Parallel channels known as linear dune canyons can be observed within some of Mars’ dunes. Contrary to what their name suggests, these canyons are frequently quite winding. It was previously believed that these landforms were created through debris flow processes influenced by liquid water. However, recent satellite imagery has revealed that they are active during the local spring due to processes involving carbon dioxide ice. During the Martian winter, ice accumulates on the dunes, breaking off at the top as temperatures rise in early spring. In new experiments conducted in the Mars Chamber, planetary researchers from Utrecht University, the University of Le Mans, the University of Nantes, the Grenoble Institute of Astrophysics, and the Open University have demonstrated that linear dune canyons form when blocks of carbon dioxide and ice slide or submerge into the sandy slopes of dunes, or shift downwards with considerable force, draining the nearby sand. This drilling action is triggered by a powerful gas flow generated by the sublimation of carbon dioxide ice, as it transitions into carbon dioxide gas. The movement of sliding carbon dioxide ice blocks contributes to the formation of shallow channels, while the excavation of carbon dioxide ice results in the development of deep, winding channels in Martian dunes.
Two examples of Martian dunes with linear dune gullies: (a) linear dune gullies in the dune field of Gall Crater; (b) A linear dune canyon in the dune field of an unnamed crater in the center of the Hellas Plain. Image credit: Roelofs et al., doi:10.1029/2024GL112860.
Linear dune canyons are remarkable and enigmatic formations located in the mid-latitude sand dune regions of Mars.
Despite their designation, these parallel and often meandering waterways, characterized by sharp bends, limited source areas, distinct banks, and hole-like channel terminations, have no equivalent on Earth.
They differ significantly from the conventional canyon topography found on steep slopes both on Mars and Earth, which typically features erosional alcoves, channels, and sedimentary aprons that are often larger than linear dune canyons.
“In our simulations, we observed how high gas pressures cause the sand to shift in all directions around the blocks,” stated Loneke Roelofs, a researcher at Utrecht University and lead author of the study.
“Consequently, the blocks become lodged into the slope and get trapped within cavities, surrounded by small ridges of settled sand.”
“However, the sublimation process persists, leading to continued sand displacement in all directions.”
“This phenomenon drives the block to gradually descend, resulting in a long, deep canyon flanked by small sand ridges on either side.”
“This is precisely the kind of canyon we find on Mars.”
In their research, Dr. Roelofs and colleagues merged laboratory experiments that let blocks of carbon dioxide and ice slide down sandy slopes under Martian atmospheric pressure with observations of the linear dune canyons located within the Russell Crater Giant Dunes.
“We experimented by simulating dune slopes of varying steepness.”
“We released chunks of carbon dioxide ice down a slope and observed the outcomes.”
“Once we discovered an appropriate slope, we began to see significant effects. The carbon dioxide ice chunks started to penetrate the slope and move downwards, resembling burrowing moles or dune sandworms. It was quite an unusual sight.”
“But how exactly do these ice blocks originate? They form in the desert dunes located in the midlands of Mars’ southern hemisphere.”
“During winter, a layer of carbon dioxide ice develops across the entire surface of the dunes, reaching thicknesses of up to 70 cm. As spring arrives, this ice begins to warm and sublimate.”
“The last remnants of the ice persist on the shaded side of the dune’s summit, where blocks will break off once temperatures rise sufficiently.”
“When a block reaches the base of the slope and halts its movement, sublimation continues until all carbon dioxide evaporates, leaving behind a cavity filled with sand at the dune’s base.”
This study was published in the October 8th issue of Geophysical Research Letters.
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Loneke Roelofs et al. 2025. Particle transport driven by explosive sublimation causes blocks of CO2 to slide and burrow, forming winding “linear dune valleys” in Martian dunes. Geophysical Research Letters 52 (19): e2024GL112860; doi: 10.1029/2024GL112860
Source: www.sci.news
