name means magma matter in semi-fluid state -result of the merger of silicates and other compounds that make up the rocks, which show properties that do not correspond with the solid state and also with those of a liquid or fluid, according to general principles of physics. The magma
appear in different types of suspension crystals and fragments partially melted rocks and carbonates, sulfides and other components dissolved volatile.
The interaction of different physical conditions determine the characteristics of magma, both in terms of their chemical composition and its viscosity, strength, plasticity and movement.
magmas types
A first classification of different types of magmas refers to its silica content. magmas with more than 60% silica dioxide are called acids, while those with less that amount are called basic .
When magma is reaching out for the weakest points of the earth's crust, magma bodies give rise to volcanoes and formed by cooling magmatic rocks, also called igneous or eruptive, whose degree of crystallization is variable, and among them are granite, basalt or porphyry.
The ascent of magma depends on its physical-chemical conditions (Viscosity, density, content of volatile elements, etc.) Of the particular tectonic region where rocks and have to cross. The
appear in different types of suspension crystals and fragments partially melted rocks and carbonates, sulfides and other components dissolved volatile.
The interaction of different physical conditions determine the characteristics of magma, both in terms of their chemical composition and its viscosity, strength, plasticity and movement.
magmas types
A first classification of different types of magmas refers to its silica content. magmas with more than 60% silica dioxide are called acids, while those with less that amount are called basic .
When magma is reaching out for the weakest points of the earth's crust, magma bodies give rise to volcanoes and formed by cooling magmatic rocks, also called igneous or eruptive, whose degree of crystallization is variable, and among them are granite, basalt or porphyry.
The ascent of magma depends on its physical-chemical conditions (Viscosity, density, content of volatile elements, etc.) Of the particular tectonic region where rocks and have to cross. The
acid magmas are light and viscous, rise with ease and create large reservoirs. The basic magmas
, higher density, less viscous and ascend more difficult than previous ones.
When mixtures of various substances, the magmas do not have a melting point defined, but a melting range. Similarly, no one can speak of crystallization temperature, but crystallization interval.
PHYSICAL PROPERTIES OF MAGMA
The physical properties of magmas vary with temperature, pressure, chemical composition and other parameters such as crystallinity and gallbladder. The two most important properties of magmas are the density and viscosity. Density
Small compositional differences can produce substantial changes in density. The molten basalt, andesite and rhyolite in liquidus temperatures have densities gm/cm3 2.7,2.5 and 2.3, respectively. Density changes associated with cooling are smaller than density changes caused by differentiation from a basaltic liquid with a rhyolite.
a melt density decreases during cooling due to crystallization of the melt separating elements more volatile densos.los have a significant effect on the density, such as water coming down the density of the fluid.
Viscosity
A silica-rich melt, such as rhyolite, is composed of long chains and rings of silica tetrahedra. Consequently, rhyolitic melts have very high viscosity, while the basalt have much lower viscosities. The viscosity also depends strongly on the temperature.
The effect of pressure es todavía desconocido, pero algunos datos experimentales indican un descenso de la viscosidad con el incremento de la presión.
A silica-rich melt, such as rhyolite, is composed of long chains and rings of silica tetrahedra. Consequently, rhyolitic melts have very high viscosity, while the basalt have much lower viscosities. The viscosity also depends strongly on the temperature.
The effect of pressure es todavía desconocido, pero algunos datos experimentales indican un descenso de la viscosidad con el incremento de la presión.
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