This process, called flux melting, generates low-density calc-alkaline magma that buoyantly rises to intrude and be extruded through the lithosphere of the overriding plate.

In the subduction zone, loss of water from the subducted slab induces partial melting of the overriding mantle and generates low-density, calc-alkaline magma that buoyantly rises to intrude and be extruded through the lithosphere of the overriding plate.

Supervolcanoes can occur when magma in the Earth rises into the crust from a hotspot but is unable to break through the crust.

Magma also contains gases, which expand as the magma rises.

Magma from the planet's mantle rises through the planet's crust, if the magma from the mantle reaches the planet's surface it behaves differently depending on the viscosity of the molten constituent rock.

Basaltic magma rises up the fractures and cools on the ocean floor to form new sea floor.

The supercritical water, which is hot and more buoyant than the surrounding rock, rises into the overlying mantle where it lowers the pressure in ( and thus the melting temperature of ) the mantle rock to the point of actual melting, generating magma.

By studying the refracted and reflected seismic waves, the scientists attempted to map the interior of the volcano, much as a CT scan images the inside of an object using X-rays, to understand its deep " plumbing " and how the magma rises to the lava lake.

The magma that forms stratovolcanoes rises when water trapped both in hydrated minerals and in the porous basalt rock of the upper oceanic crust, is released into mantle rock of the asthenosphere above the sinking oceanic slab.

The magma then rises through the crust, incorporating silica-rich crustal rock, leading to a final intermediate composition ( see Classification of igneous rock ).

The central section of the mountain rises about 3 mm every year, due to rising levels of magma below the central part of the mountain.

Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles ( dominantly water and carbon dioxide ) to exsolve into gas bubbles.

When magma rises above a certain depth the dissolved minerals start to crystallize at particular pressures and temperatures.

The magma then continues to migrate upwards causing differentiation and becomes even more sodic and silicic as it rises.

When high-silica ( dacitic ) magma rises to the Earth's surface, the trapped gases and vapors can erupt explosively to produce ash clouds and pyroclastic flows that consist of superheated gas, ash and volcanic fragments.

As more magma rises up below it, the pressure in the chamber grows.

This magma being less dense, rises to the surface and goes through the weak parts of the Earth's crust ( the faults ) resulting in volcanic processes in the area.

As molten magma rises at a mid-ocean ridge it heats the rocks around it.

As plates diverge at these ridges, magma rises into the upper mantle and crust.

Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites.

These volcanic explosion craters are formed when magma rises through water-saturated rocks and causes a phreatic eruption.

As the body of magma rises toward the surface, the volatile compounds transform to gaseous phase as pressure is reduced with decreasing depth.

The lower pressure, high temperature, and now volatile rich material in this wedge melts and the resulting buoyant magma rises through the overlying rock to produce island arc or continental margin volcanism.

The magma chamber feeds the volcano, and sends off shoots of magma that will later crystallize into dikes and sills.

The basic idea is that magma will rise through the crust as a single mass through buoyancy.

Eventually this vapor film will collapse leading to direct coupling of the cold water and hot magma.

If it finds a way to the surface, then the result will be a volcanic eruption ; consequently many volcanoes are situated over magma chambers.

Additionally, the removal of the lower melting point components will tend to make the magma more viscous ( by increasing the concentration of silicates ).

If the magma is not vented to the surface in a volcanic eruption it will slowly cool and crystallize at depth to form an intrusive igneous body composed of granite or gabbro ( see also pluton ).

As a volcano erupts, emptying the magma chamber, the surrounding rock will collapse into it.

The escaping gas accelerates the magma up the conduit, resulting in fragmentation to produce pumice and ash, which dispersed in gas will flow downslope or spread where the dispersal is denser than the atmosphere, as pyroclastic density current, sometimes known as a pyroclastic flow.

Often, but not always, a caldera will form as a result of a large ignimbrite eruption because the magma chamber underneath will drain and thus can no longer support the weight of the rock above.

