Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet

doi:10.1016/j.gca.2019.04.031

	Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet
	Zhang, Long 1; Sun, Wei-dong2,3,4 ; Zhang, Zhaofeng 5; An, Yajun 5; Liu, Fang 5
	2019-08-01
发表期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
卷号	258 页码:274-289
通讯作者	Zhang, Long([email protected]) ; Sun, Wei-dong([email protected])
摘要	We present high-precision iron isotope data for harzburgites and constituting minerals from the Yushigou suprasubduction zone ophiolite in the North Qilian orogen of northern Tibet to provide insights into iron isotope behavior in subduction zones. The Yushigou harzburgites represent typical melting residues of silica-enriched forearc mantle wedge with significant melt extraction and minimal melt percolation. The delta Fe-56 ranges from -0.096% to 0.110% in olivine, from -0.111% to 0.105% in orthopyroxene and from -0.141% to 0.054% in spinel. Coexisting minerals fall on a line with a slope of 1 in the delta-delta plot, indicating iron isotope equilibrium between mineral pairs. Iron isotopic fractionation between olivine and orthopyroxene is minor, which is consistent with theoretical predictions and previous observations. Good iron isotopic equilibrium between olivine and orthopyroxene is a further indicator that silica enrichment in arc peridotites is inherited from their mantle source. In contrast, significantly negative iron isotopic fractionation between spinel and olivine contradicts with most previous constraints, which may be ascribed to Cr substitution in spinel. Bulk rock harzburgites have delta Fe-56 ranging from -0.097% to 0.076%, the average of which (0.002 +/- 0.020%) is similar to average delta Fe-56 determined for abyssal peridotites. Based on this inference, the lower delta Fe-56 of arc magmas than MORB should be due to smaller discrepancy in Fe3+/RFe between arc magmas and arc peridotites when compared with MORB and abyssal peridotites. Our modelling demonstrates that this can be achieved if arc magmas are produced by redox-buffered melting of silica-enriched mantle wedge while MORB are produced by redox-unbuffered melting of the depleted mantle. (C) 2019 Elsevier Ltd. All rights reserved.
关键词	Iron isotopes Mantle wedge Peridotite Subduction zone North Qilian
DOI	10.1016/j.gca.2019.04.031
收录类别	SCI
语种	英语
资助项目	Strategic Priority Research Program of the Chinese Academy of Sciences[XDB18000000]###807; National Key R&D Program of China[2016YFC0600408]###322; China Postdoctoral Science Foundation[2016LH00023]###2803; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB18000000]; National Key R&D Program of China[2016YFC0600408]; China Postdoctoral Science Foundation[2016LH00023]
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000472708700017
出版者	PERGAMON-ELSEVIER SCIENCE LTD
引用统计	被引频次：12[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/337002/161841
专题	深海极端环境与生命过程研究中心
通讯作者	Zhang, Long; Sun, Wei-dong
作者单位	1.Chinese Acad Sci, Guangzhou Inst Geochem, CAS Key Lab Mineral & Metallogeny, Guangzhou 510640, Guangdong, Peoples R China 2.Chinese Acad Sci, Ctr Deep Sea Res, Inst Oceanol, Qingdao 266071, Shandong, Peoples R China 3.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Mineral Resources, Qingdao 266237, Shandong, Peoples R China 4.Chinese Acad Sci, CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China 5.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Guangdong, Peoples R China
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, Long,Sun, Wei-dong,Zhang, Zhaofeng,et al. Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2019,258:274-289.
APA	Zhang, Long,Sun, Wei-dong,Zhang, Zhaofeng,An, Yajun,&Liu, Fang.(2019).Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet.GEOCHIMICA ET COSMOCHIMICA ACTA,258,274-289.
MLA	Zhang, Long,et al."Iron isotopic composition of supra-subduction zone ophiolitic peridotite from northern Tibet".GEOCHIMICA ET COSMOCHIMICA ACTA 258(2019):274-289.

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