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内蒙古科右前旗树木沟地区黑云母二长花岗岩特征及构造意义
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Abstract:
科右前旗树木沟所处大地构造位置为天山–兴蒙造山系之大兴安岭弧盆系，三级构造单元是锡林浩特岩浆弧。本论文在详细野外调查基础上，对岩石学、岩石地球化学和年代学特征进行分析，对研究区侵入岩的成因进行了探讨，认为黑云母二长花岗岩的锆石U-Pb年龄为222 ± 2.5 Ma，形成于中三叠世印支期，且具有相对富钾，过铝质的特点，属于过铝质的高钾钙碱性岩石系列。黑云母二长花岗岩岩石类型为I型，分异程度较低，为印支期造山后–后碰撞的伸展构造环境下所形成的产物。
The tectonic position of Shumugou, Keyouqianqi is located in the Daxing’anling arc-basin system of Tianshan-Xingmeng orogenic system, and the third-order tectonic unit is Xilinhaote magmatic arc. Based on the detailed field investigation, this paper studies the petrology, rock geochemical characteristics and chronological characteristics. We discuss the origin of the intrusive rocks. The zircon U-Pb age of biotite adamellite is 222 ± 2.5 Ma, which is the product of Middle Triassic magmatism and is characterized by relatively rich potassium and peraluminous. It belongs to peraluminous high potassium calc-alkaline rock series. The biotite adamellite is the type of I, and with a low degree of differentiation, which is the product of post-orogenic-post-collision (relaxation) extensional tectonic setting.
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