What gravitational evidence do we have to counter the idea that oceans are formed when continents sink?

Question

Is there some evidence for this based on gravity anomalies? I think I know how to tell if a mountain or structure is compensated based on bougeur and free air anomalies, but this really has me stumped? Does this somehow tie into how underwater mountains are compensated by pratt rather than airy?

Answer 1

We can tell the relative density and thickness of the lithosphere based on gravity surveys. A gravity survey over the open ocean would indicate a relatively thin and dense lithosphere. This is counter to the idea that a sunken continent formed an ocean basin because the continental lithosphere is much thicker that the oceanic lithosphere.

I hope this helps!