地球内核の組成と異方性の解明
Publicly Offered Research
Project Area | Interaction and Coevolution of the Core and Mantle: Toward Integrated Deep Earth Science |
Project/Area Number |
16H01112
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Research Category |
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
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Allocation Type | Single-year Grants |
Review Section |
Science and Engineering
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Research Institution | Tohoku University |
Principal Investigator |
坂巻 竜也 東北大学, 理学研究科, 助教 (30630769)
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Project Period (FY) |
2016-04-01 – 2018-03-31
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Project Status |
Completed (Fiscal Year 2017)
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Budget Amount *help |
¥8,450,000 (Direct Cost: ¥6,500,000、Indirect Cost: ¥1,950,000)
Fiscal Year 2017: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2016: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
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Keywords | 地球核 / 高圧 / 高温 / 音速 / 密度 |
Outline of Annual Research Achievements |
SPring-8のBL35XU、BL43LXUにおいてX線非弾性散乱とレーザー加熱式ダイアモンドアンビル高圧発生装置を組み合わせることで地球深部を再現した超高温高圧条件下での鉄・鉄合金(地球核の模擬物質)の音速を測定した。 純鉄:200GPaを超える超高圧下で微小鉄試料からのX線非弾性散乱の取得するための最適な測定系の構築を進めた。そのシステムを用いて試料由来の非常に弱いシグナルを得られることを確認し、300GPaまでの測定に成功した。また、X線に対して透明なベリリウムガスケットを用いることでダイアモンドアンビルセルの加圧軸に対して同軸と垂直軸の2方向からのX線非弾性散乱測定を試み、試料の選択配向性と音速の関連性を明らかにした。これらは内核の異方性解明に繋がる研究成果である。 酸化鉄:下部マントル条件下で音速を測定し、同条件下では下部マントル構成鉱物より速度が遅いことを明らかにした。最下部マントルで報告されている地震学的低速度域の存在は、外核との反応などによってマントル中に酸化鉄が富化されることによってもたらされる可能性を示した。 鉄-珪素合金:鉄-珪素合金の音速を高温高圧下で測定した。鉄の音速-密度データと比較することで鉄中に珪素が含まれることと音速と密度の両方を減少させることが分かった。実際の地球の内核は純鉄より音速・密度共に小さいため、この差を埋めるためには珪素の存在が効果的であり、核中に含まれている軽元素の有力候補として珪素が挙げられることを示した。 鉄-ニッケル合金:ニッケルが鉄中に含まれることで同じ温度圧力条件下で密度が増加し、音速が減少することを明らかにした。また、観測されている地球核の音速-密度の傾きを説明するためには内核中に化学組成のグラデーションが必要であることを示した。
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Research Progress Status |
29年度が最終年度であるため、記入しない。
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Strategy for Future Research Activity |
29年度が最終年度であるため、記入しない。
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Report
(2 results)
Research Products
(73 results)
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[Journal Article] Melting relations in the Fe-S-Si system at high pressure and temperature: Implications for the planetary core2017
Author(s)
Sakairi, T., Ohtani, E., Kamada, S., Sakai, T., Sakamaki, T., Hirao, N.
