Mars was covered with ice sheets, not rivers

Scientists from the United States suggested that some of the depressions on Mars arose not because of rivers, but due to the ice sheet. These conditions were also better at preserving possible life on the planet.

A new study from the University of British Columbia notes that a large number of depressions on the surface of Mars were due to the melting of the ice sheet, not the flow of rivers. These findings contradict the theory that ancient Mars was “warm and humid” and that the planet had rivers, rains, and even entire oceans.

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

“Over the past 40 years, since then, researchers have discovered the valleys of Mars, many of them have suggested that there were rivers on the planet that eroded the soil. However, there are hundreds of such depressions on Mars and their origin is different. If you look at the Earth from a satellite, you can see many valleys: some of them are created by rivers, others – by glaciers, others – by other processes, and each of them has a peculiar shape. The same process can be observed on Mars, so we assume that some of these depressions appeared due to ice sheets”.

Anna Grau Galofre, University of British Columbia Scientist

The similarity of many of the Martian valleys to the subglacial channels on Devon Island in Canada prompted the authors to conduct a comparative study. In total, scientists analyzed more than 10 thousand Martian valleys, using a new algorithm in order to compare them visually and study erosion processes.

Their climate modeling showed that the climate on ancient Mars was cooler than thought, especially during the formation of the groove network. Researchers at the University of British Columbia have hypothesized that these depressions appeared under the ice sheets due to water accumulation.

This environment also helped to improve the conditions for the survival of possible ancient life on Mars. The ice sheet provides great protection and stability, as well as shelter from solar radiation.