Characterization and genesis of mantle compositional hemispheres

• Project/Area Number: 26247091
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Iwamori Hikaru 国立研究開発法人海洋研究開発機構, 地球内部物質循環研究分野, 分野長 (80221795)
• Co-Investigator(Kenkyū-buntansha): 横山 哲也 東京工業大学, 理工学研究科, 准教授 (00467028) ; 中村 仁美 国立研究開発法人海洋研究開発機構, 地球内部物質循環研究分野, 研究員 (60572659) ; 石塚 治 国立研究開発法人産業技術総合研究所, 活断層・火山研究部門, 主任研究員 (90356444) ; 吉田 晶樹 国立研究開発法人海洋研究開発機構, 地球深部ダイナミクス研究分野, 主任研究員 (00371716)
• Co-Investigator(Renkei-kenkyūsha): Hanyu Takeshi 国立研究開発法人海洋研究開発機構, 地球内部物質循環研究分野, 主任研究員 (50359197)
• Research Collaborator: Tatiana Churikova ; Boris Gordeychik ; Asobo Asaah ; Festus T. Aka ; Shimizu Kenji ; Nishizawa Tatsuji ; Ozawa Takahiro
• Project Period (FY): 2014-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥42,510,000 (Direct Cost: ¥32,700,000、Indirect Cost: ¥9,810,000); Fiscal Year 2016: ¥8,710,000 (Direct Cost: ¥6,700,000、Indirect Cost: ¥2,010,000); Fiscal Year 2015: ¥8,580,000 (Direct Cost: ¥6,600,000、Indirect Cost: ¥1,980,000); Fiscal Year 2014: ¥25,220,000 (Direct Cost: ¥19,400,000、Indirect Cost: ¥5,820,000)
• Keywords: マントル / 組成 / 同位体 / 半球構造 / 統計解析 / 独立成分分析 / 水 / 物質循環 / 南太平洋 / カムチャッカ / 不均質構造 / 対流 / カメルーン

Outline of Final Research Achievements

Geochemical heterogeneity in the Earth’s mantle has been investigated based on the Quaternary basalts over the globe. With a special attention to recently proposed “east-west mantle geochemical hemispheres”, (1) detailed inspection along the hemisphere boundary, (2) Independent Component Analysis of global geochemical data, and (3) numerical simulation of water-bearing mantle convection have been performed. As a result, it has been revealed that (A) the eastern hemisphere is relatively enriched in hydrophile components, and (B) the hemispherical structure extends from the near-surface to the inner core via “top-down hemispherical dynamics” in which the supercontinent and focused subduction towards it could have created the global hemispherical structure.

