This research used samples and/or data provided by the Ocean Drilling Program (ODP). ODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc. We thank the captain and crew of the JOIDES Resolution and the ODP technical staff for this successful cruise. We also express our thanks to D. Graham and B. Jones for their great assistance in the chemistry laboratory. We acknowledge helpful reviews by G. Dickens and R. Hesse. Funding for this research was provided in part by a grant-in-aid from the Japan Ministry of Education, Culture, Sports, Science and Technology and in part by a grant from the Japan Petroleum Exploration Company (JAPEX) to Ryo Matsumoto while the first author was at the University of Tokyo.