A new high-pressure form of Mg2SiO4 highlighting diffusionless phase transitions of olivine
書誌事項
- 公開日
- 2017-12-11
- 資源種別
- journal article
- 権利情報
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- https://creativecommons.org/licenses/by/4.0
- https://creativecommons.org/licenses/by/4.0
- DOI
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- 10.1038/s41598-017-17698-z
- 公開者
- Springer Science and Business Media LLC
説明
<jats:title>Abstract</jats:title><jats:p>High-pressure polymorphism of olivine (α-phase of Mg<jats:sub>2</jats:sub>SiO<jats:sub>4</jats:sub>) is of particular interest for geophysicists aiming to understand the structure and dynamics of the Earth’s interior because of olivine’s prominent abundance in the upper mantle. Therefore, natural and synthetic olivine polymorphs have been actively studied in the past half century. Here, we report a new high-pressure polymorph, the ε*-phase, which was discovered in a heavily shocked meteorite. It occurs as nanoscale lamellae and has a topotaxial relationship with the host ringwoodite (γ-phase of Mg<jats:sub>2</jats:sub>SiO<jats:sub>4</jats:sub>). Olivine in the host rock entrapped in a shock-induced melt vein initially transformed into polycrystalline ringwoodite through a nucleation and growth mechanism. The ringwoodite grains then coherently converted into the ε*-phase by shear transformation during subsequent pressure release. This intermediate metastable phase can be formed by all Mg<jats:sub>2</jats:sub>SiO<jats:sub>4</jats:sub> polymorphs via a shear transformation mechanism. Here, we propose high-pressure transformations of olivine that are enhanced by diffusionless processes, not only in shocked meteorites but also in thick and cold lithosphere subducting into the deep Earth.</jats:p>
収録刊行物
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- Scientific Reports
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Scientific Reports 7 (1), 17351-, 2017-12-11
Springer Science and Business Media LLC
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詳細情報 詳細情報について
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- CRID
- 1360004233483102208
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- ISSN
- 20452322
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- 資料種別
- journal article
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- データソース種別
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- Crossref
- KAKEN
- OpenAIRE
