D. Murray, J. Sparks, D. Coleman, P. Meyers, D. Schrag, C. Richter, G. Wefer, and W. Berger provided helpful comments on the manuscript. We express our deep gratitude to the two outstanding chemistry laboratory technicians for Leg 175, Anne Pimmel and Tim Bronk, for their dedication and effort on this very demanding leg. Without their conscientious work, there simply would have been no chemistry program. We thank the other members of the ODP technical support staff for their work on the catwalk, the curators (Erinn McCarty and Steve Prinz) for dealing with our continually evolving sample requests, and the co-chiefs for their overall support of the chemical laboratory. A hearty cheer to all of these persons and to our other shipmates.