Magma is a mixture the molten and also semi-molten rock uncovered beneath the surface of the Earth.
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Magma is a molten and also semi-molten rock mixture found 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; solid rocks included into the melt from the neighboring confines; and dissolved gases.
When magma is ejected through a volcano or other vent, the product is referred to as lava. Magma that has actually cooled into a hard is called igneous rock.
Magma is exceptionally hot—between 700° and 1,300° Celsius (1,292° and 2,372° Fahrenheit). This warmth makes magma a an extremely fluid and dynamic substance, able to create new landforms and also engage physical and also chemical changes in a range of various environments.
Earth is divided into three basic layers. The main point is the superheated center, the mantle is the thick, center layer, and also the tardy is the top layer ~ above which we live.
Magma originates in the lower part of the Earth’s crust and also in the upper section of the mantle. Most of the mantle and also crust space solid, therefore the existence of magma is an essential to knowledge the geology and also morphology that the mantle.
Differences in temperature, pressure, and also structural formations in the mantle and also crust reason magma to kind in different ways.
Decompression melting involves the upward activity of Earth"s mostly-solid mantle. This hot material rises to an area of lower pressure with the process of convection. Locations of lower pressure always have a lower melting point than areas of high pressure. This reduction in overlying pressure, or decompression, enables the mantle rock to melt and form magma.
Decompression melting frequently occurs at divergent boundaries, where tectonic plates separate. The rifting movement causes the buoyant magma listed below to rise and fill the an are of lower pressure. The rock then cools into brand-new crust.
Decompression melting additionally occurs in ~ mantle plumes, columns of hot rock that rise from Earth’s high-pressure main point to its lower-pressure crust. When located beneath the ocean, this plumes, likewise known as warm spots, press magma top top the seafloor. This volcanic mounds can thrive into volcanic islands over millions of years that activity.
Magma can likewise be developed when hot, liquid rock intrudes into Earth’s cold crust. As the fluid rock solidifies, it loser its warm to the bordering crust. Lot like warm fudge gift poured end cold ice cream cream, this carry of warmth is able to melt the surrounding rock (the “ice cream”) into magma.
Transfer that heat regularly happens in ~ convergent boundaries, where tectonic plates space crashing together. As the denser tectonic key subducts, or sink below, or the less-dense tectonic plate, warm rock from listed below can intrude right into the cooler key above. This process transfers heat and also creates magma. Over millions of years, the magma in this subduction region can produce a collection of energetic volcanoes well-known as a volcano arc.
Flux melt occurs once water or carbon dioxide are included to rock. This compounds reason the rock to melt at reduced temperatures. This creates magma in locations where the originally maintained a solid structure.
Much like warmth transfer, flux melting additionally occurs roughly subduction zones. In this case, water overlying the subducting seafloor would reduced the melt temperature the the mantle, generating magma the rises to the surface.
Magma leaves the confines of the top mantle and crust in two major ways: as an intrusion or as an extrusion. One intrusion can kind features such together dikes and xenoliths. One extrusion can include lava and volcanic rock.
Magma can intrude into a low-density area of an additional geologic formation, such as a sedimentary absent structure. When it cools to solid rock, this intrusion is often referred to as a pluton. A pluton is one intrusion the magma the wells increase from below the surface.
Plutons can include dikes and also xenoliths. A magmatic dike is just a large slab the magmatic product that has intruded into one more rock body. A xenolith is a piece of rock trapped in another kind of rock. Numerous xenoliths space crystals torn from inside the Earth and also embedded in magma if the magma was cooling.
The most familiar way for magma come escape, or extrude, to Earth’s surface is v lava. Lava eruptions deserve to be “fire fountains” of fluid rock or thick, slow-moving rivers the molten material. Lava cools to form volcanic rock and also volcanic glass.
Magma can also extrude into Earth’s environment as part of a violent volcano explosion. This magma solidifies in the air to form volcanic rock called tephra. In the atmosphere, tephra is much more often referred to as volcanic ash. Together it drops to Earth, tephra contains rocks such as pumice.
In areas where temperature, pressure, and structural development allow, magma have the right to 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 come the top. The densest magma sinks near the bottom of the chamber. Over numerous years, plenty of magma chambers merely cool to type a pluton or huge igneous intrusion.
If a magma room encounters an massive amount of pressure, however, it might fracture the rock approximately it. The cracks, called fissures or vents, are tell-tale indications of a volcano. Numerous volcanoes sit end magma chambers.
As a volcano’s magma chamber experiences better pressure, often due to an ext magma seeping right into the chamber, the volcano may undergo one eruption. An eruption to reduce the push inside the magma chamber. As lengthy as an ext magma pools right into a volcano’s magma chamber, there is the opportunity of an eruption and the volcano will remain active.
