Underground Plumbing System Discovered on Mars The upper-most layers of rock in many areas of Valles Marineris on Mars have been stripped away by erosion, providing a glimpse of the subsurface that was once buried deep underground.
Long ago, in the largest canyon system in our solar system, vibrations from "marsquakes" shook soft sediments that had accumulated in Martian lakes. The shaken sediments formed features that now appear as a series of low hills apparent in a geological map based on new NASA images. Enhanced color image of the Candor Colles region of Candor Chasma, Mars. Image is 1 km (0.62 miles) across. (USGS Astrogeology Science Center, Flagstaff, Arizona)
New Atlas"Spiders" from Mars? NASA spots them forming 12/20/16 These five images show different Martian features of progressively greater size and complexity, all thought to result from thawing of seasonal carbon dioxide ice that covers large areas near Mars' south pole during winter: NASA/JPL-Caltech/Univ. of Arizona