The authors thank Gary Acton and a cantankerous anonymous reviewer for valuable suggestions to improve the manuscript. 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. Funding for this research was provided a grant from JOI/U.S. Science Support Program (USSSP).