HiRISE: Frosted gullies in a central pit

The frosted gullies in this observation are located along an irregularly shaped pit approximately 15 kilometers wide. The pit lies within an impact crater in Sisyphi Planum that is about 35 kilometers in diameter and is located northwards of the Southern polar layered deposits. Carbon dioxide frost covers much of the region and helps to reveal subtle textures in the landscape. The layered sediment visible in the walls of the pit and in which these gullies formed likely originally filled much of the impact crater… [More at link]