内蒙古乌拉山沙德盖花岗岩及其暗色微粒包体岩石学与地球化学研究  

Petrology and Geochemistry of the Shadegai Granite and Associated Mafic Microgranular Enclaves (MMEs) in the Wulashan Area,Inner Mongolia

作　　者：顾枫华 章永梅[2] 刘瑞萍[2] 孙玄[2] 杨伟龙[2] 王佳琳[2] 

机构地区：[1]成都理工大学地球科学学院,成都610059 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《矿物岩石地球化学通报》2014年第5期572-581,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金青年基金项目(41302064);中国人民武装警察黄金部队项目(12120113072200;07-3KC35-2);高等学校博士学科点专项科研基金新教师类资助课题(20130022120016);中央高校基本科研业务费专项资金(2-9-2013-010)

摘　　要：近年来研究证实花岗岩的成因与其中的暗色微粒包体(MME)有着密切的关系。沙德盖岩体是华北地台北缘印支期花岗岩带上的一个典型代表,为探讨该岩体的成因,本文对沙德盖花岗岩和其中暗色微粒包体开展了岩相学及地球化学研究。结果表明,暗色包体形态多样,具有塑性流变特征和典型岩浆结构,含大量针柱状磷灰石。寄主岩和包体的主量元素在Harker图解中多呈直线分布,显示岩浆混合趋势,其稀土元素和微量元素组成具有相似的配分特征,暗示包体与寄主岩发生过物质交换。花岗岩主岩和暗色包体的Nb/Ta值指示二者分别为下地壳和地幔来源。上述说明沙德盖岩体形成于碰撞后的伸展构造环境,属壳幔物质混合的产物。It is recognized that the genesis of granite is closely associated with its mafic microgranular enclaves （MMEs）.The Shadegai granite is a representative intrusion of the Indosinian granite belt on the northern margin of the North China Craton.Petrographic and geochemical studies have been carried on Shadegai granite and its MMEs in order to understand the genesis of granite.The result shows that the enclaves are characterized by various shapes,strong plastic nature,typical magmatic textures and abundance of acicular apatite.Major element concentrations of the MMEs and their host granite commonly show linear correlations in the Harker diagrams,indicating the genesis of magma mixing.Similar distribution patterns of trace elements and REEs of both host granite and MMEs suggest material exchanges between two magmas.The Nb/Ta ratios of granite and MMEs indicate that they derived from the lower crust and mantle,respectively.It is thus suggested that the Shadegai granite was generated by mixed mantle-crust magmas in a post-collisional extension setting.

关 键 词：岩浆混合作用 暗色微粒包体 钾长花岗岩 沙德盖 内蒙古 

分 类 号：P588.121[天文地球—岩石学] P584[天文地球—地质学]