Eolian and Periglacial Activities in Vastitas Borealis (polygons)

The polygons shown in this image's subset, which covers approximately 400 x 250 mt (350 x 225 yards), are in the order of 10 mt (0.9 yards) across; in some cases they are delimited by aligned rocks. Similar features in both shape and scale are found in Terrestrial Periglacial Regions such as Antarctica, where ice is present at or near the surface.

Antarctica's polygons and rock alignments are produced by repeated expansion and contraction of the soil-ice mixture due to seasonal temperature oscillations; dry soil falling into the cracks form sand wedges and amplify this effect. This results in polygonal networks of stress fractures and in the resurfacing and sorting of rocks along these fractures.