The first author wishes to thank Drs. S.W. Wise and T.R. Janecek for helpful comments and reviews on early drafts of this paper, which was submitted in partial fulfillment of requirements for a master's degree in geology at Florida State University. We also thank Drs. Richard W. Howe and Alyssa Peleo-Alampay for external review of the final draft. Samples were provided by NSF through ODP. This study was supported by USSAC funds to S.W. Wise. Laboratory facilities were provided by NSF grant no. DPP 94-22893.