东昆仑南缘韧性剪切带变形特征及其形成时代的限定

发布时间：2018-05-22 11:41

本文选题：韧性剪切带 + 构造变形　；参考：《地质通报》2017年06期

【摘要】：中生代巴彦喀拉-松潘甘孜地体向东昆仑地体斜向俯冲,在东昆仑南缘形成一条巨型的韧性剪切带。剪切带中发育的旋转碎斑、书斜构造、解理阶步、云母鱼、S-C组构、不对称褶皱、雁列脉等宏微观构造,显示剪切带兼具右行和左行的特征,且右行早于左行剪切,但总体以左行剪切为主。对西大滩糜棱岩化花岗岩和小南川未变形花岗岩进行了LA-ICP-MS锆石UPb测年,西大滩岩体侵位于199.3±2.2Ma,小南川岩体形成于196.4±1.3Ma。西大滩与小南川岩体中的锆石为典型的岩浆锆石,其年龄代表了岩体侵位的时代。鉴于2个岩体的变形程度完全不同,东昆仑南缘在199~196Ma之间发生了左行韧性剪切。
[Abstract]:A giant ductile shear zone was formed in the southern margin of East Kunlun by the oblique subduction of the Bayankara-Songpan Ganzi terrane in the Mesozoic era. The macro and micro structures developed in the shear zone, such as rotational patchwork, diagonal structure, understanding step, S-C fabric of mica fish, asymmetric fold, echelon vein and so on, show that the shear zone has the characteristics of both right and left rows, and the right line is shearing earlier than the left line. However, the overall left-line shear is the main. The LA-ICP-MS zircon UPb dating of the Xidatan mylonitic granite and the Xiaonanchuan undeformed granite has been carried out. The Xidatan intrusion was located at 199.3 卤2.2 Ma, and the Xiaonanchuan granite was formed at 196.4 卤1.3 Ma. The zircon from the Xidatan and Xiaonanchuan pluton is typical magmatic zircon, and its age represents the age of emplacement. Since the deformation degree of the two rock masses is completely different, the left ductile shear occurred between 199~196Ma in the southern edge of East Kunlun.
【作者单位】：中国地质大学(北京)地球科学与资源学院;青海省地质调查院;
【基金】：青海省地质勘查基金项目《青海省昆仑河地区金多金属矿整装勘查区找矿部署研究》(编号:2016020003ky003) 国家自然科学基金项目《新疆西天山吐拉苏浅成低温热液-斑岩型金成矿系统物质与时空结构研究》(批准号:41572062)、《内蒙古哈达门沟-柳坝沟金矿床碱交代作用与金钼成矿关系研究》(批准号:41302064)
【分类号】：P542

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