Magma is a mixture that molten and semi-molten rock found beneath the surface ar of the Earth.
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Magma is a molten and also semi-molten rock mixture discovered under the surface ar of the Earth. This mixture is usually consisted of of 4 parts: a warm liquid base, called the melt; mineral crystallized by the melt; heavy rocks integrated into the melt native the neighboring confines; and dissolved gases.
When magma is ejected by a volcano or other vent, the product is called lava. Magma that has cooled right into a hard is dubbed igneous rock.
Magma is very hot—between 700° and 1,300° Celsius (1,292° and 2,372° Fahrenheit). This heat makes magma a an extremely fluid and also dynamic substance, able come create brand-new landforms and engage physical and also chemical revolutions in a variety of different environments.
Earth is separated into three basic layers. The main point is the superheated center, the mantle is the thick, center layer, and the tardy is the height layer top top which us live.
Magma originates in the lower component of the Earth’s crust and in the upper section of the mantle. Most of the mantle and also crust are solid, for this reason the existence of magma is vital to understanding the geology and morphology that the mantle.
Differences in temperature, pressure, and structural formations in the mantle and also crust cause magma to type in various ways.
Decompression melting entails the upward activity of Earth"s mostly-solid mantle. This hot material rises to an area of lower pressure through the process of convection. Areas of reduced pressure constantly have a lower melting suggest than areas of high pressure. This palliation in overlying pressure, or decompression, allows the mantle rock to melt and kind magma.
Decompression melting regularly occurs at divergent boundaries, wherein tectonic bowl separate. The rifting movement reasons the buoyant magma listed below to rise and fill the room of reduced pressure. The rock climate cools into new crust.
Decompression melting additionally occurs in ~ mantle plumes, columns of warm rock that climb from Earth’s high-pressure main point to its lower-pressure crust. When situated beneath the ocean, these plumes, additionally known as hot spots, press magma top top the seafloor. These volcanic mounds can flourish into volcanic archipelago over countless years that activity.
Magma can also be created when hot, fluid rock intrudes right into Earth’s cold crust. Together the liquid rock solidifies, it loses its warmth to the bordering crust. Lot like hot fudge being poured end cold ice cream cream, this move of warmth is able come melt the surrounding rock (the “ice cream”) into magma.
Transfer of heat often happens in ~ convergent boundaries, where tectonic plates room crashing together. Together the denser tectonic key subducts, or sink below, or the less-dense tectonic plate, hot rock from listed below can intrude into the cooler bowl above. This process transfers heat and also creates magma. Over numerous years, the magma in this subduction region can create a collection of active volcanoes well-known as a volcanic arc.
Flux melting occurs once water or carbon dioxide are added to rock. This compounds cause the rock to melt at lower temperatures. This creates magma in areas where that originally preserved a solid structure.
Much like warm transfer, flux melting additionally occurs approximately subduction zones. In this case, water overlying the subducting seafloor would reduced the melt temperature the the mantle, generating magma that rises to the surface.
Magma leaves the boundaries of the upper mantle and also crust in two major ways: as an intrusion or together an extrusion. One intrusion can type features such together dikes and also xenoliths. An extrusion might include lava and also volcanic rock.
Magma have the right to intrude right into a low-density area of another geologic formation, such as a sedimentary rock structure. As soon as it cools to solid rock, this intrusion is often called a pluton. A pluton is one intrusion the magma that wells up from below the surface.
Plutons can incorporate dikes and also xenoliths. A magmatic dike is just a huge slab of magmatic material that has actually intruded into another rock body. A xenolith is a piece of rock trapped in another type of rock. Plenty of xenoliths are crystals take it from within the Earth and also embedded in magma if the magma was cooling.
The most familiar method for magma come escape, or extrude, to Earth’s surface is through lava. Lava eruptions can be “fire fountains” of liquid rock or thick, slow-moving rivers the molten material. Lava cools to form volcanic rock and also volcanic glass.
Magma can additionally extrude right into Earth’s setting as component of a violent volcanic explosion. This magma solidifies in the air to kind volcanic rock dubbed tephra. In the atmosphere, tephra is much more often dubbed volcanic ash. Together it drops to Earth, tephra contains rocks such as pumice.
In areas where temperature, pressure, and also structural development allow, magma can collect in magma chambers. Most magma chambers sit much beneath the surface ar of the Earth.
The pool of magma in a magma room is layered. The least-dense magma rises to the top. The densest magma sinks near the bottom that the chamber. Over countless years, many magma chambers simply cool to type a pluton or big igneous intrusion.
If a magma room encounters an substantial amount the pressure, however, it might fracture the rock about it. The cracks, referred to as fissures or vents, room tell-tale signs of a volcano. Numerous volcanoes sit end magma chambers.
As a volcano’s magma room experiences greater pressure, often due to much more magma seeping into the chamber, the volcano might undergo an eruption. One eruption reduce the pressure inside the magma chamber. As lengthy as more magma pools right into a volcano’s magma chamber, over there is the possibility of one eruption and the volcano will remain active.
