Ancient Mars was covered in ice sheets, not flowing rivers

A new study by the University of British Columbia found the early Martian landscape likely looked like panoramas of the Devon ice cap. The red planet contained water, but these were most likely glaciers, not liquid rivers.

Many of the networks of valleys that cover the surface of Mars today have been “carved out” by water melting under glacial ice, not by flowing rivers, as was previously thought.

These findings completely change the view of ancient Mars – from a warm and humid world, it turns into a cold glacier.

To reach this conclusion, lead author Anna Grau Galofre developed and used new methods to study thousands of Martian valleys. She and her co-authors also compared the Martian valleys to subglacial channels in the Canadian Arctic Archipelago and found striking similarities.

The similarities between many of the Martian valleys and subglacial channels on Devon Island in the Canadian Arctic prompted the authors to conduct a comparative study.

“Devon Island is one of the best analogs of Mars – it is a cold, dry, polar desert, and glaciation is largely based on cold,” experts say.

In total, the researchers analyzed more than 10,000 Martian valleys using a new algorithm to determine their main erosion processes. “These results are the first evidence of extensive subglacial erosion caused by drainage drainage beneath an ancient ice sheet on Mars,” says co-author Mark Jellinek.

The results are published in the journal Nature Geoscience.