Figure 8-9 RIVUXG Evidence of Ancient Martian Water (a) The Mars rover Opportunity photographed these sedimentary layers in a region called Meridiani Planum. Some of the layers are made of dust deposited by the Martian winds, but others were laid down by minerals that precipitated out of standing water. (b) In this false-color image from Opportunity of Martian sand dunes, the bluish color shows the presence of millimeter-sized spheres of gray hematite. Such spheres naturally form in water-soaked deposits. (c) This false-color map shows highest elevations of Mars in red, revealing a fan-shaped region where water flowing downslope can deposit debris. On the ground, the Curiosity rover found rounded pebbles embedded with rocky outcrops characteristic of an ancient river. The black oval shows the targeted landing area for Curiosity.