"Tectonic plates" redirects here. For the film, see Tectonic Plates (film).
Map of Earth's 16 principal tectonic plates Divergent:
Spreading center
Extension zone
Convergent:
Subduction zone
Collision zone
Transform:
Dextral transform
Sinistral transform
Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale)
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Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building')[1] is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since about 3.4billion years ago.[2] The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s.
Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): convergent, divergent, or transform. The relative movement of the plates typically ranges from zero to 10 cm annually.[3] Faults tend to be geologically active, experiencing earthquakes, volcanic activity, mountain-building, and oceanic trench formation.
Tectonic plates are composed of the oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust. Along convergent plate boundaries, the process of subduction carries the edge of one plate down under the other plate and into the mantle. This process reduces the total surface area (crust) of the Earth. The lost surface is balanced by the formation of new oceanic crust along divergent margins by seafloor spreading, keeping the total surface area constant in a tectonic "conveyor belt".
Tectonic plates are relatively rigid and float across the ductile asthenosphere beneath. Lateral density variations in the mantle result in convection currents, the slow creeping motion of Earth's solid mantle. At a seafloor spreading ridge, plates move away from the ridge, which is a topographic high, and the newly formed crust cools as it moves away, increasing its density and contributing to the motion. At a subduction zone the relatively cold, dense oceanic crust sinks down into the mantle, forming the downward convecting limb of a mantle cell,[4] which is the strongest driver of plate motion.[5][6] The relative importance and interaction of other proposed factors such as active convection, upwelling inside the mantle, and tidal drag of the Moon is still the subject of debate.
^Little, Fowler & Coulson 1990.
^University of the Witwatersrand (2019). "Drop of ancient seawater rewrites Earth's history: Research reveals that plate tectonics started on Earth 600million years before what was believed earlier". ScienceDaily. Archived from the original on 2019-08-06. Retrieved 2019-08-11.
^Read & Watson 1975.
^Stern, Robert J. (2002). "Subduction zones". Reviews of Geophysics. 40 (4): 1012. Bibcode:2002RvGeo..40.1012S. doi:10.1029/2001RG000108. S2CID 247695067.
^Forsyth, D.; Uyeda, S. (1975). "On the Relative Importance of the Driving Forces of Plate Motion". Geophysical Journal International. 43 (1): 163–200. Bibcode:1975GeoJ...43..163F. doi:10.1111/j.1365-246x.1975.tb00631.x.
Platetectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere...
This is a list of tectonicplates on Earth's surface. Tectonicplates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere...
This is a list of articles related to platetectonics and tectonicplates. Platetectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining...
of tectonic elements which define the subdivision into numerous smaller microplates which have amalgamated into the larger Plates. Salt tectonics is concerned...
Pacific Plate is an oceanic tectonicplate that lies beneath the Pacific Ocean. At 103 million km2 (40 million sq mi), it is the largest tectonicplate. The...
The PlateTectonics Revolution was the scientific and cultural change which developed from the acceptance of the platetectonics theory. The event was...
The Nazca Plate or Nasca Plate, named after the Nazca region of southern Peru, is an oceanic tectonicplate in the eastern Pacific Ocean basin off the...
The Australian Plate is a major tectonicplate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana...
The Indian Plate (or India Plate) is a minor tectonicplate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent...
In platetectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature...
of platetectonics in 1970, but still results in net destruction when summed over major plate boundaries. Divergent boundaries are areas where plates move...
The Somali Plate is a minor tectonicplate which straddles the Equator in the Eastern Hemisphere. It is currently in the process of separating from the...
geophysical models remain controversial among geologists: it appears that platetectonics and the growth of continents may have started in the Hadean. Earth...
The Solomon Sea Plate (also known as the Solomon Plate) is a minor tectonicplate to the northwest of the Solomon Islands archipelago in the south Pacific...
The Antarctic Plate is a tectonicplate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and...
The Arabian Plate is a minor tectonicplate in the Northern and Eastern Hemispheres. It is one of the three continental plates (along with the African...
The North American Plate is a tectonicplate containing most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and...
List of tectonicplate interactions – Movements of Earth's lithosphere Platetectonics – Movement of Earth's lithosphere Strike-slip tectonics – Deformation...
The Mariana Plate is a micro tectonicplate located west of the Mariana Trench which forms the basement of the Mariana Islands which form part of the...
Cascadia Channel Geology of the Pacific Northwest Platetectonics "Sizes of Tectonic or Lithospheric Plates". Geology.about.com. 5 March 2014. Archived from...
subducted under a continent. Due to the driving forces of the rock cycle, platetectonics and the water cycle, rocks do not remain in equilibrium and change...
features related to convergent boundaries vary depending on crust types. Platetectonics is driven by convection cells in the mantle. Convection cells are the...
that tectonic subduction zones require the lubrication of oceans of water. Platetectonics also provide a means of biochemical cycling. Platetectonics and...
to the theory of platetectonics, Earth's lithosphere, its rigid outer shell, is broken into sixteen larger and several smaller plates. These are in slow...
Adriatic/Apulian Plate, an unusual circumstance in platetectonics. Oceanic crust of the African Plate is also subducting under the Adriatic/Apulian Plate off the...
are its most important tectonic feature. Subduction is the driving force behind platetectonics, and without it, platetectonics could not occur. Oceanic...
lid tectonics (comparable to the tectonics operating on Mars and Venus) prevailed during Precambrian times. According to this theory, platetectonics as...
The Caroline Plate is a minor tectonicplate that straddles the Equator in the eastern hemisphere located north of New Guinea. It forms a subduction zone...
Oceanic crust is the uppermost layer of the oceanic portion of the tectonicplates. It is composed of the upper oceanic crust, with pillow lavas and a...
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