Monday 9 February 2009

Magma

Magma is molten rock and metal found beneath the surface of the Earth. It is thought that it may exist on other terrestial planets. People commonly think of lava and magma as a liquid, but geologists find that magma is usually a mush - a liquid carrying a load of mineral crystals. We've seen in previous posts how comets, whom also carry mineral crystals, may use electrolysis to generate those huge ionic plasma tails. A comet's tail can be tens of millions of kilometers in length when seen in the reflected sunlight. Comets are very small in size relative to planets. Their average diameters usually range from 750 meters or less to about 20 km. The Earth has a diameter of 12, 800km at its equator. If we were able to look under the bonnet of the planet, so to speak, would we find the same ionic reaction taking place beneath the mantle on a far grander scale?

Scientists know a lot about lava. Lava is the stuff which erupts onto the surface. Magma remains a bit of a mystery to scientists because it is always found beneath the crust, making it difficult to observe. Drillers accidentally hit a pocket of molten rock underneath a working geothermal energy field in Hawaii, a lucky break for geologists that could allow them to map the geological plumbing that created everything we know as land. Geologists had expected to hit dark molten basalt, because basalt is abundant on the island. Tests of the glass samples found that the material was dacite, an unusual type of magma that is granitic in nature and contains 67 percent of silica. The samples of the magma were found to be "clear and glassy".


Basalt flows cover nearly 70 percent of the earth's surface. Basalt contains around 50 percent silica. Silica is a chemical compound also known as silicon dioxide (SiO2). Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms. Soda-lime glass accounts for 90 percent of manufactured glass. Soda-lime glass contains about 70 to 74 percent silica. Many glasses contain silica as their main component and glass former. Silica is also the most abundant mineral in the Earth's crust. Although there are few exceptions, the primary constituent of magma is silica. The guy on this site relishes the similarities of glass and magma, and has fun recreating lava flows in the microwave - known affectionately as "the ol' nuker". The reactions are possible due to ions being trapped in the glass.
http://www.ionizationx.com/amasci.com/weird/microwave/voltage2.html


Glass optical fibers are almost always made from silica. An optical fiber is a glass or plastic fiber that carries light along its length. Light is kept in the core of the optical fibre by total internal reflection. Now this is probably a poor comparison to make, but I think of the Earth's crust as acting like the core of the optical fibre. I picture streams of ions bouncing off the walls down there. One very direct result of this would be a vibration. I think that's the reason no gas bubbles were found in that Hawaiian magma sample. The vibrations would dissolve the gas.




Many thanks:
http://www.wisegeek.com/what-is-glass.htm
http://geology.about.com/cs/basics_roxmin/a/aa011804a.htm
http://explorevolcanoes.com/rocksandfeatures.html
http://cat.inist.fr/?aModele=afficheN&cpsidt=17424425
http://www.greentechmedia.com/articles/first-contact-with-inner-earth-5385.html
http://www.cerritos.edu/earth-science/tutor/On-Line_lecture_notes/Volcanoes/Unit_11_Lecture_Magma.htm
http://www.geotimes.org/july04/NN_Marsironcore.html
http://amonline.net.au/geoscience/earth/magmatism.htm
http://wsx.lanl.gov/Publications/wurden-comet-ieee.pdf
http://en.wikipedia.org/wiki/Optical_fiber
http://en.wikipedia.org/wiki/Glass

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