Pockmarks -- Evidence of Gas Release (IMAGE) UiT The Arctic University of Norway Caption Pockmarks are scars on the ocean floor, an evidence of gas release. These likely appeared as the ice sheet retreated from the western part of Svalbard, and the area began to submerge in seawater again. They prove that release of methane followed the retreat of the ice sheet. Credit Illustration:Alexey Portnov/CAGE Usage Restrictions Attribution, No Derivatives, 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.