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Journal Title
Progress in Earth and Planetary Science
Volume: 4:10
Issue: 1
Pages: 1-11
DOI
Related Report
Peer Reviewed / Open Access
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[Journal Article] Compressional and shear wave velocities for polycrystalline bcc-Fe up to 6.3 GPa and 800 K2016
Author(s)
Y. Shibazaki, K. Nishida, Y. Higo, M Igarashi, M. Tahara, T. Sakamaki, H. Terasaki, Y. Shimoyama, S. Kuwabara, Y. Takubo, E. Ohtani
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Journal Title
American mineralogist
Volume: 101
Issue: 5
Pages: 1150-1160
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Journal Article] Sound velocity of Fe3S, FeO, and FeH at high pressure and temperatures, and implications for sound velocity anomalies at the inner core boundary2016
Author(s)
Ohtani, E., Sakamaki, T.,, Fukui, H., Kamada, S., Tanaka, R.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016A1171
Pages: 1-1
Related Report
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[Journal Article] Study of physical properties of the core and lower mantle materials using synchrotron Mössbauer and X-ray diffraction method2016
Author(s)
Ohtani, E., Kamada, S., Sakamaki, T.,, Fumiya, M., Sakairi, T., Ohira, I., Kuga, S.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016A0104
Pages: 1-1
Related Report
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[Journal Article] Simultaneous sound velocity and density measurements of iron-silicon alloys under core conditions of Mercury and Mars2016
Author(s)
Sakamaki, T., Terasaki, H., Shibazaki, Y., Suzuki, A., Tobe, H., Higo, Y., Kurokawa, F., Maki, M., Shimoyama, Y., Saito, R.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016B1111
Pages: 1-1
Related Report
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[Journal Article] Simultaneous sound velocity and density measurements of iron-alloys for understanding the composition of Earth’s inner core2016
Author(s)
Sakamaki, T., Fukui, H., Tanaka, R., Kamada, S., Ikuta, D., Ohtani, E., Baron, A.Q.R.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016B1112
Pages: 1-1
Related Report
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[Journal Article] Sound velocity of iron-light element compounds at high pressure and temperature, and detection of the sound velocity anomalies near the transition boundary2016
Author(s)
Ohtani, E., Sakamaki, T.,, Fukui, H., Kamada, S., Tanaka, R., Terasaki, H., Baron, A.Q.R.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016B1419
Pages: 1-1
Related Report
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[Journal Article] Sound velocity and density measurements of liquid Fe-Ni-Si up to 15 GPa2016
Author(s)
Terasaki, H., Maki, M., Shimoyama, Y., Kurokawa, F., Saito, R., Sakamaki, T., Shibazaki, Y., Tobe, H., Higo, Y., Tange, Y.
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Journal Title
SPring-8 Experimental Summary Report
Volume: 2016B1518
Pages: 1-1
Related Report
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[Presentation] The sound velocity measurements of FeO at high pressure and temperature: Implications for the low velocity anomaly around the core-mantle boundary2017
Author(s)
Tanaka, R., Sakamaki, T., Fukui, H., Ohtani, E., Kamada, S., Sato, S., Tsutsui, S., Uchiyama, H., Baron, A.Q.R., Suzuki, A.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] Phase relations in the Fe-FeSi system at 10 GPa : Implications for Mercury’s core2017
Author(s)
Tobe, H., Shibazaki, Y., Sakamaki, T., Hiroi, Y., Abe, R., Suzuki, A.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] Composition of the core: Geochemical and mineral physics constraints2017
Author(s)
Ohtani, E., Sakairi, T., Sakamaki, T., Kamada, S., Tanaka, R., Fukui, H., Baron, A.Q.R.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] Phase relation in MgCO3-SiO2 system up to the lowermost mantle2017
Author(s)
Maeda, F., Ohtani, E., Kamada, S., Sakamaki, T., Hirao, N., Ohishi, Y.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] High-pressure phase transitions of MgCO3 under the lower mantle conditions2017
Author(s)
Maeda, F., Kamada, S., Sakamaki, T., Hirao, N., Ohishi, Y., Suzuki, A.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] Interior structure of Mars estimated from elastic properties of liquid Fe-Ni-S2017
Author(s)
Terasaki, H., Shimoyama, Y., Maki, M., Kurokawa, F., Urakawa, S., Nishida, K., Saito, R., Takubo, Y., Shibazaki, Y., Sakamaki, T., Machida, A., Higo, Y., Kondo, T.
Organizer
JpGU-AGU Joint Meeting 2017
Related Report
Int'l Joint Research
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[Presentation] Geochemical and mineral physics constraints on the composition of the inner core2017
Author(s)
Ohtani, E., Sakamaki, T., Sakairi, T., Tanaka, R., Kamada, S., Fukui, H., Barao, A.Q.R.
Organizer
Goldschmidt 2017
Related Report
Int'l Joint Research
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[Presentation] Phase relations of MgCO3 high-pressure carbonate under the lower mantle conditions2017
Author(s)
Maeda, F., Kamada, S., Sakamaki, T., Miyajima, N., Hirao, N., Ohishi, Y., Suzuki, A.
Organizer
55th EHPRG Meeting
Related Report
Int'l Joint Research
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[Presentation] Sound velocity of iron-light element compounds and composition of the inner core2017
Author(s)
Ohtani, E., Sakamaki, T., Kamada, S., Ikuta, D., Tanaka, R., Fukui, H., Baron, A.Q.R.
