Anisotropy of magnetic susceptibility of rocks in the Rayleigh Law region: Modelling errors arising from linear fit to non-linear data
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The anisotropy of magnetic susceptibility (AMS) within the Rayleigh Law range was investigated theoretically, using mathematical modelling. It was revealed that the orientations of the principal susceptibilities and the shape parameter vary with field so weakly that these variations can be regarded as negligible from the practical point of view. The degree of AMS increases with field according to the degree of anisotropy of the initial susceptibility used and according to the intensity of susceptibility change with field of the mineral considered. The degree of AMS calculated using linear theory is very near to the degree of AMS following from the analysis of AMS within the Rayleigh Law range. If it is desirable to correct the field-dependent degree of AMS, a simple technique is suggested based on measurement of the AMS in two fields.
Key wordsanisotropy of magnetic susceptibility Rayleigh Law mathematical model
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- Chlupáčová M., 1984. Anisotropy of magnetic susceptibility. In: M. Chlupáčová, P. Pruner, M. Krsová, F. Hrouda and V. Jelínek (Eds), Magnetic Properties of Rocks and Ores with Pyrrhotite. Report of Geofyzika, n.p. Brno, 76–106 (in Czech).Google Scholar
- Collinson D.W., 1993. Measurement of anisotropy of low-and high-field susceptibility. In: D.H. Tarling and F. Hrouda (Eds.), The Magnetic Anisotropy of Rocks. Chapman and Hall, London, 72–80.Google Scholar
- Jelínek V., 1977. The Statistical Theory of Measuring Anisotropy of Magnetic Susceptibility of Rocks and its Application. Geofyzika, n.p. Brno.Google Scholar
- Jelínek V., 1985. The physical principles of measuring magnetic anisotropy with the torque magnetometer. Travaux Géophysiques, 33, 177–198.Google Scholar
- Nagata T., 1961. Rock Magnetism. Maruzen, Tokyo.Google Scholar
- Néel L., 1942. Theory of Rayleigh’s law of magnetization. Cahier Phys., 12, 1–20.Google Scholar
- Pokorný J., Suza P. and Hrouda F., 2004. Anisotropy of magnetic susceptibility of rocks measured in variable weak magnetic fields using the KLY-4S Kappabridge. In: F. Martín-Hernández, C.M. Lüneburg, C. Aubourg and M. Jackson (Eds), Magnetic Fabric: Methods and Applications. Geological Society of London Special Publications, 238, 69–76.Google Scholar
- Schwarz E.J., 1974. Magnetic fabric in massive sulfide deposits. Can. J. Earth Sci., 11, 1669–1675.Google Scholar
- Stacey F.D. and Banerjee S.K., 1974. The Physical Principles of Rock Magnetism. Developments in Solid Earth Geophysics, 5, Elsevier, Amsterdam.Google Scholar
- Tarling D.H. and Hrouda F. (Eds.), 1993. The Magnetic Anisotropy of Rocks. Chapman and Hall, London.Google Scholar