ERSC 3V93 Lecture Notes - Lecture 15: Geographical Pole, Commonwealth Bay, Orbital Inclination
28 Apr 2016
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Document Summary
Total magnetization of a rock is sum of both the induced and remanent magnetism: Jr can have any direction (constrained by age of rock and apwp!) Most shallow magnetic exploration work assume jr is negligible . Ratio of remanent to induced magnetization remanent magnetization may be much greater than induced magnetization in. Q ~ 30 50 for rapidly quenched volcanic rocks. Q ~ 1 for slowly crystallised igneous and thermally metamorphosed continental rocks. Q < 1 in sedimentary and metamorphic rocks when iron not present. Interpretation of magnetic field due to a subsurface body can be complicated because of combined effect of two vector magnetisations that may have different magnitudes and directions. We can measure it as a vector (vector mag), or as a scalar (field intensity) Magnetic field strength, f is a vector quantity having both magnitude and direction described by: declination, d.
