Lyell (Martian crater)
Lyell Crater is an impact crater in the Mare Australe quadrangle of Mars, located at 70.1°S latitude and 15.6°W longitude. It is 121.0 km in diameter. Its name refers to British geologist Charles Lyell.
This picture was taken in the spring season on Mars when the temperature was rising. During the winter, much frost accumulates. When the temperature goes up in the spring, the frost disappears in the thin Martian atmosphere and leaves behind the dark ground. The surface appears covered with dark spots when this defrosting process is occurring. The dark spots can be seen in some of the pictures below. Many gullies are present in Lyell Crater.