The discussion drifted to the Carolina coast ~ no permafrost. They haven't had anything catastrophic other than recurring nasty earthquakes (worst ever East of New Madrid) and hurricanes.
We have only the vaguest notion of what shape polygons were produced by the freeze/thaw cycle in that neck of the woods 10,000 years ago. My guess is they were more circular than irregular.
My own front yard consists of trillions of ice shaped rocks. I have no idea what the freeze/thaw cycle did with them back in the Ice Age ~ but Fur Shur it put them on the surface, and about that peat, ain't any here!
See Post #50, I think we are digging in the wrong backyard.