Isostatic adjustment

  • Walter S. Newman
Reference work entry

Isostatic adjustment refers to the transient (102−104 years) or long term (> 105 years) nonelastic response of the earth's lithosphere to loading and unloading due to erosion, deposition, water loading, desiccation, ice accumulation, and deglaciation. Isostasy is essentially the Archimedian principle of hydrostatic balance between floating bodies. The term isostasywas proposed by C. E. Dutton in 1889 to define a suggestion made by Sir George Airy in 1855 that the earth's crust is supported by underlying denser material, and that the weight of mountains is balanced by light material extending as roots into the denser mantle. Perhaps the best example of isostasy is the contrast in levels between the earth's major first-order physiographic features: the continental platforms and the ocean basins. The mean elevation of the continents is about 1 km, while the average depth of the oceans is near 4 km. The 5-km difference is best explained by the differing densities of the rocks underlying...

This is a preview of subscription content, log in to check access.


  1. Cathles, L. M., III, 1975. The Viscosity of the Earth's Mantle. Princeton, N.J.: Princeton University Press, 386p.Google Scholar

Copyright information

© Hutchinson Ross Publishing Company 1982

Authors and Affiliations

  • Walter S. Newman

There are no affiliations available