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Investigation of the core light element based on high-pressure sound velocity measurements of liquid Fe alloys

Research Project

Project/Area Number 19K04040
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 17040:Solid earth sciences-related
Research InstitutionKumamoto University

Principal Investigator

Nakajima Yoichi  熊本大学, 大学院先端科学研究部(理), 准教授 (50700209)

Project Period (FY) 2019-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2021: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2020: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywords地球コア / コア軽元素 / 液体鉄合金 / 高圧高温実験 / 非弾性X線散乱 / X線回折 / 液体鉄軽元素合金 / 音速 / 高圧高温 / 高圧下音速測定 / 地球中心コア / 弾性波速度
Outline of Research at the Start

地球の中心には半径3,500kmの金属コアがあり、その大部分は融解状態である。地球金属コアの化学組成は地球形成過程過程、その後の地球内部の化学的・熱的進化、地球磁場形成といった問題を解決するために不可欠である。本研究では、コアの主成分である鉄と、合計で10%程度ほど溶け込んでいると考えられている水素や炭素、酸素、ケイ素、リン、硫黄といった軽い元素との液体合金の音速を実際のコアの圧力温度条件である135万気圧以上、4000ケルビン以上で測定する。測定された音速と地震波観測で得られる実際のコアの音速を直接比較することでその化学組成を決定する。

Outline of Final Research Achievements

The sound velocity of liquid Fe alloys at high pressure is essential to understanding the light elements in the Earth’s liquid core. We measured the sound velocity of liquid Fe alloys with P or Si under high-pressure conditions to determine the compositional effect of each alloying element on the velocity and density of liquid Fe. We constrained the concentrations of P and Si in the liquid core by comparing the present results with seismological observations. Considering geochemical observations, we found that the impact of P on the seismological observables of the core can be pretty little. We also investigated that Si significantly increases the sound velocity of liquid Fe. Therefore, the Si contents expected from the recent core formation models can be too much to explain the sound velocity of the present-day liquid core, indicating that the preset-day core will be depleted in Si relative to the ancient core just after the core formation process.

Academic Significance and Societal Importance of the Research Achievements

従来の研究では、隕石や岩石の化学組成や、地球形成時の元素分配に基づきコア組成が議論されてきた。本研究課題では、高圧下でコア組成の候補となる液体鉄合金の音速を実際に測定し、現在のコアの音速と密度を比較するで、コア化学組成に制約を与えた。本研究成果により、従来の間接的手法によるコア組成モデルを実際のコアの観測情報と比較できるようになったことは、大きな学術的意義をもつ。
地球コアの化学組成は、地球形成過程やその後の熱的・化学進化を解き明かす上で不可欠な情報である。我々地球の成り立ちから現在に至る歴史を紐解くことは、人類の共通のテーマの一つであり、本研究成果は社会的意義も大きいと期待している。

Report

(4 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • 2019 Research-status Report
  • Research Products

    (24 results)

All 2021 2020 2019 Other

All Int'l Joint Research (4 results) Journal Article (4 results) (of which Int'l Joint Research: 3 results,  Peer Reviewed: 4 results,  Open Access: 1 results) Presentation (16 results) (of which Int'l Joint Research: 10 results,  Invited: 3 results)

  • [Int'l Joint Research] グルノーブル・アルプ大学(フランス)

    • Related Report
      2021 Annual Research Report
  • [Int'l Joint Research] グルノーブル・アルプ大学(フランス)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Sorbonne University/Grenoble Alpes University(フランス)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] University of Bayreuth(ドイツ)

    • Related Report
      2019 Research-status Report
  • [Journal Article] New pressure-induced phase transition to Co2Si-type Fe2P2020

    • Author(s)
      Nakajima Yoichi、Araki Shunya、Kinoshita Daisuke、Hirose Kei、Tateno Shigehiko、Kawaguchi Saori I.、Hirao Naohisa
    • Journal Title

      American Mineralogist

      Volume: 105 Issue: 11 Pages: 1752-1755

    • DOI

      10.2138/am-2020-7574

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Sound Velocity of Liquid Fe?P at High Pressure2020

    • Author(s)
      Kinoshita Daisuke、Nakajima Yoichi、Kuwayama Yasuhiro、Hirose Kei、Iwamoto Asaki、Ishikawa Daisuke、Baron Alfred Q. R.
    • Journal Title

      physica status solidi (b)

      Volume: 257 Issue: 11 Pages: 2000171-2000171

    • DOI

      10.1002/pssb.202000171

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Equation of state of liquid iron under extreme conditions2020

    • Author(s)
      Y. Kuwayama, G. Morard, Y. Nakajima, K. Hirose, A.Q.R. Baron, S.I., Kawaguchi, T. Tsuchiya, D. Ishikawa, N. Hirano, Y. Ohishi
    • Journal Title

      Physcal Review Letters

      Volume: 124 Issue: 16 Pages: 165701-165701

    • DOI

      10.1103/physrevlett.124.165701

    • Related Report
      2020 Research-status Report 2019 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Melting in Fe-FeO to 204 GPa: Implications for oxygen in Earth’s core2019

    • Author(s)
      K. Oka, K. Hirose, S. Tagawa, Y. Kidokoro, Y. Nakajima, G. Morard, N. Coudurier, G. Fiquet
    • Journal Title

