气候变化领域集成服务门户(CCPortal): Iron and magnesium isotope fractionation in oceanic lithosphere and sub-arc mantle: Perspectives from ophiolites

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DOI	10.1016/j.epsl.2015.08.020
	Iron and magnesium isotope fractionation in oceanic lithosphere and sub-arc mantle: Perspectives from ophiolites
	Su, Ben-Xun; Teng, Fang-Zhen; Hu, Yan; Shi, Ren-Deng; Zhou, Mei-Fu; Zhu, Bin; Liu, Fan; Gong, Xiao-Han; Huang, Qi-Shuai; Xiao, Yan; Chen, Chen; He, Yong-Sheng
通讯作者	Su, BX (通讯作者)
发表日期	2015
ISSN	0012-821X
EISSN	1385-013X
起始页码	523
结束页码	532
卷号	430
英文摘要	We present high-precision Fe and Mg isotopic data for the Purang ophiolite, southwestern Tibet, representing the first combined Fe and Mg isotopic study of the oceanic lithosphere hitherto. The delta(56) Fe and delta Mg-26 values of the ophiolitic peridotite, dunite and gabbro vary from -0.209 to -0.187 parts per thousand and from -0.28 to -0.14 parts per thousand, respectively. The average delta Fe-56 of the peridotites is -0.030 +/- 0.143 parts per thousand (2SD, n = 17), a value indistinguishable from abyssal peridotites and chondrites, and lower than oceanic basalts. The average delta Mg-26 value of the peridotites is -0.20 +/- 0.10 parts per thousand, a value slightly higher than both chondrites and oceanic basalts. Correlations between delta Fe-56 and indices of partial melting indicate fractionation of 0.323 parts per thousand in delta Fe-56 between the oceanic lithospheric mantle and the overlying mafic crust during an early episode of partial melting, presumably beneath a spreading centre. Subsequent metasomatism in a suprasubduction zone caused elevated oxygen fugacity and heavy Fe isotopic compositions in the oceanic lithospheric mantle. The dunite with high Ba/La, a proxy for oxygen fugacity, and high delta Fe-56 values was likely formed during this process of sub-arc mantle-melt interaction. The negatively coupled Fe-Mg isotopic variations of the Purang ophiolite indicate that Mg isotope fractionation may also occur during high-temperature mantle processes. The observed isotopic variations among different lithologies in the ophiolite may satisfactorily account for the isotopic differences between arc lavas and mantle peridotites with respect to oceanic basalts, thus providing implications for crust-mantle differentiation. (C) 2015 Elsevier B.V. All rights reserved.
关键词	YUNGBWA OPHIOLITE PERIDOTITE XENOLITHS ABYSSAL PERIDOTITES FE MINERALS BASALTS DIFFERENTIATION GEOCHEMISTRY SYSTEMATICS SIGNATURES
英文关键词	ophiolite; Fe isotopes; Mg isotopes; partial melting; metasomatism
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000363070600050
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258583
推荐引用方式 GB/T 7714	Su, Ben-Xun,Teng, Fang-Zhen,Hu, Yan,et al. Iron and magnesium isotope fractionation in oceanic lithosphere and sub-arc mantle: Perspectives from ophiolites[J]. 中国科学院青藏高原研究所,2015,430.
APA	Su, Ben-Xun.,Teng, Fang-Zhen.,Hu, Yan.,Shi, Ren-Deng.,Zhou, Mei-Fu.,...&He, Yong-Sheng.(2015).Iron and magnesium isotope fractionation in oceanic lithosphere and sub-arc mantle: Perspectives from ophiolites.EARTH AND PLANETARY SCIENCE LETTERS,430.
MLA	Su, Ben-Xun,et al."Iron and magnesium isotope fractionation in oceanic lithosphere and sub-arc mantle: Perspectives from ophiolites".EARTH AND PLANETARY SCIENCE LETTERS 430(2015).