global tectonics wikipedia

Earlier theories, since disproven, proposed gradual shrinking (contraction) or gradual expansion of the globe.[4]. [72], Tectonic motion is believed to have begun around 3 to 3.5 billion years ago.[73][74][why? Tidal drag due to the gravitational force the, Other smaller deformation effects of the crust due to wobbles and spin movements of the Earth rotation on a smaller time scale. [80], Consideration of plate tectonics is a part of the search for extraterrestrial intelligence and extraterrestrial life. In the same paper the authors admit, however, that relative to the lower mantle, there is a slight westward component in the motions of all the plates. Exactly how this works is still a matter of debate. [77] Additional evidence comes from the distribution of certain sedimentary rock types,[78] faunal provinces shown by particular fossil groups, and the position of orogenic belts.[76]. When the new crust forms at mid-ocean ridges, this oceanic lithosphere is initially less dense than the underlying asthenosphere, but it becomes denser with age as it conductively cools and thickens. [55] Often, these contributions are forgotten because: In 1947, a team of scientists led by Maurice Ewing utilizing the Woods Hole Oceanographic Institution's research vessel Atlantis and an array of instruments, confirmed the existence of a rise in the central Atlantic Ocean, and found that the floor of the seabed beneath the layer of sediments consisted of basalt, not the granite which is the main constituent of continents. ??? Este ficheiro está licenciado baixo a licenza Creative Commons recoñecemento compartir igual xenérico 2.5.: Vostede é libre de: compartir – copiar, distribuír e difundir a obra; facer obras derivadas – adaptar a obra; Baixo as seguintes condicións: recoñecemento – Debe indicar a debida atribución de autoría, fornecer unha ligazón á licenza, e indicar se se realizaron cambios. They are associated with different types of surface phenomena. ?? An alternative explanation, though, was that the continents had moved (shifted and rotated) relative to the north pole, and each continent, in fact, shows its own "polar wander path". ], Various types of quantitative and semi-quantitative information are available to constrain past plate motions. In the 1990s, it was proposed that Martian Crustal Dichotomy was created by plate tectonic processes. ??? [41] In that book (re-issued in four successive editions up to the final one in 1936), he noted how the east coast of South America and the west coast of Africa looked as if they were once attached. Two- and three-dimensional imaging of Earth's interior (seismic tomography) shows a varying lateral density distribution throughout the mantle. [39] The driving forces of plate motion continue to be active subjects of on-going research within geophysics and tectonophysics. ?? (Cf. Tectonics is concerned with orogenies (mountain building) and major land features. ?? Slab suction (gravity): Plate motion driven by local convection currents that exert a downward pull on plates in subduction zones at ocean trenches. Tectonic lithosphere plates consist of lithospheric mantle overlain by one or two types of crustal material: oceanic crust (in older texts called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). Concepts close to the elements now incorporated in plate tectonics were proposed by geophysicists and geologists (both fixists and mobilists) like Vening-Meinesz, Holmes, and Umbgrove. Plate boundaries are commonly associated with geological events such as earthquakes and the creation of topographic features such as mountains, volcanoes, mid-ocean ridges, and oceanic trenches. However, in the plate tectonics context (accepted since the seafloor spreading proposals of Heezen, Hess, Dietz, Morley, Vine, and Matthews (see below) during the early 1960s), the oceanic crust is suggested to be in motion with the continents which caused the proposals related to Earth rotation to be reconsidered. Tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. This hypothesis linked these patterns to geomagnetic reversals and was supported by several lines of evidence:[62]. It asserts that super plumes rise from the deeper mantle and are the drivers or substitutes of the major convection cells. Earth may be a borderline case, owing its tectonic activity to abundant water [80] (silica and water form a deep eutectic). The much improved data from the WWSSN instruments allowed seismologists to map precisely the zones of earthquake concentration worldwide. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the fluid-like (visco-elastic solid) asthenosphere. There is debatable evidence of active tectonics in the planet's distant past; however, events taking place since then (such as the plausible and generally accepted hypothesis that the Venusian lithosphere has thickened greatly over the course of several hundred million years) has made constraining the course of its geologic record difficult. La tectonique des plaques (du latin tardif tectonicus , dérivé du grec ancien τεκτονικός / tektonikós « de construction ») est un modèle scientifique expliquant la dynamique globale de la lithosphère terrestre. Geodesy Fundamentals … Wikipedia [89], Titan, the largest moon of Saturn, was reported to show tectonic activity in images taken by the Huygens probe, which landed on Titan on January 14, 2005. Global Tectonics By Philip Kearey ofiolita wikipedia la enciclopedia libre. Reasoning in an opposite way, the continents might have shifted and rotated, while the pole remained relatively fixed. This is discussed further in plate tectonics.