Deciphering Contribution of Recycled Altered Oceanic Crust to Arc Magmas Using Ba-Sr-Nd Isotopes

doi:10.1029/2023JB028407

IOCAS-IR > 海洋地质与环境重点实验室

	Deciphering Contribution of Recycled Altered Oceanic Crust to Arc Magmas Using Ba-Sr-Nd Isotopes
	Zhang, Yuxiang1,2,3 ; Shu, Yunchao 4; Turner, Simon 5; Chen, Zuxing 1,2,3; Zeng, Zhigang 1,2,3; Huang, Fang 6
	2024-03-01
发表期刊	JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
ISSN	2169-9313
卷号	129 期号:3 页码:13
通讯作者	Zhang, Yuxiang(zhangyuxiang13@mails.ucas.ac.cn) ; Zeng, Zhigang(zgzeng@qdio.ac.cn)
摘要	Altered oceanic crust (AOC) plays a critical role in geochemical recycling in subduction zones. However, identifying contributions of subducted AOC to arc magmas remains a conundrum due to the lack of effective tracers. Here, we investigate the Ba-Sr-Nd isotopic compositions of lavas from the Mariana arc and back-arc. Based on a statistical analysis of the Sr-Nd isotopes for global arc volcanoes, we confirm that AOC-derived fluid (or hydrous melt), rather than sediment-derived melt or fluid, is responsible for the Sr-Nd isotope decoupling (i.e., 87Sr/86Sr is "excessively" enriched relative to 143Nd/144Nd when compared to the "normal" mantle derivates) observed in island arc lavas. We show that the arc lavas with increasingly decoupled Sr-Nd isotopes generally have heavier Ba isotope ratios, which is also a characteristic feature of AOC-derived fluids. Thus, these results establish an intimate link between subducted AOC, heavy Ba isotope compositions, and Sr-Nd isotope decoupling signature in island arcs, which provides a powerful tool to trace the AOC recycling in subduction zones. Furthermore, a similar correlation is observed between Sr-Nd isotope decoupling and heavy B isotope ratios for global arc lavas, implying that the recycling of AOC component is generally linked to serpentinite dehydration in subduction zones. Altered oceanic crust (AOC) is an important subduction component that contributes to the generation of arc magmas. However, identifying this contribution to arc magmas is challenging for the lack of effective tracers. Nonetheless, AOC has two characteristic features: (a) Sr-Nd isotope decoupling (i.e., enriched in 87Sr/86Sr relative to 143Nd/144Nd in contrast to the "normal" mantle array); and (b) relatively heavy Ba isotope compositions. Here, we analyze the Ba-Sr-Nd isotopic compositions of lavas from the Mariana arc and back-arc, which are combined with a statistical analysis of the Sr-Nd isotopes for global arc volcanoes. Our results confirm that fluid (or hydrous melt) derived from subducted AOC, rather than sediment, is responsible for the Sr-Nd isotope decoupling observed in island arc lavas. Strikingly, the magnitude of the Sr-Nd isotope decoupling correlates well with the Ba isotope compositions of the arc lavas. Thus, our results establish an intimate link between subducted AOC, heavy Ba isotope ratios, and Sr-Nd isotope decoupling signature in island arcs. This combination of Ba-Sr-Nd isotopes can therefore now be used as a powerful tracer to identify the contributions of subducted AOC to arc magmas. Our results also suggest that AOC and serpentinite show synergistic behavior during subduction recycling. Global arc data confirm that the Sr-Nd isotope decoupling of arc lavas is caused by AOC-derived fluid Decoupled Sr-Nd isotopes plus heavy Ba isotope is a good tracer for recycled altered oceanic crust (AOC) in arc magmas AOC and serpentinite show synergistic behaviors during subduction recycling
关键词	altered oceanic crust Ba isotope Sr-Nd isotope decoupling arc magma subduction recycling
DOI	10.1029/2023JB028407
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China ; Chinese Academy of Sciences[XDB42020402] ; National Key Research and Development Program of China[2023YFF0804304] ; National Key Research and Development Program of China[2023YFF0804301] ; [42206058] ; [91958213] ; [42221005] ; [42330409]
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:001177992100001
出版者	AMER GEOPHYSICAL UNION
WOS关键词	NORTHERN MARIANA-ISLANDS ; SUBDUCTION ZONES ; SLAB DEHYDRATION ; VOLCANIC-ROCKS ; SYSTEMATICS ; WATER ; GEOCHEMISTRY ; SERPENTINE ; FLUIDS ; PB
引用统计	被引频次：1[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/184981
专题	海洋地质与环境重点实验室
通讯作者	Zhang, Yuxiang; Zeng, Zhigang
作者单位	1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao, Peoples R China 2.Laoshan Lab, Lab Marine Mineral Resources, Qingdao, Peoples R China 3.Chinese Acad Sci, Ctr Ocean Mega Sci, Qingdao, Peoples R China 4.Univ Hong Kong, Dept Earth Sci, Hong Kong, Peoples R China 5.Macquarie Univ, Dept Earth & Environm Sci, Sydney, NSW, Australia 6.Univ Sci & Technol China, Sch Earth & Space Sci, CAS Key Lab Crust Mantle Mat & Environm, Hefei, Peoples R China
第一作者单位	中国科学院海洋研究所
通讯作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	Zhang, Yuxiang,Shu, Yunchao,Turner, Simon,et al. Deciphering Contribution of Recycled Altered Oceanic Crust to Arc Magmas Using Ba-Sr-Nd Isotopes[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2024,129(3):13.
APA	Zhang, Yuxiang,Shu, Yunchao,Turner, Simon,Chen, Zuxing,Zeng, Zhigang,&Huang, Fang.(2024).Deciphering Contribution of Recycled Altered Oceanic Crust to Arc Magmas Using Ba-Sr-Nd Isotopes.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,129(3),13.
MLA	Zhang, Yuxiang,et al."Deciphering Contribution of Recycled Altered Oceanic Crust to Arc Magmas Using Ba-Sr-Nd Isotopes".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 129.3(2024):13.