Organizer
High-Pressure Mineral Physics Seminar
Related Report
Int'l Joint Research
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[Presentation] Compressibility of MgCO3 phase II under the lowermost mantle conditions2017
Author(s)
Maeda, F., Kamada, S., Sakamaki, T., Hirao, N., Ohishi, Y., Suzuki, A.
Organizer
High-Pressure Mineral Physics Seminar
Related Report
Int'l Joint Research
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[Presentation] Sound velocity and elastic properties of liquid Fe-Ni-Si at high pressure2017
Author(s)
Terasaki, H., Maki, M., Shimoyama, Y., Nishida, K., Urakawa, S., Takubo, Y., Shibazaki, Y., Sakamaki, T., Higo, Y., Machida, A., Kondo, T.
Organizer
High-Pressure Mineral Physics Seminar
Related Report
Int'l Joint Research
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[Presentation] Structure measurements of basaltic glass at high pressure using X-ray and neutron diffraction techniques2017
Author(s)
Ohashi, T., Sakamaki, T., Hattori, T., Sano-Furukawa, A., Funakoshi, K., Suzuki, A.
Organizer
The 5th Workshop for Extreme Materials Science “Silicate Melt/Glass”
Related Report
Int'l Joint Research
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[Presentation] Structures of basaltic glass under high pressure by in-situ X-ray and neutron diffraction investigations2017
Author(s)
Ohashi, T., Sakamaki, T., Hattori, T., Sano-Furukawa, A., Funakoshi, K., Suzuki, A.
Organizer
Interaction and Coevolution of the Core and Mantle Toward Integrated Deep Earth Science Internarional Symposium Annual General Meeting
Related Report
Int'l Joint Research
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[Presentation] Sound velocity of iron-light element compounds and the chemical structure of the inner core2016
Author(s)
Ohtani, E., Sakamaki, T., Fukui, H., Tanaka, R., Shibazaki, Y., Kamada, S., Sakairi, T., Takahashi, S., Tsutsui, S., Baron, A.Q.R.
Organizer
AGU Fall Meeting 2016
Place of Presentation
San Francisco USA
Year and Date
2016-12-12
Related Report
Int'l Joint Research
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[Presentation] Sound velocity and density of FeO at high pressure and temperature2016
Author(s)
Tanaka, R., Sakamaki, T., Fukui, H., Ohtani, E., Kamada, S., Sato, S., Tsutsui, S., Uchiyama, H., Baron, A.Q.R., Suzuki, A.
Organizer
AGU Fall Meeting 2016
Place of Presentation
San Francisco USA
Year and Date
2016-12-12
Related Report
Int'l Joint Research
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[Presentation] Pressure-induced change of iron in complicated silicate glasses2016
Author(s)
Maeda, F., Kamada, S., Ohtani, E., Sakamaki, T., Hirao, N., Mitsui, T., Masuda, R., Nakano, S.
Organizer
The 54th European High Pressure Research Group (EHPRG) International Meeting on High Pressure Science and Technology
Place of Presentation
Bayreuth GERMANY
Year and Date
2016-09-04
Related Report
Int'l Joint Research
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[Presentation] Synchrotron 57Fe Mössbauer study of basaltic glass up to the lowermost mantle pressure2016
Author(s)
Maeda, F., Kamada, S., Ohtani, E., Sakamaki, T., Hirao, N., Mitsui, T., Masuda, R.
Organizer
Intenational Workshop: New Challenges in Volatile Cycling in the Deep Earth
Place of Presentation
Sendai JAPAN
Year and Date
2016-07-04
Related Report
Int'l Joint Research
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[Presentation] Sound velocity of Fe3C and carbon in the core2016
Author(s)
Takahashi, S., Ohtani, E., Sakamaki, T., Kamada, S., Fukui, H., Baron, A.Q.R.
Organizer
Goldshmidt2016
Place of Presentation
Yokohama JAPAN
Year and Date
2016-06-26
Related Report
Int'l Joint Research
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[Presentation] Sound velocity Fe3S at high pressure and high temperature based on inelastic X-ray scattering2016
Author(s)
Kamada, S., Sakairi, T., Sakamaki, T., Ohtani, E., Terasaki, H., Fukui, H., Baron, A.Q.R., Suzuki, A., Uchiyama, H., Tsutsui, S.
Organizer
Japan Geoscience Union Meeting 2016
Place of Presentation
Chiba JAPAN
Year and Date
2016-05-22
Related Report
Int'l Joint Research