Divergent boundary
Information about Divergent boundary
In plate tectonics, a divergent boundary (divergent fault boundary or divergent plate boundary), (but also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. These areas can form in the middle of continents but eventually form ocean basins. Divergent boundaries within continents initially produce rifts which produce rift valleys. If the rifting process stops, a failed rift results. Therefore, most active divergent plate boundaries exist between oceanic plates and are often called oceanic rifts. Divergent boundaries are a type of stress called tension. It is when two bodies of land are spread apart.
Although still an area of active research, it appears that due to complex convection within the Earth's mantle material rises to the base of the lithosphere beneath the divergent plate boundary.[1] This supplies the area with vast amounts of heat and a reduction in pressure that melts rock from the asthenosphere (or upper mantle) beneath the rift area forming large flood basalt flows. Each eruption occurs in only a part of the plate boundary at any one time, but when it does occur, it fills in the opening gap as the two opposing plates move away from each other. The average rate of movement is comparable to how fast human fingernails grow, about 2 cm a year.
Over millions of years the plates have moved many hundreds of kilometers away from both sides of the divergent plate boundary. Because of this, rock closest to the boundary is younger than rock further away on the same plate.
Continental crust is often split along divergent plate boundaries.
Although still an area of active research, it appears that due to complex convection within the Earth's mantle material rises to the base of the lithosphere beneath the divergent plate boundary.[1] This supplies the area with vast amounts of heat and a reduction in pressure that melts rock from the asthenosphere (or upper mantle) beneath the rift area forming large flood basalt flows. Each eruption occurs in only a part of the plate boundary at any one time, but when it does occur, it fills in the opening gap as the two opposing plates move away from each other. The average rate of movement is comparable to how fast human fingernails grow, about 2 cm a year.
Over millions of years the plates have moved many hundreds of kilometers away from both sides of the divergent plate boundary. Because of this, rock closest to the boundary is younger than rock further away on the same plate.
Continental crust is often split along divergent plate boundaries.
Divergent boundaries
- The Mid-Atlantic Ridge
- The boundary between the African Plate and Arabian Plate (the Red Sea)
- Great Rift Valley
- West Antarctic Rift
- East Pacific Rise
- Pacific-Antarctic Ridge
- Galapagos Rise
- Gakkel Ridge
Other plate boundary types
See also
References
1. ^ Toshiro Tanimoto, Thorne Lay (November 7, 2000). "Mantle dynamics and seismic tomography". PNAS vol. 97 (no. 23): pp. 12409–12410. DOI:10.1073/pnas.210382197.2000&rft.volume=vol.%2097&rft.issue=no.%2023&rft.au=Toshiro%20Tanimoto,%20Thorne%20Lay&rft.pages=pp.%2012409%26%238211%3B12410&rft_id=info:doi/10.1073%2Fpnas.210382197&rft_id=http%3A%2F%2Fwww.pnas.org%2Fcgi%2Fcontent%2Ffull%2F97%2F23%2F12409">
Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth's lithosphere.
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list of tectonic plates on Earth. Tectonic plates are pieces of the Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (60 miles) thick and consist of two principal types of material: oceanic crust (also called sima
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continent is one of several large landmasses on Earth. They are generally identified by convention rather than any strict criteria, but seven areas are commonly regarded as continents – they are (from largest in size to smallest): Asia, Africa, North America, South America,
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rift is a place where the Earth's crust and lithosphere are being pulled apart. Typical features are a central linear downdropped fault segment, called a graben, with parallel normal faulting and rift-flank uplifts on either side forming a rift valley.
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rift valley in geology is a valley created by the formation of a rift. The Great Rift Valley, located in the Middle East and Africa, is the most famous of the world's rift valleys. Rift valleys are produced by tensional tectonic forces which occur at divergent plate boundaries.
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Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima. It is thinner than continental crust, or sial, generally less than 10 kilometers thick, however it is more dense, having a mean density
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Convection in the most general terms refers to the movement of currents within fluids (i.e. liquids, gases and rheids).
Convection is one of the major modes of heat and mass transfer.
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Convection is one of the major modes of heat and mass transfer.
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EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001. Their greatest hit, their debut single "time after time", peaked at #13 in the Oricon singles chart.
