著者

奥地 拓生 プレジャブ ナランゴー 富岡 尚敬

出版者

日本結晶学会

雑誌

日本結晶学会誌 (ISSN:03694585)

巻号頁・発行日

vol.59, no.6, pp.309-315, 2017-12-31 (Released:2017-12-31)

参考文献数

30

被引用文献数

1

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Water in the Earth has been transported from the oceans into its deep interior, where it forms hydrous deep mantle minerals. Wadsleyite [(Mg,Fe)2SiO4] has been considered as one of the most important host minerals incorporating this type of water as hydroxyl groups. To constrain the capacity of water in its structure and also to understand the effect of such water on its physical properties, it is essential to quantitatively determine the hydrogenʼs site and occupancy in the wadsleyite structure. Here we conduct a neutron time-of-flight single-crystal Laue diffraction study of it. Single crystals, which have size and quality suitable for this method, were successfully synthesized by a slow-cooling method at the relevant high pressure and temperature condition. The results unambiguously demonstrate a unique incorporation mechanism of hydrogen into the wadsleyite structure.

著者

奥地 拓生

出版者

北海道大学低温科学研究所

雑誌

低温科学 (ISSN:18807593)

巻号頁・発行日

vol.66, pp.169-174, 2008-03-31

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宇宙空間から惑星内部にわたる多様な惑星形成・進化の場には,極低温から高温,また真空から超高圧までの,あらゆる外場条件が存在する.氷はこの多様な条件に対応して,自由な陽子の急速な拡散を始めとする多様な性質を示すことが理論的に予想されているが,その実験的立証はいまだに行われ ていない.このような実験を行うためには,従来の高圧実験技術を活用しつつも,さらに新しい手法をその上に作りあげる必要があった.筆者がそのために開発してきたダイヤモンドアンビルセルNMR の手法と成果を解説し,また将来への展望を述べる.

著者

奥地 拓生

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.33, no.4, pp.247-254, 1999

参考文献数

37

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The fate of H₂O accreted to the primordial Earth is discussed using the results of the hydrogen partitioning experiments between molten iron and silicate melt at high pressure. Previous works related to this problem give no weight to the partitioning of hydrogen into the core, so that the origin and abundance of H₂O in the hydrosphere, crust and mantle of the present Earth should be reconsidered from the viewpoint of the evolution of the primordial Earth including core formation processes. The results indicate that there is large possibility for most of H₂O accreted to the Earth to be transported into the core as molten iron hydride (FeH<i>x</i>), rather than to be left into the hydrosphere and mantle in every case of H₂O concentration in the accreting planetesimals. In other words, the mantle must have been dried up after the core formation. These results are consistent with the observed H₂O concentration in the hydrosphere, crust and upper mantle of the present Earth. The presence of hydrogen in the core may quantitatively settle the problem of density deficit of the present Earth's core.