Volcano definition is - a vent in the crust of the earth or another planet or a moon from which usually molten or hot rock and steam issue; also : a hill or mountain composed wholly or in part of the ejected material. Lettris is a curious tetris-clone game where all the bricks have the same square shape but different content. Well-known examples are the Basin and Range Province in the western USA, the East African Rift valley, and the Rhine Graben. n. a plume of smoke une colonne de fumée. Mismatches between the predictions of the hypothesis and observations are commonly explained by auxiliary processes such as "mantle wind", "ridge capture", "ridge escape" and lateral flow of plume material. However, so far conclusive proof for this is lacking.[30]. To make squares disappear and save space for other squares you have to assemble English words (left, right, up, down) from the falling squares. Based on these experiments, mantle plumes are now postulated to comprise two parts: a long thin conduit connecting the top of the plume to its base, and a bulbous head that expands in size as the plume rises. A … Active volcano: a volcano that has erupted in the past 10,000 years, may be currently erupting, ... Mantle plume: a column of hot rock that rises up to the surface from Earth’s interior. Volcano Hazards Program ... Eruption cloud is often used interchangeably with plume or ash cloud. Plumes may reach heights of 80 km in large eruptions. [32] There is, however, vigorous on-going discussion regarding whether the structures imaged are reliably resolved, and whether they correspond to columns of hot, rising rock.[33]. Ancient, high 3He/4He ratios would be particularly easily preserved in materials lacking U or Th, so 4He was not added over time. Thus, although unusually low wave speeds have been taken to indicate anomalously hot mantle beneath "hot spots", this interpretation is ambiguous. Find more ways to say plume, along with related words, antonyms and example phrases at Thesaurus.com, the world's most trusted free thesaurus. Flood basalts in the oceans are known as oceanic plateaus, and include the Ontong Java plateau of the western Pacific Ocean and the Kerguelen Plateau of the Indian Ocean. On June 22, 2019, the Raikoke volcano on the Kuril Islands erupted. Définitions de volcanique. Seismic tomography shows that subducted oceanic slabs sink as far as the bottom of the mantle transition zone at 650 km depth. Volcanism, any of various processes and phenomena associated with the surficial discharge of molten rock, pyroclastic fragments, or hot water and steam, including volcanoes, geysers, and fumaroles. [11] These eruptions have been linked to flood basalts, although many of those erupt over much shorter time scales (less than 1 million years). When a plume head encounters the base of the lithosphere, it is expected to flatten out against this barrier and to undergo widespread decompression melting to form large volumes of basalt magma. Get XML access to reach the best products. Another word for plume. B. Back-arc basin Basalt Basaltic andesite Base surge Batholith Benchmark Bishop Tuff Block and ash flow Bomb Breadcrust Bomb. Du gibier à plume, sans s. remarque Plume signifie ici « plumage » comme poil signifie « pelage » dans gibier à poil. Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii.The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder. Definition: Fine fragments (less than 2-4 mm in diameter) of volcanic rock formed by a volcanic explosion or ejection from a volcanic vent. A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. There is no other known major thermal boundary layer in the deep Earth, and so the core-mantle boundary was the only candidate. 2. a mountain or hill, usually having a cuplike crater at the summit, formed around such a vent from the ash and lava expelled through it. Geology. Realism in Fiction . Anglais Définition Anglais Synonymes Anglais Simplifi ... Other crucial factors are the wind and wind direction because the plume of smoke rising from the volcano's crater also includes ash and some very heavy rock fragments. the mantle plume, driven by heat exchange across the core-mantle boundary carrying heat upward in a narrow, rising column, and postulated to be independent of plate motions. In the context of the alternative "Plate model", continental breakup is a process integral to plate tectonics, and massive volcanism occurs as a natural consequence when it starts. Although there is strong evidence[clarification needed] that at least two deep mantle plumes[which?] The sizes and occurrence of mushroom mantle plumes can be predicted easily by transient instability theory developed by Tan and Thorpe. Find more ways to say plume, along with related words, antonyms and example phrases at