(CNN) "According to geologist and report author Nick Hoffman, when craters with steep walls and other unstable terrain collapsed, large amounts of underground liquid carbon dioxide were released.
The quick drop in pressure vaporized some of the liquid, just like carbon dioxide released from the valve of a fire extinguisher. The freed gas then formed clouds of gaseous and frozen carbon dioxide, mixed in with water ice, dust and rubble."

"The resulting mixture, which included some liquid carbon dioxide as a lubricant, transformed into a chaotic avalanche, capable of traveling down slope for up to thousands of kilometers, and carved out deep and long canyons on the surface, said Hoffman, a professor at La Trobe University in Australia."

Oh, really?