Large eruptions can virtually empty the magma chamber. The layers of magma might be documented by the form of eruption material the volcano emits. Gases, ash, and also light-colored rock space emitted first, from the least-dense, top layer the the magma chamber. Dark, dense volcanic rock from the lower component of the magma chamber may be released later.
In violent eruptions, the volume of magma shrinks so lot that the whole magma room collapses and also forms a caldera.
All magma consists of gases and a mixture of an easy elements. Being that oxygen and also silicon space the most abundant aspects in magma, geologists define magma types in terms of 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 reasonably low silica content, about 50%, and greater contents in iron and magnesium. This kind of magma has actually a short gas content and low viscosity, or resistance come flow. Mafic magma likewise has high average temperatures, in between 1000o and also 2000o Celsius (1832o and 3632o Fahrenheit), which contributes come its lower viscosity.
Low viscosity way that mafic magma is the most fluid of magma types. It erupts non-explosively and moves very quickly when it reaches Earth’s surface as lava. This lava cools right into basalt, a rock that is heavy and dark in shade due to its higher iron and also magnesium levels. Basalt is one of the most typical rocks in Earth’s crust and the volcano islands created by warm spots. The Hawaiian Islands space a direct result of mafic magma eruptions. Steady and relatively calm “lava fountains” proceed to readjust and broaden the “Big Island” of Hawaii.
Intermediate magma has higher silica content (roughly 60%) than mafic magma. This results in a greater gas content and viscosity. Its mean temperature arrays from 800o to 1000o Celsius (1472o come 1832o Fahrenheit).
As a an outcome of its higher viscosity and also gas content, intermediary magma build up pressure listed below the Earth’s surface prior to it can be released as lava. This more gaseous and also sticky lava often tends to explode violently and also cools together andesite rock. Intermediate magma most frequently transforms into andesite as result of the deliver of warm at convergent plate boundaries. Andesitic rocks are often uncovered at continent volcanic arcs, such together the Andes hills in southern America, after i beg your pardon they are named.
Felsic magma has actually the highest silica content of every magma types, in between 65-70%. Together a result, felsic magma likewise has the highest possible gas content and viscosity, and lowest median temperatures, between 650o and also 800o Celsius (1202o and also 1472o Fahrenheit).
Thick, viscous felsic magma can trap gas balloon in a volcano’s magma chamber. This trapped bubbles can cause explosive and also destructive eruptions. These eruptions eject lava violently right into the air, i m sorry cools right into dacite and rhyolite rock. Lot like intermediate magma, felsic magma may be most frequently found at convergent plate boundaries where deliver of heat and flux melt create large stratovolcanoes.
Magma exists as pockets and plumes beneath the surface ar of the Earth.
Photograph through Carsten Peter, nationwide Geographic
Magma is normally studied as lava or igneous rock. However most magma stays molten or partially molten beneath Earth’s surface. In fact, magma has only been discovered three time in the “natural” habitat deep in Earth’s crust. Geothermal drilling projects uncovered two magma website on the “Big Island” of Hawaii, and one ~ above Iceland.
In 2009, the icelandic Deep Drilling Project developed a well that provides magma to generate geothermal energy. Normally, geothermal energy is developed by pump water into hot volcanic bedrock, creating heavy steam that is then harnessed to generate electricity. While normal geothermal resources average about 60° come 80°Celsius (140° come 176° Fahrenheit), the magma well’s vapor reached a record-breaking temperature that 450° Celsius (842° Fahrenheit)! This huge increase in temperature permitted just one magma well to generate about 36 megawatts that electricity, powering 36,000 homes. In comparison, one solitary wind wind turbine generates between 1 to 3 megawatts.
Hawaii"s Molten MagmaHawaiian magma is different than magma in other parts of the Earth since it has an ext molten rock and less liquified gases and also rock fragments. The Hawaiian volcano Kilauea, on the "Big Island" the Hawaii, has actually erupted with enough molten lava come pave a road approximately the planet three times.
type that mineral that is clear and, as soon as viewed under a microscope, has a repeating pattern of atoms and molecules.
upward activity of Earth"s mantle come an area of lower pressure, enabling mantle absent to melt, leading to magma formation.
area where 2 or much more tectonic key are moving away from each other. Also called one extensional boundary.
process that occurs as soon as water is included to hot, solid rock, lowering that melting point and allowing the production of magma.
state of issue with no fixed form that will fill any container uniformly. Gas molecules are in constant, random motion.
study the the physical background of the Earth, that is composition, that structure, and also the processes that type and change it.
intensely hot an ar deep in ~ the earth that rises to just underneath the surface. Some hot spots create volcanoes.
phenomenon where lava is forcefully but not violent ejected native a volcano with a fissure or vent.
massive slab of heavy rock consisted of of Earth"s lithosphere (crust and upper mantle). Likewise called lithospheric plate.
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an opening in the Earth"s crust, v which lava, ash, and also gases erupt, and also the cone constructed by eruptions.
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