Structural origin of large Martian channels

Large Martian channels have been attributed to fluvial erosion primarily because they widen in a downstream direction, appear to be braided in places, have tributaries, and may be sinuous. However, tension fractures in a variety of materials produce features that superficially resemble the Martian channels at, of course, a very different scale. Based on the morphology of these channels as viewed on Mariner 9 images, it is not possible to determine that these features have a fluvial origin. It is probable that most large Martian channels have a structural origin and reflect local or planet-wide tensional forces.