Gullies in Sisyphi Planum (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

Image PSP_004804_1105 shows the Walls of a large Pit inside Lyell Crater, near the South Polar Region.

This image was acquired during a period of elevated Atmospheric Dust, following a series of Dust Storms that encircled the Planet; this is the cause of the longitudinal bands of contrasting gray levels in the image. We can still see through the thick Atmosphere, though, Gullies and other subtle features which could have been produced by water and ice present at or near the Surface.

The otherwise subdued Surface in this Region is criss-crossed by numerous fissures, forming Polygons some 10 mt (9 yards) across. Similar features in both shape and scale can be found in terrestrial Periglacial Regions such as Antarctica, where ice is present at or near the Surface. Antarctica's features are the product of repeated expansion and contraction of the soil-ice mixture due to seasonal temperature oscillations. This results in Polygonal Networks of Stress Fractures.