>>7622047You mean isostasy in the context of geology, right?
One way think of isostasy to cut the earth into a bunch of different cross sections from the core to the surface. Each cross section is supposed to have roughly the same weight, because if the crust of one section were heavier than the others, it would sink into the mantel, displacing semifluid mantel material until it equaled the other cross sections.
Basically, if you add mass like an icecap to a continent, that continent will sink. Melt the icecap and the land will rise again. Also if a large area underwent substantial erosion, the land would rise.
