What is isostasy?

  • Isostasy is a fundamental concept in the Geology.
  • It is the idea that the lighter crust must be floating on the denser underlying mantle.
  • It is invoked to explain how different topographic heights can exists on the Earth’s surface.
  • Isostatic equilibrium is an ideal state where the crust and mantle would settle into in absence of disturbing forces.
  • The waxing and waning of ice sheets, erosion, sedimentation, and extrusive volcanism are examples of processes that perturb isostasy.
  • The physical properties of the lithosphere (the rocky shell that forms Earth’s exterior) are affected by the way the mantle and crust respond to these perturbations.
  • Therefore, understanding the dynamics of isostasy helps us figure out more complex phenomena such as mountain building, sedimentary basin formation, the break-up of continents and the formation of new ocean basins.