We thank members of the ODP Leg 195 shipboard scientific party for numerous discussions and acknowledge the support and cooperation of the ODP personnel, Captain T. Hardy, and the crew of the JOIDES Resolution. We are grateful to Stefanie Brachfeld for her helpful and critical comments on the original manuscript. 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 gratefully acknowledge JOI for a JOI/USSAC (U.S. Science Advisory Committee) grant to C. Richter that provided funding for this work.