Channel to Ridge

This VIS image illustrates one of the complexities of studying Mars. The small channel that enters the crater appears to become a ridge as it crosses onto the crater floor. This inversion of topography is due to several processes. Initially the channel would have carved into the crater rim and onto the floor. At some time material infilled the channel on the floor of the crater. This infilling material is more resistant to erosion than the surrounding material that has subsequently been removed. So the channel fill now is topographically a ridge, but is located where the original channel cut into the crater.