Thesaurus.com, the world's most trusted free thesaurus. The general usage of the term ‘plume’ in the geophysics and geochemistry literature implies the following definition; A geophysical plume is the result of a thermal instability created in a homogeneous fluid heated from below that rises as a bulbous head followed by a cylindrical tail. With a SensagentBox, visitors to your site can access reliable information on over 5 million pages provided by Sensagent.com. Volcanic eruptions may be very destructive. The temperature of the core is approximately 1,000 degrees Celsius higher than that of the overlying mantle. The waves pounded the rocks, throwing up white plumes of spray. While not denying the presence of deep mantle convection and upwelling in general, the plate hypothesis holds that these processes do not result in mantle plumes, in the sense of columnar vertical features that span most of the Earth's mantle, transport large amounts of heat, and contribute to surface volcanism. If the Le Bas (2000) ’s definition for picrites (samples with > 12 wt.% MgO) is considered, ... A mantle plume is a buoyant mass of material in the mantle, which rises because of its buoyancy. Another word for plume. [14], The current mantle plume theory is that material and energy from Earth's interior are exchanged with the surface crust in two distinct modes: the predominant, steady state plate tectonic regime driven by upper mantle convection, and a punctuated, intermittently dominant, mantle overturn regime driven by plume convection. Volcano Hazards Program ... Eruption cloud is often used interchangeably with plume or ash cloud. In 1997 it became possible using seismic tomography to image submerging tectonic slabs penetrating from the surface all the way to the core-mantle boundary. This material may flow slowly out of a fissure, or crack, in the ground, or it may explode suddenly into the air. Alternatively, if the definition of a plume is too broad, or flexible, or circular, then the term ’plume' carries no information. The plume hypothesis postulates that this melt rises to the surface and erupts to form "hot spots". [2] The theory was really inspired by the Hawaiian volcano system. Hardened lava flows … Fighter Jets Suffer Volcanic Damage: Why Resume Flying? [7] Thermal or compositional fluid-dynamical plumes produced in that way were presented as models for the much larger postulated mantle plumes. The chemical and isotopic composition of basalts found at hotspots differs subtly from mid-ocean-ridge basalts. Another hypothesis for unusual volcanic regions is the "Plate model". Another example is an urban thermal plume, which is the term applied to the heated air above an urban area created by conditions in an urban environment. As a result, scientific interaction is often hampered because individuals use the word “plume” to mean different physical models without each other realising. Définitions. [12] The Hawaiian Islands chain in the Pacific Ocean is the type example. Definition: Fine fragments (less than 2-4 mm in diameter) of volcanic rock formed by a volcanic explosion or ejection from a volcanic vent. [34] They were detectable because they were 600–800 km wide, more than three times the width expected from contemporary models. …giant plumes of heat, termed mantle plumes, that ascend from deep within the mantle, possibly from the core-mantle boundary, some 2,900 km (1,800 miles) below the surface. In radiogenic isotope systems the originally subducted material creates diverging trends, termed mantle components. a visible pattern of smoke resulting from emissions from a stack, flue, or chimney. ", "Hot mantle upwelling across the 660 beneath Yellowstone", Seismic-tomography image of Yellowstone mantle plume, mantleplumes.org - mantle-plume skeptic website managed and maintained by Gillian R. Foulger, https://en.wikipedia.org/w/index.php?title=Mantle_plume&oldid=995556170, Short description is different from Wikidata, Wikipedia articles needing factual verification from October 2020, Wikipedia articles needing clarification from September 2020, Wikipedia articles needing clarification from July 2015, Wikipedia articles needing clarification from May 2020, All articles with specifically marked weasel-worded phrases, Articles with specifically marked weasel-worded phrases from May 2020, Creative Commons Attribution-ShareAlike License, the broad convective flow associated with plate tectonics, driven primarily by the sinking of cold plates of. These plumes are thought to be stationary relative to the lithospheric plates that move over them. It is thus not clear how strongly this observation supports the mantle plume hypothesis. The plate hypothesis suggests that "anomalous" volcanism results from lithospheric extension that permits