This research used samples and 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. Funding for this research was provided by ODP France and by the French Institut National des Sciences de l'Univers–Centre National de la Recherche Scientifique (INSU-CNRS) "ad hoc OCEANS" Program 2001–2003. We are grateful to C. Papy and L. Marié for thin section preparation. We are grateful to F. Samrad for critically reading the manuscript. We thank J.P. André, G. Cabioch, C. Betzler, and J. Reijmer for their helpful reviews of the manuscript.