*Jodi Fox^1,2、Kenichiro Tani¹、Osamu Ishizuka³、Asuka Yamaguchi ⁴、Minoru Ikehara⁵ (1.National Museum of Nature and Science, Tsukuba, Japan、2.Institute for Marine and Antarctic Studies, University of Tasmania, Australia、3.Geological Survey of Japan/AIST, Tsukuba, Japan、4.Atmosphere and Ocean Research Institute, University of Tokyo, Japan、5.Marine Core Research Institute, Kochi University, Kochi, Japan )