1. Department of Chemistry, Faculty of Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
2. Marine Works Japan, 3-54-1 Oppamahigashi, Yokosuka, Kanagawa 237-0063, Japan
3. Institut de Recherche XLIM, UMR CNRS No. 7252, 123 Avenue Albert Thomas, 87060 Limoges CEDEX, France
4. Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 200 Monobe Otsu, Nankoku City, Kochi 783-8502, Japan