Open AccessA theoretical and experimental comparison of the anisotropies of magnetic susceptibility and remanence in rocks and minerals
Author(s) -
Stephenson A.,
Sadikun S.,
Potter D. K.
Publication year - 1986
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1986.tb04351.x
Subject(s) - anisotropy , remanence , ellipsoid , magnetic susceptibility , magnetic anisotropy , condensed matter physics , geology , magnetization , rock magnetism , magnetite , demagnetizing field , mineralogy , materials science , magnetic field , physics , optics , quantum mechanics , paleontology , geodesy
Summary. Susceptibility, thermo‐remanent magnetization (TRM) and isothermal remanent magnetization (IRM) anisotropy ellipsoids have been determined for several rock samples. The results indicate that the ellipsoid of initial susceptibility is less anisotropic than the TRM and low field IRM ellipsoids which are found experimentally to be of identical shape. This suggests that palaeomagnetic data for anisotropic rocks may be corrected by using the anisotropy ellipsoid determined from magnetically non‐destructive low field IRM measurements. Such IRM measurements can also be used to obtain anisotropy axes of samples which are inherently anisotropic but which have a susceptibility which is too weak to be accurately measured. The results for a series of artificial anisotropic samples containing magnetite particles of different sizes (in the range 0.2–90 μm) were very similar to those for the rocks. In contrast, a comparison of the susceptibility and IRM ellipsoids for anisotropic samples containing particles from a magnetic tape gave very different results in accordance with theory. Such results imply that susceptibility and IRM ellipsoids could be used to determine whether anisotropic rocks contain uniaxial single‐domain particles (magnetization confined to the easy axis) or whether the particles are essentially multidomain.