Sorted polygon in glacial debris covering floor of Bull Pass in Southern Victoria Land, Antarctica. Both coarse and fine-grained materials can be found in polygonal depressions, and both raised and depressed centers can occur. These polygons have coarse, raised centers, coarse marginal trenches, and coarse-depleted, gently sloping shoulders.
Sorted polygons are among a number of enigmatic landforms developed in periglacial environments.
A leading explanation for these types of sorted polygons is that the upper regolith in periglacial environments convects, or experiences diapirism, driven either by temperature or density gradients. Ice Falls, Wright Valley, Southern Victoria Land, Antarctica. At the beginning of the sequence, a portion of the Labyrinth is visible. This set of hills and troughs are carved into a sill of the Ferrar dolerite. McMurdo Station is on Ross Island, a volcanic island off the coast of, but linked by the permanent ice field of the McMurdo Ice Shelf, to mainland Antarctica.