We thank members of the ODP Leg 175 shipboard scientific party, especially shipboard paleomagnetists Gina Frost, Toshi Yamazaki, and Peter Solheid, for numerous discussions and acknowledge the support and cooperation of the ODP personnel, Captain T. Ribbens, and the crew of the JOIDES Resolution. Thorough reviews by Stefanie Brachfeld and ODP Editor John Scroggs improved the manuscript. We thank the Institute for Rock Magnetism for the use of its facilities and its outstanding scientific and technical support. The Institute for Rock Magnetism is funded by the Keck Foundation, the National Science Foundation, and the University of Minnesota. This research was supported by U.S. Science Support Program JOI/USSSP grant 175-F000863 and the Deutsche Forschungsgemeinschaft.