Research Products

• [Int'l Joint Research] ロシア科学アカデミー(ロシア連邦)
• [Journal Article] Classification of geochemical data based on multivariate statistical analyses: Complementary roles of cluster, principal component, and independent component analyses (2017)
  • Author(s): Hikaru Iwamori, Kenta Yoshida, Hitomi Nakamura, Tatsu Kuwatani, Morihisa Hamada, Satoru Haraguchi, Kenta Ueki,
  • Journal Title: Geochem. Geophys. Geosyst. Volume: 18 Issue: 3 Pages: 994-1012
  • DOI: 10.1002/2016gc006663
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] A consistent model for fluid distribution, viscosity distribution, and flow-thermal structure in subduction zone (2016)
  • Author(s): Horiuchi, S., and Iwamori, H.
  • Journal Title: J. Geophys. Res. Volume: 121(5) Issue: 5 Pages: 3238-3260
  • DOI: 10.1002/2015jb012384
  • Peer Reviewed / Open Access
• [Journal Article] Effects of water transportation on subduction dynamics: Roles of viscosity and density reduction (2016)
  • Author(s): Nakao, A., Iwamori, H., and Nakakuki, T.
  • Journal Title: Earth Planet. Sci. Lett. Volume: 454 Pages: 178-191
  • DOI: 10.1016/j.epsl.2016.08.016
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Geochemistry of lavas from maar-bearing volcanoes in the Oku Volcanic Group of the Cameroon Volcanic Line (2015)
  • Author(s): A.N.E. Asaah, T. Yokoyama, F.T. Aka, T. Usui, T. Kuritani, M.J. Wirmvem, H. Iwamori, E.M. Fozing, J. Tamen, G.Z. Mofor, T. Ohba, G. Tanyileke, and J.V. Hell.
  • Journal Title: Chemical Geology Volume: 印刷中 Pages: 55-69
  • DOI: 10.1016/j.chemgeo.2015.03.030
  • Peer Reviewed
• [Journal Article] Water circulation and global mantle dynamics: Insight from numerical modeling (2015)
  • Author(s): T. Nakagawa, T. Nakakuki, H. Iwamori
  • Journal Title: Geochemistry, Geophysics, Geosystems Volume: 16 Issue: 5 Pages: 1449-1464
  • DOI: 10.1002/2014gc005701
  • Peer Reviewed
• [Journal Article] Isotopic heterogeneity of oceanic, arc and continental basalts and its implications for mantle dynamics (2014)
  • Author(s): Iwamori, H. and Nakamura, H
  • Journal Title: Gondwana Res Volume: 27 Issue: 3 Pages: 1131-1152
  • DOI: 10.1016/j.gr.2014.09.003
  • Peer Reviewed / Open Access
• [Journal Article] Numerical modeling of trace element transportation in subduction zones : implications for geofluid processes (2014)
  • Author(s): Ikemoto, A., H.Iwamori
  • Journal Title: Earth Planet and Space Volume: 66 Issue: 1 Pages: 26-26
  • DOI: 10.1186/1880-5981-66-26
  • Peer Reviewed / Open Access
• [Journal Article] Arima hot spring waters as a deep-seated brine from subducting slab (2014)
  • Author(s): Kusuda, C., Iwamori, H., Nakamura, H., Kazahaya, K. and Morikawa, N.
  • Journal Title: Earth, Planets and Space Volume: 66:119 Issue: 1 Pages: 119-119
  • DOI: 10.1186/1880-5981-66-119
  • Peer Reviewed / Open Access
• [Presentation] Role of Water in Subduction Zone Dynamics (2016)
  • Author(s): Iwamori, H., Horiuchi, S., Nakao, A., Nakakuki, T.
  • Organizer: Goldschmidt Conference
  • Place of Presentation: Pacifico Yokohama (神奈川県横浜市）
  • Year and Date: 2016-06-30
  • Int'l Joint Research / Invited
• [Presentation] Experimental Presentation of Plate Tectonics Using Paraffin Wax (2016)
  • Author(s): Vaglarov B.S., Ueki K., Sakuyama T., Hanyu T., Nichols A., Iwamori H.
  • Organizer: Goldschmidt Conference
  • Place of Presentation: Pacifico Yokohama (神奈川県横浜市）
  • Year and Date: 2016-06-30
  • Int'l Joint Research / Invited
• [Presentation] Subduction factory and its impact on global mantle heterogeneity (2016)
  • Author(s): Iwamori, H., Ikemoto, A., Nakamura, H., Yoshida, M., Yanagi, R.
  • Organizer: Goldschmidt Conference
  • Place of Presentation: Pacifico Yokohama (神奈川県横浜市）
  • Year and Date: 2016-06-29
  • Int'l Joint Research / Invited
• [Presentation] Areal Distribution, Chemical Feature and Flux of Slab-Derived Fluid Upwelling to the Surface in Japan: Geochemical Evidence from Groundwater Surveys (2016)
  • Author(s): Kazahaya K, Togo Y, Takahashi H, Takahashi M, Yasuhara M, Sato T, Morikawa N, Iwamori H., Tanaka H.
  • Organizer: Goldschmidt Conference
  • Place of Presentation: Pacifico Yokohama (神奈川県横浜市）
  • Year and Date: 2016-06-28
  • Int'l Joint Research / Invited
• [Presentation] East-west mantle geochemical hemispheres and its implications for a coupled supercontinent-mantle-core dynamics (2015)
  • Author(s): Iwamori, H., Nakamura, H., Yoshida, M.
  • Organizer: The 26th General Assembly of the International Union of Geodesy and Geophysics (IUGG)
  • Place of Presentation: Prague, Czech Republic
  • Year and Date: 2015-06-28
  • Int'l Joint Research / Invited
• [Presentation] 地球内部の東西半球構造とグローバルダイナミクス, (2015)
  • Author(s): 岩森光，中村仁美，吉田昌樹、田中聡、中川貴司、中久喜伴益
  • Organizer: 日本地球惑星科学連合大会2015年大会
  • Place of Presentation: 幕張メッセ（千葉県千葉市）
  • Year and Date: 2015-05-26
• [Presentation] Mantle geochemical hemispheres and their implications on mantle dynamics (2014)
  • Author(s): Hikaru Iwamori, Hitomi Nakamura
  • Organizer: China-Japan Joint Forum on Geochemistry and Cosmochemistry
  • Place of Presentation: Toyama University, 富山県富山市
  • Year and Date: 2014-09-16
  • Int'l Joint Research / Invited
• [Presentation] Subduction Processes and a New Hypothesis for ``Top-down Hemispherical Dynamics of the (2014)
  • Author(s): Hikaru Iwamori, Hitomi Nakamura, Takeshi hanyu, Junichi Kimura, Tomoeki Nakakuki, Takashi Nakagawa, Masaki Yoshida, Satoru Tanaka, Daisuke Suetsugu, Masayuki Obayashi
  • Organizer: 日本地球惑星科学連合2014年大会
  • Place of Presentation: Pacifico Yokohama, 神奈川県横浜市
  • Year and Date: 2014-04-28
  • Int'l Joint Research / Invited