*Yuki Tomimatsu¹, Tatsuo Nozaki^2,3,4,5, Honami Sato⁵, Yutaro Takaya⁶, Jun-Ichi Kimura⁷, Chang Qing⁷, Hiroshi Naraoka⁸, Manuel Rigo⁹, Tetsuji Onoue⁸ (1.Graduate school of Science and Technology, Kumamoto University, 2.Submarine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology, 3.Frontier Research Center for Energy and Resources (FRC- ER), Graduate School of Engineering, Tokyo University, 4.Department of Planetology, Graduate School of Science, Kobe University, 5.Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, 6.Department of Resources and Environmental Engineering School of Creative Science and Enginerring, Waseda University, 7.Department of Solid Earth Geochemistry, Japan Agency for Marine-Earth Scienc and Technology, 8.Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, 9.Department of Geosciences, University of Padova)

*Tetsuji Onoue¹, Kanna Yamasaki², Yuki Tomimatsu^2,1, Yixing Du³, Daisuke Yamashita⁴, Katsuhito Soda², Manuel Rigo³ (1.Kyushu Univ., 2.Kumamoto Univ., 3.Univ. Padova, 4.Satsumasendai City Office)