melt to rise passively from the asthenosphere beneath. Some common and basic lines of evidence cited in support of the theory are linear volcanic chains, noble gases, geophysical anomalies, and geochemistry. [18] These basalts, also called ocean island basalts (OIBs), are analysed in their radiogenic and stable isotope compositions. osmium, have been suggested to be tracers of material arising from near to the Earth's core, in basalts at oceanic islands. ○   Wildcard, crossword A windows (pop-into) of information (full-content of Sensagent) triggered by double-clicking any word on your webpage. "[49][50] Data acquired through Earthscope, a program collecting high-resolution seismic data throughout the contiguous United States has accelerated acceptance of a plume underlying Yellowstone.[51][52]. Stable isotopes like Fe are used to track processes that the uprising material experiences during melting.[22]. They tend to be pitted and full of holes, which gives them a low density.Along with water vapor and other hot gases, volcanic ash is part of the dark ash column that rises above a volcano when it erupts. Pillow lava: a smooth, rounded type of lava flow that erupts underwater. [34] Nonetheless, vertical plumes, 400 C hotter than the surrounding rock, were visualized under many hotspots, including the Pitcairn, Macdonald, Samoa, Tahiti, Marquesas, Galapagos, Cape Verde, and Canary hotspots. It is postulated that plumes rise from their surface or their edges. These processes are well understood at mid-ocean ridges, where most of Earth's volcanism occurs. Jet Phase is dominated by upward momentum. Active volcano: a volcano that has erupted in the past 10,000 years, may be currently erupting, ... Mantle plume: a column of hot rock that rises up to the surface from Earth’s interior. This is consistent with a system that tends toward equilibrium: as matter rises in a mantle plume, other material is drawn down into the mantle, causing rifting.[44]. However, paleomagnetic data show that mantle plumes can be associated with Large Low Shear Velocity Provinces (LLSVPs)[5] and do move.[6]. Published: April 2, 2016. Hawaii is a large volcanic edifice in the center of the Pacific Ocean, far from any plate boundaries. [38][39] These extremely rapid, large scale eruptions of basaltic magmas have periodically formed continental flood basalt provinces on land and oceanic plateaus in the ocean basins, such as the Deccan Traps,[40] the Siberian Traps[41] the Karoo-Ferrar flood basalts of Gondwana,[42] and the largest known continental flood basalt, the Central Atlantic magmatic province (CAMP). [2], Mantle plumes were first proposed by J. Tuzo Wilson in 1963[3][non-primary source needed] and further developed by W. Jason Morgan in 1971. Give contextual explanation and translation from your sites ! Some scientists have linked this to a mantle plume postulated to have caused the breakup of Eurasia and the opening of the north Atlantic, now suggested to underlie Iceland. This disambiguation page lists articles associated with the same title. How to Write a Concept Paper for Academic Research: An Ultimate Guide. A ‘A‘ā Agglutinate Alluvium Andesite Ash Ash-flow tuff . [28], Other elements, e.g. There are two competing interpretations for this. Definition of plume noun from the Oxford Advanced Learner's Dictionary. The core-mantle boundary is a strong thermal (temperature) discontinuity. It is made of dense white clouds of steam, toxic gas and tiny shards of volcanic glass. We hope that you find the site useful. Ocean island basalts are also relatively enriched in immobile elements relative to the water-mobile elements. [36], The unexpected size of the plumes leaves open the possibility that they may conduct the bulk of the Earth's 44 terawatts of internal heat flow from the core to the surface, and means that the lower mantle convects less than expected, if at all. b : contour feather. Two very broad, large low-shear-velocity provinces, exist in the lower mantle under Africa and under the central Pacific. A clear, widely accepted definition of a plume does not currently exist. These include thermal, seismic, and elevation anomalies. In major elements, ocean island basalts are typically higher in iron (Fe) and titanium (Ti) than mid-ocean ridge basalts at similar magnesium (Mg) contents. Some scientists suggest that several tens of plumes exist,[37] whereas others suggest that there are none. Contact Us An example of a thermal plume may include hot water moving upward from a heat source in a body of water, such as an underwater volcano. Cavité située à la face, composée des lèvres, des gencives, des joues, du palais, et faisant partie des systèmes digestif et respiratoire It has recently been discovered that the volcanic locus of this chain has not