Planetary science: Ancient ice sheets on Mars

Certain valleys on early Mars may have formed under extensive ice sheets, suggests a paper published in Nature Geoscience. These findings may help to reconcile geological evidence and simulations of the climate of early Mars.

Understanding the climate in the first billion years of Mars’s history is important in determining whether the planet was ever habitable. Previous research suggested that valley networks in the ancient southern highlands of the planet were eroded by rivers, which implies a warm and wet climate when they formed. However, computational models of the planet suggested that the climate at the time was cold, with ice on the surface.

Anna Grau Galofre and colleagues analysed the morphology of valleys on Mars to determine the different ways in which they could have formed and found that tthe majority of the valleys analysed had morphologies that were most similar to those eroded by either rivers or water in channels beneath ice sheets. They compared valleys thought to have formed under ice on Mars to examples on Earth and found morphological similarities.

The authors conclude that these findings support the theory that Mars had a predominantly cold and icy early climate rather than a warm and wet climate, as previous research had indicated.

doi: 10.1038/s41561-020-0618-x

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