Scientist have long wondered why Mars is covered in long ridges and furrows. These 400m year old structures are now thought to be a product of landslides on the red planet.
Researchers have created a detailed three-dimensional image of an extensive landslide on Mars. This 55-kilometre-wide landslide is now believed to be the reason why Mars has a collection of previously unexplained land structures.
Published in Nature Communications, the findings demonstrated that the landslide came from mountains, measuring several kilometres in height. These are believed to be formed at high speeds, of up to 360 kilometres per hour, due to underlying layers of fragmented rocks. However, this theory contradicts the previously believed theory, that underlying layers of slippery ice can only explain such vast ridges.
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.”
A team from UCL, the Natural History Museum, London, Ben Gurion University of Negev, Israel, and the University of Wisconsin Madison, USA, used images taken by NASA’s Mars Reconnaissance Obiter to analyse some of the better-defined landslides.
Co-author, Dr Tom Mitchell, Associate Professor of Earthquake Geology and Rock Physics (UCL Earth Sciences), said: “The Martian landslide we studied covers an area larger than Greater London and the structures within it are huge. Earth might harbour comparable structures, but they are harder to see and our landforms erode much faster than those on Mars due to rain.
“While we aren’t ruling out the presence of ice, we know is that ice wasn’t needed to form the long run-outs we analysed on Mars. The vibrations of rock particles initiate a convection process that caused upper denser and heavier layers of rock to fall and lighter rocks to rise, similar to what happens in your home where warmed less dense air rises above the radiator. This mechanism drove the flow of deposits up to 40 km away from the mountain source and at phenomenally high speeds.”