Recent investigations into the enigmatic gullies on Mars suggest that they may have been formed by blocks of carbon dioxide (CO2) ice, according to research led by Dr. Lonneke Roelofs from Utrecht University. While definitive evidence of life on Mars remains elusive, the processes behind these gullies are now better understood through experimental simulations.
In her research, Dr. Roelofs discovered that CO2 ice blocks can “dig” gullies in a manner reminiscent of sandworms from the film “Dune.” This insight was made possible through a series of experiments conducted in a specialized facility known as the “Mars chamber,” located at the Open University in Milton Keynes, England. Financial support from the British Society of Geomorphology facilitated this research.
During the Martian winter, temperatures plummet to around minus 120 degrees Celsius, allowing CO2 ice to form on the surface of the dunes. As winter gives way to spring, the warming temperatures cause these ice blocks, which can reach lengths of up to one meter, to break away from the dunes. When they detach, the lower side of the ice sublimates rapidly due to the thin Martian atmosphere, resulting in an explosive release of gas that propels sand in all directions.
“In our simulation, I observed how the high gas pressure forces sand away from the block in all directions,” Dr. Roelofs explained. “This process causes the block to burrow into the slope, creating a hollow surrounded by small ridges of settled sand.” As sublimation continues, the block gradually descends, leaving behind a long, deep gully typical of those observed on Mars.
The research team, including master”s student Simone Visschers, meticulously altered the angles of the dune slopes during their experiments to optimize conditions for observing the behavior of the CO2 ice blocks. After extensive trials, they successfully simulated the gully formation process, likening the ice”s movement to that of a burrowing mole.
Understanding how these gullies form is crucial, as they may provide key insights into the geological history of Mars. According to Dr. Roelofs, these findings could also aid in exploring questions about the origins of life and the potential for extraterrestrial existence. “Mars is our closest neighbor and the only rocky planet in the solar system”s habitable zone,” she noted. “Researching other planetary landscapes can challenge our Earth-centric views and lead to new insights.”
The study, titled “Sliding and burrowing blocks of CO2 create sinuous “linear dune gullies” on Martian dunes by explosive sublimation-induced particle transport,” is published in Geophysical Research Letters.
