Characteristics and Pressure-Temperature Conditions of Nimu Metamorphic Rocks, Tibet
详细信息
- 责任者：Sun Kai (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Zhou Su
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(12)
- 关键词：变质岩 ; metamorphic rocks ; 温压条件 ; P-T conditions ; 西藏 ; Tibet
- 页码：p.3718-3726
- 图表：9 illus., 5 tables, 31 refs.
- 分类号：0802
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The Nimu metamorphic rocks are mainly composed of garnet biotite gneiss and biotite-plagioclase hornblende hornfels, which are exposed on the north side of Yarlung suture zone, southern Tibet. The studies show that the rocks have metamorphosed to hornblende hornfels facies-pyroxene hornfels facies; garnet porphyroblasts with growth zonation, amphiboles are calcic amphiboles, most of the biotites are ferrobiotites and siderophyllites, most of the feldspars are oligoclases and andesine, with a small amount of orthoclases. The results of both field and laboratory studies indicate that the protolith were the Yeba volcanic rocks and the upper sedimentary rocks in the southern margin of the Gangdise, which underwent high-temperature and low-pressure contact metamorphism.