Principle that a body submerged in a fluid is buoyed up by a force equal in magnitude to the weight of the fluid that is displaced, and directed upward along a line through the center of gravityAttractive force between all matter - one of the four fundamental forces. Click on Term to Read More of the displaced fluid. Applied on a crustal scale this is the principle of isostasyMechanism whereby areas of the crust rise or subside until the mass of their topography is buoyantly supported or compensated by the thickness of crust below, which “floats” on the denser mantle. Isostatic gravity anomalies are derived from the assumption that the gravitational effect of the mass associated with the Click on Term to Read More.