Drill Core (IMAGE) Proceedings of the National Academy of Sciences Caption More than 250 m of drill core was examined at the Geological Survey of Norway repository in Trondheim, Norway. Credit Image credit: Matthew Robert Warke 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.