Rare-earth, major, and trace element geochemistry of deep-sea sediments in the Indian Ocean: Implications for the potential distribution of REY-rich mud in the Indian Ocean

• Yasukawa Kazutaka

  Department of Systems Innovation, School of Engineering, The University of Tokyo

• Nakamura Kentaro

  Department of Systems Innovation, School of Engineering, The University of Tokyo Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

• Fujinaga Koichiro

  Frontier Research Center for Energy and Resources, School of Engineering, The University of Tokyo

• Machida Shiki

  Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

• Ohta Junichiro

  Department of Systems Innovation, School of Engineering, The University of Tokyo

• Takaya Yutaro

  Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Waseda University

• Kato Yasuhiro

  Department of Systems Innovation, School of Engineering, The University of Tokyo Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Frontier Research Center for Energy and Resources, School of Engineering, The University of Tokyo

Bibliographic Information

Other Title

• The chemical composition of subducting sediment and its consequences for the crust and mantle

Abstract

We analyzed 1338 deep-sea sediment samples from 19 Deep Sea Drilling Project/Ocean Drilling Program sites covering a large portion of the Indian Ocean, and constructed a new and comprehensive data set of their bulk chemical compositions, including rare-earth, major, and trace elements. The bulk-sediment rare-earth and yttrium (REY) composition of the REY-enriched samples, characterized by relatively small negative Ce anomalies, almost no Y anomalies, and enrichment in heavy rare-earth elements, can be interpreted as the superposition of the REY compositions of apatite and hydrogenous Fe-Mn oxides. Although the hydrothermal component is a key factor in the formation of REY-rich mud in the Pacific Ocean, it is less important in the Indian Ocean, probably because there is less hydrothermal input of Fe-oxyhydroxides from seafloor hydrothermal vents there. The relationships among Fe₂O₃, MnO, P₂O₅, Co, and total REY contents suggest that a primary factor controlling REY enrichment in deep-sea sediments is the sedimentation rate. A low sedimentation rate allows both fish debris apatite and hydrogenous Fe-Mn (oxyhydr)oxides to accumulate in the surface sediments. On the basis of these results, we identified two potential areas in the Indian Ocean where REY-rich mud may be present in surface sediments: the south-southeastern Wharton Basin and the southern Central Indian Ocean Basin. The resource potential of the latter area might be particularly high if the distributions of REY-rich mud and Fe-Mn nodule fields broadly overlap.

Journal

• GEOCHEMICAL JOURNAL

  GEOCHEMICAL JOURNAL 49 (6), 621-635, 2015-11-26

  GEOCHEMICAL SOCIETY OF JAPAN

Keywords

• deep-sea sediments
• Indian Ocean
• rare-earth elements
• REY-rich mud
• deep-sea mineral resource

Details

• CRID: 1390001204554245376
• NII Article ID: 130005112464
• NII Book ID: AA00654975
• DOI: 10.2343/geochemj.2.0361
• ISSN: 18805973
• ISSN: 00167002
• NDL BIB ID: 026964784
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I026964784
• Web Site: https://www.jstage.jst.go.jp/article/geochemj/49/6/49_2.0361/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed