ID | 55450 |
フルテキストURL | |
著者 |
Yoshino, Takashi
Institute for Planetary Materials, Okayama University
Zhang, Baohua
Key Laboratory for High-Temperature and High-Pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences
Rhymer, Brandon
Department of Geosciences, State University of New York at Stony Brook
Zhao, Chengcheng
Institute for Planetary Materials, Okayama University
Fei, Hongzhan
Bayerisches Geoinstitut, University of Bayreuth
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抄録 | Electrical conductivity of dry forsterite has been measured in muli-anvil apparatus to investigate the pressure dependence of ionic conduction in forsterite. The starting materials for the conductivity experiments were a synthetic forsterite single crystal and a sintered forsterite aggregate synthesized from oxide mixture. Electrical conductivities were measured at 3.5, 6.7, 9.6, 12.1, and 14.9 GPa between 1300 and 2100 K. In the measured temperature range, the conductivity of single crystal forsterite decreases in the order of [001], [010], and [100]. In all cases, the conductivity decreases with increasing pressure and then becomes nearly constant for [100] and [001] and slightly increases above 7 GPa for [010] orientations and a polycrystalline forsterite sample. Pressure dependence of forsterite conductivity was considered as a change of the dominant conduction mechanism composed of migration of both magnesium and oxygen vacancies in forsterite. The activation energy (ΔE) and activation volume (ΔV) for ionic conduction due to migration of Mg vacancy were 1.8–2.7 eV and 5–19 cm3/mol, respectively, and for that due to O vacancy were 2.2–3.1 eV and −1.1 to 0.3 cm3/mol, respectively. The olivine conductivity model combined with small polaron conduction suggests that the most part of the upper mantle is controlled by ionic conduction rather than small polaron conduction. The previously observed negative pressure dependence of the conductivity of olivine with low iron content (Fo90) can be explained by ionic conduction due to migration of Mg vacancies, which has a large positive activation volume.
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備考 | This is an article published by Taylor & Francis Group
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発行日 | 2017-01-14
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出版物タイトル |
Journal of Geophysical Research. Solid Earth
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巻 | 122巻
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号 | 1号
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出版者 | American Geophysical Union
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開始ページ | 158
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終了ページ | 171
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ISSN | 2169-9313
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NCID | AA10819743
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資料タイプ |
学術雑誌論文
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言語 |
英語
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OAI-PMH Set |
岡山大学
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著作権者 | https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
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論文のバージョン | publisher
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DOI | |
Web of Science KeyUT | |
関連URL | https://doi.org/10.1002/2016JB013555
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