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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]
In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (usually increasingly silicic) magmas produced by igneous differentiation is known as a magma series.
During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion , [ 8 ] such as a dike , a sill , a ...
Bodies of intrusive rock are known as intrusions and are surrounded by pre-existing rock (called country rock). The country rock is an excellent thermal insulator, so the magma cools slowly, and intrusive rocks are coarse-grained . The mineral grains in such rocks can generally be identified with the naked eye.
As the magma develops over time and the crystal content of the magma increases, phase separation is taking place and the liquid phase of the magma is pushed up, driven by its buoyancy as a result of its lower density. Volcanoes, as valves of the open system, provide the path for gas release and magma eruption. The amount of dissolved gases may ...
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 ...
This process is known as lithification. Igneous rocks have crystallised from a melt or magma. The melt is made up of various components of pre-existing rocks which have been subjected to melting either at subduction zones or within the Earth's mantle. The melt is hot and so passes upward through cooler country rock.
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 .