Molybdenum isotope fractionation during low-temperature alteration of the upper ocean crust at DSDP sites 417 and 418
文献类型：期刊论文
| 作者 | Chen, Shuo2; Xue, Qiqi2; Niu, Yaoling3; Sun, Pu2; Guo, Pengyuan2; Rodney, Joel B.1; Elliott, Tim1 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2026-03-15 |
| 卷号 | 417页码:26-36 |
| 关键词 | Molybdenum isotopes Low-temperature alteration Ocean crust Mantle heterogeneity |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2026.01.054 |
| 通讯作者 | Chen, Shuo(shuochen@qdio.ac.cn) |
| 英文摘要 | While there is growing interest in using Mo isotope systematics to understand subduction processes and crustmantle recycling, how Mo isotopes may fractionate during seafloor alteration and the role of altered oceanic crust in these processes remains poorly understood. This study investigates Mo concentrations and isotope compositions (698/95Mo, relative to NIST SRM3134) in basalts from DSDP Sites 417A, 417D, and 418A in the Atlantic, which experienced varying extent of seafloor alteration. These samples display significant Mo concentration (28 to 738 ng/g) and Mo isotopic variability (698/95Mo = -2.33%o to +0.99%o), resulting from distinct alteration conditions. Basalts from Site 417A, which generally underwent oxidative alteration at high water-rock ratios, exhibit low Mo concentrations and low 698/95Mo values (-0.43 +/- 0.26%o; 1 sigma). In these samples, the Mo mobilization ratios (RMo = [Mo]AOC/[Mo]fresh) show a positive correlation with 698/95Mo and negative correlations with fluid-rock interaction proxies (e.g., K, Rb, 87Sr/86Sr), which is consistent with preferential leaching of isotopically heavy Mo from primary minerals during basalt dissolution. In contrast, samples from Site 417D generally exhibit Mo enrichment (RMo up to 3) and higher 698/95Mo (up to +0.99%o), likely resulting from carbonate precipitation under relatively reducing conditions. Samples from Site 418A mostly show Mo uptake (RMo up to 4.5) but lower 698/95Mo (-0.80 +/- 0.53%o; 1 sigma), consistent with adsorption onto Fe-oxyhydroxides in sub-oxic environments. These findings indicate the dual role of altered ocean crust as both Mo sink and source on varying localized scales, which needs consideration in discussing global Mo cycling. The heterogeneity of Mo isotopes in altered ocean crust challenges its characterization as a uniform reservoir and supports the notion that deep, unaltered ocean crust may dominate slab-derived Mo fluxes in subduction zones. Our study highlights the need for mineral-scale isotopic analyses and experimental constraints to refine models of global Mo cycling and mantle heterogeneity. |
| WOS关键词 | ELEMENT ABUNDANCES ; SUBDUCTION ; SR ; ND ; EXCHANGE ; PRECISE ; RATIOS ; GEOCHEMISTRY ; ADSORPTION ; SEPARATION |
| 资助项目 | National Natural Science Foundation of China[42176087] ; National Natural Science Foundation of China[42322605] ; Youth Innovation Promotion Association, Chinese Academy of Sciences[2021206] |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001688236400001 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/204733]  |
| 专题 | 海洋研究所_海洋地质与环境重点实验室 |
| 通讯作者 | Chen, Shuo |
| 作者单位 | 1.Univ Bristol, Sch Earth Sci, Bristol Isotope Grp, Bristol BS8 1RJ, England 2.Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Observat & Forecasting, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 3.China Univ Geosci, Beijing 100083, Peoples R China |
| 推荐引用方式 GB/T 7714 | Chen, Shuo,Xue, Qiqi,Niu, Yaoling,et al. Molybdenum isotope fractionation during low-temperature alteration of the upper ocean crust at DSDP sites 417 and 418[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2026,417:26-36. |
| APA | Chen, Shuo.,Xue, Qiqi.,Niu, Yaoling.,Sun, Pu.,Guo, Pengyuan.,...&Elliott, Tim.(2026).Molybdenum isotope fractionation during low-temperature alteration of the upper ocean crust at DSDP sites 417 and 418.GEOCHIMICA ET COSMOCHIMICA ACTA,417,26-36. |
| MLA | Chen, Shuo,et al."Molybdenum isotope fractionation during low-temperature alteration of the upper ocean crust at DSDP sites 417 and 418".GEOCHIMICA ET COSMOCHIMICA ACTA 417(2026):26-36. |
入库方式： OAI收割
来源：海洋研究所
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