One type of feature of scientific interest on the mountain inside Gale crater is exposure of cemented fractures, evidence that groundwater once reached to at least that height of the mountain.
This image of that part of the mountain, taken by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter, shows symmetry in how material on one side of each fracture is balanced by material on the other side. This pattern indicates that mineral-saturated groundwater once filled the fractures. The water deposited minerals on both sides of the opening, eventually filling the gap.
This observation increases the appeal of Gale crater, which has been selected as the landing site for NASA's Mars Science Laboratory mission.
Photo credit: NASA/JPL-Caltech/Univ. of Arizona