Materials property and evolution of Earth's core

2016 Fiscal Year Final Research Report

• Project/Area Number: 24000005
• Research Category: Grant-in-Aid for Specially Promoted Research
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering; Mathematics and Physics
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: HIROSE Kei 東京工業大学, 地球生命研究所, 教授 (50270921)
• Co-Investigator(Kenkyū-buntansha): OHISHI Yasuo 公益財団法人高輝度光科学研究センター, 利用促進部門, 研究員 (20344400) ; ALFRED Baron 国立研究開発法人理化学研究所, 放射線光科学研究センター, 准主任研究員 (90442920) ; KOMABAYASHI Tetsuya エジンバラ大学, 地球科学科, 講師 (20444119)
• Co-Investigator(Renkei-kenkyūsha): HERNLUND John 東京工業大学, 地球生命研究所, 教授 (30723712) ; TATENO Shigehiko 岡山大学, 地球物質科学研究センター, 特任准教授 (30572903) ; OZAWA Haruka 岡山大学, 地球物質科学研究センター, スーパーテクニシャン (10598832) ; KIMURA Jyunichi 海洋研究開発機構, 地球内部物質循環分野, 技術研究主幹 (30241730) ; NOMURA Ryuichi 愛媛大学, 地球深部ダイナミクス研究センター, 助教 (40734570) ; UMEMOTO Koichiro 東京工業大学, 地球生命研究所, WPI研究員 (60726991)
• Project Period (FY): 2012 – 2015
• Keywords: 地球深部 / コア / 下部マントル / 高圧 / 放射光

Outline of Final Research Achievements

We have measured electrical conductivity of iron and alloys at high pressure and temperature corresponding to the Earth's core. Results demonstrate that core thermal conductivity calculated from electrical conductivity is three times as high as traditional estimate, indicating fast core cooling. The age of the inner core should be younger than one billion years. In addition, we also found that the solidus temperature of the lowermost mantle is lower by 500 K than previously thought. Since the lowermost mantle is not extensively molten, it suggests core temperature is also low. The core should include substantial mount of hydrogen to depress its melting temperature.

Free Research Field

高圧地球科学、地球深部物質学