ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    内蒙古阿巴嘎旗二长花岗岩锆石U-Pb年龄确定及其构造意义

    Zircon U-Pb Age of Monzonite Granite from Abag Banner in Inner Mongolia and Its Tectonic Significance

    • 摘要: 通过详细的野外考察及测试分析发现,位于内蒙古阿巴嘎旗北部哈日化地区的花岗岩体,具有高硅、铝、富碱而贫钙、镁的特征;且稀土总量含量偏低,轻稀土相对富集,亏损重稀土元素,具中等负Eu异常,富集Rb、Th、U等大离子亲石元素,高场强元素Nb、P、Ti则表现为强烈亏损,高的Sr及低Rb/Sr值表明岩浆来自强烈富集地幔源区,属火山弧环境,显示TTG岩类特征;LA-ICP-MS锆石U-Pb测年结果表明,岩体侵位时代为(367.5±1.4) Ma,属于晚泥盆世。

       

      Abstract: Through detailed field investigation and test analysis, it's found that the granite in Hazhanhua area, north of Abag Banner in Inner Mongolia has the geochemical characteristics of high silicon, aluminum and alkali, but poor calcium and magnesium. It has low content of total rare earth, with relative enrichment of light rare earth and loss of heavy rare earth elements, as well as a moderate negative Eu anomaly. It riches in Rb, Th, U and othter large ion lithophile elements, but it is strongly loss in high field strength elements, such as Nb, P and Ti. The high Sr content and low Rb/Sr ratio show that the magma was sourced from strong enrichment mantle, which was formed in volcanic arc environment, displaying the characteristics of TTG rock series. The LA-ICP-MS zircon U-Pb dating shows that this monzonite granite was emplaced in Late Devonian, with an age of (367.5+1.9) Ma.

       

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