The idea that Mars may have been, at least partially, frozen some 4 billion years ago has been predicted by climate modeling, but the existence of valleys and channels carved by rivers was at odds with the theory.
"Since Mars’s valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys," said Anna Grau Galofre, a planetary scientist at Arizona State University and first author on the study, in a press release.
The valleys had been previously imaged using instruments aboard NASA’s Mars Global Surveyor spacecraft and the European Space Agency’s Mars Express, and their characteristics such as length, width and angles were measured by the research team.
Grau Galofre’s work shows some of the valleys and channels found on Mars resemble those seen in Earth’s polar regions, such as the Devon ice cap in northern Canada.
"These results are the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars," said Mark Jellinek, a geoscientist at the University of British Columbia and co-author on the study.
However, they found evidence that many of the valleys likely formed underneath glaciers — ice sheets — where water would run off and carve out channels in the planet’s surface.
The research team looked at these geological fingerprints in Mars’ valleys and compared them to similar valleys on Earth.
Today, the planet’s southern highlands are crisscrossed by deep valleys, surface features believed to have formed by ancient rivers and oceans.
The study, published in the journal Nature Geoscience on Monday, suggests that ancient Mars may not have been warm and wet as planetary scientists have previously suggested.
But new research suggests the valleys may have formed underneath glaciers, strengthening the idea our planetary neighbor was partly frozen in its formative years.
"Using the geomorphology of Mars’ surface to rigorously reconstruct the character and evolution of the planet in a statistically meaningful way is, frankly, revolutionary," said Jellinek.
Frozen Mars? Ancient valleys show planet may have been covered in ice https://t.co/nxHLUANj3e— CNET News (@CNETNews) August 3, 2020