Evaluation of mineral resource potential of rare-earth elements and yttrium-rich mud off the southeastern coast of Hawaiian Islands

• OHTA Junichiro

  Department of Environment Systems, Graduate School of Frontier Science, The University of Tokyo. 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba-ken 277-8561, Japan

• FUJINAGA Koichiro

  Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo. 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

• TAKAYA Yutaro

  Magma-Hydrothermal Deposits Research Group, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)

• KATO Yasuhiro

  Frontier Research Center for Energy and Resources, Graduate School of Engineering, The University of Tokyo. 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Bibliographic Information

Other Title

• ハワイ南東方沖におけるレアアース泥の資源ポテンシャル評価
• ハワイ ミナミトウホウオキ ニ オケル レアアース デイ ノ シゲン ポテンシャル ヒョウカ

Abstract

We report bulk-sediment compositions of rare-earth elements and yttrium (REY), major and trace elements for “REY-rich mud” from 6 drill cores obtained by Ocean Drilling Program (Site 1215A, 1216A, 1217A, 1218A, 1220A and 1222A) off the southeastern coast of Hawaiian Islands. The REY-rich mud in study area has high REY contents, 400-1,178 ppm total REY (ΣREY), which are comparable to those of ion-absorption-type REY deposits in southern China. The core profiles indicate that the REY-rich mud has accumulated to thicknesses of 25-70 m. Some portions of REY-rich mud are typically enriched in Fe₂O₃, and their post-Archean average Australian shale (PAAS)-normalized REE patterns show strikingly negative Ce anomalies with the same magnitude of seawater. These geochemical characteristics are similar to those of modern hydrothermal Fe-rich sediments near the East Pacific Rise. This indicates that one of the main hosts for REY in the mud is a Fe-oxyhydroxide precipitate from hydrothermal plumes that has taken up REY from ambient seawater. On the other hand, the correlation diagram between ΣREY and Fe₂O₃ shows another ΣREY enrichment trend characterized by relatively low Fe contents, which infers an existence of the second REY-rich component. As the REY-rich samples on this trend contain significant amounts of phillipsite, the second REY-rich component is considered to be phillipsite. Here we estimate that a volume of 1 km² × Maximum Cumulated Concentration Depth (MCCD; in metric unit), which represents an appropriate mining depth, at Site 1222A holds nearly 12,200 t (14,000 tREO), which could provide one-tenth of the current annual world consumption of REY. We conclude that deep-sea REY-rich mud off the southeastern coast of Hawaiian Islands has a potential as a new mineral resource for REY.

Journal

• Shigen-Chishitsu

  Shigen-Chishitsu 62 (3), 197-209, 2012

  The Society of Resource Geology

Keywords

• rare earth elements (REEs)
• REY-rich mud
• REY resource
• potential evaluation
• deep-sea mineral resource
• hydrothermal sediment

Details

• CRID: 1390282679446816768
• NII Article ID: 10031141221
• NII Book ID: AN10379890
• DOI: 10.11456/shigenchishitsu.62.197
• ISSN: 21854033
• ISSN: 09182454
• NDL BIB ID: 024128452
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I024128452
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
  • KAKEN
  • Crossref
• Abstract License Flag: Disallowed