Yesterday, we talked a lot about climate change and retreating glaciers here on Earth. But Earth isn’t the only planet in our solar system that has had glaciers – Mars did, too. And while the cycle of advance and retreat of our glaciers and ice sheets has left the Earth’s surface scarred with valleys and fjords, the same is not similarly true for the red planet. That difference had scientists thinking that glaciers on Mars didn’t move.

Now, however, new research published in Geophysical Research Letters and led by Anna Grau Galofre presents evidence that the glaciers on Mars did move – just really, really slowly. And the difference is due to the smaller feedback loop from Mars’ lower gravity.

On Earth, the weight of the glaciers and ice sheets causes pressure and friction with the surface underneath. As the glaciers move, they melt on the bottom, forming channels of water that flow out from underneath the ice and essentially lubricate the downhill slope. This lubrication increases the flow rate of the glacier. With a much lower gravity – about 40% less strong than Earth’s – ice on Mars doesn’t have the same amount of friction against the surface. The effect is that Mars has different marks from its ice as a result. Grau Galofre explains: Whereas on Earth you would get drumlins, lineations, scouring marks, and moraines, on Mars you would tend to get channels and esker ridges under an ice sheet of exactly the same characteristics.

Additionally, the models show that Mars actually drained off the icy meltwater more efficiently than Earth did, which added to the lack of subglacial lubrication. This more efficient drainage could also have led to better conditions for life on Mars – protected from solar radiation in those subglacial lakes and insulated from temperature changes.

Now we need more rock samples from Jezero crater if we want to find evidence of that ancient life.

More Information

AGU press release

“Valley Networks and the Record of Glaciation on Ancient Mars,” A. Grau Galofre, K. X. Whipple, P. R. Christensen, and S. J. Conway, 2022 July 25, Geophysical Research Letters