Breunnerite grain and magnesium isotope chemistry reveal cation partitioning during aqueous alteration of asteroid Ryugu

IR (HANDLE) Open Access
  • Yoshimura, Toshihiro
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Araoka, Daisuke
    Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST)
  • Naraoka, Hiroshi
    Department of Earth and Planetary Sciences, Kyushu University
  • Sakai, Saburo
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Ogawa, Nanako O.
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Yurimoto, Hisayoshi
    Creative Research Institution (CRIS), Hokkaido University
  • Morita, Mayu
    HORIBA Techno Service Co., Ltd.
  • Onose, Morihiko
    HORIBA Techno Service Co., Ltd.
  • Yokoyama, Tetsuya
    Department of Earth and Planetary Sciences, Tokyo Institute of Technology
  • Bizzarro, Martin
    Centre for Star and Planet Formation, Globe Institute, University of Copenhagen
  • Tanaka, Satoru
    HORIBA Techno Service Co., Ltd.
  • Ohkouchi, Naohiko
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Koga, Toshiki
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • Dworkin, Jason P.
    Solar System Exploration Division, NASA Goddard Space Flight Center
  • Nakamura, Tomoki
    Department of Earth Science, Tohoku University
  • Noguchi, Takaaki
    Department of Earth and Planetary Sciences, Kyoto University
  • Okazaki, Ryuji
    Department of Earth and Planetary Sciences, Kyushu University
  • Yabuta, Hikaru
    Earth and Planetary Systems Science Program, Hiroshima University
  • Sakamoto, Kanako
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Yada, Toru
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Nishimura, Masahiro
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Nakato, Aiko
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Miyazaki, Akiko
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Yogata, Kasumi
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Abe, Masanao
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Okada, Tatsuaki
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Usui, Tomohiro
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Yoshikawa, Makoto
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Saiki, Takanao
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Tanaka, Satoshi
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Terui, Fuyuto
    Kanagawa Institute of Technology
  • Nakazawa, Satoru
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Watanabe, Sei-ichiro
    Department of Earth and Planetary Sciences, Nagoya University
  • Tsuda, Yuichi
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA)
  • Tachibana, Shogo
    Institute of Space and Astro-nautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA); UTokyo Organization for Planetary and Space Science (UTOPS), University of Tokyo
  • Takano, Yoshinori
    Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

Description

Returned samples from the carbonaceous asteroid (162173) Ryugu provide pristine information on the original aqueous alteration history of the Solar System. Secondary precipitates, such as carbonates and phyllosilicates, reveal elemental partitioning of the major component ions linked to the primordial brine composition of the asteroid. Here, we report on the elemental partitioning and Mg isotopic composition (²⁵Mg/²⁴Mg) of breunnerite [(Mg, Fe, Mn)CO₃] from the Ryugu C0002 sample and the A0106 and C0107 aggregates by sequential leaching extraction of salts, exchangeable ions, carbonates, and silicates. Breunnerite was the sample most enriched in light Mg isotopes, and the ²⁵Mg/²⁴Mg value of the fluid had shifted lower by ~0.38‰ than the initial value (set to 0‰) before dolomite precipitation. As a simple model, the Mg²⁺ first precipitated in phyllosilicates, followed by dolomite precipitation, at which time ~76−87% of Mg²⁺ had been removed from the primordial brine. A minor amount of phyllosilicate precipitation continued after dolomite precipitation. The element composition profiles of the latest solution that interacted with the cation exchange pool of Ryugu were predominantly Na-rich. Na⁺ acts as a bulk electrolyte and contributes to the stabilization of the negative surface charge of phyllosilicates and organic matter on Ryugu.

Journal

Keywords

Details 詳細情報について

  • CRID
    1050302315064391808
  • ISSN
    20411723
  • HANDLE
    2433/290504
  • Text Lang
    en
  • Article Type
    journal article
  • Data Source
    • IRDB

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