Formed by Compression Melting (IMAGE) University of Wyoming Caption Rolling Thunder Mountain near Talus Lake is part of the Teton Range. The orange rock in the foreground is Webb Canyon gneiss, granite formed by decompression melting more than 2.6 billion years ago. Credit Carol Frost 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.