been fixed over time, and it thus joined the club of the many type examples that do not exhibit the key characteristic originally proposed. plume - anything that resembles a feather in shape or lightness; "a plume of smoke"; "grass with large plumes" shape , form - the spatial arrangement of something as distinct from its substance; "geometry is the mathematical science of shape" "Ocean island basalt" is also similar to basalts found throughout the oceans on both small and large seamounts (thought to be formed by eruptions on the sea floor that did not rise above the surface of the ocean). Pahoehoe: (pronounced pah-hoy-hoy) a type of lava that forms a thin, ropy crust when it hardens. [25] Their low seismic velocities were thought to suggest that they are relatively hot, although it has recently been shown that their low wave velocities are due to high density caused by chemical heterogeneity. This method involves using a network of seismometers to construct three-dimensional images of the variation in seismic wave speed throughout the mantle.[31]. [20][21] This geochemical signature arises from the mixing of near-surface materials such as subducted slabs and continental sediments, in the mantle source. The plume has 3 phases. By using our services, you agree to our use of cookies. 2 a : material (such as a … Mantle plume, or volcanic plume, an upwelling of abnormally hot rock within the Earth's mantle, which can cause volcanic hotspots. The term volcano can also refer to the landform created by the accumulation of solidified lava and volcanic debris near the vent. a Picture of the plume emission from Mina Azufral, Sierra Negra volcano. The same day that Rabaul Volcano released a plume, Bagana Volcano, roughly 400 kilometers (250 miles) to the southeast, on the island of Bougainville, also sent a plume of ash and/or steam toward the northeast. [19] Identified mantle components are DMM (depleted mid-ocean ridge basalt (MORB) mantle), HIMU (high U/Pb-ratio mantle), EM1 (enriched mantle 1), EM2 (enriched mantle 2) and FOZO (focus zone). The narrow vertical pipe, or conduit, postulated to connect the plume head to the core-mantle boundary, is viewed as providing a continuous supply of magma to a fixed location, often referred to as a "hotspot". Olivine and dunite, both found in subducted crust, are materials of this sort.  |  Furthermore, it is essentially impossible to disprove the plume hypothesis at any given location because the term “plume” has become so vague. Your email address will not be published. It is thus the conceptual inverse of the plume hypothesis because the plate hypothesis attributes volcanism to shallow, near-surface processes associated with plate tectonics, rather than active processes arising at the core-mantle boundary. The base of the mantle is known as the D″ layer, a seismological subdivision of the Earth. Examples include the Deccan traps in India, the Siberian traps of Asia, the Karoo-Ferrar basalts/dolerites in South Africa and Antarctica, the Paraná and Etendeka traps in South America and Africa (formerly a single province separated by opening of the South Atlantic Ocean), and the Columbia River basalts of North America. The wordgames anagrams, crossword, Lettris and Boggle are provided by Memodata. [23] Other "hot spots" with time-progressive volcanic chains behind them include Réunion, the Chagos-Laccadive Ridge, the Louisville Ridge, the Ninety East Ridge and Kerguelen, Tristan, and Yellowstone. Very little is produced, and little has been added to the Earth by other processes since then. Company Information a cloud of something that rises and curves upwards in the air. Littéraire. A ‘A‘ā Agglutinate Alluvium Andesite Ash Ash-flow tuff . a plume of smoke; A radioactive plume could reach the city within hours. [34] Due to computational limitations, high-frequency data still could not be used, and seismic data remained unavailable from much of the seafloor. (Redirected from Eruption plume) An eruption column consists of hot volcanic ash emitted during an explosive volcanic eruption. Definition: Volcanic rock (or lava) that characteristically is dark in color (gray to black), contains 45 to 53 percent silica, and is rich in iron and magnesium. Image from MODIS Terra showing the ash plume from Raikoke on June 22, 2019. Its regular, time-progressive chain of islands and seamounts superficially fits the plume theory well. Mantle plumes were originally postulated to rise from this layer because the "hot spots" that are assumed to be their surface expression were thought to be fixed relative to one another. ○   Boggle. Choose the design that fits your site. The English word games are: A mantle plume is a proposed mechanism of convection of abnormally hot rock within the Earth's mantle. Volcanic ash is a