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This picture of Martian channeled and chaotic terrain is a view of the transition between a cratered and channeled upland surface (top half of the picture) and a lower-lying chaotic terrain (bottom half of the picture). On the cliff face that marks the transition, talus chutes (fragmental material on a steep slope) are separated by spurs of bedrock. Some layering can be seen at the top of the bedrock spurs, but not the large number of regular layers seen to great depths in the walls of the Valles Marineris farther to the west. The term chaotic terrain is applied to areas where the martian surface has seemingly collapsed to form a jumbled mass of blocks at a lower elevation than the surrounding terrain. Many of the large flood channels emerge from this kind of terrain. It has been suggested that some of the floods formed by violent eruptions of deep groundwater. The eruptions were so violent that part of the bedrock was entrained in the water, causing the ground to collapse after the floods to form the chaotic terrain. This MOC picture is difficult to reconcile with that simple interpretation because the cliff that we see has a very distinct, raised rim. If the low-lying area in the foreground were formed simply by collapse, such a rim would not be expected.
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