MadSci Network: Earth Sciences |
The pressure at the center of the inner core is about 3.64 x 10^12 dynes per centimeter squared, and the temperature should be near 5000 degrees, according the measurements and adjustment to the high pressure physics models. The comparison of the composition of the Earth with meteorites and the behavior of seismic waves and the inertia moment of the Earth, as well geomagnetic field models, suggests the inner core is composed by Fe, Ni and S (more than 99% is Fe and Ni), with some little amounts of O and Si. These Fe, Ni and S are present forming an alloy. For sure the behavior of these materials are different than they are at surface, because the great pressure and temperature conditions. This is a big problem in using indirect data to try to determine the composition and properties of this regions, because we have to obtain lab data with great pressures and extrapolate the results in order to obtain the best approximation. The strength of the magnetic field and eletric current in this region is unknown, and even the most elaborated magnetohydrodinamic models have to make some assumptions and simplifications in order to be feasible to calculate. I suggest the book "Physics and Geology", from Jacobs, Russel & Wilson, McGraw-Hill, second edition, 1974, where you can find many detailed information about these data and models. Best regards Eder C. Molina eder@iag.usp.br Dept. of Geophysics University of Sao Paulo BRASIL
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