Exotic CO2 Process May Have Carved Martian Gullies SpaceDaily

Last June scientists announced that gullies seen on some martian cliffs and crater walls suggest that liquid water has seeped down the slopes in the geologically recent past. Researchers found small channels on slopes facing away from mid-day sunlight, with most channels occurring at high latitudes, near Mars’ south pole. Now UA researchers propose an alternative explanation involving carbon dioxide erosion. They point to several reasons why CO2 is a better candidate than water in gully formation. One reason is that most gullies are found in the southern highlands, the oldest and coldest part of the planet, a place where liquid water is least likely to be stable.