滇西高黎贡变质岩带南段淡色花岗岩脉年代学特征及构造意义

发布时间：2018-02-04 04:19

  本文关键词： 高黎贡变质岩带 构造特征 淡色花岗岩脉 U-Pb定年　出处：《岩石学报》2016年08期 　论文类型：期刊论文

【摘要】：高黎贡构造带作为藏东三江地区大地构造上的一条重要构造带,在印度-欧亚板块碰撞过程中起着重要的调节作用,并被认为是该地区发生"大陆逃逸"与地块旋转的西边界。本文以高黎贡构造带中的深变质岩为研究对象,通过对高黎贡变质岩带南段进行详细地构造解析,发现其内部广泛发育一系列或顺岩石面理、或切割面理分布的淡色花岗岩脉;并选取了5个淡色花岗岩脉样品进行锆石U-Pb测年,这5个样品的锆石~(206)Pb/~(238)U年龄值主要分布于二个区间:68~40Ma和24~21Ma,并在45Ma左右形成一个巨大的峰值。基于锆石的晶形、晶内结构和微量元素组成特征等方面进行锆石成因学分析,认为本文所测试的5个淡色花岗岩脉样品的锆石为深熔作用过程中形成的锆石;从而推测高黎贡变质岩带南段发生深熔作用并形成淡色花岗岩脉的时代主要集中于68~40Ma和24~21Ma。
[Abstract]:As an important tectonic belt in the Sanjiang area of eastern Tibet, the Goligon tectonic belt plays an important role in the process of the Indo-Eurasian plate collision. This paper takes the deep metamorphic rocks in the Goligong tectonic belt as the research object and makes a detailed structural analysis of the southern section of the Goligong metamorphic rock belt. It is found that a series of pale granite veins are widely developed in its interior. The zircon U-Pb dating was performed on five samples of pale granite veins. The zircon dating values of the five samples are mainly distributed in two sections: 68 ~ (40) Ma and 24 ~ (21) Ma. A huge peak value was formed at about 45Ma. The genetic analysis of zircon was carried out on the basis of the crystal shape, intracrystalline structure and trace element composition of the zircon. It is considered that the zircon of the five pinkish granite veins tested in this paper is zircon formed during the process of deep melting. It is inferred that the age of deep melting and the formation of pallor granite veins in the southern section of the Gaoligong metamorphic belt are mainly concentrated at 6840 Ma and 2421 Ma.
【作者单位】： 中国地质科学院地质研究所;中国地质调查局成都地质调查中心;中国科学院紫金山天文台;
【基金】：国家“973”项目(2015CB452601) 国家自然科学基金项目(41302170、41302157) 中国地质调查局项目(1212010000150009、121201010000150007、1212011220412)联合资助
【分类号】：P588.121;P597.3
【正文快照】： 1.中国地质科学院地质研究所,北京1000372.中国地质调查局成都地质调查中心,成都6100813.中国科学院紫金山天文台,南京2100081.Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China2.Chengdu Center,China Geological Survey,Chengdu 610081,C，

本文编号：1489302