Study Shows That Early Mars Was Covered In Ice And Not Flowing Rivers

According to a new study carried out by researchers from the University of British Columbia shows that a large number of the valley networks on Mars’s surface were carved by water melting beneath glacial ice and not by previously though free-flowing rivers.

Lead author Anna Grau Galofre, former Ph.D. student in the department of earth, ocean, and atmospheric sciences, developed and used new techniques to examine a lot of Martian valleys and reached this conclusion. She and her co-authors also compared the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago. They observed striking similarities in both the valleys

“For the last 40 years, since Mars’s valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys,” says Grau Galofre. “But there are hundreds of valleys on Mars, and they look very different from each other. If you look at Earth from a satellite you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape. Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them.”

The team found out that a lot of valleys on mars were similar to subglacial channels on Devon Islands in the Canadian arctic. Due to these similarities, the researchers started a comparative study.

“Devon Island is one of the best analogs we have for Mars here on Earth—it is a cold, dry, polar desert, and the glaciation is largely cold-based,” says co-author Gordon Osinski, a professor in Western University’s department of earth sciences and Institute for Earth and Space Exploration.

The team analyzed more than 10,000 Martian valleys, using a novel algorithm to infer their underlying erosion processes. “These results are the first evidence for extensive subglacial erosion driven by channelized meltwater drainage beneath an ancient ice sheet on Mars,” says co-author Mark Jellinek, professor in UBC’s department of earth, ocean and atmospheric sciences.

Though the tools and algorithms were developed with Mars as focus, they can also be applied to our own planet Earth to analyze and explore erosion features left over from very early Earth history.

Journal Reference:
Valley formation on early Mars by subglacial and fluvial erosion, Nature Geoscience (2020). DOI: 10.1038/s41561-020-0618-x , www.nature.com/articles/s41561-020-0618-x