[1]. By explaining both the zebra-like magnetic striping and the construction of the mid-ocean ridge system, the seafloor spreading hypothesis (SFS) quickly gained converts and represented another major advance in the development of the plate-tectonics theory. As the Earth spins eastward beneath the moon, the moon's gravity ever so slightly pulls the Earth's surface layer back westward, just as proposed by Alfred Wegener (see above). It explains movement of the Earth's lithosphere: this is the earth's crust and the upper part of the mantle. In 1973, George W. Moore[35] of the USGS and R. C. Bostrom[36] presented evidence for a general westward drift of the Earth's lithosphere with respect to the mantle. He concluded that tidal forces (the tidal lag or "friction") caused by the Earth's rotation and the forces acting upon it by the Moon are a driving force for plate tectonics. The distinction between oceanic crust and continental crust is based on their modes of formation. [8] Continental lithosphere is typically about 200 km thick, though this varies considerably between basins, mountain ranges, and stable cratonic interiors of continents. Dissipation of heat from the mantle is acknowledged to be the original source of the energy required to drive plate tectonics through convection or large scale upwelling and doming. This is based on the fact that rocks of different ages show a variable magnetic field direction, evidenced by studies since the mid–nineteenth century. With special reference to the geology of Central Calabria", "Alfred Wegener (1880–1930): A Geographic Jigsaw Puzzle", "Alfred Wegener (1880–1930): The origin of continents and oceans", "Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus", "A voice from the past: John Lyman and the plate tectonics story", "Moon Is Dragging Continents West, Scientist Says", 10.1130/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2, 10.1130/0091-7613(1973)1<99:WTLATD>2.0.CO;2, "Rises, Trenches, Great Faults, and Crustal Blocks", 10.1130/0016-7606(1961)72[1267:MSOTWC]2.0.CO;2, "Topography and geomorphology of the Huygens landing site on Titan", "Slab pull and the seismotectonics of subducting lithosphere", "The Marine Physical Laboratory at Scripps", "Plate tectonics and net lithosphere rotation over the past 150 My", "Die Herausbildung der Grossformen der Erdrinde (Kontinente und Ozeane), auf geophysikalischer Grundlage", "A new class of faults and their bearing on continental drift", "A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup", "Degree-1 mantle convection and the crustal dichotomy on Mars", This Dynamic Earth: The Story of Plate Tectonics, Bird, P. (2003); An updated digital model of plate boundaries, MORVEL plate velocity estimates and information, 750 million years of global tectonic activity, Multiple videos of plate tectonic movements, https://en.wikipedia.org/w/index.php?title=Plate_tectonics&oldid=999665330, Short description is different from Wikidata, Wikipedia indefinitely semi-protected pages, Articles containing Ancient Greek (to 1453)-language text, Articles with unsourced statements from November 2018, Wikipedia articles needing clarification from December 2020, Wikipedia articles needing clarification from December 2014, All articles with specifically marked weasel-worded phrases, Articles with specifically marked weasel-worded phrases from January 2016, Creative Commons Attribution-ShareAlike License. Therefore, when various scientists during the early 1960s started to reason on the data at their disposal regarding the ocean floor, the pieces of the theory quickly fell into place. Sykes, Isacks, and Oliver all agreed to determine the order of authorship for Seismology and the New Global Tectonics by lot after realizing it would take the hard work of all of them to stay on the leading-edge of seismological research involving plate tectonics. plattektonik – wikipedia. Cf. ↑plate … Useful english dictionary Such density variations can be material (from rock chemistry), mineral (from variations in mineral structures), or thermal (through thermal expansion and contraction from heat energy). Tectonics is the study of the earth's structural features, especially the folding and faulting (cracking) of the Earth's crust. As explained above, tectonic plates may include continental crust or oceanic crust, and most plates contain both. ????. During the late 1950s it was successfully shown on two occasions that these data could show the validity of continental drift: by Keith Runcorn in a paper in 1956,[43] and by Warren Carey in a symposium held in March 1956. The overall pattern, defined by these alternating bands of normally and reversely polarized rock, became known as magnetic striping, and was published by Ron G. Mason and co-workers in 1961, who did not find, though, an explanation for these data in terms of sea floor spreading, like Vine, Matthews and Morley a few years later.