Large eruptions can virtually empty the magma chamber. The class of magma might be documented by the type of eruption material the volcano emits. Gases, ash, and light-colored rock are emitted first, native the least-dense, height layer that the magma chamber. Dark, dense volcanic rock from the lower part of the magma chamber may be exit later.
In violent eruptions, the volume the magma shrinks so lot that the entire magma chamber collapses and forms a caldera.
All magma includes gases and also a mixture of an easy elements. Being that oxygen and also silicon room the most abundant elements in magma, geologists specify magma types in regards to their silica content, expressed together SiO2. These differences in chemistry composition are straight related to differences in gas content, temperature, and also viscosity.
Mafic magma has relatively low silica content, approximately 50%, and higher contents in iron and magnesium. This type of magma has actually a low gas content and low viscosity, or resistance come flow. Mafic magma additionally has high median temperatures, in between 1000o and also 2000o Celsius (1832o and also 3632o Fahrenheit), which contributes come its lower viscosity.
Low viscosity way that mafic magma is the most liquid of magma types. That erupts non-explosively and also moves very quickly as soon as it will Earth’s surface as lava. This lava cools right into basalt, a rock the is heavy and dark in color due come its higher iron and also magnesium levels. Basalt is just one of the most usual rocks in Earth’s crust and the volcano islands created by hot spots. The Hawaiian Islands space a direct an outcome of mafic magma eruptions. Steady and relatively calm “lava fountains” continue to adjust and increase the “Big Island” the Hawaii.
Intermediate magma has higher silica contents (roughly 60%) 보다 mafic magma. This outcomes in a higher gas content and also viscosity. Its average temperature arrays from 800o to 1000o Celsius (1472o come 1832o Fahrenheit).
As a an outcome of its higher viscosity and gas content, intermediate magma builds up pressure listed below the Earth’s surface before it can be released as lava. This an ext gaseous and also sticky lava has tendency to explode violently and also cools together andesite rock. Intermediate magma most frequently transforms into andesite because of the transport of warm at convergent plate boundaries. Andesitic rocks are often found at continent volcanic arcs, such together the Andes hills in south America, after i beg your pardon they room named.
Felsic magma has the highest silica content of every magma types, between 65-70%. As a result, felsic magma additionally has the highest possible gas content and viscosity, and also lowest typical temperatures, in between 650o and 800o Celsius (1202o and 1472o Fahrenheit).
Thick, viscous felsic magma have the right to trap gas bubbles in a volcano’s magma chamber. This trapped balloon can reason explosive and also destructive eruptions. These eruptions eject lava violently right into the air, i m sorry cools right into dacite and rhyolite rock. Much like intermediary magma, felsic magma might be most commonly found at convergent plate boundaries where move of heat and also flux melt create big stratovolcanoes.
Magma exists together pockets and plumes in ~ the surface ar of the Earth.
Photograph through Carsten Peter, nationwide Geographic
Magma is commonly studied together lava or igneous rock. But most magma stays molten or partially molten in ~ Earth’s surface. In fact, magma has only been discovered three times in that is “natural” habitat deep in Earth’s crust. Geothermal drilling projects found two magma web page on the “Big Island” that Hawaii, and one top top Iceland.
In 2009, the iceland Deep Drilling Project created a well that offers magma to create geothermal energy. Normally, geothermal energy is created by pumping water into hot volcanic bedrock, creating vapor that is climate harnessed to create electricity. While normal geothermal sources average about 60° come 80°Celsius (140° to 176° Fahrenheit), the magma well’s vapor reached a record-breaking temperature that 450° Celsius (842° Fahrenheit)! This vast increase in temperature allowed just one magma fine to generate about 36 megawatts of electricity, powering 36,000 homes. In comparison, one single wind turbine generates between 1 to 3 megawatts.
Hawaii"s Molten MagmaHawaiian magma is various than magma in various other parts the the Earth due to the fact that it has much more molten rock and less dissolved gases and rock fragments. The Hawaiian volcano Kilauea, ~ above the "Big Island" of Hawaii, has actually erupted with enough molten lava come pave a road roughly the earth three times.
type of mineral the is clean and, once viewed under a microscope, has a repeating sample of atoms and molecules.
upward movement of Earth"s mantle to an area of reduced pressure, permitting mantle absent to melt, resulting in magma formation.
area where two or an ext tectonic key are moving away from each other. Additionally called one extensional boundary.
process the occurs when water is included to hot, hard rock, lowering that is melting allude and enabling the production of magma.
state of issue with no fixed form that will certainly fill any type of container uniformly. Gas molecules room in constant, arbitrarily motion.
study of the physical background of the Earth, that is composition, its structure, and also the procedures that type and readjust it.
intensely hot region deep in ~ the earth that rises to simply underneath the surface. Some hot spots create volcanoes.
phenomenon whereby lava is forcefully however not violently ejected indigenous a volcano v a fissure or vent.
massive slab of heavy rock made up of Earth"s lithosphere (crust and upper mantle). Also called lithospheric plate.
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an opened in the Earth"s crust, v which lava, ash, and gases erupt, and also the cone constructed by eruptions.
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