东昆仑西大滩混合岩带的基本特征及其成因初探  

ON THE GEOLOGICAL FEATURE AND GENESIS OF THE MIGMATITIC ZONE OF XIDATAN IN EASTERN KUNLUN

作　　者：朱红[1] 崔军文[1] 武长得[1] 邓宗策[1] 冯晓枫[1] 

机构地区：[1]中国地质科学院岩石圈研究中心

出　　处：《地球学报》1990年第2期77-86,共10页Acta Geoscientica Sinica

摘　　要：研究沿昆仑山口北侧大致呈东西向展布的西大滩混合岩带,对探讨东昆仑地区的构造演化,厘定东昆仑地体和巴颜喀拉地体的边界性质,有着十分重要的意义。为此,我们在开展青藏高原地学断面研究之际,横穿东昆仑构造带,进行了近南北方向的地质调查,重点对西大滩三道沟混合岩进行变质构造研究,以期对昆仑地质构造演化提供必要的实际素材。After Bayan Har terrane came into collision with Kunlun terrane, the Carboniferous and Permian sedimentary rocks have changed to migmatites by migmatization, granitization and remeltization in suture zone which is called the southern marginal fracture in Eastern Kunlun. The time of collision is late Variscan to early Indosinian. According to the data of isotopic age, the migmatites were the products of intra-continental subduction in 170-117Ma (Yanshanian).The migmatitic zone extends E-W and parallels to the suture zone. The migmatites under strongly plastic deformation developed the gneissic, augen structure and various metasomatic textures. The rocks are composed mainly of plagioclase, microcline, quartz and biotite. The porphyroblasts of plagioclase and microcline often suffer shear deformation and the biotites arrange in an orientation paralleling to the main regional structure line. The fact that the potash feldspars are chiefly made of microclines, shows the lower temperature of their formation. With the increasing of SiO2 contant, viz with the increasing degree of migmatization, potassium increases but iron, aluminium magnesium and calcium decrease. The migmatites enriching in aluminium is due to the original rocks containing a lot of clay material.We consider the suture zone of Bayan Har terrane and Kunlun terrane passes through the fracture of Xidatan on the study of migmatitic zone.

关 键 词：东昆仑 混合岩化 西大滩 地学断面 构造研究 构造演化 微斜长石 片麻状构造 黑云母花岗岩 地质调查 

分 类 号：P5[天文地球—地质学]