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mantle is a ~2,900 km thick rocky shell comprising approximately 70% of Earth's volume. It is predominantly solid and overlies the Earth's iron-rich core, which occupies about 30% of Earth's volume.
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lithosphere (IPA: [ˈlɪθ.ə.sfiɹ], from the Greek for "rocky" sphere) is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost mantle which is joined to the crust across the Mohorovičić
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Balanced Rock stands in Garden of the Gods park in Colorado Springs, CO]] A rock is a naturally occurring aggregate of minerals and/or mineraloids. The Earth's lithosphere is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic.
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asthenosphere (from an invented Greek ἀσθενός a + sthenos "without strength") is the region of the Earth between 100-200 km below the surface — but perhaps extending as deep as
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flood basalt or trapp basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales (large igneous provinces) in prehistory, creating great plateaus
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nail is a horn-like structure at the end of a human's or an animal's finger or toe. See also claw.
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Parts of the nail
Anatomically fingernails and toenails..... Click the link for more information.
The continental crust is the layer of granitic, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves.
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Mid-Atlantic Ridge is a mostly underwater mountain range of the Atlantic Ocean and Arctic Ocean that runs from 87°N (about 333 km South of the North Pole) to subantarctic Bouvet Island at 54°S. The highest peaks of this mountain range extend above the water mark, to form islands.
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African Plate is a tectonic plate covering the continent of Africa and extending westward to the Mid-Atlantic Ridge.
The westerly side is a divergent boundary with the North American Plate to the north and the South American Plate to the south forming the central and
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The westerly side is a divergent boundary with the North American Plate to the north and the South American Plate to the south forming the central and
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Arabian Plate is made up of three tectonic plates (the African, Arabian and Indian crustal plates) which have been moving northward over millions of years toward an inevitable collision with Eurasia.
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Red Sea is an inlet of the Indian Ocean between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb sound and the Gulf of Aden. In the north are the Sinai Peninsula, the Gulf of Aqaba) and the Gulf of Suez (leading to the Suez Canal).
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Great Rift Valley is a vast geographical and geological feature, approximately 6,000 kilometres (0 mi) in length, which runs from northern Syria in Southwest Asia to central Mozambique in East Africa.
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The West Antarctic Rift is a major, active rift valley lying between East and West Antarctica. It encompasses the Ross Sea, the area under the Ross Ice Shelf and a part of West Antarctica.
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The East Pacific Rise is a long north-south welt of seafloor spreading under the eastern Pacific Ocean from near Antarctica in the south northward to its termination at the northern end of the Gulf of California in the Salton Sea basin in southern California.
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Pacific-Antarctic Ridge is an oceanic ridge at the boundary between the Pacific and Antarctic Plates. Convection currents in the Earth's mantle are causing the plates to separate, creating new oceanic crust at a rate of approximately 2.9 cm each year.
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The Galapagos Rise is a divergent boundary located between the South American coast and the triple junction of the Nazca Plate, the Cocos Plate, and the Pacific Plate. The volcanically active Galapagos Islands exist on a hotspot above the Galapagos Rise.
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Gakkel Ridge is a mid-oceanic ridge located in the Arctic Ocean between Greenland and Siberia with a length of about 1,800 kilometers. It was discovered by a Soviet polar explorer Yakov Yakovlevich Gakkel and named after him in 1966.
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In plate tectonics, a convergent boundary – also known as a convergent plate boundary or a destructive plate boundary – is an actively deforming region where two (or more) tectonic plates or fragments of lithosphere move toward one another.
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In plate tectonics, a transform boundary (also known as transform fault boundary, transform plate boundary, transform plate margin, strike-slip boundary, sliding boundary, or conservative plate boundary
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Seafloor spreading occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.
Earlier theories (e.g.
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Earlier theories (e.g.
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Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth's lithosphere.
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Continental drift refers to the movement of the Earth's continents relative to each other.
Frank Bursley Taylor had proposed the concept in a Geological Society of America meeting in 1908 and published his work in the GSA Bulletin in June 1910.
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Frank Bursley Taylor had proposed the concept in a Geological Society of America meeting in 1908 and published his work in the GSA Bulletin in June 1910.
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