Calcium isotopic signatures of depleted mid-ocean ridge basalts from the northeastern Pacific
文献类型：CNKI期刊论文
| 作者 | ZHU Hongli; DU Long; ZHANG Zhaofeng; SUN Weidong
|
| 发表日期 | 2020-09-15 |
| 出处 | Journal of Oceanology and Limnology
 |
| 关键词 | Ca isotopes mid-ocean ridge basalts(MORBs) mantle partial melting magma dif ferentiation |
| 英文摘要 | A number of high-temperature processes(e.g., melt-rock reactions, metasomatism, partial melting) can produce significant Ca isotopic fractionation and heterogeneity in the mantle, but the mechanism for such fractionation remains obscure. To investigate the effect of mantle partial melting on Ca isotopic fractionation, we reported high-precision Ca isotopic compositions of depleted mid-ocean ridge basalts(MORBs) from the East Pacific Rise and Ecuador Rift in the northeastern Pacific. The δ~(44/40) Ca of these MORB samples exhibit a narrow variation from 0.84‰ to 0.88‰ with an average of 0.85‰±0.03‰, which are similar to those of reported MORBs(0.83‰±0.11‰) and back-arc basin basalts(BABBs, 0.80‰±0.08‰) in literature, but are lower than the estimate value for the bulk silicate Earth(BSE, 0.94‰±0.05‰). The low δ~(44/40)Ca signatures of MORB samples in this study cannot be caused by fractional crystallization, since intermediate-mafic differentiation has been demonstrated having only limited effects on Ca isotopic fractionation. Instead, the offset of δ~(44/40) Ca between MORBs and the BSE is most likely produced by mantle partial melting. During this process, the light Ca isotopes are preferentially transferred to the melt, while the heavy ones tend to stay in the residue, which is consistent with the fact that δ~(44/40) Ca of melt-depleted peridotites increases with partial melting in literature. The behavior of Ca isotopes during mantle partial melting is closely related to the inter-mineral(Cpx and Opx) Ca isotopic fractionation and melting mineral modes. Mantle partial melting is one of the common processes that can induce lower δ~(44/40) Ca values in basalts and Ca isotopic heterogeneity in Earth's mantle. |
| 文献子类 | CNKI期刊论文 |
| 资助机构 | Supported by the National Natural Science Foundation of China (Nos. 41773009 ; 41873002) ; the Stake Key Laboratory of Geological Processes and Mineral Resources (No. GPMR201708) ; the National Science Foundation for Post-doctoral Scientists of China (No. 2018M640660) ; the Taishan Scholar Program of Shandong (No. TS201712075) ; the AoShan Talents Cultivation Program Supported by Qingdao National Laboratory for Marine Science and Technology (No. 2017ASTCP-OS07) |
| 卷 | v.38期:05页:135-146 |
| 语种 | 英文; |
| 分类号 | P736.4 |
| ISSN号 | 2096-5508 |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/188020]  |
| 专题 | 中国科学院海洋研究所 |
| 作者单位 | 1.StateKeyLaboratoryofIsotopeGeochemistry,GuangzhouInstituteofGeochemistry,ChineseAcademyofSciences 2.CenterofDeepSeaResearch,InstituteofOceanography,ChineseAcademyofSciences 3.LaboratoryforMarineMineralResources,PilotNationalLaboratoryforMarineScienceandTechnology(Qingdao) 4.CenterforOceanMega-Science,ChineseAcademyofSciences 5.CollegeofEarthScienceandEngineering,ShandongUniversityofScienceandTechnology 6.UniversityofChineseAcademyofSciences |
| 推荐引用方式 GB/T 7714 | ZHU Hongli,DU Long,ZHANG Zhaofeng,et al. Calcium isotopic signatures of depleted mid-ocean ridge basalts from the northeastern Pacific. 2020. |
入库方式： OAI收割
来源：海洋研究所
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