气候变化领域集成服务门户(CCPortal): Heterogeneous mantle beneath the Neo-Tethys Ocean revealed by ultramafic rocks from the Xiugugabu Ophiolite in the Yarlung-Tsangpo Suture Zone, southwestern Tibet

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DOI	10.1007/s00410-023-02039-3
	Heterogeneous mantle beneath the Neo-Tethys Ocean revealed by ultramafic rocks from the Xiugugabu Ophiolite in the Yarlung-Tsangpo Suture Zone, southwestern Tibet
	Zhang, Chang; Liu, Chuan-Zhou; Benard, Antoine; Muntener, Othmar; Ji, Wen-Bin; Liu, Tong; Zhang, Zhen-Yu; Zhang, Wei-Qi; Wu, Fu-Yuan
发表日期	2023
ISSN	0010-7999
EISSN	1432-0967
卷号	178 期号:8
英文摘要	Ultramafic rocks of the Yarlung-Tsangpo ophiolites (lherzolites, harzburgites, dunites and pyroxenites) have been interpreted as lithospheric mantle relics of the Cretaceous Neo-Tethys Ocean (NTO). Studying these rocks could provide key constraints on the NTO's evolution and invaluable information on sub-ridge mantle heterogeneity. The Xiugugabu ophiolite crops out in the western segment of the Yarlung-Tsangpo Suture Zone (YTSZ) and is dominantly composed of mantle components with minor crustal material. Here we report a comprehensive field, petrological and geochemical study of the ultramafic rocks from this ophiolitic massif. The lherzolites and harzburgites are less refractory than the Xigaze ultramafic rocks in the middle part of the YTSZ. Petrology and simple models are consistent with 10-20% fractional melting from an anhydrous, depleted mantle source, within the spinel and garnet stability fields. Part of dunites (Dunite-II) and pyroxenites formed during pervasive melt impregnation into host peridotites and record the modal and geochemical effects of post-melting melt-rock interactions. The discrepancy of light rare earth element (LREE) contents between whole rocks and their two pyroxene components in peridotites indicates that they have trapped interstitial melts along grain boundaries at a post-melting stage. These melts were potentially derived from shallow sources in spinel domains. Bulk rock osmium isotopic compositions suggest that the pyroxenites and part of the dunites are highly radiogenic. These enriched Os signatures are likely imposed by percolating melts derived from mantle sources hybridized by ancient recycled crustal materials. When comparing with results from previous studies of other YTSZ peridotites with ultra-depleted nature and unradiogenic Os isotopic compositions, we conclude that the sub-ridge mantle beneath the Neo-Tethyan Ocean was heterogeneous, with not only unradiogenic but also highly radiogenic mantle domains.
关键词	Indus-Yarlung-Tsangpo Suture Zone Xiugugabu Ophiolite Ultramafic Rocks Mantle Heterogeneity Neo-Tethys Ocean
英文关键词	SUPRA-SUBDUCTION ZONE; TRACE-ELEMENT FRACTIONATION; OSMIUM ISOTOPIC CONSTRAINTS; SPINEL OXYGEN GEOBAROMETER; ABYSSAL PERIDOTITES; OS-ISOTOPE; LITHOSPHERIC MANTLE; XIGAZE OPHIOLITE; ORTHO-PYROXENE; RIDGE BASALT
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001040945500001
来源期刊	CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283547
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; University of Lausanne; Northwest University Xi'an
推荐引用方式 GB/T 7714	Zhang, Chang,Liu, Chuan-Zhou,Benard, Antoine,et al. Heterogeneous mantle beneath the Neo-Tethys Ocean revealed by ultramafic rocks from the Xiugugabu Ophiolite in the Yarlung-Tsangpo Suture Zone, southwestern Tibet[J],2023,178(8).
APA	Zhang, Chang.,Liu, Chuan-Zhou.,Benard, Antoine.,Muntener, Othmar.,Ji, Wen-Bin.,...&Wu, Fu-Yuan.(2023).Heterogeneous mantle beneath the Neo-Tethys Ocean revealed by ultramafic rocks from the Xiugugabu Ophiolite in the Yarlung-Tsangpo Suture Zone, southwestern Tibet.CONTRIBUTIONS TO MINERALOGY AND PETROLOGY,178(8).
MLA	Zhang, Chang,et al."Heterogeneous mantle beneath the Neo-Tethys Ocean revealed by ultramafic rocks from the Xiugugabu Ophiolite in the Yarlung-Tsangpo Suture Zone, southwestern Tibet".CONTRIBUTIONS TO MINERALOGY AND PETROLOGY 178.8(2023).