东昆仑约格鲁岩体暗色微粒包体特征及成因

    Features and origin of mafic microgranular enclaves in the Yuegelu granite in the Eastern Kunlun

    • 摘要: 对东昆仑约格鲁花岗岩体中暗色微粒包体的形态、大小、成分和分布等主要特征进行了较详细地研究。发现包体形态多样,以强烈的塑性流变为特征;包体大小悬殊,多数直径为几十厘米,最大者长轴达4m;包体成分以闪长质为主,结构总体上比寄主岩石的粒度细,岩体中不同部位的包体成分和结构都有所变化;包体分布不均匀,经常呈族状、条带状密集分布,具定向性。镜下研究发现,在包体中经常见到针状磷灰石、石英捕虏晶和斜长石的自形内核环带及增生边等现象,显示了岩浆混合成因的特点。

       

      Abstract: The form,size,composition and distribution of mafic microgranular enclaves in the Yuegelu granite in the Eastern Kunlun are studied in detail.The enclaves are characterized by a great variety of forms and strong plastic rheology;their sizes are highly varied,being usually tens of centimeters in diame-ter,and the largest one has a long-axis length of up to400cm;they are mainly dioritic in composition and fine-grained than the host rock in texture as a whole,with the composition and texture varying somewhat in different parts of the rock;they are of uneven distribution,usually occurring densely as clus-ters and bands,and are oriented.Under the microscope,acicular apatite,quartz xenoliths and the idiomor-phic inner core zone and overgrowths of plagioclase are often found,all of which show the features of magma mixing.

       

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