[S-CG61] Ocean Floor Geoscience

[SCG61-04] Geochemistry of REY-rich mud in the basins southeastern off Minamitorishima Island

*Koichiro Fujinaga^1,2, Kazutaka Yasukawa^3,1, Shiki Machida^1,2, Honami Sato¹, Ryo Shimomura³, Erika Tanaka³, Kazuhide Mimura³, Yoichi Usui⁴, Koichi Iijima⁴, Ayu Takahashi⁴, Hirofumi Yamamoto⁴, Katsuhiko Suzuki⁴, Kentaro Nakamura³, Yasuhiro Kato^2,3,1,4, MR16-07 cruise members (1.Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, 2.Frontier Research Center for Energy and Resources, School of Engineering, University of Tokyo, 3.Department of Systems Innovation, School of Engineering, the University of Tokyo, 4.Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology)

Keywords:rare earth elements, REY-rich mud, Minamitorishima Island, seafloor mineral resources, deep-sea sediment

Since the discovery of the new and high-grade resource for rare-earth elements and yttrium (REY), or “REY-rich mud” with 400 – 8000 ppm of total REY content, in the Japanese exclusive economic zone (EEZ) surrounding Minamitorishima Island (Iijima et al., 2016; Fujinaga et al., 2016), we conducted eight research cruises over five years. During the MR16-07 cruise by R/V MIRAI from November 1 to 25, 2016, we investigated the distribution of the REY-rich mud in several basins located southeastern off Minamitorishima Island, mainly the area outside the Minamitorishima EEZ. We collected 12 sediment cores by piston coring, and implemented bulk chemical analyses by using ICP-MS for trace and rare-earth elements, and XRF for major elements. In the presentation, we report the sedimentological and geochemical features of the deep-sea sediments, and the distribution of REY-rich mud in the southeastern basins nearby the Minamitorishima EEZ.