Scientific Drilling Ship JOIDES Resolution (IMAGE) University of Hawaii at Manoa Caption The sediment archives obtained during ocean drilling programs give scientists a glimpse into Earth's climatic history. Inset: Deep sea sediment cores across the Paleocene-Eocene boundary. The sections of light brown color consist mainly of calcium carbonate, whereas the dark red/brown section is a clay layer, representing the onset of the interval of intense global warming and ocean acidification 55 million years ago. Credit Integrated Ocean Drilling Program and J.C. Zachos Usage Restrictions None 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.