The fact that this is apparently consensus and not a crackpot theory is the most amazing thing about it. The little kid in me is kind of wishing I had gone into geology...

Or the sunken microcontinent in the Southern Indian Ocean: https://en.wikipedia.org/wiki/Kerguelen_Plateau

Well that's a bit terrifying. And that small blobby bit on the far right looks like it's pointing upward under my house.