isostasy

Noun

isostasy (usually uncountable, plural isostasies)

1. (usually) The state of balance or pressure equilibrium thought to exist within the Earth's crust, whereby the upper lithosphere floats on denser magma beneath.
   • The process of vertical movement, known as isostasy, was a foundation of geological belief for generations, though no-one had any really good theories as to how or why it happened.2003, Bill Bryson, A Short History of Nearly Everything, BCA, page 155
   • A great thickness of comparatively light sedimentary rocks accumulating in a geosyncline would ultimately ‘rebound’ because of isostasy – like a depressed rubber duck bouncing back upwards in a bath.2004, Richard Fortey, The Earth, Folio Society, published 2011, page 173