Oblique perspective view of part of Nirgal Vallis
Oblique perspective view of part of Nirgal Vallis
Nirgal Vallis stretches 700 kilometres across the Southern Highlands of Mars, cutting across ancient lava deposits. This view shows an approximately 75-kilometre-long section in the western part of the upper valley. The U-shaped profile of Nirgal Vallis and its steep slopes (shown to slightly exaggerated effect here), which tower several hundred metres on both sides of the valley, are both very striking. It is also noticeable that the side valleys are comparatively short. They were formed not by the run-off of surface water, but rather by retrograde erosion caused by water seepage from a groundwater horizon below the upper rim of the surrounding terrain. The data used to create the images of this region were acquired by the High Resolution Stereo Camera (HRSC) on 16 November 2018 during Mars Express Orbit 18,818. The image resolution is approximately 14 metres per pixel. This oblique perspective view was generated from a digital terrain model and data from the nadir and colour channels of HRSC.
