22 October 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the broken, platy texture of flow surfaces in the Zephyria region of Mars. Some investigators have suggested that these materials represent the remains of an ice-covered lake; others suggest that these are the surfaces of hardened lava that -- when it was erupting -- was very hot and fluid. Although not illustrated here, a key piece of evidence against the ice-covered lake hypothesis is that there are some small craters formed on these surfaces (one can be seen in the lower left/southwest corner), and some of them have boulders in their ejecta. The boulders indicate that the material is rock-solid.

Location near: 5.3°N, 208.6°W
Image width: width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn