Carbonated Mesas (IMAGE) Brown University Caption A Brown-led team found carbonate-bearing rocks in the sides of eroded mesas in the Nili Fossae region. Scientists believe the carbonates may have been formed at the surface when olivine-rich rocks were exposed, and altered, by running water. Credit NASA/JPL/JHUAPL/University of Arizona/Brown University 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.