Theoretical study of lithium diffusion and fractionation in forsterite and its high-pressure phases | |
Jiajun Jiang; Feiwu Zhang; Hua Yang; Tiancheng Yu | |
2019 | |
Source Publication | Physics and Chemistry of Minerals
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Pages | 1-11 |
Abstract | As a geochemical tracer in mantle studies, lithium isotopes play an important role in diffusion and fractionation in major mantle minerals. Olivine and its high-pressure phases, wadsleyite and ringwoodite, are considered to predominate in the upper mantle and transition zone on the earth. We carried out simulations of lithium isotopes’ diffusion and fractionation in Mg end member olivine and its high-pressure phases to learn the details of the signatures of lithium isotopes preserved in mantle materials. In this work, the diffusion and fractionation mechanisms between different lattice sites of lithium isotopes in forsterite (Mg2SiO4), wadsleyite (β-Mg2SiO4) and ringwoodite (γ-Mg2SiO4) at the atomic level are studied using empirical atomistic simulation techniques. It is found that Li can pass through the high-pressure phases (wadsleyite and ringwoodite) energetically much easier due to the low migration energy barriers via either substitutional or interstitial mechanism. The activation energy is high for Li diffusion along the interstitial path in the forsterite and decreases drastically with the assist of Mg vacancies. The temperature-dependent fractionation for two Li isotopes between two different lattice sites is calculated at the temperatures from 300 to 2500 K. This behavior generates the lighter Li storage in the near-surface mantle-derived rocks and provides insights into zoning and composition of lithium isotopes in olivine and its high-pressure phases. |
Keyword | Olivine wadsleyite ringwoodite lithium diffusion fractionation simulation |
Indexed By | SCI |
Language | 英语 |
Document Type | 期刊论文 |
Identifier | http://ir.gyig.ac.cn/handle/42920512-1/10611 |
Collection | 矿床地球化学国家重点实验室 |
Affiliation | 1.State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China 2.University of the Chinese Academy of Sciences, Beijing 100049, China 3.Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 4.School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009, China |
Recommended Citation GB/T 7714 | Jiajun Jiang;Feiwu Zhang;Hua Yang;Tiancheng Yu. Theoretical study of lithium diffusion and fractionation in forsterite and its high-pressure phases[J]. Physics and Chemistry of Minerals,2019:1-11. |
APA | Jiajun Jiang;Feiwu Zhang;Hua Yang;Tiancheng Yu.(2019).Theoretical study of lithium diffusion and fractionation in forsterite and its high-pressure phases.Physics and Chemistry of Minerals,1-11. |
MLA | Jiajun Jiang;Feiwu Zhang;Hua Yang;Tiancheng Yu."Theoretical study of lithium diffusion and fractionation in forsterite and its high-pressure phases".Physics and Chemistry of Minerals (2019):1-11. |
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