HSV_01 (IMAGE) University of Leicester Caption View across a now-dry lakebed near Swartkolkvloer. During the last glacial period this and adjacent basin supported what are believed to have been perennial lakes, some up to 60 feet in depth. Credit Brian Chase Usage Restrictions Use only with credit. License Original 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.