viernes, 25 de marzo de 2011
some explanaitions
EDebajo earth's crust there is a large region, deep ocean like a hot semi-fluid and composed of materials that form the molten magma and, at times, projected out to the outside with great intensity through volcanoesMagma name designates the state semi-fluid matter-the result of fusion of silicates and other compounds that make up the rock-forming region below the crust. Due to the conditions they are subjected (high pressures and high temperatures), magmatic materials show properties that do not correspond to the solid state and also with those of a liquid or fluid, according to general principles of physics.In the suspended magma displayed different types of crystals and fragments of partially melted rocks and carbonates, sulfides and other volatile components dissolved. 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.Types of magmasA 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 than this amount are called basic.According to the state of the gas they contain, can be distinguished, the hipomagma or magma deep unsaturated gases, which are found in solution because the external pressure exceeds the vapor pressure of the magma, the piromagma, supersaturated gases, which are a stage in the form of bubbles due to outside pressure is lower than the vapor pressure, and the epimagma or magma degassing, which includes only mineral cast (gases escaping from the rest of the magma due to low external pressure).When epimagma 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 which 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. Acid magmas are light and viscous, rise with ease and create large reservoirs. The basic magmas, higher density, less viscous and ascend with greater difficulty than before.To be mixtures of various substances, the magmas do not have a defined melting point but a melting range. Similarly, no one can speak of crystallization temperature, but crystallization interval.Magma crystallizationThe magma originates in a place where the crust or upper mantle temperature reaches a point where the minerals with lower melting point starts to melt (start of partial melting of rocks). However, the melting temperature depends not only on the type of rock, but also other factors like the pressure he is or the presence or absence of water. The increased pressure in conditions of lack of water makes it difficult to merge, so that, with depth, tends to increase the melting temperature of the rocks. By contrast, fa 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 increasingly lower temperature, according to an orderly sequence known as a series of crystallization of Bowen.Bowen Series refers to two main lines of crystallization. One indicates the order in which they are rich in iron silicates 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 other series is the crystallization of plagioclase. Of being called continuous because the minerals formed on the same structure and only changes the relative proportion of sodium and calcio.Al end of crystallization, while sodium plagioclase (albite> and the mica and quartz are formed the orthoclase.
Magmatic differentiationSometimes, as is the crystallization of magma, if the density difference between minerals and liquid formed and the residual is high and if the viscosity of it is low, the newly formed crystals may be isolated from the rest of the magma, which therefore will be progressively enriched in silica from continuing 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 of magma crystallizationThe cooling of magma within the crust results in a series of successive phases of crystallization, lower and lower temperatures. The first is called Frise ortomagmática that. usually occurs above 700 ° C (depending on the composition of other physical conditions). It crystallizes most of the plutonic rocks forming magma.Pegmatitic phase occurs roughly between 700 and 550 0C. At these temperatures, the residue fundid6 is highly enriched in volatiles, so that is inserted through the cracks, where it 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 roughly between 550 and 375 ° C, the residue of crystallization is basically composed of volatile, penetrating into 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 ore processing and metal and formed.Magmatism and plate tectonicsThe origin of magma is often associated with the global dynamics of the crust and mantle, as generally occurs at plate boundaries. In the ridges, the magma is basically formed by decompression of the upper mantle material at shallow depth and results in 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 mostly intermediate rocks (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.
Magmatic differentiationSometimes, as is the crystallization of magma, if the density difference between minerals and liquid formed and the residual is high and if the viscosity of it is low, the newly formed crystals may be isolated from the rest of the magma, which therefore will be progressively enriched in silica from continuing 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 of magma crystallizationThe cooling of magma within the crust results in a series of successive phases of crystallization, lower and lower temperatures. The first is called Frise ortomagmática that. usually occurs above 700 ° C (depending on the composition of other physical conditions). It crystallizes most of the plutonic rocks forming magma.Pegmatitic phase occurs roughly between 700 and 550 0C. At these temperatures, the residue fundid6 is highly enriched in volatiles, so that is inserted through the cracks, where it 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 roughly between 550 and 375 ° C, the residue of crystallization is basically composed of volatile, penetrating into 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 ore processing and metal and formed.Magmatism and plate tectonicsThe origin of magma is often associated with the global dynamics of the crust and mantle, as generally occurs at plate boundaries. In the ridges, the magma is basically formed by decompression of the upper mantle material at shallow depth and results in 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 mostly intermediate rocks (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.
project
our project is about volcanoes oh sorry about the components of magma The magma is composed ofhighly volatile materials to escape during the cooling process, or
low volatility materials finally solidified, so
as
a cluster lead compound, in most cases, quartz, feldspar and mica, and a
secondary cluster (eg, zircon, apatite, magnetite, etc..) that is less important compared with the principal.
The fraction volatize scarcely be composed primarily of SiO2, as well as oxides of Al, Fe, Ca, Mg, Na and K (minor), whose participation is relatively low because the SiO2 content ranges between 50 and 75%. Unlike sediments, magmatites remain within a narrow framework of normality from a mineralogical point of view.
The party easily volatize is composed mainly of H2O, CO2, HCl, HF, H2S, among others. Your total amount in the magma is not significant (only a very small percentage of weight), however, it influences the solidification of magma
viernes, 18 de marzo de 2011
holis
hola es mi primera publicacion en bloogger soy muy nueva espero meterle mas cosas a mi blog pero por ahora estoy en clase de computo entonces no puedo ponerle nada bua que mal pero ahora cuando llegue a la casa la puede subir mas cosas jajajajajajaja thanx
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