Not sure where to post this, as it covers a bit of geology, astronomy, archeology and even palaeontology. Hope it doesn't get lost here in Popular Science...
Anyway, it just occurred to me that when pretty-much all the Earth's continents were joined together as Pangea around 225mya, wouldn't that have made the Earth lop-sided? Continental crust is much thicker and heavier than oceanic crust, so wouldn't there be a higher concentration of surface mass on one side of the planet than the other?
I'd have though that would have caused an imbalance in the rotational axis and/or speed. This could have a knock-on effects in weather, currents, tides etc.
Having said that, even today the Pacific Ocean covers a third of the surface, so do we know if that vast an expanse with no continental crust causes any mass imbalance?