このエントリーをはてなブックマークに追加
ID 55296
フルテキストURL
著者
Tsujino, Noriyoshi Institute for Planetary Materials, Okayama University
Nishihara, Yu Geodynamics Research Center, Ehime-University
Yamazaki, Daisuke Institute for Planetary Materials, Okayama University
Seto, Yusuke Department of Planetology, Kobe University
Higo, Yuji Japan Synchrotron Radiation Research Institute
Takahashi, Eiichi Department of Earth and Planetary Sciences, Tokyo Institute of Technology
抄録
 Seismic shear wave anisotropy is observed in Earth's uppermost lower mantle around several subducted slabs. The anisotropy caused by the deformation-induced crystallographic preferred orientation (CPO) of bridgmanite (perovskite-structured (Mg,Fe)SiO3) is the most plausible explanation for these seismic observations. However, the rheological properties of bridgmanite are largely unknown. Uniaxial deformation experiments have been carried out to determine the deformation texture of bridgmanite, but the dominant slip system (the slip direction and plane) has not been determined. Here we report the CPO pattern and dominant slip system of bridgmanite under conditions that correspond to the uppermost lower mantle (25 gigapascals and 1,873 kelvin) obtained through simple shear deformation experiments using the Kawai-type deformation-DIA apparatus. The fabrics obtained are characterized by [100] perpendicular to the shear plane and [001] parallel to the shear direction, implying that the dominant slip system of bridgmanite is [001](100). The observed seismic shear- wave anisotropies near several subducted slabs (Tonga-Kermadec, Kurile, Peru and Java) can be explained in terms of the CPO of bridgmanite as induced by mantle flow parallel to the direction of subduction.
キーワード
Geophysics
Geodynamics
Mineralogy
発行日
2016-11
出版物タイトル
Nature
539巻
7627号
出版者
Nature Publishing Group
開始ページ
81
終了ページ
84
ISSN
0028-0836
NCID
AA00752384
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
author
PubMed ID
DOI
Web of Sience KeyUT
関連URL
https://doi.org/10.1038/nature19777