isostasy

or i·sos·ta·cy

[ ahy-sos-tuh-see ]

noun

1. Geology. the equilibrium of the earth's crust, a condition in which the forces tending to elevate balance those tending to depress.
2. the state in which pressures from every side are equal.

isostasy

/ ˌaɪsəʊˈstætɪk; aɪˈsɒstəsɪ /

noun

1. the state of balance, or equilibrium, which sections of the earth's lithosphere (whether continental or oceanic) are thought ultimately to achieve when the vertical forces upon them remain unchanged. The lithosphere floats upon the semifluid asthenosphere below. If a section of lithosphere is loaded, as by ice, it will slowly subside to a new equilibrium position; if a section of lithosphere is reduced in mass, as by erosion, it will slowly rise to a new equilibrium position

isostasy

/ ī-sŏs′tə-sē /

1. Equilibrium in the Earth's crust, in which an elevated part in one area is counterbalanced by a depressed part in another. Isostasy exists because the Earth's crust is relatively light compared to the denser mantle over which it lies, and therefore behaves as if it is floating. Areas of the Earth's crust rise or subside to accommodate added load (as from a glacier) or diminished load (as from erosion), so that the forces that elevate landmasses balance the forces that depress them.

Derived Forms

• isostatic, adjective

Word History and Origins

Origin of isostasy¹

1885–90; iso- + -stasy < Greek -stasia; stasis, -y ³

Word History and Origins

Origin of isostasy¹

C19: iso- + -stasy, from Greek stasis a standing

Example Sentences

And the third is a process known as isostasy, which keeps mountains afloat above the hot and soft mantle material in a similar way to icebergs floating in water.

From Nature

The process of vertical movement known as isostasy, was a foundation of geological beliefs for generations, though no one had any good theories as to how or why it happened.

From Literature

Nature's methods rarely allow so gradual an adjustment to the forces of isostasy.

From Project Gutenberg

The metals of different density floating in mercury in this diagram illustrate isostasy according to the theory of Pratt and Hayford.

From Project Gutenberg

This state of equilibrium, which was first recognised by Pratt, as part of the dynamics of the Earth's crust, has been named isostasy.

From Project Gutenberg