The senior author thanks the Ocean Drilling Program (ODP) for providing the samples for this study and David Feary for his support and interest during the investigation. Thanks to Catherine Nigrini for reviewing a preliminary draft of the manuscript and to Jean-Pierre Caulet and David Lazarus for scientific reviews. We also thank John Barron for his valuable suggestions.
This research used samples and/or data provided by ODP. ODP is sponsored by the U.S. National Science Foundation (NSF) and participating countries under management of Joint Oceanographic Institutions (JOI), Inc.