1. Department of Geology; Chungnam National University; Daejeon; 305-764; South Korea
2. National Oceanography Centre, Southampton; University of Southampton; Southampton; SO14 3ZH; UK
3. Earth and Planetary Sciences Department; University of California; Santa Cruz; California; 95064; USA
4. Kochi Institute for Core Sample Research; JAMSTEC; Kochi; 783-8502; Japan
5. CEREGE; Université Aix Marseille III; F-13545; Aix-en-Provence; France
6. Civil and Earth Resources Engineering Department; Kyoto University; Kyoto; 615-8540; Japan