Isostasy

Mechanism 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 surface topography is approximately compensated by a deficit of either the density or the subsurface thickness of the crustal material.

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