Olympica Fossae

Olympica Fossae is a complex channel located on the volcanic plains between Alba Mons and Olympus Mons. The sinuosity of the large channel in the middle of the image indicates that this is a channel created by liquid flow. In this case the location and other surface features point to lava rather than water as the liquid. Subtle dark slope streaks are visible both in the channel walls and in the small crater at the bottom of the image. These features are thought to form by downslope movement of material which either reveals the darker rock beneath the dust coating, or creates the darker surface by flow of a volatile just beneath the dust coating.