*Katsuhiko Suzuki^1,2, Yoshihiro Furukawa², Yoshio Takahashi³, Atsuyuki Ohta⁴, Teruyuki Maruoka⁵, Timothy J Fagan⁶, Qiang Wang⁷, Riko Iizuka-Oku⁸ (1.Submarine Resources Research Center, Japan Agency for Marine-Earth Science and Technology, 2.Graduate Schoool of Science, Tohoku University, 3.Department of Earth and Planetary Sciences, Graduate Schoool of Science, The University of Tokyo, 4.Geological Survey of Japan, National Institute of Advanced Industrial Science, 5.Faculty of Life and Environmental Sciences, University of Tsukuba, 6.School of Education, Waseda University, 7.Guangzhou Insititute of Geochemistry, Chinese Academy of Science, 8.Geochemical Research Center, Graduate Schoool of Science, The University of Tokyo)

*Teruyuki Maruoka¹, Yoshiro Nishio² (1.Faculty of Life and Environmental Sciences, University of Tsukuba, 2.Kochi University)

*Yuichi Onda¹, Taichi Kawano¹, Keisuke Taniguchi², Junko Takahashi¹, Teruyuki Maruoka¹ (1.Center for Research on Isotopes and Environmental Dynamics, University of Tsukuba, 2.National Institute of Technology, Tsuyama College)