Wataru Tanikawa¹, Goichiro Uramoto², Yohei Hamada³, Masafumi Murayama⁴, Yuhji Yamamoto⁵, Takehiro Hirose³, Osamu Tadai⁶, Kouki Tanaka⁷, Hiromasa Ozaki⁸, Minoru Yoneda⁹ and Hidekazu Tokuyama², (1)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan, (2)Center for Advanced Marine Core Research, Kochi University, Nankoku, Japan, (3)JAMSTEC, Kochi Institute for Core Sample Research, Nankoku, Japan, (4)Kochi University, Faculty of Agriculture and Marine Science, Nankoku, Japan, (5)Kochi University, Center for Advanced Marine Core Research, Kochi, Japan, (6)Marine Works Japan Ltd., Nankoku, Japan, (7)Usa Marine Biological Institute, Kochi University, Tosa, Japan, (8)The University of Tokyo, Tokyo, Japan, (9)University of Tokyo, Bunkyo-ku, Japan