plate tectonics

American  

[pleyt tek-ton-iks] / ˈpleɪt tɛkˈtɒn ɪks /

noun

Geology.

1. 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 adjacent plates.

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plate tectonics British  

noun

1. (functioning as singular) geology the study of the structure of the earth's crust and mantle with reference to the theory that the earth's lithosphere is divided into large rigid blocks ( plates ) that are floating on semifluid rock and are thus able to interact with each other at their boundaries, and to the associated theories of continental drift and seafloor spreading

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plate tectonics Scientific  

1. In geology, a theory that the Earth's lithosphere (the crust and upper mantle) is divided into a number of large, platelike sections that move as distinct masses. The movement of the plates is believed to result from the presence of large convection cells in the Earth's mantle which allow the rigid plates to move over the relatively plastic asthenosphere. The theory of plate tectonics was developed in the 1960s in an effort to explain the jigsawlike pattern of the Earth's continents.

2. See Note at fault See more at tectonic boundary

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plate tectonics Cultural  

1. In geology, a theory that explains the distribution of continents, earthquakes, volcanoes,, mountains and other geologic phenomena in terms of the formation, movement, and destruction of tectonic plates. These plates move in response to forces deep within the Earth. Because continents, such as North America, often ride piggy-back on plates, their movement is referred to as continental drift.

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Closer Look

Although German physicist, meteorologist, and explorer Alfred Wegener proposed the theory of continental drift in 1912, suggesting that the continents were once joined as one large landmass, the explanation for the movement of such large landmasses into their current positions was not developed for several more decades. According to the theory of plate tectonics, which was proposed in the 1960s, the continents (and ocean floors) ride atop about a dozen semirigid plates—huge slabs of Earth's lithosphere—that are much larger than the continents themselves. The plates' constant movement is powered by huge convection currents of molten rock in Earth's mantle, thought by many geologists to be heated by the decay of radioactive elements deep within Earth. Although the plates move only a few inches per year, over the hundreds of millions of years of geological time, the continents are carried thousands of miles. Along their margins, the independently moving plates interact in three main ways. Where plates pull apart, new crust is formed. Where they collide, one plate is submerged beneath the other, and material from the bottom one returns to Earth's mantle. If the converging plates have land masses on them, the boundaries crumple, forming mountains. Plates also slide past each other, creating the faults that produce earthquakes. The six major plates are the Eurasian, American, African, Pacific, Indian, and Antarctic.

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Earthquakes and volcanoes tend to occur at the boundaries between plates: the San Andreas Fault is on such a boundary.

New plate material is constantly created by the process of sea floor spreading, and old material is destroyed when two plates collide and one plate moves under the other.

Other Word Forms

• plate-tectonic adjective

Etymology

Origin of plate tectonics

First recorded in 1965–70

Compare meaning

How does plate-tectonics compare to similar and commonly confused words? Explore the most common comparisons:

• continental drift vs. plate tectonics

Example Sentences

Stagnant lid: A tectonic state where the planet's outer shell is rigid and unmoving, with very little surface recycling compared to modern plate tectonics.

From Science Daily

More than anything else, Japan has been shaped by the push and pull of plate tectonics.

From Literature

The resulting 1978 masterpiece—sublimely detailed and marvelously strange in its presentation of unseen ridges, troughs and endless plains—reflected the newly established theories of plate tectonics and continental drift.

From The Wall Street Journal

These findings highlight a direct connection between deep-Earth processes and surface evolution, showing how plate tectonics, the carbon cycle, and biological development were intertwined over deep time.

From Science Daily

These findings highlight the overwhelming odds against discovering Earth-like planets that possess both plate tectonics and a nitrogen-oxygen atmosphere containing the right balance of oxygen and carbon dioxide.

From Science Daily