When we think of a glacier, we think about the beautiful gigantic chunks of ice in the far north. A recent discovery has scientists thinking that glaciers exist on Mars made out of dry ice.
Dry Ice Glaciers
In Kreslavsky and Head’s article titled “Carbon dioxide glaciers on Mars: Products of recent low obliquity epochs”, they theorize that a couple dry ice glaciers exist on Mars. On Mars, there are a few areas where there are markings from unusual glaciers. In the past, these have been theorized to have been from high-latitude water ice glaciers. Kreslavsky and Head are now theorizing that these areas were made from dry ice glaciers instead of water glaciers.
The two explain how a dry ice glacier would behave differently from a water glacier. A dry ice glacier is softer than a water ice glacier. On earth, glaciers move across the earth digging up the ground. A dry ice glacier on Mars would be stuck to the ground and not plowing through the ground. The glacier instead would move by its leading edge rolling over the ground.
The dry ice glaciers are not active today. The climate on Mars does not allow this. When the glaciers were formed millions of years ago, Mars was on different axis and the temperature was right for the glaciers to move.
The image below shows ridges that were instrumental in Kreslavsky and Head’s discovery of the dry ice glaciers. These finger-like ridges are believed to be caused when the climate prevents the dry ice glacier from moving any further. Dust and debris are left behind when the dry ice sublimates, forming the ridges.
Source Article: http://www.planetary.brown.edu/pdfs/3803.pdf