Evolution of Canyons by Landsliding. This mosaic of Viking Orbiter 1 pictures was taken of the junction of Gangis and Capri Chasmae.
Rugged terrain consisting of numerous tilted blocks occurs within alcoves in the canyon wall.
Extending where the two patterns intersect, one thin lobe clearly overlies the other and cuts off its striations. These features are giant landslide deposits that formed when sections of canyon rim collapsed. The broad, thin lobes of material apparently flowed at high velocity from the bases of the collapsing masses. The mechanism by which the surface striations formed is not well understood, although similar features have been observed on terrestrial landslides. Groups of hills, similar to chaotic terrain, and sand dunes contribute to a varied canyon floor landscape.