plate tectonics

plate tectonics
Tectonics Tec*ton"ics, n. 1. The science, or the art, by which implements, vessels, dwellings, or other edifices, are constructed, both agreeably to the end for which they are designed, and in conformity with artistic sentiments and ideas. [1913 Webster]

2. (Geol. & Phys. Geog.) the branch of geology concerned with the rock structures and external forms resulting from the deformation of the earth's crust; also, similar studies of other planets. Also called {structural geology}. [PJC]

{plate tectonics} a geological theory which considers the earth's crust as divided into a number of large relatively rigid plates, which move relatively independently on the more plastic asthenosphere under the influence of magmatic upwellings, so as to drift apart, slide past, or collide with each other, causing the formation, breakup, or merging of continents, and causing volcanism, the building of mountain ranges, and the subduction of one plate beneath another. In recent decades a large body of data have accumulated to support the theory and provide some details of the mechanisms at work. One set of supporting observations consists of data showing that the continents have slowly moved relative to each other over long periods of time, a phenomenon called {continental drift}. Africa and South America, for example, have apparently moved apart from a connected configuration at about 2 to 3 cm per year over tens of millions of years. [PJC]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • plate tectonics — plate tectonic, adj. Geol. a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past… …   Universalium

  • plate tectonics — plate tectonics, n. (Geol.) A geological theory which holds that the crust of the earth (the lithosphere) is divided into a small number of large separate plates which float and move slowly around on the more plastic asthenosphere, breaking apart …   The Collaborative International Dictionary of English

  • plate tectonics — n. Geol. the theory that the earth s surface consists of plates, or large crustal slabs, whose constant motion explains continental drift, mountain building, etc …   English World dictionary

  • Plate tectonics — The tectonic plates of the world were mapped in the second half of the 20th century …   Wikipedia

  • plate tectonics — /pleɪt tɛkˈtɒnɪks/ (say playt tek toniks) noun a theory concerning the movements of the earth s lithosphere that explains how tectonic plates ride on the moving asthenosphere; supporting the theory of continental drift and sea floor spreading.… …   Australian English dictionary

  • plate tectonics — noun the branch of geology studying the folding and faulting of the earth s crust • Syn: ↑tectonics, ↑plate tectonic theory • Members of this Topic: ↑Pangaea, ↑Pangea • Hypernyms: ↑morphology, ↑ …   Useful english dictionary

  • plate tectonics — N UNCOUNT Plate tectonics is the way that large pieces of the earth s surface move slowly around. [TECHNICAL] …   English dictionary

  • plate tectonics — plate′ tecton′ics n. gel a geologic theory that describes the earth s crust as divided into a number of rigid plates, movement of which accounts for such phenomena as continental drift and the distribution of earthquakes • Etymology: 1965–70… …   From formal English to slang

  • plate tectonics — plate tec tonics n [U] technical the study of the forming and movement of the large sheets of rock that form the surface of the Earth …   Dictionary of contemporary English

  • plate tectonics — plate tec tonics noun uncount SCIENCE the study of the large layers of rock under the surface of the Earth, and how they were formed and move …   Usage of the words and phrases in modern English

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