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What is magma? What is the importance of magma in geology world? What is the composition of it? What are the classification of it?

 ORIGIN AND GENERATION OF MAGMA



Before knowing about the origin and generation of magma, we need to be familiar with the term “Magma”. So, magma is extremely hot molten or semi-molten rocks, which are found beneath the earth's surface from which Igneous rocks are formed. When magma comes out of the surface of the earth, then the magma is called Lava. Basically, magmas are formed from pre-existing rocks like metamorphic or sedimentary rocks. As we know that, the temperature and pressure increase with depth. So, at a great depth below the earth's surface, the temperature and pressure cross 200 degrees Celsius and 350 MPA respectively, the pre-existing rocks start to melt, and then these pre-existing rocks converted into molten or semi-molten state and magma formed. The temperature of magma can be directly measured with the help of a “pyrometer or thermocouple”. But it is very difficult to measure the temperature of intrusive magma. The temperature of extrusion lavas is mostly in the range of 800 degrees Celsius to 1200 degrees Celsius.

CHEMICAL COMPOSITION OF MAGMA




The substance organization incorporates components, oxides, and the various kinds of minerals present in magma. By and large, magma is comprised of just eight components, arranged by significance: Oxygen, Silicon, aluminum, iron, calcium, sodium, magnesium, and potassium. Significant oxides are- silica (SiO2), aluminum oxide (Al2O3), iron oxide (FeO), magnesium oxide (MgO), carbon dioxide (CO2), sodium oxide (Na2O), carbon monoxide (CaO), nitrogen dioxide (N2o), and so on Some significant minerals are-Feldspar, Pyroxene, Quartz, mica, etc. 


CLASSIFICATION OF MAGMA

For the most part, magma is characterized into three kinds-

1) Basaltic magma: Basaltic magma is ordinarily delivered by direct liquefying of the Earth's mantle, the district of the Earth beneath the external outside. On mainlands, the mantle starts at profundities of 30 to 50 km. Safeguard volcanoes, like those that make up the Islands of Hawai'i, are made for the most part out of basalt. Here the measure of calcium, iron, and magnesium is high, yet the measure of sodium and potassium is low. Here the scope of temperature is going from 1000 degrees Celsius to 1200 degrees Celsius. The silica rate present in basaltic magma is between 45% to 55%. 


2) Andesitic magma: Granitic, or Rhyolitic, magmas, and andesitic magmas are created at joined plate limits where the maritime lithosphere (the external layer of Earth made out of the outside and upper mantle) is subducted so its edge is situated beneath the edge of the mainland plate or another maritime plate. Here the measure of Calcium, magnesium, iron, sodium, and potassium is moderate. Here the scope of temperature is going from 800 degrees Celsius to 1000 degrees Celsius. The silica rate present in andesitic magma is between 55% to 65%. 


3) Rhyolitic magma: Rhyolitic magma structures because of the wet softening of mainland covering. Rhyolites are rocks that contain water and minerals that contain water, like biotite. ... This crystallization delivers the basaltic magma's warmth, making the temperature of the mainland outside ascent and liquefy. Rhyolites typically structure in mainland or landmass edge volcanic ejections where granitic magma arrives at the surface. Rhyolites are seldom created at maritime ejections. Here the measure of calcium, magnesium, and iron are low, yet the measure of sodium and potassium is high. Here the scope of temperature is going from 600 degrees Celsius to 800 degrees Celsius. The silica rate present in Rhyolites magma is between 65% to 75%.

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