【作者】 施建荣；

【导师】 董永胜；

【作者基本信息】 吉林大学 ， 构造地质学， 2010， 硕士

【摘要】 藏北羌塘中部的龙木错-双湖板块缝合带是冈瓦纳大陆与欧亚大陆的界线,缝合带以南为冈瓦纳大陆的羌南—保山板块,以北为欧亚大陆的羌北一昌都板块。戈木日地区位于板块缝合带内,出露的地质单元包括晚古生代展金岩群浅变质层状岩系、变质基性侵入岩(岩墙)组合、变质蛇绿混杂岩组合以及由榴辉岩与石榴石白云母片岩组成的高压变质带。除变质基性侵入岩(岩墙)外,其余各地质单元均以岩片的形式构造接触,共同组成了板块缝合带的构造混杂岩带。论文以高压变质带为重点研究对象,通过对区内各地质单元详细的野外地质调查和室内矿物学、岩石学、变质作用的研究,结合同位素年代学资料,查明了各地质单元的岩石类型组合、岩石学特征、变质作用特征。研究表明,上述各地质单元变质岩石的形成和变质作用演化以及目前的空间展布格局与古特提斯洋闭合、龙木错-双湖板块缝合带形成及后期演化过程密切相关,论文成果为龙木错-双湖板块缝合带的构造演化研究提供了变质岩和变质作用方面的资料和依据。更多还原

【Abstract】 There are many distribution of the large area of low-grade metamorphic series in the Gemuri area, including the low-grade metamorphic layered series from zhan-jin rock group(Hunan-shan petrofabric、Tongbei-liang petrofabric、Jiliang-shan petrofabric、Xiema-ri petrofabric)、low-grade metamorphic mafic intrusive assemblages(dike)、metamorphic ophiolite melange assemblages, and also developed an order of high-pressure metamorphic belt of eclogite and garnet muscovite schist rock combination, which is tectonic contact with zhan jin rock group. The is a ductile deformation zone of mylonite and mylonite rocks in the contact zone.In order to study the causes and tectonic significance from the low-grade metamorphic series and high-pressure metamorphic belt in the Gemuri area. We study the main line of high-pressure metamorphic belt, and ascertain the metamorphic rocks units of different types of combination、spatial distribution of cases, and carify the various elements of the original rock characteristics and formation environment of the construction. Then Combined with the study of eclogite and garnet muscovite schist from the high-pressure metamorphic belt, we initially distinguish the metamorphism phase、metamorphic condition in the different metamorphic units,and so on. Then we will have a final discussion about the tectonic evolution history in the Lungmu Co- Shanghu plate suture. The results obtained are as follows:1. Qiangtang Gemuri area’s metamorphic rocks are mainly composed by the low-grade layered rock series, low-grade metamorphic mafic intrusive assemblages, metamorphic ophiolite melange assemblages, the high-pressure metamorphic rocks assemblages (high-pressure metamorphic belt) . 2. There is an greenschist facies metamorphism in the the low-grade layered rock series, low-grade metamorphic mafic intrusive assemblages, metamorphic ophiolite melange assemblages.3. High-pressure metamorphic zone experienced -> lawsonite - glaucophane schis facies before the peak period -> eclogite facies in the peak period -> glaucophane schis facies after the early period of peak -> epidote amphibolite facies after the late period of peak.4. The high-pressure metamorphic zone experienced the formation of eclogite in the early time , the formation of high-pressure metamorphic zone, the tectonic emplacement process of high-pressure metamorphic zone, ductile deformation zone is the important mechanism in the appearing of high-pressure zone.5. Tectonic evolution history in the sutures zone was divide into the metamorphism before the collision、the collision metamorphism, metamorphism after collision. Metamorphism before the collision resulted in the formation of eclogite;the collision metamorphism was widely distributed in the research area, and formed the active continental margin of a metamorphic series;metamorphism after collision was a process that high-pressure metamorphic rocks were exposed at the surface, and accompanied by blue-greenschist facies metamorphism occurred. In the suture zone. the tectonic evolution history of metamorphic rocks reflect the whole process of Paleo-Tethys Ocean closure.更多还原