This picture (centered at latitude 10 degrees S., longitude 74 degrees W.) shows much of Melas Chasm and a portion of Candor Chasm (upper right) in central Valles Marineris. Several interesting compositional units can be seen in the enhanced-color image (PIA00156): white materials (center-right) may consist of carbonates or some other evaporite deposit, pinkish materials (upper right) may be relatively rich in crystalline iron oxides, and greenish materials (lower left) correspond to dark sand dunes. Viking Orbiter Picture Numbers 279B41 (violet), 279B49 (green), and 279B51 (red) at 257 m/pixel resolution. Picture width is 261 km. North is 50 degrees clockwise from top.