[S-IT06] Interaction and Coevolution of the Core and Mantle

[SIT06-15] Dissolution of hydrogen into iron by the dissociation of hydrous minerals under pressure

飯塚 理子²、*八木 健彦¹、後藤 弘匡³、奥地 拓生⁴、服部 高典⁵、佐野 亜沙美⁵ (1.東京大学大学院理学系研究科附属地殻化学実験施設、2.愛媛大学地球深部ダイナミクス研究センター、3.東京大学物性研究所、4.岡山大学地球物質科学研究センター、5.日本原子力研究開発機構 J-PARCセンター 物質・生命科学ディビジョン　中性子利用セクション)

キーワード：hydrogen, iron, neutron

Although hydrogen is the most abundant element in the solar system and one of the candidates of the light element in the core, the process how the hydrogen can get into iron remains not so clear. High-pressure and high-temperature in situ neutron diffraction study on the iron-hydrous mineral system using “PLANET” at J-PARC clearly showed that when the dissociation of hydrous mineral occurred at about 4 GPa, the released water reacted with iron and formed both iron oxide and iron hydride. Iron oxide reacted with silicates and formed iron containing olivine and pyroxene. Iron hydride remained stable after further increase in temperature. This formation of iron hydride occurred below 1000K, at the temperatures no materials melted. This suggest the possibility that in the very early stage of Earth evolution, hydrogen has dissolved into iron before any other light elements have dissolved.