We wish to thank all the participants of ODP Leg 206 for their contributions relevant to this paper and the members from the Calcareous Nannofossil Laboratory at Florida State University for their helpful comments and assistance. We thank Drs. Gary Acton, José-Abel Flores, and Koji Kameo for helpful and constructive reviews. This research used samples and/or data 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 for this research was provided by a United States Science Advisory Committee (USSAC) grant (Task Order F001790) to both authors.