Coring the Basin (IMAGE) Smithsonian Tropical Research Institute Caption With the damming of the Chagres River over a century ago, Gatun lake was formed. Jorge Salgado retrieved sediment cores from a basin in the lake and built a chronological sequence of biological and environmental changes. Credit Jorge Salgado / STRI 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.