气候变化领域集成服务门户(CCPortal): Decoupling of Hf-Nd Isotopes in Challenger Deep Sediments, Mariana Trench: Implications for Sedimentary Hf and Nd Recycling in Subduction Zones

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DOI	10.1029/2021JB021641
	Decoupling of Hf-Nd Isotopes in Challenger Deep Sediments, Mariana Trench: Implications for Sedimentary Hf and Nd Recycling in Subduction Zones
	Pang C.-J.; Tian L.; Wang X.-C.; Zhang H.; Wen S.-N.; Krapež B.; Liu W.-J.; Liu Z.-X.; Wu T.
发表日期	2021
ISSN	21699313
卷号	126 期号:6
英文摘要	Decoupling between Hf and Nd isotopes in trench sediments is an important way to produce, via subduction-related recycling, the mantle chemical heterogeneity that is evident in many arc-related magmas. Sediments collected from >7,000 m water depths on the southern and northern slopes of the Challenger Deep were analyzed to understand the factors controlling the variation in Hf and Nd isotopic compositions. These sediments were transported to both flanks of the Challenger Deep by synchronous density currents. All sediment samples show positive ɛHf values and negative ɛNd values, mostly plotting above the seawater and terrestrial arrays in Hf-Nd isotope space. Hafnium isotopic compositions in each depositional unit vary (high up to 9.2 ɛHf units) from lower, coarse-grained laminae to upper, fine-grained graded intervals, showing a good correspondence between ɛHf values and lamination within depositional units. Such variations are explained by the concentration of Fe-Mn oxyhydroxide-bearing clays in the upper graded intervals, whereas diatom fragments and arc-volcanic detritus are preferentially sorted into lower laminae. These findings demonstrate that the decoupling of Hf-Nd isotopes in trench sediments is not only linked to the nature of provenance but also to hydrodynamic sorting processes during sediment transport. Our results suggest that geographical and stratigraphic variations in sedimentary components (resedimented density-current deposits vs. oceanic pelagites), as well as overall grain size, of the subduction wedge can complicate Hf-Nd isotopic decoupling in resulting arc magmas. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Challenger Deep; density-current deposits; Hf-Nd isotopic decoupling; oceanic hydrodynamic mineral sorting; sedimentary Hf-Nd recycling; subduction factory
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187059
作者单位	Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration, Guilin University of Technology, Guilin, China; Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China; The School of Earth Sciences, Yunnan University, Kunming, China; The School of Earth Science and Resources, Chang'an University, Xi'an, China; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing, China; Ocean College, Zhejiang University, Zhoushan, China
推荐引用方式 GB/T 7714	Pang C.-J.,Tian L.,Wang X.-C.,et al. Decoupling of Hf-Nd Isotopes in Challenger Deep Sediments, Mariana Trench: Implications for Sedimentary Hf and Nd Recycling in Subduction Zones[J],2021,126(6).
APA	Pang C.-J..,Tian L..,Wang X.-C..,Zhang H..,Wen S.-N..,...&Wu T..(2021).Decoupling of Hf-Nd Isotopes in Challenger Deep Sediments, Mariana Trench: Implications for Sedimentary Hf and Nd Recycling in Subduction Zones.Journal of Geophysical Research: Solid Earth,126(6).
MLA	Pang C.-J.,et al."Decoupling of Hf-Nd Isotopes in Challenger Deep Sediments, Mariana Trench: Implications for Sedimentary Hf and Nd Recycling in Subduction Zones".Journal of Geophysical Research: Solid Earth 126.6(2021).