[60]. The question particularly intrigued Harry Hammond Hess, a Princeton University geologist and a Naval Reserve Rear Admiral, and Robert S. Dietz, a scientist with the U.S. Coast and Geodetic Survey who first coined the term seafloor spreading. Current plate boundaries are defined by their seismicity. Ce modèle théorique a été constitué à partir du concept de dérive des continents , qui fut développé par Alfred Wegener au début du XX e siècle. Basin Analysis Principles and Application to Petroleum. remain convinced that plate tectonics is or was once active on this planet. [50] Those calculations had implied that, even if it started at red heat, the Earth would have dropped to its present temperature in a few tens of millions of years. Furthermore, paleomagnetic data had shown that the magnetic pole had also shifted during time. Furthermore, when the rock strata of the margins of separate continents are very similar it suggests that these rocks were formed in the same way, implying that they were joined initially. In this hypothesis, the shifting of the continents can be simply explained by a large increase in the size of the Earth since its formation. Reviews of Geophysics, Band 13, S. 326–332 The first time the evidence of magnetic polar wander was used to support the movements of continents was in a paper by Keith Runcorn in 1956,[43] and successive papers by him and his students Ted Irving (who was actually the first to be convinced of the fact that paleomagnetism supported continental drift) and Ken Creer. This division should not be confused with the chemical subdivision of these same layers into the mantle (comprising both the asthenosphere and the mantle portion of the lithosphere) and the crust: a given piece of mantle may be part of the lithosphere or the asthenosphere at different times depending on its temperature and pressure. [30] Therefore, Wegener later changed his position and asserted that convection currents are the main driving force of plate tectonics in the last edition of his book in 1929. Hess therefore concluded that the Atlantic Ocean was expanding while the Pacific Ocean was shrinking. Some scientists interpreted these as requiring plate tectonic processes, such as seafloor spreading. His paper, though little noted (and even ridiculed) at the time, has since been called "seminal" and "prescient". There are dozens of smaller plates, the seven largest of which are the Arabian, Caribbean, Juan de Fuca, Cocos, Nazca, Philippine Sea, and Scotia. Despite much opposition, the view of continental drift gained support and a lively debate started between "drifters" or "mobilists" (proponents of the theory) and "fixists" (opponents). This was described in the crucial paper of Bruce Heezen (1960),[57] which would trigger a real revolution in thinking. Today, extensive studies are dedicated to the calibration of the normal-reversal patterns in the oceanic crust on one hand and known timescales derived from the dating of basalt layers in sedimentary sequences (magnetostratigraphy) on the other, to arrive at estimates of past spreading rates and plate reconstructions. Warmly praised in its first edition, particularly for its careful balance between geology and geophysics, Global Tectonics is an even better textbook in its second edition. The Himalayas, the world's tallest mountain range, are assumed to have been formed by the collision of two major plates. Van Bemmelen later on modulated on the concept in his "Undulation Models" and used it as the driving force for horizontal movements, invoking gravitational forces away from the regional crustal doming. Plate movement is thought to be driven by a combination of the motion of the seafloor away from spreading ridges due to variations in topography (the ridge is a topographic high) and density changes in the crust (density increases as newly formed crust cools and moves away from the ridge). During the thirties up to the late fifties, works by Vening-Meinesz, Holmes, Umbgrove, and numerous others outlined concepts that were close or nearly identical to modern plate tectonics theory. Venus shows no evidence of active plate tectonics. global tectonics — earth movements and interactions on a global scale, esp. During the 20th century, improvements in and greater use of seismic instruments such as seismographs enabled scientists to learn that earthquakes tend to be concentrated in specific areas, most notably along the oceanic trenches and spreading ridges. The important step Hess made was that convection currents would be the driving force in this process, arriving at the same conclusions as Holmes had decades before with the only difference that the thinning of the ocean crust was performed using Heezen's mechanism of spreading along the ridges. [6] The driving mechanism behind this movement is described below. In terms of heat transfer, the lithosphere loses heat by conduction, whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. The same is true for the enormous Eurasian Plate. Wegener's work was initially not widely accepted, in part due to a lack of detailed evidence. 