内蒙古东乌珠穆沁旗查干哈达音亨嘎高温型强过铝质花岗岩年代学、地球化学特征及其地质意义

    Geochronology and geochem-ical characteristics of the Chaganhadayinhengga strongly peraluminous granites in East Ujimqin Banner of Inner Mongolia and their geological significance

    • 摘要: 内蒙古东乌珠穆沁旗查干哈达音亨嘎强过铝质岩体位于华北板块与西伯利亚板块之间的中亚-蒙古造山带中东段的兴蒙褶皱带,主要岩石类型为含石榴子石二云母二长花岗岩。基于锆石U-Pb同位素定年、地球化学分析和构造环境判别,结合区域对比,认为查干哈达音亨嘎岩体源区可能与变质泥岩部分熔融有关,晚古生代,强过铝质花岗岩形成之前,二连—东乌旗一带已经发生了碰撞造山作用,之后为后碰撞-造山后的伸展扩张时期。经研究确定,查干哈达音亨嘎岩体为鲜有报道的石炭纪—早二叠世具有典型后碰撞特征的高温型强过铝质S型花岗岩类。

       

      Abstract: The Chaganhadayinhengga strongly peraluminous granites in East Ujimqin Banner of Inner Mongolia are located in the Xing-Meng fold belt along the central and eastern section of Central Asia-Mongolia orogenic belt between the North China plate and the Siberia plate. The main rock type is garnet-bearing two-mica monzonitic granite. Based on zircon U-Pb isotopic dating, geochemical analysis and tectonic environment discrimination in combination with regional correlation, the authors have reached the following conclusions:The source area of the Chaganhadayinhengga rock mass might have been related to the partial melting of meta-morphosed mudstone; during Late Paleozoic period, before the formation of strong peraluminous granite, even Erlian-East Ujimqin Banner area underwent collisional orogeny, and then after collision, the evolution entered into the post orogenic extension-expan-sionl period. Studies show that the Chaganhadayinhengga rock mass belongs to the Carboniferous-Early Permian typical post colli-sional high temperature type peraluminous granites rarely reported by previous researchers.

       

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