新疆塔里木南缘叶城棋盘一带古生代岩浆活动及构造意义

发布时间：2018-05-16 10:41

本文选题：塔里木南缘 + 古生代　；参考：《新疆大学》2015年硕士论文

【摘要】：通过对叶城棋盘一带分布的古生代侵入岩、火山岩系统的研究,从野外特征、地球化学分析及同位素年代的限定,运用各类构造判别图解,并结合前人研究成果,将该区古生代岩体大致分为两种构造成因类型:高钾钙碱性系列(加里东期)及碱性系列岩类(海西期),钙碱性或高钾钙碱性系列岩石(128km岩体、尤仑岩体、大同西岩体、雀普河岩体、丘克苏岩体),LREE和LILE富集,HFSE相对亏损,其中128km岩体和尤仑岩体的Sr、Nd、O同位素组成显示幔壳混源的特点。碱性系列岩石,富碱,富HFSE,而LILE明显亏损。早古生代构造强烈,加里东中晚期产出大量造山后期花岗岩,暗示出原特提斯洋已基本封闭;早泥盆系辉绿岩脉(408.5±7.3Ma)大规模侵入,标志着加里东造山作用的结束;呈夹层状产出于棋盘组(P2q)的早二叠世柱状玄武岩(298.3±2.8Ma),代表了晚古生代又一次拉张裂解作用。研究区古生代岩浆活动总体上从拉张开放环境向挤压闭合环境的转变。
[Abstract]:Through the study of the Paleozoic intrusive rocks and volcanic rock systems in the Yecheng checkerboard, from the field characteristics, geochemical analysis and isotopic dating, the Paleozoic rock mass is divided into two tectonic types: high potassium calc alkaline series (Caledonian) and the previous research results. And alkaline series of rocks (Hercynian), calcium alkaline or high potassium calc alkaline series of rocks (128km rock, urun rock mass, Dutong West rock mass, Poup river rock, chksu rock mass), LREE and LILE enrichment, HFSE relative loss, of which 128km rock and urun rock mass Sr, Nd, O isomer shows the characteristics of mantle crust mixed source. Alkaline series of rocks, alkali rich, rich HFS The early Paleozoic structure is strong and the early Paleozoic structure is strong. A large number of late orogenic granites are produced in the middle and late Caledonian period, suggesting that the original Tethys ocean has been basically closed; the early Devonian diabase (408.5 + 7.3Ma) intrusions marked the end of the Caledonian orogeny, and the early Permian columnar basalt (P2q) of the chessboard group (P2q) was found in the pinch layer. 298.3 + 2.8Ma), representing the Late Palaeozoic and another tensile cracking effect, the Paleozoic magma activity in the study area changed from the open environment to the closed environment.

【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P542;P588.11

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