Glacial Polish (IMAGE) University of California - Santa Cruz Caption Glacial polish reflects sunlight at Pothole Dome in Yosemite National Park, California. The granitic bedrock here was polished by glacier sliding during the Last Glacial Maximum. UCSC researchers found that glacial polish forms by the accretion of a thin coating layer on top of glacially abraded surfaces. Credit Shalev Siman-Tov Usage Restrictions For use only with news coverage of this research. 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.