Sediment Cores (IMAGE) University of Hawaii at Manoa Caption Deep-sea sediment core sections of the Paleocene-Eocene boundary. The red clay band marks the onset of the PETM. Credit James Zachos Usage Restrictions Image may be used with appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.