Mead Crater (IMAGE) Brown University Caption Mead crater, the largest impact basin on Venus, is encircled by two rocky rings, which provide valuable information about the planet's lithosphere. Credit NASA 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.