alt Hacker NewsThe suggested mechanism is that sedimentary rocks form over ice. That puzzles me in itself, because it implies a river with ice at the bottom. But anyway, then some heat source arrives and melts the ice, causing a sort of rug pull that means the rock layer drops down and breaks up. Kaboom.
I think the most likely case for sedimentary deposition over ice would be something like volcanic eruption or an impact event redepositing material onto pre-existing ice.