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A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. [2] Because the plume head partially 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.
Magma emplacement can take place at any depth above the source rock. [4] Magma emplacement is primarily controlled by the internal forces of magma including buoyancy and magma pressure. [2] Magma pressure changes with depth as vertical stress is a function of the depth. [20] Another parameter of magma emplacement is the rate of magma supply. [2]
Plumes are used to locate, map, and measure water pollution within the aquifer's total body of water, and plume fronts to determine directions and speed of the contamination's spreading in it. [3] Plumes are of considerable importance in the atmospheric dispersion modelling of air pollution. A classic work on the subject of air pollution plumes ...
Over half the original magma remains in the lower crust as cumulates in a system of dikes and sills. [34] [21] As the magma rises, the drop in pressure also lowers the liquidus, the temperature at which the magma is fully liquid. This likely explains the lack of phenocrysts in erupted flood basalt.
A further control on the morphology and characteristics of a deposit is the water to magma ratio. It is considered that the products of phreatomagmatic eruptions are fine grained and poorly sorted where the magma/water ratio is high, but when there is a lower magma/water ratio the deposits may be coarser and better sorted. [4]
“As Earth’s rocky portion stirs and convects like hot water on a stove top, material ascends, cools, and sinks. ... it ascended to the surface through the mantle in the form of magma plumes ...
Magma exists in three main forms that vary in composition. [3] When magma crystallizes within the crust, it forms an extrusive igneous rock. Dependent on the composition of the magma, it may form either rhyolite, andesite, or basalt. [3] Volatiles, particularly water and carbon dioxide, significantly impact the behavior of each form of magma ...
Plumes are postulated to rise through the mantle and begin to partially melt on reaching shallow depths in the asthenosphere by decompression melting. This would create large volumes of magma. The plume hypothesis postulates that this melt rises to the surface and erupts to form "hot spots".