plate tectonics

[ pleyt tek-ton-iks ]

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.

plate tectonics

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

plate tectonics

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 faultSee more at tectonic boundary

plate tectonics

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 .

Notes

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 Words From

• plate-tec·ton·ic adjective

Word History and Origins

Origin of plate tectonics¹

First recorded in 1965–70

A 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.

Example Sentences

Pressure from the collision of the Indian and the Eurasian plates 40-50 million years ago formed the Himalayas and plate tectonics remains the major reason for their continued rise.

From BBC

Earth scientists have long studied and debated the origin of plate tectonics, and other theories have been offered.

From New York Times

"When we first want to understand how earthquakes work, we look to plate tectonics, because that is and will always be the number one reason why an earthquake happens," Frank says.

From Science Daily

Researchers have used zircons to try to date the onset of plate tectonics and the origin of continental crust.

From Science Magazine

This will help us to understand how rapidly heat is escaping from Earth's deep interior, which is key for understanding processes such as plate tectonics.

From Science Daily