basin.