Disappearing Act (Released 2 December 2003)

Just across Ares Vallis from Aram Chaos lies a heavily eroded crater filled by material that is on its way out. This two- frame mosaic of THEMIS VIS images shows the floor of a crater that was filled by material of unknown origin. That material is now being eroded in a manner that is quite enigmatic. Note that the irregular depressions have varying depths across the scene. It appears that the crater fill material begins to erode through the formation of depressions that then deepen over time. Why the depressions form in the first place is a mystery.