      American Mineralogist

      Volume: 104 Issue: 11 Pages: 1603-1607

    • DOI

      10.2138/am-2019-7081

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Co2Pの圧力誘起相転移2021

    • Author(s)
      見﨑湧哉, 中島陽一, 上野雄生, 岩本朝希, 河口沙織, 平尾直久
    • Organizer
      第62回高圧討論会
    • Related Report
      2021 Annual Research Report
  • [Presentation] 高圧下における液体Fe-S合金の非弾性X線散乱測定2021

    • Author(s)
      中島陽一, 岩本朝希, 上野雄生, 桑山靖弘, 廣瀬敬, MORARD Guillaume, 石川大介, BARON Alfred Q.R
    • Organizer
      第62回高圧討論会
    • Related Report
      2021 Annual Research Report
  • [Presentation] Density and Sound Velocity of Liquid Fe and FeO at High Pressure2021

    • Author(s)
      桑山 靖弘, 廣瀬 敬, 中島 陽一, 安達 由紀, Baron Alfred, Morard Guillaume, 河口 沙織, 石川 大介, 平尾 直久, 大石 泰生
    • Organizer
      日本地球惑星科学連合2021年大会
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Sound velocity measurements of liquid Fe-N up to 100 GPa2021

    • Author(s)
      岩本 朝希, 中島 陽一, 木下 大輔, 桑山 靖弘, 廣瀬 敬, 石川 大介, Baron Alfred
    • Organizer
      日本地球惑星科学連合2021年大会
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Fe2Pの高圧相転移と弾性特性2020

    • Author(s)
      中島 陽一, 荒木 駿也, 木下 大輔, 廣瀬 敬, 舘野 繁彦, 河口 沙織, 平尾 直久
    • Organizer
      第61回高圧討論会
    • Related Report
      2020 Research-status Report
  • [Presentation] Nitrogen in the core based on sound velocity measurements of liquid Fe-N at high pressure2020

    • Author(s)
      A. Iwamoto, Y. Nakajima, D. Kinoshita, Y. Kuwayama, K. Hirose, D. Ishikawa, A.Q.R. Baron
    • Organizer
      JpGU-AGU Joint Meeting 2020
    • Related Report
      2020 Research-status Report
    • Int'l Joint Research
  • [Presentation] Sound wave velocity of liquid Fe-P at high pressure2020

    • Author(s)
      Y. Nakajima, D. Kinoshita, Y. Kuwayama, K. Hirose, A. Iwamoto, D. Ishikawa, A.Q.R. Baron
    • Organizer
      JpGU-AGU Joint Meeting 2020
    • Related Report
      2020 Research-status Report
    • Int'l Joint Research
  • [Presentation] Equation of state for liquid iron under extreme conditions2020

    • Author(s)
      Y. Kuwayama, G. Morard, Y. Nakajima, K. Hirose, A.Q.R. Baron, S.I. Kawaguchi, T. Tsuchiya, D. Ishikawa, N. Hirao, Y. Ohishi
    • Organizer
      JpGU-AGU Joint Meeting 2020
    • Related Report
      2020 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Inelastic X-ray scattering measurements of liquid Fe alloys under high pressures2019

    • Author(s)
      Nakajima Y., Kuwayama Y., Hirose K., Ishikawa D., Baron A.Q.R.
    • Organizer
      Opto-X-NANO 2019 conference
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Inelastic X-ray scattering measurements on liquid Fe-S Inelastic X-ray scattering measurements on liquid Fe-S alloys under high pressures2019

    • Author(s)
      Nakajima Y.
    • Organizer
      Pan Pacific International Symposium on Chalcogenide Functional Materials
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Inelastic X-ray scattering measurements of liquid Fe-P alloys under high pressures2019

    • Author(s)
      Nakajima Y., Kinoshita D., Kuwayama Y., Hirose K., Iwamoto A., Ishikawa D., Baron A.Q.R.
    • Organizer
      14th International Conference on the Structure of Non-Crystalline Materials
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Inelastic X-ray measurements of liquid Fe-N alloy under high pressure2019

    • Author(s)
      Iwamoto A., Nakajima Y., Kinoshita D., Kuwayama Y., Hirose K., Ishikawa D., Baron A.Q.R.
    • Organizer
      14th International Conference on the Structure of Non-Crystalline Materials
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Metal-silicate partitioning of Mo and W in Earth’s mantle during core formation2019

    • Author(s)
      Jennings E., Rubie D.C., Jacobson S.A., Morbidelli A., Nakajima Y., Vogel A.K., Rose-Weston L.A., Frost D.J.
    • Organizer
      EPSC-DPS Joint Meeting 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] 高圧下における液体Fe-Pの弾性特性2019

    • Author(s)
      中島陽一,木下大輔, 桑山靖弘, 廣瀬敬, 岩本朝希, 石川大介, Alfred Q.R. BARON
    • Organizer
      第60回高圧討論会
    • Related Report
      2019 Research-status Report
  • [Presentation] 高圧下における液体Fe-N合金のX線非弾性散乱測定2019

    • Author(s)
      岩本朝希, 中島陽一,木下大輔, 桑山靖弘, 廣瀬敬, 石川大介, Alfred Q.R. BARON
    • Organizer
      第60回高圧討論会
    • Related Report
      2019 Research-status Report
  • [Presentation] 第一原理計算に基づく高圧下における液体Fe-O合金の構造と電子状態II2019

    • Author(s)
      田中昇兵, 中口慎也, 高良明英, 中島陽一, 下條冬樹
    • Organizer
      日本物理学会2019年秋季大会
    • Related Report
      2019 Research-status Report

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Published: 2019-04-18   Modified: 2023-01-30  

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