气候变化领域集成服务门户(CCPortal): EM1-Signature in the North Fiji Basin: Evidence for Stagnant Slab-Derived Mantle Upwelling Beneath the Trench-Distal Back-Arc Basin

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DOI	10.1029/2020JB021017
	EM1-Signature in the North Fiji Basin: Evidence for Stagnant Slab-Derived Mantle Upwelling Beneath the Trench-Distal Back-Arc Basin
	Oh J.; Lee I.; Stuart F.M.; Park M.; Kim J.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Basaltic volcanism at the mature back-arc spreading axis in the North Fiji Basin (NFB) exhibits significant geochemical heterogeneity from depleted mid-ocean ridge basalt (MORB) to enriched MORB compositions. The volatile and Sr-Nd-Pb-He isotope composition of basaltic glasses from the Central Spreading Ridge (CSR) of the NFB suggests that a second enrichment mantle component is present in addition to the previously observed Samoan mantle plume. The hydrous OIB-like basalts from the northern CSR have a weak enriched mantle 1 (EM1) isotopic signature and negative correlation between Ba/Th and Zr/Hf ratios, similar to rejuvenated Samoan lavas associated with tectonic driven volcanism. The EM1 signature is distinct from shield-stage Samoan basalts and back-arc basin basalts from the Lau Basin by high Ba/La ratio and negative correlation between Ba/Th and Ba/Ta ratios, indicating contributions from dehydrated and altered oceanic crust and sediments. Our new geochemical data suggest that focused melting above the mantle transition zone (MTZ) triggered by dehydration of stagnant slab can be a source of the EM1-like melts containing both elevated 3He/4He ratios (up to 12.52 RA) and altered oceanic slab components. Given the spatial coincidence of the inferred EM1 basalts with the clustered deep earthquakes, our results support the presence of detached oceanic slabs in the MTZ beneath the northern NFB. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	EM1; mantle heterogeneity; mantle transition zone; mantle upwelling; North Fiji Basin; stagnant slab
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/187185
作者单位	Deep-sea and Seabed Mineral Resources Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea; School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea; Scottish Universities Environmental Research Center, Isotope Geoscience Unit, East Kilbride, United Kingdom; Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, South Korea
推荐引用方式 GB/T 7714	Oh J.,Lee I.,Stuart F.M.,et al. EM1-Signature in the North Fiji Basin: Evidence for Stagnant Slab-Derived Mantle Upwelling Beneath the Trench-Distal Back-Arc Basin[J],2021,126(4).
APA	Oh J.,Lee I.,Stuart F.M.,Park M.,&Kim J..(2021).EM1-Signature in the North Fiji Basin: Evidence for Stagnant Slab-Derived Mantle Upwelling Beneath the Trench-Distal Back-Arc Basin.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Oh J.,et al."EM1-Signature in the North Fiji Basin: Evidence for Stagnant Slab-Derived Mantle Upwelling Beneath the Trench-Distal Back-Arc Basin".Journal of Geophysical Research: Solid Earth 126.4(2021).