In the case of images taken by the Mars Reconnaissance spacecraft, subsurface minerals appear in grooves eroded down the side of the giant sand dunes.
“Some of these canyons produce a variety of colors that are highlighted on west-facing (illuminated) slopes, where the canyons appear to glow in the winter light,” explains the team supervising the stunning HiRISE camera, aboard the Mars Reconnaissance orbiter.
The Mars Reconnaissance orbiter has been orbiting Mars since 2006, and the HiRISE camera captures high-resolution images showing the diversity of the Martian surface.
Kaiser Crater, a giant sand dune field inland, has been a frequent target of study for HiRISE, so scientists have come to identify the seasonal changes that occur in this ever-changing landscape.
The Kaiser Crater’s gigantic sand dunes are eroded by steep canyons each year in late winter, the HiRISE teams say, as the sun warms the slopes and the seasonal carbon dioxide frost seeps in (meaning it changes from a solid to a gas).
Kaiser Crater is located on Noachis Terra, a region on Mars that lies between the two giant impact basins on Mars: Argyre and Hellas.