Contents of 13.1 Why are continents high and oceans low?

13.1 Why are continents high and oceans low?

Illustration shows balance scales with a large block of wood balancing out with a much smaller but equally heavy block of lead.

Fig 13.3

Isostasy (from Greek roots meaning equal-standing) determines elevation. This means pressure at the base of various parts of the crust is equal, so if crust types are of different densities, then to have the same pressure beneath means the thickness (volumes) must differ.