Subduction re-initiation at dying ridge of Neo-Tethys: Insights from mafic and metamafic rocks in Lhaze ophiolitic melange, Yarlung-Tsangbo Suture Zone

doi:10.1016/j.epsl.2019.07.009

	Subduction re-initiation at dying ridge of Neo-Tethys: Insights from mafic and metamafic rocks in Lhaze ophiolitic melange, Yarlung-Tsangbo Suture Zone
	Zhang, Chang 1; Liu, Chuan-Zhou 1,2; Xu, Yang 3; Ji, Wen-Bin 1; Wang, Jia-Min 1; Wu, Fu-Yuan 1,2; Liu, Tong 1; Zhang, Zhen-Yu 1,4; Zhang, Wei-Qi 1,4
刊名	EARTH AND PLANETARY SCIENCE LETTERS
	2019-10
卷号	523
关键词	Yarlung-Tsangbo ophiolites Neo-Tethys metamorphic sole subduction re-initiation
ISSN号	0012-821X
DOI	10.1016/j.epsl.2019.07.009
英文摘要	Ophiolitic melanges provide critical information on the history of subduction and metamorphism and, thus, on the evolution of ancient oceans. Blocks of mafic rocks, garnet-clinopyroxenites and amphibolites have recently been discovered in the Lhaze ophiolitic melange of the Yarlung-Tsangbo Suture Zone, Southern Tibet. These blocks represent different origins from the Neo-Tethys. The unmetamorphosed MORB-type mafic rocks are considered as the oceanic crusts formed during the spreading of the dying mid-ocean-ridges. The garnet-clinopyroxenites and amphibolites are interpreted to be parts of dismembered metamorphic soles beneath the lowest part of the ophiolites. In spite of different mineral assemblages and metamorphic facies, both clinopyroxenites and amphibolites show strong affinities to the oceanic crust rocks, as evidenced by their geochemical and isotopic data. In addition, the inherited igneous zircon U-Pb results indicate that the protolith ages of these metamorphic rocks are 124-125 Ma, which are coeval with the formation ages of oceanic crusts and the metamorphic ages of amphibolites within the YTSZ. Geothermobarometry calculations indicate that these rocks went through metamorphism to peak conditions of granulite-facies in excess of 900 degrees C at minimum pressure of 9 kbar for garnet-clinopyroxenites and of high-amphibolite facies of 650 degrees C at 7.5 kbar for amphibolites, corresponding to a quite high geothermal gradient (25-30 degrees C/km). Such a high geotherm implies that the lithospheric mantle and the subducted oceanic crusts were nascent and still hot when the mantle obducted onto the ocean crust of the Neo-Tethys. A scenario of subduction re-initiation at the dying mid-ocean-ridge close to the Eurasian continental margin is proposed to reveal the evolution of the Neo-Tethys and to provide new insights into the mechanism of formation of ophiolites and metamorphic soles worldwide. (C) 2019 Elsevier B.V. All rights reserved.
资助项目	China Scholarship Council[201804910292]
WOS关键词	XIGAZE FORE-ARC ; METAMORPHIC SOLE ; GARNET AMPHIBOLITES ; SEMAIL OPHIOLITE ; TIBET PROVENANCE ; TRACE-ELEMENT ; LAZI REGION ; SW TIBET ; MANTLE ; CONSTRAINTS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000482521000010
内容类型	期刊论文
源URL	[http://ir.fio.com.cn:8080/handle/2SI8HI0U/30059]
专题	自然资源部第一海洋研究所
通讯作者	Zhang, Chang; Liu, Chuan-Zhou
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China 3.Minist Nat Resources, Key Lab Marine Sedimentol & Environm Geol, Inst Oceanog 1, Qingdao 266061, Shandong, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Chang,Liu, Chuan-Zhou,Xu, Yang,et al. Subduction re-initiation at dying ridge of Neo-Tethys: Insights from mafic and metamafic rocks in Lhaze ophiolitic melange, Yarlung-Tsangbo Suture Zone[J]. EARTH AND PLANETARY SCIENCE LETTERS,2019,523.
APA	Zhang, Chang.,Liu, Chuan-Zhou.,Xu, Yang.,Ji, Wen-Bin.,Wang, Jia-Min.,...&Zhang, Wei-Qi.(2019).Subduction re-initiation at dying ridge of Neo-Tethys: Insights from mafic and metamafic rocks in Lhaze ophiolitic melange, Yarlung-Tsangbo Suture Zone.EARTH AND PLANETARY SCIENCE LETTERS,523.
MLA	Zhang, Chang,et al."Subduction re-initiation at dying ridge of Neo-Tethys: Insights from mafic and metamafic rocks in Lhaze ophiolitic melange, Yarlung-Tsangbo Suture Zone".EARTH AND PLANETARY SCIENCE LETTERS 523(2019).