Water ice mixed with dust form the residual north polar ice cap (brown color) in these images from NASA's Viking Orbiter 2.

Water ice mixed with dust form the residual north polar ice cap (brown color). Seasonal frost of relatively pure ice (white color) partly blankets the polar deposits. A large trough, which is occupied by linear sand dunes (dark band), exposes polar layered deposits. The layered deposits hold a partial record of the history of atmospheric activity and climate of Mars. Center of picture is at latitude 82 degrees N., longitude 84 degrees W. Viking Orbiter Picture Numbers 82B11-12 (violet), 82B15-16 (green), and 82B17-18 (red) at 53 m/pixel resolution. Picture width is 106 km. North is 6 degrees counter-clockwise from top.

View all Images