Interesting idea. Here are some things to consider:
1) You may want to have the gods keep the seas there. If they can hold the planet together, this should be a trivial task . Otherwise, you get into some Dark Sun-like environmental issues. This isn't necessarily a bad thing, but make sure it's what you want before you go there.
2) You may want to look at Spelljammer, the old 2nd Edition AD&D setting. This world seems right up its alley.
3) If you're going to have continuing impacts, then it's really implausible that you'd have a civilization. This may be another job for the gods .