Iron isotope heterogeneity in magmas of subduction zones and its origin

doi:10.1016/j.lithos.2023.107360

	Iron isotope heterogeneity in magmas of subduction zones and its origin
	Liao, Renqiang1 ; Zhu, Hongli1 ; Li, Congying 1; Liu, He 1; Sun, Weidong1,2,3
	2023-11-15
发表期刊	LITHOS
ISSN	0024-4937
卷号	458 页码:14
通讯作者	Zhu, Hongli(zhuhongli@qdio.ac.cn)
摘要	Iron isotope heterogeneity of subduction-related primitive magmas was traditionally thought to be predomi-nantly attributed to the addition of slab-derived components. However, the specific subducted material responsible for inducing Fe isotope heterogeneity in the subarc-backarc mantle remains poorly constrained. Here we report Fe isotopic compositions of a series of backarc basin basalts (BABBs) from the Woodlark Basin (an intra-arc rift basin), Vate Trough (a nascent rear-rift basin), and Lau Basin (a relatively mature basin) in the southwestern Pacific. Even though these BABBs have various geochemical compositions ranging from mid-ocean ridge basalts (MORB)-like to arc-like, which should be affected by various amounts of the slab-derived fluids and/or sediment melts, their delta 56Fe values (0.05-0.18%o) are within the range of global MORB (0.05-0.17%o). After correction for crystal fractionation, the primitive delta 56Fe values (delta 56Fe-prim) displayed no co-variation with indicators of subduction contributions (e.g., Ce/Pb, Nb/U, Ba/La, and Th/Yb) or source redox conditions caused by slab inputs (e.g., V/Yb, V/Ti), suggesting that the delta 56Fe-prim values of these BABBs are rarely affected by subduction metasomatism and the change in oxygen fugacity caused by subducted input. Therefore, we proposed that the MORB-like delta 56Fe values of the studied BABBs were primarily caused by mantle melting processes. Furthermore, we presented a compilation of available Fe isotopic data for BABBs and island arc basalts (IABs) and used these data to evaluate Fe isotope heterogeneity in subduction settings. In particular, compared with delta 56Fe-prim of MORB, the delta 56Fe-prim of BABBs from the Central Lau Spreading Centre in the Lau Basin and the IABs have lower values, whereas BABBs from the Rochambeau Ridges in the Lau Basin have higher delta 56Fe-prim values. By comprehensively considering the factors affecting the variation in Fe isotopic compositions in magmatic rocks in subduction zones (e.g., crystal fractionation, partial melting of the mantle, redox conditions, and subduction-related metasomatism), we proposed that the varied Fe isotopic compositions in subduction settings could reflect their heterogeneous sources, which may be related to plate subduction. Specifically, during plate subduction, a melt-depleted refractory forearc mantle peridotite (with low delta 56Fe values) could be dragged by subducted slab into subarc or backarc depths, resulting in light Fe isotopic enrichment in island arc magmas or BABBs; additionally, serpentinites (both in the slab and mantle wedge) can generate light Fe isotopic enrichment in island arc magmas. High delta 56Fe values in the BABB (e.g., from the Rochambeau Ridges in the Lau Basin) may result from the toroidal influx of nearby upwelling plume components or the assimilation of hydrothermally altered oceanic crust.
关键词	Fe isotope Mantle heterogeneity Subduction zone Backarc basin basalts Island arc basalts
DOI	10.1016/j.lithos.2023.107360
收录类别	SCI
语种	英语
资助项目	Science and Technology Innovation Project of Laoshan Laboratory[LSKJ202204100] ; National Natural Science Foundation of China[42322302] ; National Natural Science Foundation of China[42206057] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42020303] ; Youth Innovation Promotion Association, Chinese Academy of Sciences[2020212] ; Youth Innovation Promotion Association, Chinese Academy of Sciences[2022207] ; China Post-doctoral Science Foundation[2022M713180] ; Shandong Provincial Natural Science Foundation[ZR2021QD098]
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001082962000001
出版者	ELSEVIER
WOS关键词	GEOLOGICAL REFERENCE MATERIALS ; ARC BASIN BASALTS ; TRACE-ELEMENT ; LAU BASIN ; FE ISOTOPES ; OXYGEN FUGACITY ; OCEANIC LITHOSPHERE ; CORIOLIS TROUGHS ; OXIDATION-STATE ; SOURCE REGIONS
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/181638
专题	深海极端环境与生命过程研究中心
通讯作者	Zhu, Hongli
作者单位	1.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanol, Qingdao 266071, Peoples R China 2.Laoshan Lab, Deep Sea Multidisciplinary Res Ctr, Qingdao 266237, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, 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	Liao, Renqiang,Zhu, Hongli,Li, Congying,et al. Iron isotope heterogeneity in magmas of subduction zones and its origin[J]. LITHOS,2023,458:14.
APA	Liao, Renqiang,Zhu, Hongli,Li, Congying,Liu, He,&Sun, Weidong.(2023).Iron isotope heterogeneity in magmas of subduction zones and its origin.LITHOS,458,14.
MLA	Liao, Renqiang,et al."Iron isotope heterogeneity in magmas of subduction zones and its origin".LITHOS 458(2023):14.

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