Elucidation of the genesis of extremely REY-rich mud based on independent component analysis

• Project/Area Number: 15H06144
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Earth system and resources engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Yasukawa Kazutaka 東京大学, 大学院工学系研究科(工学部), 助教 (00757742)
• Project Period (FY): 2015-08-28 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 海洋資源 / 地球化学 / 多変量解析 / 独立成分分析 / 岩石・鉱物・鉱床学

Outline of Final Research Achievements

This study aims to elucidate the genesis of "extremely REY-rich mud" that is recently discovered within the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island. In this study, I constructed a huge geochemical data set composed of major- and trace-element contents in bulk sediments collected from the Minamitorishima EEZ. The data set contains 1192 sediment samples, and 625 samples of them were newly analyzed by this study. Subsequently, I statistically analyzed the data matrix by using independent component analysis. As a result, I found that the multi-elemental data structure of the sediments in the Minamitorishima EEZ can be explained by five geochemical independent components. On the basis of the features of their downhole variations, it is implied that the extremely REY-rich mud is closely associated with an enhancement of a bottom water current.

Research Products

• [Journal Article] Geochemistry of REY-rich mud in the Japanese Exclusive Economic Zone around Minamitorishima Island (2016)
  • Author(s): Fujinaga, K., Yasukawa, K., Nakamura, K., Machida, S., Takaya, Y., Ohta, J., Araki, S., Liu, H., Usami, R., Maki, R., Haraguchi, S., Nishio, Y., Usui, Y., Nozaki, T., Yamazaki, T., Ichiyama, Y., Ijiri, A., Inagaki, F., Machiyama, H., Iijima, K., Suzuki, K., Kato, Y., KR13-02, MR13-E02 Leg 2, KR14-02 Cruise Members
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 50 Issue: 6 Pages: 575-590
  • DOI: 10.2343/geochemj.2.0432
  • NAID: 130005435148
  • ISSN: 0016-7002, 1880-5973
  • Year and Date: 2016-11-30
  • Peer Reviewed / Open Access
• [Journal Article] Discovery of extremely REY-rich mud in the western North Pacific Ocean (2016)
  • Author(s): Iijima, K., Yasukawa, K., Fujinaga, K., Nakamura, K., Machida, S., Takaya, Y., Ohta, J., Haraguchi, S., Nishio, Y., Usui, Y., Nozaki, T., Yamazaki, T., Ichiyama, Y., Ijiri, A., Inagaki, F., Machiyama, H., Suzuki, K., Kato, Y., KR13-02 Cruise members
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 50 Issue: 6 Pages: 557-573
  • DOI: 10.2343/geochemj.2.0431
  • NAID: 130005435147
  • ISSN: 0016-7002, 1880-5973
  • Year and Date: 2016-11-30
  • Peer Reviewed / Open Access
• [Journal Article] Tracking the spatiotemporal variations of statistically independent components involving enrichment of rare-earth elements in deep-sea sediments (2016)
  • Author(s): Yasukawa, K., Nakamura, K., Fujinaga, K., Iwamori, H., and Kato, Y.
  • Journal Title: Sci. Rep. Volume: 6 Issue: 1 Pages: 29603-29603
  • DOI: 10.1038/srep29603
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Geological factors responsible for REY-rich mud in the western North Pacific Ocean: Implications from mineralogy and grain size distributions (2016)
  • Author(s): J. Ohta, K. Yasukawa, S. Machida, K. Fujikawa, K. Nakamura, Y. Takaya, K. Iijima, K. Suzuki, and Y. Kato
  • Journal Title: GEOCHEMICAL JOURNAL Volume: 50 Issue: 6 Pages: 591-603
  • DOI: 10.2343/geochemj.2.0435
  • NAID: 130005435146
  • ISSN: 0016-7002, 1880-5973
  • Peer Reviewed / Open Access
• [Journal Article] 第4の海底鉱物資源『レアアース泥』 (2016)
  • Author(s): 野崎達生・飯島耕一・藤永公一郎・中村謙太郎・高谷雄太郎・安川和孝・大田隼一郎・加藤 泰浩
  • Journal Title: 日本海水学会誌 Volume: 70 Pages: 90-96
  • NAID: 130006101492
• [Presentation] レアアース泥の起源と地球システムのダイナミクス：独立成分分析による数理統計的アプローチの成果 (2016)
  • Author(s): 安川和孝・中村謙太郎・藤永公一郎・岩森光・加藤泰浩
  • Organizer: 日本地質学会第123年学術大会
  • Place of Presentation: 東京・日本大学 (桜上水)
  • Year and Date: 2016-09-11
  • Invited
• [Presentation] Spatiotemporal distribution of independent components constituting deep-sea sediments (2016)
  • Author(s): Yasukawa, K., Nakamura, K., Fujinaga, K., Iwamori, H., Kato, Y.
  • Organizer: Goldschmidt 2016
  • Place of Presentation: 横浜・パシフィコ横浜
  • Year and Date: 2016-06-29
  • Int'l Joint Research
• [Presentation] 南鳥島EEZ内の深海堆積物を構成する地球化学的独立成分 (2016)
  • Author(s): 安川和孝・中村謙太郎・藤永公一郎・大田隼一郎・岩森光・加藤泰浩
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 千葉・幕張メッセ
  • Year and Date: 2016-05-25
• [Presentation] 南鳥島EEZ内の深海堆積物を構成する地球化学的独立成分 (2016)
  • Author(s): 安川和孝・中村謙太郎・藤永公一郎・大田隼一郎・岩森光・加藤泰浩
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 幕張メッセ国際会議場 (千葉県千葉市)
  • Year and Date: 2016-05-25
• [Presentation] 前期始新世「超温暖期」を記録するインド洋深海堆積物の多元素組成データ構造 (2016)
  • Author(s): 安川和孝・中村謙太郎・加藤泰浩・池原実
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 千葉・幕張メッセ
  • Year and Date: 2016-05-23
  • Invited
• [Presentation] 深海堆積物へのレアアース濃集を支配する地球化学的独立成分 (2016)
  • Author(s): 安川和孝・中村謙太郎・藤永公一郎・岩森光・加藤泰浩
  • Organizer: 日本地球惑星科学連合2016年大会
  • Place of Presentation: 千葉・幕張メッセ
  • Year and Date: 2016-05-22