フルテキストURL J_Geophys_Res_122_158.pdf
著者 Yoshino, Takashi| Zhang, Baohua| Rhymer, Brandon| Zhao, Chengcheng| Fei, Hongzhan|
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.
備考 This is an article published by Taylor & Francis Group
発行日 2017-01-14
出版物タイトル Journal of Geophysical Research. Solid Earth
122巻
1号
出版者 American Geophysical Union
開始ページ 158
終了ページ 171
ISSN 2169-9313
NCID AA10819743
資料タイプ 学術雑誌論文
言語 English
OAI-PMH Set 岡山大学
著作権者 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.ja
論文のバージョン publisher
DOI 10.1002/2016JB013555
Web of Sience KeyUT 000395658900009
関連URL https://doi.org/10.1002/2016JB013555