Geochronology and Precambrian tectonic evolution of the Namche Barwa complex from the eastern Himalayan syntaxis, Tibet

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	Geochronology and Precambrian tectonic evolution of the Namche Barwa complex from the eastern Himalayan syntaxis, Tibet
	Zhang, ZM (Zhang ZeMing); Wang, JL (Wang JinLi); Zhao, GC (Zhao GuoChun); Shi, C (Shi Chao)
刊名	ACTA PETROLOGICA SINICA
	2008
卷号	24 期号:7 页码:1477-1487
关键词	Namche Barwa complex Granulite Geochronology Himalayan orogen Precambrian tectonic-magmatic event Supercontinent
ISSN号	1000-0569
英文摘要	The Namche Barwa complex located in the eastern syntaxis of the Himalayan orogenic belt and south of the India-Yarlung Tsangpo suture zone has been subjected to the high-pressure regional metamorphism and intensely migmatization. The felsic gneisses distributing widely in this area were chosen to study its lithology and isotopic geochronology. Most of the gneisses have the metamorphic mineral assemblages of amphibolite facies except minor pelitic gneisses with a high-pressure granulite facies mineral assemblage of garnet + kyanite + ternary feldspar + quartz. Most of their protoliths are diorite and granodiorite characterized by the chemical composition of igneous rocks formed in a magmatic are environment. The zircons in gneisses commonly have a core-rim texture. SHRIMP and LA-ICP-MS U-Pb zircon in-situ analyses indicate that the zircon rims give multi-stage metamorphic and megamatic event ages ranging from 500Ma to 10Ma, while the zircon cores yield at least four populations of Precambrian ages similar to 2500Ma, similar to 1800Ma, similar to 1600Ma and similar to 1000Ma. The zircon grains analyzed show obvious magmatic crystallization zoning and have relatively high Th/U ratios, typical of magmatic origin, and thus these four populations of ages are interpreted as ages of multiphase Precambrian tectonic-magmatic events. Moreover, these ages are comparable to those of Precambrian tectonic-megmatic events of the Greater Himalayan Crystalline complex and the Indian craton. Therefore, we conclude that the protoliths of the Namche Barwa complex and the Greater Himalayan Crystalline rock may have been derived from the intrusive rocks formed from the late Archean to the late Proterozoic, recorded the formation and breakup of the Columbia, Rodinia and Gondwana supercontinent, and undergone the regional metamorphism and magmatism during the Himalayan orogeny.
学科主题	前寒武纪地质
WOS关键词	EARLY PALEOZOIC TECTONISM ; HIGH-PRESSURE GRANULITES ; CENTRAL NEPAL HIMALAYA ; U-PB ; MESOPROTEROZOIC SUPERCONTINENT ; KHONDALITE BELT ; ION MICROPROBE ; CENTRAL INDIA ; THRUST SHEET ; SOUTH-INDIA
WOS研究方向	Geology
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000260313300005
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38769]
专题	中国地质调查局
作者单位	Univ Hong Kong, Dept Earth Sci, Hong Kong, Hong Kong, Peoples R China
推荐引用方式 GB/T 7714	Zhang, ZM ,Wang, JL ,Zhao, GC ,et al. Geochronology and Precambrian tectonic evolution of the Namche Barwa complex from the eastern Himalayan syntaxis, Tibet[J]. ACTA PETROLOGICA SINICA,2008,24(7):1477-1487.
APA	Zhang, ZM ,Wang, JL ,Zhao, GC ,&Shi, C .(2008).Geochronology and Precambrian tectonic evolution of the Namche Barwa complex from the eastern Himalayan syntaxis, Tibet.ACTA PETROLOGICA SINICA,24(7),1477-1487.
MLA	Zhang, ZM ,et al."Geochronology and Precambrian tectonic evolution of the Namche Barwa complex from the eastern Himalayan syntaxis, Tibet".ACTA PETROLOGICA SINICA 24.7(2008):1477-1487.