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DOI | 10.1007/s00531-017-1468-7 |
Early Cretaceous wedge extrusion in the Indo-Burma Range accretionary complex: implications for the Mesozoic subduction of Neotethys in SE Asia | |
Zhang, Ji'en; Xiao, Wenjiao; Windley, Brian F.; Cai, Fulong; Sein, Kyaing; Naing, Soe | |
通讯作者 | Zhang, JE (通讯作者) |
发表日期 | 2017 |
ISSN | 1437-3254 |
EISSN | 1437-3262 |
起始页码 | 1391 |
结束页码 | 1408 |
卷号 | 106期号:4 |
英文摘要 | The Indo-Burma Range (IBR) of Myanmar, the eastern extension of the Yarlung-Tsangpo Neotethyan belt of Tibet in China, contains m,langes with serpentinite, greenschist facies basalt, chert, sericite schist, silty slate and unmetamorphosed Triassic sandstone, mudstone and siltstone interbedded with chert in the east, and farther north high-pressure blueschist and eclogite blocks in the Naga Hills m,lange. Our detailed mapping of the Mindat and Magwe sections in the middle IBR revealed a major similar to 18 km antiformal isocline in a m,lange in which greenschist facies rocks in the core decrease in grade eastwards and westwards symmetrically 'outwards' to lower grade sericite schist and silty slate, and at the margins to unmetamorphosed sediments, and these metamorphic rocks are structurally repeated in small-scale imbricated thrust stacks. In the Mindat section the lower western boundary of the isoclinal m,lange is a thrust on which the metamorphic rocks have been transported over unmetamorphosed sediments of the Triassic Pane Chaung Group, and the upper eastern boundary is a normal fault. These relations demonstrate that the IBR metamorphic rocks were exhumed by wedge extrusion in a subduction-generated accretionary complex. Along strike to the north in the Naga Hills is a comparable isoclinal m,lange in which central eclogite lenses are succeeded 'outwards' by layers of glaucophane schist and glaucophanite, and to lower grade greenschist facies sericite schist and slate towards the margins. In the Natchaung area (from west to east) unmetamorphosed Triassic sediments overlie quartzites, sericite schists, actinolite schists and meta-volcanic amphibolites derived from MORB-type basalt, which are in fault contact with peridotite. Olivine in the peridotite has undulatory extinction suggesting deformation at 600-700 A degrees C, similar to the peak temperature of the amphibolite; these relations suggest generation in a metamorphic sole. The amphibolites have U/Pb zircon ages of 119 +/- 3 Ma and 115 Ma, which are close to the zircon ages of nearby calc-alkaline granite and diorite, which belong to an active continental margin arc that extends along the western side of the Shan-Thai block. The IBR accretionary complex and the active continental margin arc were generated during Early Cretaceous (115-128 Ma) subduction of the Neotethys Ocean. |
关键词 | MANIPUR OPHIOLITE COMPLEXMYANMAR OROGENIC BELTZIRCON U-PBNORTHEAST INDIANAGA HILLSTECTONIC EVOLUTIONWESTERN MYANMAREMPLACEMENT HISTORYPLATE STRATIGRAPHYSOUTHEAST-ASIA |
英文关键词 | Myanmar; Indo-Burma Range; Accretionary complex; Wedge extrusion; Early Cretaceous; Neotethys |
语种 | 英语 |
WOS研究方向 | Geology |
WOS类目 | Geosciences, Multidisciplinary |
WOS记录号 | WOS:000401629200013 |
来源期刊 | INTERNATIONAL JOURNAL OF EARTH SCIENCES |
来源机构 | 中国科学院青藏高原研究所 |
文献类型 | 期刊论文 |
条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/259055 |
推荐引用方式 GB/T 7714 | Zhang, Ji'en,Xiao, Wenjiao,Windley, Brian F.,et al. Early Cretaceous wedge extrusion in the Indo-Burma Range accretionary complex: implications for the Mesozoic subduction of Neotethys in SE Asia[J]. 中国科学院青藏高原研究所,2017,106(4). |
APA | Zhang, Ji'en,Xiao, Wenjiao,Windley, Brian F.,Cai, Fulong,Sein, Kyaing,&Naing, Soe.(2017).Early Cretaceous wedge extrusion in the Indo-Burma Range accretionary complex: implications for the Mesozoic subduction of Neotethys in SE Asia.INTERNATIONAL JOURNAL OF EARTH SCIENCES,106(4). |
MLA | Zhang, Ji'en,et al."Early Cretaceous wedge extrusion in the Indo-Burma Range accretionary complex: implications for the Mesozoic subduction of Neotethys in SE Asia".INTERNATIONAL JOURNAL OF EARTH SCIENCES 106.4(2017). |
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