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Determination of hydrogen partitioning between metal and silicate by in situ synchrotron X-ray observation under high pressure and micro-area analysis

Research Project

Project/Area Number 18K13635
Research Category

Grant-in-Aid for Early-Career Scientists

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

Principal Investigator

Kuwahara Hideharu  愛媛大学, 地球深部ダイナミクス研究センター, 助教 (50505394)

Project Period (FY) 2018-04-01 – 2021-03-31
Project Status Discontinued (Fiscal Year 2020)
Budget Amount *help
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2020: ¥130,000 (Direct Cost: ¥100,000、Indirect Cost: ¥30,000)
Fiscal Year 2019: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Fiscal Year 2018: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Keywords核 / マントル / 水素 / 分配 / 元素分配 / マグマオーシャン / 高圧実験 / 地球型惑星
Outline of Final Research Achievements

The purpose of this study is to constrain the distribution of hydrogen between the core and mantle during planetary differentiation. Since in-situ observation experiments using synchrotron radiation, which were originally planned, were not successful, we decided to analyze quenched experimental samples.
The high-pressure experiments were carried out at 2 GPa and 1923 K. The samples were encapsulated in boron nitride or SiO2 capsules. The starting sample consisted of a mixture of iron and oxide powders with Mg(OH)2 as a hydrogen source. The capsule was sealed in a platinum tube to prevent water loss from the capsule during the experiment.
The amount of water in the quenched silicate glass of the recovered sample was 0.13~0.24 mass% for the starting sample containing 0.25 mass% water and 0.53 mass% for the starting sample containing 0.5 mass% water, suggesting that most of the hydrogen was partitioned to the silicate under the experimental conditions.

Academic Significance and Societal Importance of the Research Achievements

地球の海は地球質量の0.023%しかなく、これに対して惑星材料物質と考えられている始原天体は数質量%の水を含んでいると推定されている。地球の海と始原天体における水量の不一致の解決策として水素に富む金属核の存在が指摘されてきたが、この仮説を検証するためには惑星形成過程において水素が核に取り込まれた可能性について明らかにしなければいけなかった。
本研究課題で得られた成果は惑星がまだ小さかった場合の核形成過程において、圧力や温度の低い初期段階では水素は核ではなく、マントルに分配されることを示唆するものである。今後より、高温高圧下での実験により地球核が水素の貯蔵層となりうるのか検証することが望まれる。

Report

(3 results)
  • 2020 Final Research Report ( PDF )
  • 2019 Annual Research Report
  • 2018 Research-status Report
  • Research Products

    (8 results)

All 2019 2018 Other

All Journal Article (3 results) (of which Int'l Joint Research: 2 results,  Peer Reviewed: 3 results,  Open Access: 2 results) Presentation (2 results) (of which Int'l Joint Research: 1 results) Remarks (3 results)

  • [Journal Article] The Effects of Carbon Concentration and Silicate Composition on the Metal‐Silicate Partitioning of Carbon in a Shallow Magma Ocean2019

    • Author(s)
      Kuwahara H.、Itoh S.、Nakada R.、Irifune T.
    • Journal Title

      Geophysical Research Letters

      Volume: 46 Issue: 16 Pages: 9422-9429

    • DOI

      10.1029/2019gl084254

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Fluorine and chlorine fractionation during magma ocean crystallization: Constraints on the origin of the non-chondritic F/Cl ratio of the Earth2019

    • Author(s)
      Kuwahara Hideharu、Kagoshima Takanori、Nakada Ryoichi、Ogawa Nobuhiro、Yamaguchi Asuka、Sano Yuji、Irifune Tetsuo
    • Journal Title

      Earth and Planetary Science Letters

      Volume: 520 Pages: 241-249

    • DOI

      10.1016/j.epsl.2019.05.041

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Simultaneous determination of melting phase relations of mantle peridotite and mid-ocean ridge basalt at the uppermost lower mantle conditions2018

    • Author(s)
      Kuwahara Hideharu、Nomura Ryuichi、Nakada Ryoichi、Irifune Tetsuo
    • Journal Title

      Physics of the Earth and Planetary Interiors

      Volume: 284 Pages: 36-50

    • DOI

      10.1016/j.pepi.2018.08.012

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] 高圧下における鉄-ケイ酸塩液相間の炭素分配係数の再評価と地球内部の炭素分布への制約2019

    • Author(s)
      桑原秀治、伊藤正一、中田亮一、入舩徹男
    • Organizer
      2019年度日本地球化学会年会
    • Related Report
      2019 Annual Research Report
  • [Presentation] Metal-silicate partitioning of carbon in a shallow magma ocean: Implications for the distribution of carbon in the Earth during the core formation2018

    • Author(s)
      Hideharu Kuwahara, Shoichi Itoh, Ryoichi Nakada, Tetsuo Irifune
    • Organizer
      Japan Geoscience Union Meeting 2018
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Remarks] 地球のフッ素、塩素の量はどのように決まったのか?

    • URL

      https://research.ehime-u.ac.jp/ja/environment_geoscience/20200218-01.html

    • Related Report
      2019 Annual Research Report
  • [Remarks] 惑星形成期における核-マントル間の炭素分配

    • URL

      https://research.ehime-u.ac.jp/ja/environment_geoscience/20200218-02.html

    • Related Report
      2019 Annual Research Report
  • [Remarks]

    • URL

      https://sites.google.com/view/hideharukuwahara/home/publications

    • Related Report
      2018 Research-status Report

URL: 

Published: 2018-04-23   Modified: 2022-01-27  

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