Plate 2 Elements of Martian habitability. Top left—Mastcam image of a section of the Murray Buttes at Gale crater captured by the Curiosity rover on 8 September 2016. The buttes and mesas are eroded remnants of ancient sandstones. Credits: NASA/JPL-Caltech/MSSS. Top right—Lava deposits and sequences of sedimentary layered deposits in the background captured in the foothill of Mount Sharp, Gale crater, Mars. Credits: NASA/JPL-Caltech/MSSS. Middle panel—The Comanche outcrop holds key mineralogical evidence for an ancient lake in Gusev crater. Image by NASA/JPL-Caltech/Cornell University: Mars Exploration Rover mission and Spirit rover. Bottom left—Opaline silica deposits in a series of depressions in Noctis Labyrinthus as viewed from orbit by HiRISE onboard MRO. The opal could have formed by chemical weathering of basaltic lava flows or ash in the presence water. Credit image: NASA/JPL/University of Arizona. Image ID: ESP_023359_1710. Bottom right—Mastcam image showing a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake. Credits: NASA/JPL-Caltech/MSSS: NASA's Curiosity Mars rover.
