Thought experiment....
What would happen over time to craters that were made in this terrain. If this expansion/contraction is responsible for shaping the terrain wouldn't it- over long time periods- work to erase craters?
Also if, as they speculate, the subsurface consists of large amounts of water ice, what would happen to rocks embedded in the ice- I know that freeze/thaw cycles on earth can lead to rocks being pushed up to the surface, could something similar happen on mars without actual thawing?
