Composition of the earliest ocean inferred from experimental reactions between highly acidic subcritical fluid and crustal rocks

• Project/Area Number: 15K13583
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: SHIBUYA Takazo 国立研究開発法人海洋研究開発機構, 深海・地殻内生物圏研究分野, 研究員 (00512906)
• Co-Investigator(Renkei-kenkyūsha): SAITOH Masafumi 国立研究開発法人海洋研究開発機構, 次世代海洋資源調査技術研究開発プロジェクトチーム, 特任研究員 (80637588)
• Research Collaborator: UEDA Hisahiro
• Project Period (FY): 2015-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 地球史 / 冥王代 / 原始海洋 / 高温高圧実験

Outline of Final Research Achievements

To reproduce the formation process of the primitive ocean on Earth, a new gold-coated hydrothermal reactor and experimental techniques were developed. Using the new experimental methods, reactions between the subcritical atmosphere and the primitive crusts were simulated, which indicates that the composition of the primitive ocean in the early Earth was clearly different from the modern equivalent and that the primitive ocean was enriched in cations other than Na in contrast to the modern seawater. Furthermore, it was also revealed that the composition of the primitive ocean varies depending on the composition of the primitive crust (komatiite or basalt). In addition, it was previously suggested that the primitive ocean was inappropriate as an environment of the emergence of life because the primitive ocean was strongly acidic but our results implies that the pH value of the primitive ocean was near-neutral and appropriate for the emergence of life on Earth.

Research Products

• [Journal Article] Genome-enabled metabolic reconstruction of dominant chemosynthetic colonizers in deep-sea massive sulfide deposits (2018)
  • Author(s): Kato Shingo、Shibuya Takazo、Takaki Yoshihiro、Hirai Miho、Nunoura Takuro、Suzuki Katsuhiko
  • Journal Title: Environmental Microbiology Volume: 20 Issue: 2 Pages: 862-877
  • DOI: 10.1111/1462-2920.14032
  • Peer Reviewed
• [Journal Article] Deepest and hottest hydrothermal activity in the Okinawa Trough: the Yokosuka site at Yaeyama Knoll (2017)
  • Author(s): J. Miyazaki, S. Kawagucci, A. Makabe, A. Takahashi, K. Kitada, J. Torimoto, Y. Matsui, E. Tasumi, T. Shibuya, K. Nakamura, S. Horai, S. Sato, J. Ishibashi, H. Kanzaki, S. Nakagawa, M. Hirai, Y. Takaki, K. Okino, H. K. Watanabe, H. Kumagai, C. Chen
  • Journal Title: Royal Society Open Science Volume: 4 Issue: 12 Pages: 171570-171570
  • DOI: 10.1098/rsos.171570
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Removal of organic contaminants from iron sulfides as a pretreatment for mineral-mediated chemical synthesis under prebiotic hydrothermal conditions (2017)
  • Author(s): Nishizawa, M., Saitoh, M., Matsui, Y., Usui, Y. and Shibuya, T.
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 51 Issue: 6 Pages: 495-505
  • DOI: 10.2343/geochemj.2.0481
  • NAID: 130006243143
  • ISSN: 0016-7002, 1880-5973
  • Peer Reviewed
• [Journal Article] Weak hydrothermal carbonation of the Ongeluk volcanics: evidence for low CO2 concentrations in seawater and atmosphere during the Paleoproterozoic global glaciation (2017)
  • Author(s): Shibuya Takazo、Komiya Tsuyoshi、Takai Ken、Maruyama Shigenori、Russell Michael J.
  • Journal Title: Progress in Earth and Planetary Science Volume: 4 Issue: 1 Pages: 1-13
  • DOI: 10.1186/s40645-017-0145-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Reactions between komatiite and CO2-rich seawater at 250 °C and 350 °C, 500 bars: Implications for hydrogen generation in the Hadean seafloor hydrothermal system (2016)
  • Author(s): Ueda, H., Shibuya, T., Sawaki, Y., Saitoh, M., Takai, K., Maruyama, S.
  • Journal Title: Progress on Earth and Planetary Sciences Volume: 3(35) Issue: 1 Pages: 1-14
  • DOI: 10.1186/s40645-016-0111-8
  • Peer Reviewed / Open Access
• [Journal Article] Hydrogen-rich hydrothermal environments in the Hadean ocean inferred from serpentinization of komatiites at 300° C and 500 bar (2015)
  • Author(s): Shibuya, T., Yoshizaki, M., Sato, M., Shimizu, K., Nakamura, K., Omori, S., Suzuki, K., Takai, K., Tsunakawa, H., Maruyama, S.
  • Journal Title: Progress in Earth and Planetary Science Volume: 2 Issue: 1 Pages: 1-11
  • DOI: 10.1186/s40645-015-0076-z
  • Peer Reviewed / Open Access
• [Journal Article] High-temperature water-rock interactions and hydrothermal environments in the chondrite-like core of Enceladus (2015)
  • Author(s): Sekine, Y., Shibuya, T., Postberg, F., Hsu, H.-W., Suzuki, K., Masaki, Y., Kuwatani, T., Mori, M., Hong, P.K., Yoshizaki, M., Tachibana, S., Sirono, S.
  • Journal Title: Nature Communications Volume: 6 Issue: 1 Pages: 1-8
  • DOI: 10.1038/ncomms9604
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] 初期地球のコマチアイト熱水系における流体の化学的性質に関する実験的研究 (2017)
  • Author(s): 上田 修裕、渋谷 岳造、澤木 佑介、斎藤 誠史、高井 研、丸山 茂徳
  • Organizer: 日本地球惑星科学連合2017年大会
• [Presentation] 初期地球海底熱水系における液体・超臨界 CO2と化学進化 日本 (2017)
  • Author(s): 渋谷 岳造、高井 研
  • Organizer: 日本地球化学会第64回年会
• [Presentation] 初期地球コマチアイト熱水系における流体の化学的性質 (2017)
  • Author(s): 上田 修裕,渋谷 岳造,澤木 佑介,斎藤 誠史,高井 研,丸山 茂徳
  • Organizer: 日本地球化学会第64回年会
• [Presentation] Experimental study on H2 generation by reactions between komatiite and CO2-rich seawater (2016)
  • Author(s): Ueda, H., Shibuya, T., Sawaki, Y., Saitoh, M., Takai, K., Maruyama, S.
  • Organizer: Goldschmidt2016
  • Place of Presentation: パシフィコ横浜（神奈川県横浜市）
  • Year and Date: 2016-06-29
  • Int'l Joint Research
• [Presentation] Reactions between komatiite and CO2-rich seawater at 250 °C and 350 °C, 500 bars (2016)
  • Author(s): Ueda, H., Shibuya, T., Sawaki, Y., Saitoh, M., Takai, K., Maruyama, S.
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 幕張メッセ（千葉県千葉市）
  • Year and Date: 2016-05-25