mixture of rock, mineral, and glass particles expelled from a volcano during a volcanic eruption.The particles are very small—less than 2 millimeters in diameter. a : a large conspicuous or showy feather. All rights reserved. A great plume of dust and ash rose from the volcano. English Encyclopedia is licensed by Wikipedia (GNU). In parallel with the mantle plume model, two alternative explanations for the observed phenomena have been considered: the plate hypothesis and the impact hypothesis. This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension. Because the plume head partly melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian traps. Plumes are postulated to rise through the mantle and begin to partially melt on reaching shallow depths in the asthenosphere by decompression melting. When such a plume rises into the shallow mantle, it partially melts and the melt may then rise to the surface where it can erupt as a hotspot volcano. This, and other observations, have been interpreted as indicating that the distinct geochemical signature of ocean island basalts results from inclusion of a component of subducted slab material. Volcanic eruptions may be very destructive. This enriched fluid rises to metasomatize the overlying mantle wedge and leads to the formation of island arc basalts. The Plume website and emails use cookies and similar technologies to analyze your interactions with our website and emails, enhance your experience and allow us … B. Back-arc basin Basalt Basaltic andesite Base surge Batholith Benchmark Bishop Tuff Block and ash flow Bomb Breadcrust Bomb. Hotspot volcanism is distinct in that it does not originate from processes that produce the more common submarine volcanism that occurs at boundaries of Earth’s tectonic plates. Under this hypothesis, variable volumes of magma are attributed to variations in chemical composition (large volumes of volcanism corresponding to more easily molten mantle material) rather than to temperature differences. plume. Furthermore, it is essentially impossible to disprove the plume hypothesis at any given location because the term “plume” has become so vague. Volcano, vent in the crust of Earth or another planet or satellite, from which issue eruptions of molten rock, hot rock fragments, and hot gases. Because the plume head partly melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian traps. You can also try the grid of 16 letters. As the overlying tectonic plate (lithosphere) moves over this hotspot, the eruption of magma from the fixed conduit onto the surface is expected to form a chain of volcanoes that parallels plate motion. Beginning in the early 2000s, dissatisfaction with the state of the evidence for mantle plumes and the proliferation of ad hoc hypotheses drove a number of geologists, led by Don L. Anderson, Gillian Foulger, and Warren B. Hamilton, to propose a broad alternative based on shallow processes in the upper mantle and above, with an emphasis on plate tectonics as the driving force of magmatism.[45]. They also have limited resolution, however, and only structures at least several hundred kilometers in diameter can be detected. Glossary Terms. Term: Basalt. a vertically or longitudinally moving, rising, or expanding fluid body, as of smoke or water. The majority of active terrestrial volcanoes and related phenomena occur where two tectonic plates meet. Volcanic plume may refer to: Eruption column, or volcanic plume, a column of hot volcanic ash and gas emitted into the atmosphere during an explosive volcanic eruption. [23] Because there is little material transport across the core-mantle boundary, heat transfer must occur by conduction, with adiabatic gradients above and below this boundary. In the late 1980s and early 1990s, experiments with thermal models showed that as the bulbous head expands it may entrain some of the adjacent mantle into the head. However, the plate hypothesis is inconsistent with both the geochemistry of shallow asthenosphere melts (i.e., Mid-ocean ridge basalts) and with the isotopic compositions of ocean island basalts. Get XML access to fix the meaning of your metadata. This is consistent with a system that tends toward equilibrium: as matter rises in a mantle plume, other material is drawn down into the mantle, causing rifting.[44]. This must have been recycled in the mantle, then re-melted and incorporated in the lavas erupted. The second strongest candidate for a plume location is often quoted to be Iceland, but according to opponents of the plume hypothesis its massive nature can be explained by plate tectonic forces along the mid-Atlantic spreading center. Seismic waves that have traveled a thousand or more kilometers (also called teleseismic waves) can be used to image large regions of Earth's mantle.