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| Iron isotope fractionation during mid-ocean ridge basalt (MORB) evolution: Evidence from lavas on the East Pacific Rise at 10 degrees 30 ' N and its implications | |
Chen, Shuo1,2,3; Niu, Yaoling2,4,5; Guo, Pengyuan1,2,3; Gong, Hongmei1,2,3; Sun, Pu1,2,3 ; Xue, Qiqi1; Duan, Meng1,2,3; Wang, Xiaohong1,2,3
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| 2019-12-15 | |
| Source Publication | GEOCHIMICA ET COSMOCHIMICA ACTA
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| ISSN | 0016-7037 |
| Volume | 267Pages:227-239 |
| Abstract | Whether the Earth's mantle has a chondritic delta Fe-56 (deviation in Fe-56/Fe-54 from the IRMM-014 standard in parts per thousand) value or not remains under debate. The current view is that the observed average delta Fe-56 of mid-ocean ridge basalts (MORB) cannot be explained by partial melting of mantle source with chondritic value alone. Here, we report Fe isotope compositions on 29 MORB glasses sampled along a flowline traverse across the East Pacific Rise (EPR) axis at 10 degrees 30'N. These glasses show large MgO variation (1.8-7.4 wt.%) that forms a compositional continuum resulting from varying extent of fractional crystallization, which is accompanied by systematic Fe isotopic variation. Fractional crystallization modeling suggests that early crystallization of olivine, pyroxene and plagioclase gives rise to an iron enrichment trend and an increase in delta Fe-56. Once Fe-Ti oxides appear on the liquidus and begin to crystallize, the FeOt and TiO2 contents of the residual melt decrease rapidly, which lead to a slight decrease in delta Fe-56. These observations indicate that significant Fe isotope fractionation can indeed take place during MORB melt evolution. Hence, delta Fe-56 values of variably evolved MORB melts do not represent those of primary MORB melts and thus cannot be used to infer mantle source Fe isotope compositions. Importantly, delta Fe-56 values of primary MORB melts after correction for the effect of fractional crystallization can be well reproduced by mantle melting. Therefore, our study supports the idea that the Fe isotope composition of the accessible Earth is close to be chondritic. We note that conclusion would assume that the core, which takes up similar to 90% of the Earth's Fe, must have a chondritic Fe isotope composition. (C) 2019 Elsevier Ltd. All rights reserved. |
| Keyword | Fe isotope Mid-ocean ridge basalts East Pacific Rise Bulk silicate earth |
| DOI | 10.1016/j.gca.2019.09.031 |
| Indexed By | SCI |
| Language | 英语 |
| Funding Project | National Natural Science Foundation (NSFC)-Shandong Joint Fund for Marine Science Research Centers[U1606401] ; China Postdoctoral Science Foundation[2019M652496] ; NSFC[41630968] ; NSFC[41776067] ; NSFC[41130314] ; 111 project[B18048] |
| WOS Research Area | Geochemistry & Geophysics |
| WOS Subject | Geochemistry & Geophysics |
| WOS ID | WOS:000491872600013 |
| Publisher | PERGAMON-ELSEVIER SCIENCE LTD |
| Citation statistics | |
| Document Type | 期刊论文 |
| Version | 出版稿 |
| Identifier | http://ir.qdio.ac.cn/handle/337002/165032 |
| Collection | 中国科学院海洋研究所 |
| Corresponding Author | Chen, Shuo; Niu, Yaoling |
| Affiliation | 1.Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Shandong, Peoples R China 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao 266061, Shandong, Peoples R China 3.Chinese Acad Sci, Ctr Ocean Megasci, 7 Nanhai Rd, Qingdao 266071, Shandong, Peoples R China 4.Univ Durham, Dept Earth Sci, Durham DH1 3LE, England 5.China Univ Geosci, Beijing 100083, Peoples R China |
| First Author Affilication | Institute of Oceanology, Chinese Academy of Sciences; Center for Ocean Mega-Science, Chinese Academy of Sciences |
| Corresponding Author Affilication | Institute of Oceanology, Chinese Academy of Sciences; Center for Ocean Mega-Science, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | Chen, Shuo,Niu, Yaoling,Guo, Pengyuan,et al. Iron isotope fractionation during mid-ocean ridge basalt (MORB) evolution: Evidence from lavas on the East Pacific Rise at 10 degrees 30 ' N and its implications[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2019,267:227-239. |
| APA | Chen, Shuo.,Niu, Yaoling.,Guo, Pengyuan.,Gong, Hongmei.,Sun, Pu.,...&Wang, Xiaohong.(2019).Iron isotope fractionation during mid-ocean ridge basalt (MORB) evolution: Evidence from lavas on the East Pacific Rise at 10 degrees 30 ' N and its implications.GEOCHIMICA ET COSMOCHIMICA ACTA,267,227-239. |
| MLA | Chen, Shuo,et al."Iron isotope fractionation during mid-ocean ridge basalt (MORB) evolution: Evidence from lavas on the East Pacific Rise at 10 degrees 30 ' N and its implications".GEOCHIMICA ET COSMOCHIMICA ACTA 267(2019):227-239. |
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| File Name/Size | DocType | Version | Access | License | ||
| Iron isotope fractio（1932KB） | 期刊论文 | 作者接受稿 | 限制开放 | CC BY-NC-SA | ||
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