*Yuji Kato¹, Akira Ijiri², Minoru Ikehara¹ (1.Marine Core Research Institute, Kochi University, 2.Graduate School of Maritime Sciences, Kobe University)

*Keiko Takehara¹, Yuji Kato², Yoshihiro Nakayama³, Takuya Itaki⁴, Xiangyu Zhao⁵, Yusuke Suganuma⁶, Vigan Mensah³, Osamu Seki³, Kay I. Ohshima³, Minoru Ikehara² (1.Kochi university Graduate School of Integrated Arts and Sciences, 2.Center for Advanced Marine Core Research, Kochi University, 3.Institute of Low Temperature Science, Hokkaido University, 4.Geological Survey of Japan, AIST, 5.Shanghai Jiao Tong University, 6.National Institute of Polar Research)