A recent study has found that ancient Mars was covered by massive ice sheets and not free-flowing rivers, as previously thought.
Researchers say that a vast number of valley networks on the Martian surface were actually carved by water melting beneath glacial ice on the red planet, and not flowing rivers as was previously suggested.
Mars continues to amaze us. While NASA recently launched the Perseverance Rover to Mars, which is set to touch down on the surface of the red planet in February 2021, hopefully helping us find out where Mars had life on its surface at one point during its history, experts back on Earth are using scientific data gathered throughout the years to find out more about Mars and its past.
Now, a new study argues that ancient Mars was covered by massive ice sheets and that its networks of valleys were carved by water melting under glacial ice, and not free-flowing rivers as previously believed.
The new research from scientists from the University of British Columbia (UBC ) in Canada, published in the journal Nature Geoscience offers new clues about the red planet.
These findings throw a jug of cold water over the dominant hypothesis of warm and humid ancient Mars, which postulates that rivers, lakes, and oceans once existed on the red planet.
To reach this conclusion, lead author Anna Grau Galofre, a former doctoral student in the Department of Earth, Ocean, and Atmospheric Sciences, developed and used new techniques to examine thousands of Martian valleys.
She and her co-authors also compared Martian valleys to subglacial channels in the Canadian Arctic archipelago and discovered striking similarities, which led them to believe that Mars’ stunning valleys were carved not by rivers but by melting ice.
“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 similarity between many Martian valleys and subglacial channels on the island of Devon, in the Canadian Arctic, prompted the authors to carry out their 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 glaciation is primarily based on cold,” explains co-author Gordon Osinski, Gordon Osinski, a professor from the Department of Earth Sciences of Western University and the Institute of Earth and Space Exploration.
In total, the researchers analyzed more than 10,000 Martian valleys, using a new algorithm to infer their underlying erosion processes.
“These results are the first evidence of extensive subglacial erosion driven by channeled meltwater drainage under an ancient ice cap on Mars,” said co-author Mark Jellinek, a professor in the Department of Earth, Ocean and Atmospheric Sciences at UBC.
The researchers revealed how only a fraction of the valley networks match the typical patterns of surface water erosion, which is in stark contrast to the conventional view. With the help of geomorphology, scientists were able to rigorously rebuild the character and evolution of the planet in a statistically significant way that is downright revolutionary.
Furthermore, the study also helps explain how Martian valleys would have formed 3.8 billion years ago on a planet that is further from the sun than Earth, during a time when the sun was not as active as it is today.
And while this new research focused on Mars, the analytical tools developed for this study can be applied to discover more about the early history of our own planet.