地质通报2016，Vol.35Issue(11)：1771-1783,13.
东昆仑东段浪木日上游早古生代榴辉岩的发现及其意义
The discovery of Early Paleozoic eclog-ite in the upper reaches of Langmuri in eastern East Kunlun Mountains and its significance
摘要
Abstract
Eclogite was recognized recently in the upper reaches of Langmuri in eastern East Kunlun Mountains. In the field, the eclogite occurs in lenticular and massive forms and exhibits fault contact with surrounding rocks. The ecologite-bearing metamor⁃phic zone is 1~3km in width. The lenticular eclogite is distributed in metamorphic rocks of Paleoproterozoic Baishahe Formation and Neoproterozoic granite gneiss.The eclogite facies rock association is composed of eclogite and pomegranate amphibolite, and the eclogite facies mineral assemblage consists of eclogite+omphacite+rutile+quartz. According to eclogite-clinopyroxene mineral temperature and pressure gauge, the temperature and pressure conditions of eclogite rock are estimated as follows: T=650~750℃,p=1.8~2.0GPa, falling into the C-type eclogite zone in garnet Alm+Spess-Pyr-Gross triangular diagram. Zircons in the eclogite CL images show that most zircons have the fan zoning or“fir leaves”structure, with a few weak band structures. Th/U ratios of 31 zir⁃con samples are relatively low (0.06~0.135). The LA-ICP-MS zircon U-Pb ages can be divided into two kinds:a kind of concor⁃dant age is 431.9±2.3Ma, representing the eclogite facies metamorphic peak age;the other concordant age is 487±5.9Ma. Original rock might have resulted from the deterioration that occurred under the influence of tectonic events during the subduction process. In consideration of regional ophiolite and tectonic magmatic events, the authors hold that the peak of high-pressure metamorphism in the study area occurred in late Early Silurian in the East Kunlun subduction-collision environment. Combined with the same type of eclogites found in adjacent areas, the authors restored a Palaeozoic high-pressure metamorphic belt in East Kunlun region.关键词
东昆仑东段/高压变质/榴辉岩/早志留世/LA-ICP-MS锆石U-Pb年龄/浪木日上游Key words
East Kunlun Mountains/high-pressure metamorphism/eclogite/Early Silurian/LA-ICP-MS zircon U-Pb ages/upper reaches of Langmuri分类
天文与地球科学引用本文复制引用
祁晓鹏,范显刚,杨杰,崔建堂,汪帮耀,范亚洲,杨高学,李真,晁文迪..东昆仑东段浪木日上游早古生代榴辉岩的发现及其意义[J].地质通报,2016,35(11):1771-1783,13.基金项目
中国地质调查局项目 （）
