We are indebted to the captain, crew, and technicians of the drill ship JOIDES Resolution, whose hard work made Leg 192 a success. We are also indebted to the many scientists we sailed with for help with the logs and for their many stimulating discussions. Special thanks to Stephanie Laurence, who transferred much of the data in the alteration and vein logs from handwritten form to electronic files. We would also like to thank Jeff Alt for a helpful review and Lorri Peters and Gigi Delgado for editorial handling. This research used samples and data provided by the Ocean Drilling Program (ODP). The ODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc. Participation in Leg 192 was funded by Canada ODP for N.R.B. and by ODP France for J.H. Funding for this research was provided by the National Sciences and Engineering Research Council of Canada and the Institut National des Sciences de l'Univers of France.