論文

査読有り 筆頭著者 責任著者
2013年9月

Growth kinetics of MgSiO3 perovskite reaction rim between stishovite and periclase up to 50 GPa and its implication for grain boundary diffusivity in the lower mantle

EARTH AND PLANETARY SCIENCE LETTERS
  • Masayuki Nishi
  • ,
  • Yu Nishihara
  • ,
  • Tetsuo Irifune

377
開始ページ
191
終了ページ
198
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.eps1.2013.06.045
出版者・発行元
ELSEVIER SCIENCE BV

The growth rate of MgSiO3 perovskite reaction rims between periclase and stishovite was investigated at 24-50 GPa and 1650-2150 K using a Kawai-type high-pressure apparatus. The textural observations of the recovered samples and rim growth kinetic data revealed that the reaction is controlled by coupled grain boundary diffusion of MgO and grain coarsening in the perovskite reaction layer. Assuming a high diffusivity of O compared with Mg, the grain boundary diffusivity of Mg in the perovskite was determined to be delta D-gb(Mg) [m(3)/s] = 10(-15.1) exp{-[176,000 + (P - 24) x 3.8 x 10(3)]/RT), which is similar to 3-5 gb orders of magnitude faster than that of Si. We found that the bulk diffusivity of Mg in polycrystalline perovskite is affected by the grain boundary when we consider the possible grain sizes and temperatures in the lower mantle. Accordingly, grain boundary diffusion in perovskite may be an effective mechanism for chemical transportation of divalent cations in the lower mantle. (C) 2013 Elsevier B.V. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.eps1.2013.06.045
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000325192100018&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.eps1.2013.06.045
  • ISSN : 0012-821X
  • Web of Science ID : WOS:000325192100018

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