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