A new study published Monday, August 3, on Nature Geoscience suggests that it was ice sheets that carved Mars valleys and not rivers.
This new report from the University of British Columbia basically throws off existing preconceptions that The Red Planet was formerly filled with water bodies. Rivers, oceans, and even rainfall shaped the valleys and creases now found on Mars.
HALE CRATER, MARS - UNSPECIFIED DATE: In this handout provided by NASA's Mars Reconnaissance Orbiter, dark, narrow streaks on the slopes of Hale Crater are inferred to be formed by seasonal flow of water on surface of present-day Mars.
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"Valley networks on Mars have historically been interpreted as surface water flows, either sourced by surface liquid water or by ground water," said Anna Grau Galofre. Galofre is the lead author for the study and a former PhD student in UBC's Department of Earth, Ocean and Atmospheric Sciences.
To arrive with the new theory about Martian surface development, Grau Galofre's team compared Red Planet valleys to subglacial channels found underneath the Canadian Arctic Archipelago, leading to surprising discoveries.
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Grau Galofre commented that "for the last 40 years, since Mars's valleys were first discovered," the most common assumption that rivers flowed on Mars' surface, carving these valleys through erotion. She added that "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." Grau Galofre added that Mars is similar in this manner, suggesting that there are other processes that helped shape the planet aside.
If the Red Planet was actually covered by ice sheets, in theory, it would also increase the chances of Mars supporting life. A layer of ice would offer additional protection and stability to water underneath. Moreover, the layer would provide cover from solar radiation in a planet without a magnetic field. Mars supposedly had its own magnetic field, before disappearing billions of years ago during its early formation.
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Comparing Glacial Channels on Earth to Martian Valleys
They noted that the similarity between the Devon Island subglacial channel and those of the Martian valley is "one of the best analogues" between the Red Planet and our own. Both are cold, dry polar deserts whose glaciations are largely cold-based.
In drawing comparisons, the researchers analyzed more than 10,000 valleys from Mars. A customized algorithm ran the valley data and made inferences about the erosion processes involved. Mark Jellinek, co-author of the study and a professor in the UBC Department of Earth, Ocean and Atmospheric Sciences, said that the results proved "extensive subglacial erosion" made possible by channelized meltwater drainage under ancient Martian ice sheets.
Jelliinek added: "The findings demonstrate that only a fraction of valley networks match patterns typical of surface water erosion, which is in marked contrast to the conventional view." He added that they inquired on the geomorphology of Mars' surface to reconstruct the "character and evolution of the planet in a statistically meaningful way" he called "revolutionary."
The novel theory of ice sheets playing an important role in Mars' formation also helps justify the formation of its valleys billions of years ago. Mars is further than Earth from the Sun, and considering that the Sun burned at considerably lower temperatures, makes it a lot cooler - ideal for keeping sheets of ice on its surface.
