One of the places that we would love to explore but are not currently allowed because of potential biological contamination is the glaciers on Mars. First, some of them are made of carbon dioxide, which is interesting on its own. But now, thanks to research from our own Planetary Science Institute, we have found out that those glaciers are actually flowing, even today.

The new paper, published in Journal for Geophysical Research – Planets and led by Isaac Smith, is the result of glacial modeling from existing data. The models showed that carbon dioxide ice flows almost 100 times faster than water ice under Martian conditions when there are decent slopes involved. Since we haven’t seen the water ice glaciers flowing, that result makes sense. In fact, Smith explains: If the ice had never flowed, then it would mostly be where it was originally deposited, and the thickest ice would only be about 45 meters thick. Instead, because it flowed downhill into basins and spiral troughs – curvilinear basins – where it ponded, it was able to form deposits reaching one kilometer thick.

The ice itself began forming about 600,000 years ago at the south pole. The volume and mass have increased because of climate cycles during that time, although there were a few periods where mass was lost due to sublimation. Even more wildly, Smith notes: The glaciers have enough mass that if sublimated, they would double the atmospheric pressure of the planet. The longest glacier is about 200 kilometers long and about 40 kilometers across.

That is a lot of carbon dioxide ice. Fortunately, Smith has also identified some possible analogs here on Earth that he was able to match to the Martian features, which helped when comparing them to the models.

Maybe someday we can get a core sample? We can only hope.

More Information

PSI press release

“Carbon Dioxide Ice Glaciers at the South Pole of Mars,” I. B. Smith et al., 2022 April 26, JGR Planets