Tag Archives: landslides

Big landslides on Mars might not require ice

According to a new paper, scientists now think the biggest and longest landslides found on Mars might not require a base of ice on which it could slide such extensive distances.

The findings, published today in Nature Communications, show for the first time that the unique structures on Martian landslides from mountains several kilometres high could have formed at high speeds of up to 360 kilometres per hour due to underlying layers of unstable, fragmented rocks.

This challenges the idea that underlying layers of slippery ice can only explain such long vast ridges, which are found on landslides throughout the Solar System.

First author, PhD student Giulia Magnarini (UCL Earth Sciences), said: “Landslides on Earth, particularly those on top of glaciers, have been studied by scientists as a proxy for those on Mars because they show similarly shaped ridges and furrows, inferring that Martian landslides also depended on an icy substrate. “However, we’ve shown that ice is not a prerequisite for such geological structures on Mars, which can form on rough, rocky surfaces. This helps us better understand the shaping of Martian landscapes and has implications for how landslides form on other planetary bodies including Earth and the Moon.”

The lighter gravity of Mars, about one third of Earth’s, is part of the explanation, though many other factors are involved. Either way, this is one more data point in the evidence that the though geology on Mars might look like what we see on Earth, it is likely very different than we expect, due to the alien nature of Mars itself.


Evaporating dry ice chunks create gouges on Mars

Scientists think they have solved the mystery of the gouges that appear seasonally on some hillsides on Mars: Chunks of dry ice that slide down the slope and then evaporate, leaving no trace.

During the martian winter, carbon dioxide ice freezes over parts of the planet’s surface and sublimates back into a gas during the spring thaw. But according to the model presented here today at a meeting of the American Geophysical Union, chunks of warming dry ice may also break off from the crests of dunes and skid down slopes. This is no ordinary tumble—according to the model, the bases of the chunks are continually sublimating, resulting in a hovercraftlike motion that gouges the dune while propelling the ice down slopes. Solid ice that survives to the bottom settles into a pit before dissipating back into the atmosphere.