The south canyon wall here is incised by several large, branching tributary canyons that appear to have developed headward along joints or zones of weakness in upland rocks. It has been suggested that these canyons developed through a sapping process, in which the melting of ground ice caused the upland to collapse. The floor of the main canyon between A and B appears to have been fractured and down-faulted below the level of the mouths of the tributary canyons.
North is to the left of the image.