气候变化领域集成服务门户(CCPortal): Widespread Os-isotopically ultradepleted mantle domains in the Paleo-Asian oceanic upper mantle: evidence from the Paleozoic Tianshan ophiolites (NW China)

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DOI	10.1007/s00531-019-01759-x
	Widespread Os-isotopically ultradepleted mantle domains in the Paleo-Asian oceanic upper mantle: evidence from the Paleozoic Tianshan ophiolites (NW China)
	Gong X.-H.; Xu J.-F.; Liu X.-J.; Huang X.-X.; Zhang Z.-G.; Zhou H.-L.; Yang Z.-Y.; Zhao W.-X.
发表日期	2020
ISSN	14373254
起始页码	1421
结束页码	1438
卷号	109 期号:4
英文摘要	The scale and extent of isotopic heterogeneities in the Paleo-Asian oceanic mantle remain poorly constrained. Here, we report Os isotopic data for mantle peridotites from the Paleozoic Gangou and Kumishi ophiolites, which are preserved in the western Chinese Tianshan sutures (Xinjiang, China) and considered to sample the Paleo-Asian oceanic upper mantle. These heavily serpentinized peridotites display positive correlations between Al2O3, Ti, and Yb contents, indicating variable degrees of melt extraction from fertile mantle sources. However, enriched light rare-earth element patterns in the peridotites are inconsistent with simple residues of partial melting, thus reflecting the effect of post-melting melt percolation. Peridotites from both ophiolites show wide variation of Os isotopic compositions, several of which are characterized by highly unradiogenic 187Os/188Os values (0.117–0.118), reflecting Proterozoic melt depletion. Such feature is common in modern oceanic peridotites and most Phanerozoic ophiolites, meaning that Os-isotopically ultradepleted domains should be widespread in the Paleo-Asian oceanic mantle. The overall similarity of Os-isotope distribution between the Paleozoic Tianshan ophiolites and modern oceanic peridotites suggests that they derive from the same heterogeneous upper mantle reservoir. This might support the hypothesis that isotopically ultradepleted domains are inherent components of the convecting upper mantle and have not been sufficiently homogenized by convection. Alternatively, Re-depletion ages (TRD) for these ancient domains are broadly coincident with the major peaks in crustal zircon ages that are thought to reflect episodes of continental crust growth in the adjacent Yili–Central Tianshan microcontinents. This suggests that the ultradepleted mantle domains in some of the Tianshan ophiolites may derive from ancient subcontinental lithospheric mantle, which detached and were exhumed to form the substrate of ocean basins. © 2019, Geologische Vereinigung e.V. (GV).
英文关键词	Mantle heterogeneity; NW China; Os isotope; Paleozoic Tianshan ophiolites
语种	英语
scopus关键词	mantle source; ophiolite; osmium; Paleozoic; peridotite; petrogenesis; petrology; serpentinization; upper mantle; Tien Shan
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147686
作者单位	State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100083, China; Xinjiang Research Center for Mineral Resources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, 830011, China; Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration, Guilin University of Technology, Guilin, 541004, China; College of Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450045, China; Instrumentation Analysis and Research Center, Sun Yat-Sen University, Guangzhou, 510275, China
推荐引用方式 GB/T 7714	Gong X.-H.,Xu J.-F.,Liu X.-J.,et al. Widespread Os-isotopically ultradepleted mantle domains in the Paleo-Asian oceanic upper mantle: evidence from the Paleozoic Tianshan ophiolites (NW China)[J],2020,109(4).
APA	Gong X.-H..,Xu J.-F..,Liu X.-J..,Huang X.-X..,Zhang Z.-G..,...&Zhao W.-X..(2020).Widespread Os-isotopically ultradepleted mantle domains in the Paleo-Asian oceanic upper mantle: evidence from the Paleozoic Tianshan ophiolites (NW China).International Journal of Earth Sciences,109(4).
MLA	Gong X.-H.,et al."Widespread Os-isotopically ultradepleted mantle domains in the Paleo-Asian oceanic upper mantle: evidence from the Paleozoic Tianshan ophiolites (NW China)".International Journal of Earth Sciences 109.4(2020).