Paleozoic circum-Gondwana orogens: Petrology and geochronology of the Namche Barwa Complex in the eastern Himalayan syntaxis, Tibet

CORC > 中国地质调查局 > 中国地质调查局

	Paleozoic circum-Gondwana orogens: Petrology and geochronology of the Namche Barwa Complex in the eastern Himalayan syntaxis, Tibet
	Zhang, ZM (Zhang ZeMing); Wang, JL (Wang JinLi); Shen, K (Shen Kun); Shi, C (Shi Chao)
刊名	ACTA PETROLOGICA SINICA
	2008
卷号	24 期号:7 页码:1627-1637
关键词	Namche Barwa Complex Zircon U-Pb dating Petrology Circum-Gondwana orogen Eastern Himalayan syntaxis
ISSN号	1000-0569
英文摘要	The Namche Barwa Complex located in the eastern Himalayan syntaxis is a part of the High Himalayan crystalline Complex, and consista of gneiss, amphibolite, schist and cale-silicate rocks which have been subjected to granulite-facies metamorphism and amphilolite-facies retrogression. The geochronological data shows that the magmatic and metamorphic rocks in the Namche Barwa Complex have the Paleozoic ages. The felsic gneiss consist of plagioclase, K-feldspar, quartz, garnet, and biolite with or without allanite, and show the typical textural and structural features of metamorphic rocks. However, zircons of the gneiss have concentric oscillatory zoning, HREE-enriched REE patterns with distinctly negative Eu anomalies, and high Th/U values, typical of zircon from granitic intrusives. These inherited magmatic zircons give U-Pb ages of 490 similar to 500Ma. The cale-silicate has a metamorphic mineral assemblage of scapolite, diopside, quartz and titanite. The zircons from a cale-silicate have relatively low REE contents with slightly negative Eu anomalies and low Th/U ratios, and show no zoning, typical of zircon from high-grade metamorphic rocks. These metamorphic growth zircons give a weighted mean U-Pb age of 505Ma. The protoliths of these Paleozoic gneisses are granite and granodiorite, which were formed in the tectonic setting of magnetic are. The present paper and available studies demonstrate further that the Himalaya is a composite orogenic belt, which was originally formed in the Paleozoic and then reworked in the Cenozoic by the collision between the India and Eurasian plates. It is considered that the Paleozoic orogeny was related to the Andean-type orogenic activity on the northern margin of the Indian continent, following the Gondwana assembly, and was driven by coupling across the plate margin either during on-going subduction of the proto-Tethys ocean beneath to the India plate or through accretion of microcontinental ribbons, possibly represented by the Lhasa and Qiangtang blocks, but did not belonged to the Pan-Africa orogen which was formed by the continent-continent collision during the Gondwana assembly.
学科主题	构造地质学
WOS关键词	TECTONIC EVOLUTION ; PAN-AFRICAN ; SOUTHERN TIBET ; ION MICROPROBE ; ZIRCON AGES ; SEDIMENTATION ; METAMORPHISM ; EVENTS ; GROWTH ; BELT
WOS研究方向	Geology
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000260313300019
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38730]
专题	中国地质调查局
作者单位	Lab Geol Sci, Jinan 250013, Peoples R China
推荐引用方式 GB/T 7714	Zhang, ZM ,Wang, JL ,Shen, K ,et al. Paleozoic circum-Gondwana orogens: Petrology and geochronology of the Namche Barwa Complex in the eastern Himalayan syntaxis, Tibet[J]. ACTA PETROLOGICA SINICA,2008,24(7):1627-1637.
APA	Zhang, ZM ,Wang, JL ,Shen, K ,&Shi, C .(2008).Paleozoic circum-Gondwana orogens: Petrology and geochronology of the Namche Barwa Complex in the eastern Himalayan syntaxis, Tibet.ACTA PETROLOGICA SINICA,24(7),1627-1637.
MLA	Zhang, ZM ,et al."Paleozoic circum-Gondwana orogens: Petrology and geochronology of the Namche Barwa Complex in the eastern Himalayan syntaxis, Tibet".ACTA PETROLOGICA SINICA 24.7(2008):1627-1637.