A true "South Polar Oddity": Inca City (3 - False Colors)

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) has provided new information about the "Inca City" ridges, though the camera's images still do not solve the mystery. The new information comes in the form of a MOC red wide angle context frame taken in Mid-Southern Spring (Image 1). The MOC image shows that the "Inca City" ridges, located at 82° South and about 67° West (293° East), are part of a larger circular structure that is about 86 Km (about 53 mi) across. It is possible that this pattern reflects an origin related to an ancient, eroded meteor impact crater that was filled-in, buried, then partially exhumed. In this case, the ridges might be the remains of filled-in fractures in the bedrock into which the crater formed, or filled-in cracks within the material that filled the crater. Or both explanations could be wrong. While the new MOC image shows that "Inca City" has a larger context as part of a circular form, it does not reveal the exact origin of these Striking and Unusual Martian Landforms.