This research used samples and/or data provided by the Ocean Drilling Program (ODP). ODP is sponsored by U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc. This study was supported by NSF grant OCE-0136500 to D.H. and an ODP Schlanger fellowship to M.G.P. The authors gratefully acknowledge members of the Scientific Party of Leg 201, who collected samples for us. We also extend our gratitude to the Co-Chief Scientists of Leg 201, Drs. S. D'Hondt and B.B. Jørgensen for being very helpful in obtaining the samples, and thus making this study possible. The technical assistance of M. Rincon and T. Gunderson at USC is greatly appreciated. The thoughtful reviews of three anonymous reviewers and S. D'Hondt improved this manuscript significantly.