The cerium isotope fingerprints of redox fluctuation in bauxites
文献类型：期刊论文
| 作者 | Li, Wenshuai3,4; Liu, Xiao-Ming4; Nakada, Ryoichi5; Takahashi, Yoshio; Hu, Yongfeng6; Shakouri, Mohsen6; Zhang, Zhaofeng1 ; Okumura, Takuma7; Yamada, Shinya2
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| 刊名 | EARTH AND PLANETARY SCIENCE LETTERS
 |
| 出版日期 | 2023-01-15 |
| 卷号 | 602页码:10 |
| 关键词 | cerium anomaly stable isotopes bauxites redox XANES |
| ISSN号 | 0012-821X |
| DOI | 10.1016/j.epsl.2022.117962 |
| 英文摘要 | We measured the Ce concentration, oxidation state, and isotope composition of bauxites developed on the Columbia River Basalts (CRBs) to evaluate the impacts of redox and non-redox processes on the Ce isotopic variability on Earth's surface. Bauxites recovered from drill cores show upward increasing Ce concentration (5.4-88.7 mu g/g) and overall depletion of Ce (mass transfer coefficient, tau Ce,Nb:-0.96 to-0.52, i.e., net depletion of 52-96% relative to their parent CRBs). There is a wide range of the Ce anomaly (Ce/Ce*) from 0.4 to 6.3 and 0.6 to 1.4 in the Cowlitz and Columbia bauxites, respectively. The most positive Ce anomalies appear at the shallow regolith (2-5 m depth). Cerium primarily presents in its trivalent form in deposited exogenous materials (wind-blown dust from an old, weathered region of the continent) and primary CRBs. There is a downward increase in the fraction of Ce (IV) in the regolith. Bauxite 8142Ce ranges from-0.161 +/- 0.034 to-0.018 +/- 0.043%o and-0.277 +/- 0.034 to-0.046 +/- 0.034%o in the Cowlitz and Columbia profiles, respectively. The Ce isotope record reflects the redox cycle of Ce and Mn and is masked by dust accretion on the top. The enrichment of Ce (IV) occurs in the transition zone (the bottom of the shallow regolith) with minor Ce isotope shifts from the CRBs (8142Ce from-0.080 +/- 0.034 to-0.04 +/- 0.034%o) likely caused by minor isotopic fractionation linked to O2-driven CeO2 precipitation. There are negative Ce isotope shifts from the basaltic parents and the enrichment of oxidized Ce and Mn in the deep regolith (5-9 m depth), where large isotopic fractionation probably induced by Ce oxidative adsorption on MnO2 plays a vital role. The vertical difference between Ce/Ce* and 8142Ce may be attributed to the climatic oxidation-reduction cycle of Mn and Ce, leaving discrete CeO2 grains in the shallow regolith while transferring isotopically light Ce associated to oxidized Mn deposits down to the deep regolith. We conclude that a combination of Ce species isotopes and anomalies potentially records terrestrial redox status and fluctuation. (c) 2022 Elsevier B.V. All rights reserved. |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000923192700001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/72624]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Liu, Xiao-Ming |
| 作者单位 | 1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 2.Rikkyo Univ, Dept Phys, Toshima Ku, Tokyo 1718501, Japan 3.Univ Tokyo, Grad Sch Sci, Dept Earth & Planetary Sci, Tokyo 1130033, Japan 4.Univ N Carolina, Dept Earth Marine & Environm Sci, Chapel Hill, NC 27599 USA 5.Japan Agcy Marine Earth Sci & Technol JAMSTEC, Kochi Inst Core Sample Res, Kochi 7838502, Japan 6.Univ Saskatchewan, Canadian Light Source, Saskatoon, SK S7N 2V3, Canada 7.Tokyo Metropolitan Univ, Dept Chem, Hachioji, Tokyo 1920397, Japan |
| 推荐引用方式 GB/T 7714 | Li, Wenshuai,Liu, Xiao-Ming,Nakada, Ryoichi,et al. The cerium isotope fingerprints of redox fluctuation in bauxites[J]. EARTH AND PLANETARY SCIENCE LETTERS,2023,602:10. |
| APA | Li, Wenshuai.,Liu, Xiao-Ming.,Nakada, Ryoichi.,Takahashi, Yoshio.,Hu, Yongfeng.,...&Yamada, Shinya.(2023).The cerium isotope fingerprints of redox fluctuation in bauxites.EARTH AND PLANETARY SCIENCE LETTERS,602,10. |
| MLA | Li, Wenshuai,et al."The cerium isotope fingerprints of redox fluctuation in bauxites".EARTH AND PLANETARY SCIENCE LETTERS 602(2023):10. |
入库方式： OAI收割
来源：广州地球化学研究所
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