We are grateful to the staff of the ODP East and Gulf Coast Repositories for their support in collection of these samples and to the Leg 38 and 152 Scientific Parties for their useful descriptions of the cored basalt. S. Bernstein and P. Thy gave thorough and highly useful reviews, which improved the manuscript, and P. Garman did an excellent job of providing editorial suggestions. We thank USSSP for support for expenses associated with the research. Most of all, the first author is grateful for the support and friendship of his Leg 163 shipboard colleagues, many of whom put their lives at risk ensuring that Leg 163 would not end in a catastrophic loss of the ship.