Mars outlet crater (IMAGE) University of Texas at Austin Caption A colored topographical image showing river valleys on Mars. The outlet canyon Loire Vallis (white line) formed from the overflow of a lake in Parana Basin (outlined in white). Black lines indicate other river valleys formed by processes other than lake overflows. Background is colored Mars Orbiter Laser Altimeter-derived topography over a Thermal Emission Imaging System image mosaic. Image is approximately 650 kilometers across. Credit NASA/GSFC/ JPL ASU Usage Restrictions No restrictions. License Public Domain 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.