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High-temperature fractional crystallization of relatively water-poor granite magmas may produce single-alkali-feldspar granite, and lower-temperature crystallization of relatively water-rich magma may produce two-feldspar granite. [13] During the process of fractional crystallization, melts become enriched in incompatible elements. [14]
Within the field of geology, Bowen's reaction series is the work of the Canadian petrologist Norman L. Bowen, [1] who summarized, based on experiments and observations of natural rocks, the sequence of crystallization of common silicate minerals from typical basaltic magma undergoing fractional crystallization (i.e. crystallization wherein early-formed crystals are removed from the magma by ...
For instance, a magma of gabbroic composition can produce a residual melt of granitic composition if early formed crystals are separated from the magma. [92] Gabbro may have a liquidus temperature near 1,200 °C, [ 93 ] and the derivative granite-composition melt may have a liquidus temperature as low as about 700 °C. [ 94 ]
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in ...
As magma cools, minerals typically crystallize from the melt at different temperatures (fractional crystallization). As minerals crystallize, the composition of the residual melt typically changes. If crystals separate from the melt, then the residual melt will differ in composition from the parent magma.
At the bottom of the magma reservoir, a cumulate rock forms. Cumulate rocks are the typical product of precipitation of solid crystals from a fractionating magma chamber. These accumulations typically occur on the floor of the magma chamber, although they are possible on the roofs if anorthite plagioclase is able to float free of a denser mafic ...
Rhyolite is an extrusive igneous rock, formed from magma rich in silica that is extruded from a volcanic vent to cool quickly on the surface rather than slowly in the subsurface. It is generally light in color due to its low content of mafic minerals, and it is typically very fine-grained ( aphanitic ) or glassy .
Because of its low viscosity, this is the least explosive form of magma. Basaltic magma may found in regions such as Hawaii, known for its shield volcanoes. [1], [7] Basaltic magma forms minerals such as calcium-rich plagioclase feldspar and pyroxene. The water composition of basaltic magma varies dependent on the evolution of the magma chamber.