Quantitavie analysis of hydrogen sites and occupancies in deep-mantle hydrous minerals by time of flight single crystal neutron diffraction

2017 Fiscal Year Final Research Report

• Project/Area Number: 26287135
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Okayama University
• Principal Investigator: Okuchi Takuo 岡山大学, 惑星物質研究所, 准教授 (40303599)
• Co-Investigator(Kenkyū-buntansha): 富岡 尚敬 国立研究開発法人海洋研究開発機構, その他部局等, 研究員 (30335418)
• Co-Investigator(Renkei-kenkyūsha): YAMASHITA Shigeru 岡山大学, 惑星物質研究所, 准教授 (30260665) ; KURIBAYASHI Takahiro 東北大学, 理学研究科, 准教授 (20302086)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: パルス中性子 / 単結晶回折 / マントル含水鉱物 / 水素

Outline of Final Research Achievements

Water in the Earth has been transported from the oceans into its deep interior, where it forms hydrous deep mantle minerals. Wadsleyite and ringwoodite have been considered as the two most important host minerals incorporating this type of water as hydroxyl groups. To constrain the capacity of water in their structures and also to understand the effect of such water on their physical properties, it is essential to quantitatively determine the sites and occupancies of hydrogen in their structures. We thus conducted neutron time-of-flight Laue single crystal diffraction studies of synthetic crystals of them. Single crystals, which have size and quality suitable for the method, were synthesized by a newly-developed slow-cooling method at the relevant high pressure and temperature conditions. The structures of two hydrous minerals have been successfully determined in very high resolution in space.

Free Research Field

高圧実験、鉱物学