Yarlung Zangbo ophiolite: A critical updated view

	Yarlung Zangbo ophiolite: A critical updated view
	Wu FuYuan; Liu ChuanZhou; Zhang LiangLiang; Zhang Chang; Wang JianGang; Ji WeiQiang; Liu XiaoChi
刊名	ACTA PETROLOGICA SINICA
	2014-02-01
卷号	30 期号:2 页码:293-325
关键词	Ultraslow spreading Neo-Tethyan ocean Ophiolite Yarlung Zangbo Tibet
ISSN号	1000-0569
文献子类	Article
英文摘要	The Yarlung Zangbo ophiolite belt, located in southern Tibet, is one of the extensively studied ophiolites in China, and is internationally renowned as well. Distributed in east-west direction with a distance of similar to 2000km, this ophiolite had been used as an important petrological indicator to constrain the suture zone between India and Asia, and represents the vanished Neo-Tethyan Ocean between them. According to previous studies and our recent field investigations, however, this ophiolite belt is characterized by the following lines of features : (1) Mantle peridotites are predominated over mafic rocks; mantle peridotites mainly consist of harzburgites, but with a significant amount of lherzolites; (2) Cumulative gabbro is usually absent although it was identified in three localities with a maximum thickness less than 1000m; (3) Sheeted dyke is absent, but with gabbroic-doleritic sills intruding into the peridotites. In some cases, dolerites occur as dykes in basalts; (4) Generally, basalts are directly overlying the peridotites, although the interface between them is mostly occupied by doleritic sills; (5) Peridotites and mafic rocks are significant different in terms of formation age and Sr-Nd isotopic compositions; (6) Gabbros and dolerites were emplaced during ca. 120 similar to 130Ma with a limited temporal interval across the whole belt, and were derived from the depleted asthenospheric mantle. These lines of evidence suggest that the ultramafic and mafic rocks were formed in separated stages without any genetic connection. Therefore, we proposed that the mantle peridotites outcropped in the Yarlung Zangbo ophiolite belt are probably sub-continental lithospheric mantle beneath the Asian plate. During the Early Cretaceous, extension of the leading edge of the Asian continent resulted in the exhumation of the subcontinental lithospheric mantle, and the formation of an oceanic basin. Exhumation and thinning of the lithosphere resulted in upwelling and melting of the asthenosphere, which led to the eruption of basalt and intrusion of gabbro and dolerite. During the maximum extension, partial melting of the metasomatized refractory lithsopheric mantle gave rise to some amount of boninitic melts. Therefore, the Yarlung Zangbo ophiolite is much different from the ideal ophiolite section defined by the Penrose conference, and it could not be considered as a remnant of the Neo-Tethyan ocean between the Indian and Asian continents. Considering that the mafic rocks were limitedly developed in the area, we propose that the Yarlung Zangbo ophiolites represent an oceanic lithosphere formed at an ultraslow spreading center with a spreading rate much lower than that in western Alps. Therefore, the Yarlung Zangbo can be defined as an end-member of the ultraslow spreading setting; we term it as the Xigaze type since it is typically developed around Xigaze area in the central segment of this ophiolite belt.
WOS关键词	MID-ATLANTIC RIDGE ; ZIRCON U-PB ; MARIANA FORE-ARC ; OCEANIC CORE COMPLEXES ; COAST-RANGE-OPHIOLITE ; TSANGPO SUTURE ZONE ; EAST PACIFIC RISE ; SOUTHERN TIBET ; XIGAZE OPHIOLITE ; UPPER-MANTLE
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000333224500001
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/85126]
专题	中国科学院地质与地球物理研究所
通讯作者	Wu FuYuan
作者单位	Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Wu FuYuan,Liu ChuanZhou,Zhang LiangLiang,et al. Yarlung Zangbo ophiolite: A critical updated view[J]. ACTA PETROLOGICA SINICA,2014,30(2):293-325.
APA	Wu FuYuan.,Liu ChuanZhou.,Zhang LiangLiang.,Zhang Chang.,Wang JianGang.,...&Liu XiaoChi.(2014).Yarlung Zangbo ophiolite: A critical updated view.ACTA PETROLOGICA SINICA,30(2),293-325.
MLA	Wu FuYuan,et al."Yarlung Zangbo ophiolite: A critical updated view".ACTA PETROLOGICA SINICA 30.2(2014):293-325.