Cristalización magmática
El magma se origina cuando en un lugar de la corteza o del manto superior la temperatura alcanza un punto en el que los minerales con menor punto de fusión empiezan a fundirse (inicio de fusión parcial de las rocas).
Sin embargo, la temperatura de fusión no depende sólo del tipo de roca, sino también other factors such as the pressure he is or the presence or absence of water.
The increased pressure able to absence of water makes the merger , therefore, with depth, tends to increase the melting temperature of the rocks. By contrast, the presence of water decreases the melting point .
After its formation, the magma rises, it is less dense than the surrounding rocks. During ascent cools and begins to crystallize , Forming minerals with the lowest ever temperature, according to an orderly sequence known as a series of crystallization of Bowen.
The series Bowen refers to two main lines of crystallization. One indicates the order in which they are silicates rich in iron and magnesium (called ferromagnesian). Discontinuous series called because the crystals formed will be replaced by others with different and more complex structure as the temperature drops.
The another series of crystallization is that of plagioclase . called be of continuing trained on because the minerals have the same structure and only changes the relative proportion of sodium and calcium. At the end of crystallization, while sodium plagioclase (albite) and the lenses are formed quartz and orthoclase. Magmatic differentiation
sometimes occurs as the crystallization of a magma when the density difference between minerals and liquid formed and the residual is high and if This viscosity is low, crystals newly formed can be isolated from the rest of the magma, which therefore will be progressively enriched in silica.
to continue the process will produce, from a single magma, a series of igneous rocks of different composition, fractional crystallization . This process is called magmatic differentiation, and may originally acidic rock formation from basic to intermediate magmas. Phases
The magmatic crystallization cooling of magma within the crust results in a series of successive phases of crystallization, lower and lower temperatures.
The first is called ortomagmática phase, which generally occurs from above 700 ° C (depending on the composition of other physical conditions .) It crystallizes most of the magma forming plutonic rocks.
pegmatitic phase takes place more or less between 700 and 550 º C . At these temperatures, the residual melt is very rich in volatiles , so you enter through cracks, which crystallizes causing yacimentos Philonian of pegmatites. The minerals are silicates are rich in silica (quartz, orthoclase, albite), hydroxyl group (micas) and elements such as boron (tourmaline), phosphorus (apatite), fluoride (fluorite), etc.
In the third phase, called neumatolítica , which takes place about the 550 and 375 ° C , crystallizing the residue is composed mainly of volatile , which penetrate the host rocks and veins leading to consist of minerals such as muscovite, quartz, topaz, oxides and metal sulfides, etc. . Similarly, acting on volatile minerals of igneous rocks sticking or transforming them.
The last stage, called hydrothermal , starts below 375 ° C results in streaks and veins of quartz and calcite, a mineral and metal transformation minerals already formed.
magmatism and plate tectonics
The origin of magma is often associated with the global dynamics of the crust and mantle, and that, in general, takes place at the edges of plates. The dorsal
, the magma is basically formed by decompression of the upper mantle materials, shallow, and leads to basic rocks (basalts and gabbros) . In
subduction zones, magma originates at a depth of 150 km from partial melting of oceanic crust and / or the mantle and crust located above. This process results in the formation of rocks mostly intermediate (andesites and granodiorites).
In areas of continental collision in relation to orogenic processes, there is partial melting of the crust, and there are essentially acidic rocks like granite. There are also
specific areas of intraplate magmatism, which is due to the existence of hot spots in the mantle.
El magma se origina cuando en un lugar de la corteza o del manto superior la temperatura alcanza un punto en el que los minerales con menor punto de fusión empiezan a fundirse (inicio de fusión parcial de las rocas).
Sin embargo, la temperatura de fusión no depende sólo del tipo de roca, sino también other factors such as the pressure he is or the presence or absence of water.
The increased pressure able to absence of water makes the merger , therefore, with depth, tends to increase the melting temperature of the rocks. By contrast, the presence of water decreases the melting point .
After its formation, the magma rises, it is less dense than the surrounding rocks. During ascent cools and begins to crystallize , Forming minerals with the lowest ever temperature, according to an orderly sequence known as a series of crystallization of Bowen.
The series Bowen refers to two main lines of crystallization. One indicates the order in which they are silicates rich in iron and magnesium (called ferromagnesian). Discontinuous series called because the crystals formed will be replaced by others with different and more complex structure as the temperature drops.
The another series of crystallization is that of plagioclase . called be of continuing trained on because the minerals have the same structure and only changes the relative proportion of sodium and calcium. At the end of crystallization, while sodium plagioclase (albite) and the lenses are formed quartz and orthoclase. Magmatic differentiation
sometimes occurs as the crystallization of a magma when the density difference between minerals and liquid formed and the residual is high and if This viscosity is low, crystals newly formed can be isolated from the rest of the magma, which therefore will be progressively enriched in silica.
to continue the process will produce, from a single magma, a series of igneous rocks of different composition, fractional crystallization . This process is called magmatic differentiation, and may originally acidic rock formation from basic to intermediate magmas. Phases
The magmatic crystallization cooling of magma within the crust results in a series of successive phases of crystallization, lower and lower temperatures.
The first is called ortomagmática phase, which generally occurs from above 700 ° C (depending on the composition of other physical conditions .) It crystallizes most of the magma forming plutonic rocks.
pegmatitic phase takes place more or less between 700 and 550 º C . At these temperatures, the residual melt is very rich in volatiles , so you enter through cracks, which crystallizes causing yacimentos Philonian of pegmatites. The minerals are silicates are rich in silica (quartz, orthoclase, albite), hydroxyl group (micas) and elements such as boron (tourmaline), phosphorus (apatite), fluoride (fluorite), etc.
In the third phase, called neumatolítica , which takes place about the 550 and 375 ° C , crystallizing the residue is composed mainly of volatile , which penetrate the host rocks and veins leading to consist of minerals such as muscovite, quartz, topaz, oxides and metal sulfides, etc. . Similarly, acting on volatile minerals of igneous rocks sticking or transforming them.
The last stage, called hydrothermal , starts below 375 ° C results in streaks and veins of quartz and calcite, a mineral and metal transformation minerals already formed.
magmatism and plate tectonics
The origin of magma is often associated with the global dynamics of the crust and mantle, and that, in general, takes place at the edges of plates. The dorsal
, the magma is basically formed by decompression of the upper mantle materials, shallow, and leads to basic rocks (basalts and gabbros) . In
subduction zones, magma originates at a depth of 150 km from partial melting of oceanic crust and / or the mantle and crust located above. This process results in the formation of rocks mostly intermediate (andesites and granodiorites).
In areas of continental collision in relation to orogenic processes, there is partial melting of the crust, and there are essentially acidic rocks like granite. There are also
specific areas of intraplate magmatism, which is due to the existence of hot spots in the mantle.
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