After the recrystallization of magma, more < sup > 40 </ sup > K will decay and < sup > 40 </ sup > Ar will again accumulate, along with the entrained argon atoms, trapped in the mineral crystals.

This fresh magma will eventually become new lithosphere.

As silicates rich in calcium, it is to be expected that these minerals will be found where impure limestones have been crystallized by contact with an igneous magma.

If the conditions no longer exist for the magma to stay in its liquid state, it will cool and solidify into an igneous rock.

Diagram showing a cross section though the Earth's lithosphere ( in yellow ) with magma rising from the Mantle ( geology ) | mantle ( in red ).

Diagram showing a cross section though the Earth's lithosphere ( in yellow ) with magma rising from the Mantle ( geology ) | mantle ( in red )

This process operates regardless of the origin of the parental magma to the granite, and regardless of its chemistry.

This magma tends to be very viscous due to its high silica content, so often does not reach the surface and cools at depth.

Melting of solid rocks to form magma is controlled by three physical parameters: its temperature, pressure, and composition.

This fissure opens along its entire length during major eruptions and is fed by a magma reservoir estimated to have a top 4 km below the surface with centroid 2. 5 km lower.

Depositing its strata has drained off a large magma chamber inside the mountain.

Mount Nyiragongo is dangerous because its magma has an unusually low silica content, making it quite fluid ( even when comparing to Hawaiian lava ) and having lower viscosity.

This recognition was tied to two events: ( 1 ) the observation of magnetic anomaly stripes on the seafloor, parallel to oceanic ridge systems, interpreted by Frederick Vine and Drummond Matthews to represent the formation of new crust at the oceanic ridge and its subsequent symmetric spreading away from that ridge, and ( 2 ) the observation of a sheeted dike complex within the Troodos ophiolite ( Cyprus ) by Ian Graham Gass and co-workers, which must have formed by repetitive extension of crust and intrusion of magma resulting in a formation consisting of 100 % dikes with no older wall rocks preserved within the complex.

These elements are excluded from the major minerals of the lunar crust which crystallized out from its primeval magma ocean, and the KREEP basalt may have been trapped as a chemical differentiate between the crust and the mantle, with occasional eruptions to the surface.

When this basaltic material mixes with the evolved rhyolitic magma, the composition is returned to andesite, its intermediate phase.

The composition of the molten rock ( magma ) that feeds volcanism in the Lassen volcanic area ranges widely in its content of silica or ; the higher the silica content, the greater the ability of the magma to trap and hold onto gas and water vapor.

Dacite magma that is extruded nonexplosively as lava forms lava domes because it is too viscous ( sticky ) to flow far away from its source.

After the magma chamber under the Yellowstone area collapsed 600, 000 years ago in its previous great eruption, it formed a large caldera that was later partially filled by subsequent lava flows ( see Yellowstone Caldera ).

There are swarms of near-vertical dykes of basalt on the northwest coast between Kilmory and Guirdil, created by basaltic magma forcing its way into fissures in the pre-existing rock.

While Mazama slept, its magma chamber was going through some differentiation, with lighter, more gas-and silica-rich rocks collecting closer to the surface.

The last pyroclastic flow of this stage was andesitic scoria, indicating that Mazama was drawing on material deep from within its magma chamber.

The magma was replaced by about the same volume of material when most of Mazama fell into its caldera.

Hence, a magma is medial if and only if its binary operation is a magma homomorphism from to.

It is possible to see a particular area known as Hutton ’ s Section in the Salisbury Crags where the magma forced its way through the sedimentary rocks above it to form the dolerite sills that can be seen in the Section.

Eyjafjallajökull lies 25 km west of another subglacial volcano, Katla, under the Mýrdalsjökull ice cap, which is much more active and known for its powerful subglacial eruptions and its large magma chamber.

Because most of the volcano lies underneath Vatnajökull, most of its eruptions have been subglacial and the interaction of magma and meltwater from the ice causes phreatomagmatic explosive activity.