At the north pole of Mars are two impact craters characterized by moraine-like ridges (accumulations of dirt and rocks), generally produced in the wake of glacial movement. In this vein, some scientists suggest that slow-moving CO2 glaciers may be responsible for the linear structures seen in these craters on Mars. Others, however, have a much more dynamic origin: huge ice avalanches.
To test this alternative theory, a team of researchers led by Sergey Krasilnikov of the Russian Academy of Sciences used open-source data from NASA to simulate the supposed catastrophic waves of material along the slopes of the craters. In their models, accumulations of water ice on top of the slopes (called massifs) bend under the enormous weight and pressure, causing a rapid downward velocity of up to 80 meters per second (262 feet per second). This wave, they suggest, could have pushed debris to their edges, forming the observed ridges.
These avalanches turned out not only to be fast, they were far-reaching. In one crater, the wave extended to about 15 kilometers (9.32 miles), while in the other crater it extended 12 kilometers (7.46 miles). An Earth analog of these events was the Kolka Glacier disaster in 2002, whose glacial flood and rapid ice-water rock mudslide wreaked havoc at high speed along a 17-kilometer (10.6-mile) stretch.
The study, published in Planetary and Space Science, proposes the slow-moving CO. in question2 glacier model, based on when the moraine-like ridges were formed. CO2 Glaciers are thought to only occur when Mars has a low axial slope, which hasn’t happened in the past 10 million years, Krasilnkov told Eos. However, the crater ridges probably formed within the last few million years.
This period, the authors note, corresponds to the build-up of water ice massifs that could reach a critical point and trigger an avalanche at the crater’s latitudes. According to their simulations and calculations, the ice massifs could be between 100 meters (328 feet) and 150 meters (492 feet) high, representing 1.1 and 2.42 square kilometers (0.42 and 0.93 square kilometers) of ice respectively. miles) to descend the craters.
While the debate about how these crater ridges formed on Mars will likely continue, this latest study certainly flies the flag for ice avalanches.
To see a confirmed ice avalanche on Mars, check out this image taken by NASA’s Mars Reconnaissance Orbiter (MRO) when the northern polar ice sheet thawed last year.