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[ 4 ] density is convection... Volcanic belts that directly affect much of the globe, a System of mid-oceanic ridges was detected [ ]... Tasmania in March 1956 the Earth are divided into the lithosphere to the lithosphere of the lithosphere of the and... For tectonic plates to move [ 13 ] forandret fra utgangspunktet, kan enkelte detaljer være unøyaktige had... The so-called `` expanding Earth '' hypothesis of S. Warren Carey ( see above ) continuously spreads away the! Evidence was used in the mantle result in convection ; that is, being continually along! Are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources and... Semi-Quantitative information are available to constrain past plate motions going back into the Indian and Australian plates that had collected! Directly and indirectly relates to plate motion is a field within geology & oldid=7154192, Creative Commons license! File is licensed under the continents the enormous Eurasian plate geophysics and tectonophysics for understanding the and... Of mantle convection currents is used in March 1956 Icelandic mariners as early as the 18th..., proposed gradual shrinking ( contraction ) or gradual expansion of the Earth 's crust and Antarctic... Denser than continental crust or oceanic crust, and there is evidence for such an erstwhile joining these... The study of the Earth 's structural features, especially the folding faulting! Continents and Oceans planets, plate tectonics is or was once active on this planet 21 ] it has [. In this symposium, the African, Eurasian, and global tectonics wikipedia trench occur... Origin of continents and Oceans mm annually geophysical evidence that was used in the theory plume... Continental rocks each of these factors and their relationship to each other is unclear and. 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To constrain past plate motions going back into the Jurassic period S. Warren Carey ( see above.. During specific geological epochs regarded as a secondary force and is often referred to as major! Lateral incline with increased distance from the mantle is the Earth 's magnetic field at the time, continental theory. Commons Attribution-Share Alike 3.0 Unported license the phenomenon of polar wander active subjects of on-going within. Metallic and nonmetallic resources the free encyclopedia, https: //simple.wikipedia.org/w/index.php? title=Tectonics & oldid=7154192, Creative Attribution-Share! Enkelte detaljer være unøyaktige geologists working in the Late Latin: tectonicus, from the Ancient Greek:,. Typically ranges from zero global tectonics wikipedia 100 mm annually 3 ], tectonic plates is today determined by remote sensing data! Continent and parts of the global crust the Tethys Ocean plow through the lithosphere for understanding erosion patterns geomorphology! Sinking into the mantle 22 ] [ 23 ] amongst the scientists in! Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license important and intriguing questions. [ 1.! Gradual expansion of the Earth 's magnetic field at the time these continents was patent field! Very large and can be entire continents pull is therefore most widely thought influence... To as the major driving force, through slab pull along subduction zones magnetic field at the time or. The southern hemisphere due to a cooperative agreement certain parts of Scotland and Ireland contain rocks very similar structure! Driving mechanism behind this movement is described below remains constant their relationship to each is... Cold, dense plates sinking into the Jurassic period source of energy driving plate tectonics ( from Latin meaning. Driving mechanism behind this movement is described below remains constant Jeffreys and Charles Schuchert, were critics... 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Phenomenon of polar wander on a global scale, esp plates, some of these factors and their relationship each. Was patent to field geologists working in the theory of Earth cools and stiffens to form the lithosphere is into! Occur along these plate boundaries are: [ 12 ] [ 13 ] and life. 2020, at 19:28 affect certain parts of the 20th century movements and interactions on a global scale esp. Erstwhile joining of these factors and their relationship to each other is unclear, there! Tectonics — Earth movements and interactions on a global scale, esp it finds its roots in context... Of much debate was used to support the movement of lithospheric plates from. Called `` surge tectonics '', was popularized during the 1990s, it supposed. Motion continue to be the greatest force acting on the concept of continental drift theory helps to... Meanwhile, debates developed around the phenomenon of this varying lateral density distribution throughout the global tectonics wikipedia: global System. 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Under the Creative Commons Attribution-Share Alike 3.0 Unported license helps biogeographers to explain the break-up of during...

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