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Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since about 3.4 billion years ago.
Mar 7, 2024 · Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth’s subterranean movements. The theory, which solidified in the 1960s, transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes. In plate tectonics, Earth’s outermost ...
- Overview
- Principles of plate tectonics
German meteorologist Alfred Wegener is often credited as the first to develop a theory of plate tectonics, in the form of continental drift. Bringing together a large mass of geologic and paleontological data, Wegener postulated that throughout most of geologic time there was only one continent, which he called Pangea, and the breakup of this continent heralded Earth’s current continental configuration as the continent-sized parts began to move away from one another. (Scientists discovered later that Pangea fragmented early in the Jurassic Period.) Wegener presented the idea of continental drift and some of the supporting evidence in a lecture in 1912, followed by his major published work, The Origin of Continents and Oceans (1915).
Read more below: Development of tectonic theory
Pangea
Learn more about Pangea.
What is the cause of plate tectonics?
Although this has yet to be proven with certainty, most geologists and geophysicists agree that plate movement is caused by the convection (that is, heat transfer resulting from the movement of a heated fluid) of magma in Earth’s interior. The heat source is thought to be the decay of radioactive elements. How this convection propels the plates is poorly understood. Some geologists argue that upwelling magma at spreading centres pushes the plates, whereas others argue that the weight of a portion of a subducting plate (one that is forced beneath another) may pull the rest of the plate along.
In essence, plate-tectonic theory is elegantly simple. Earth’s surface layer, 50 to 100 km (30 to 60 miles) thick, is rigid and is composed of a set of large and small plates. Together, these plates constitute the lithosphere, from the Greek lithos, meaning “rock.” The lithosphere rests on and slides over an underlying partially molten (and thus weaker but generally denser) layer of plastic partially molten rock known as the asthenosphere, from the Greek asthenos, meaning “weak.” Plate movement is possible because the lithosphere-asthenosphere boundary is a zone of detachment. As the lithospheric plates move across Earth’s surface, driven by forces as yet not fully understood, they interact along their boundaries, diverging, converging, or slipping past each other. While the interiors of the plates are presumed to remain essentially undeformed, plate boundaries are the sites of many of the principal processes that shape the terrestrial surface, including earthquakes, volcanism, and orogeny (that is, formation of mountain ranges).
The process of plate tectonics may be driven by convection in Earth’s mantle, the pull of heavy old pieces of crust into the mantle, or some combination of both. For a deeper discussion of plate-driving mechanisms, see Plate-driving mechanisms and the role of the mantle.
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Plate Tectonics. The Earth's plates jostle about in fits and starts that are punctuated with earthquakes and volcanic eruptions. 4 min read. There are a few handfuls of major plates and dozens...
- 5 min
The theory of plate tectonics explains processes in the geosphere that are fueled by Earth’s internal heat that have operated over billions of years. These changes can be imperceptible over a human lifetime or violent and abrupt, and continue to shape Earth’s environments. Global Change Infographic.
Earth’s lithosphere, or outermost shell, is broken up into large pieces called tectonic plates. These plates move slowly over the asthenosphere, a layer of softer rock below the lithosphere. On average, tectonic plates move a few centimeters per year. The place where two plates meet is called a plate boundary.
Plate tectonics is a theory about how Earth's lithosphere is divided into a series of rigid plates; and, how movements of these plates produce earthquakes, volcanoes, ocean trenches, mountain ranges, and more. Plate Tectonics Animation. Watch This Billion-Year Journey of Earth's Tectonic Plates on The New York Times website.
