We acknowledge critical reviews of the manuscript by Michael Underwood, Brian Taylor, and an anonymous reviewer. This research used samples and/or 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 by JOI/USSSP contract USSSP 180-F000907; Lamont-Doherty Earth Observatory publication #6346.