Heavy magnesium isotopic compositions of basalts erupted during arc inception: Implications for the mantle source underlying the nascent Izu-Bonin-Mariana arc

doi:10.1016/j.gca.2023.04.017

IOCAS-IR

	Heavy magnesium isotopic compositions of basalts erupted during arc inception: Implications for the mantle source underlying the nascent Izu-Bonin-Mariana arc
	Yuan, Shuai1,2,3 ; Li, He 1,2,7; Arculus, Richard J.4; He, Yongsheng 5; Ke, Shan 5; Sun, Weidong1,3,6
	2023-07-01
发表期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
卷号	352 页码:14-23
通讯作者	Li, He(lihe@qdio.ac.cn)
摘要	Basalts formed during the early development of an arc are usually buried, but they record critical information relating to the mantle source of the overriding plate prior to the addition of subducting slab components. Basalts recovered at Site U1438 of International Ocean Discovery Program (IODP) Expedition 351, in the Amami Sankaku Basin (ASB), formed during the transition from forearc basalt (FAB) and boninite eruptions to stratovolcano developments in the Izu-Bonin-Mariana (IBM) arc. In this study, we present magnesium (Mg) isotopic data (delta 26Mg) for the ASB basalt core samples, formed at arc inception in the absence of down-going slab components, and report the implications of these data for the characteristics of the mantle sources underlying the proto-IBM arc. The delta 26Mg values of the ASB basalts range from -0.21%o to +0.08%o, with an average value of -0.13 +/- 0.07%o. These values are systematically higher than those of mid-ocean ridge basalts (MORBs) (-0.25 +/- 0.06%o). No obvious effects of post-eruptive alteration, fractional crystallization, partial melting, or subduction component addition can be identified in the Mg isotopic compositions either of the ASB basalts or their mantle source, given the absence of correlations between the delta 26Mg values and the proxies of these processes (e.g., K/Nb, Nb/Zr, Ba/La, Nb/Y, etc.). We conclude that the high delta 26Mg values of the ASB basalts are inherited from their mantle source that was enriched in heavy Mg isotopes. Melting of an ultra-depleted, refractory spinel peridotite source containing talc-bearing serpentinite components can explain the origin of the heavy Mg isotopic compositions in the ASB basalts. The presence of water-rich serpentinite components in the mantle provides a new perspective on how a refractory mantle source can undergo partial melting at temperatures and pressures similar to the formation of MORBs without the influence of subducted materials, which has important implications for the initiation of plate subduction. Furthermore, the Mg isotopic contributions of subducted additions and mantle source materials should be carefully discussed in future studies due to the heterogeneity of Mg isotopes in the mantle.
关键词	Mg isotopes Basalts Nascent arc Ultra-depleted mantle Serpentinite components
DOI	10.1016/j.gca.2023.04.017
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[91958110] ; National Natural Science Foundation of China[92258303] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42020203] ; Taishan Scholars Program[tsqn202211251] ; Open Research Project from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences[GPMR202111]
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:001002459500001
出版者	PERGAMON-ELSEVIER SCIENCE LTD
WOS关键词	SUBDUCTION INITIATION ; CONTINENTAL-CRUST ; OCEANIC-CRUST ; MG ; FRACTIONATION ; ORIGIN ; CHINA ; GEOCHEMISTRY ; MAGMATISM ; RECORD
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/183239
专题	中国科学院海洋研究所
通讯作者	Li, He
作者单位	1.Chinese Acad Sci, Inst Oceanol, Ctr Deep Sea Res, Qingdao 266071, Peoples R China 2.Lab Marine Mineral Resources, Laoshan Lab, Qingdao 266237, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 2601, Australia 5.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 6.Deep Sea Multidisciplinary Res Ctr, Laoshan Lab, Qingdao 266237, Peoples R China 7.Chinese Acad Sci, Inst Oceanol, 7 Nanhai Rd, Qingdao 266071, Peoples R China
第一作者单位	深海极端环境与生命过程研究中心
通讯作者单位	深海极端环境与生命过程研究中心; 中国科学院海洋研究所
推荐引用方式 GB/T 7714	Yuan, Shuai,Li, He,Arculus, Richard J.,et al. Heavy magnesium isotopic compositions of basalts erupted during arc inception: Implications for the mantle source underlying the nascent Izu-Bonin-Mariana arc[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2023,352:14-23.
APA	Yuan, Shuai,Li, He,Arculus, Richard J.,He, Yongsheng,Ke, Shan,&Sun, Weidong.(2023).Heavy magnesium isotopic compositions of basalts erupted during arc inception: Implications for the mantle source underlying the nascent Izu-Bonin-Mariana arc.GEOCHIMICA ET COSMOCHIMICA ACTA,352,14-23.
MLA	Yuan, Shuai,et al."Heavy magnesium isotopic compositions of basalts erupted during arc inception: Implications for the mantle source underlying the nascent Izu-Bonin-Mariana arc".GEOCHIMICA ET COSMOCHIMICA ACTA 352(2023):14-23.