Deep Earth water research using synchrotron X-ray and neutron radiations

2017 Fiscal Year Final Research Report

• Project/Area Number: 26247073
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Hiroshima University (2017); Ehime University (2014-2016)
• Principal Investigator: INOUE Toru 広島大学, 理学研究科, 教授 (00291500)
• Co-Investigator(Kenkyū-buntansha): 肥後 祐司 公益財団法人高輝度光科学研究センター, 利用研究促進部門, 研究員 (10423435) ; 栗林 貴弘 東北大学, 理学研究科, 准教授 (20302086) ; 丹下 慶範 公益財団法人高輝度光科学研究センター, 利用研究促進部門, 研究員 (70543164) ; 大藤 弘明 愛媛大学, 地球深部ダイナミクス研究センター, 教授 (80403864)
• Co-Investigator(Renkei-kenkyūsha): YURIMOTO Hisayoshi 北海道大学, 大学院理学研究院, 教授 (80191485) ; Greaux Steeve 愛媛大学, 地球深部ダイナミクス研究センター, 研究員 (90543166)
• Research Collaborator: CAI Nao ; SUENAMI Hideki ; KAKIZAWA Sho ; XU Chaowen ; NODA Masamichi
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 地球・惑星内部構造 / 地球・惑星内部ダイナミクス / 地球・惑星内部物性 / 高圧含水鉱物 / 放射光X線 / 中性子回折 / 地球深部水

Outline of Final Research Achievements

We have explored the possible existence of water in the deep Earth by using the techniques of the state-of-the-art high-pressure synthesis experiment, synchrotron X-ray in situ observation and neutron scattering experiment. As the result, it became clear that bridgmanite, which is the most abundant mineral in the lower mantle, can contain significant amounts of water in its crystal structure. The fact was confirmed by chemical compositional change, possible existence of hydrogen and lattice constant change by single crystal X-ray diffraction, the detection of OH vibration peak by IR spectroscopy, the detection of hydrogen position by neutron diffraction, and the changes of physical properties such as bulk modulus. Furthermore, it became clarified that the similar substitution can occur in superhydrous phase B and phase D, which are the other high-pressure hydrous phases in the deep mantle.

Free Research Field

地球内部物性