Porphyry Lake Sediment Coring (IMAGE) University of Colorado at Boulder Caption CU-Boulder Assistant Professor Jason Neff extracts sediment cores from Porphyry Lake in Colorado's San Juan Mountains. Credit Dan Fernandez, University of Colorado at boulder 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.