1Department of Earth and Planetary Sciences, Faculty of Science, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan 2Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan 3Graduate School of Natural Science and Technology, Okayama University, Okayama, Okayama 700-8530, Japan 4Graduate School of Science, Hiroshima University, Higashihiroshima, Hiroshima 739-8526, Japan 5School of Science and Engineering, Kinki University, Higashiosaka, Osaka 577-8502, Japan 6Graduate School of Science and Engineering, Tokyo Institute for Technology, Meguro-ku, Tokyo 152-8551, Japan 7Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan 8Institute of Biogeosciences (Biogeos), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan 9Submarine Resources Research Project (SRRP), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan 10Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Nangoku, Kochi 783-8502, Japan