Corona and pancake domes on Venus, Magellan radar image. The large circular structure near the centre is a corona, approximately 200 kilometres in diameter and provisionally named Aine Corona. Just below Aine is one of the flat-topped volcanic constructs knows as pancake domes for their shape and appearance. This pancake dome is about 35 kilometres in diameter and thought to have formed by eruption of an extremely viscous lava. The range of volcanic features associated with the coronae suggests that volcanism plays a significant role in their formation. Rough areas appear bright, flat ones dark. The region seen here is approximately 300 kilometres across. Data obtained in January 1991.