Lesley Dotter and Barbara Gardner of CSIRO are thanked for chemical and Pb isotope analyses, respectively, and Robina Sharpe and Keith Harris (University of Tasmania) for S isotope microanalyses. This research used samples provided by the Ocean Drilling Program (ODP). ODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc. Funding was provided by CSIRO and the P2+ consortium of Australian mineral companies.