HiRISE: Bedrock in a trough in Asimov Crater

This image was acquired in southern winter over part of Asimov Crater (latitude 47.5 S), showing the equator-facing slope of a deep trough inside the crater. The crater appears to have been completely filled by a thick sequence of materials, perhaps including sediments and lava flows. Later, deep troughs formed around the outer edge of the fill material, probably by collapse over void spaces at depth. What made the void space is not known, but one idea is that there were lenses of ice that slowly sublimated into the atmosphere. Another idea is…. [More at link]