Anisotropy of magnetic susceptibility: Sedimentological, igneous, and structural‐tectonic applications

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Abstract
As was noted by Graham [1954], anisotropy of magnetic susceptibility (AMS) data has many applications to the study of geological processes. This type of anisotropy expresses directional variation in the magnetization induced in a rock, most notably in its iron oxides and especially in its magnetite and hematite. The AMS is commonly expressed by an ellipsoid, of which the principal axes are K1, K2, and K3, from greatest to least. This ellipsoid is generally interpreted in terms of the distribution and shape of grains of magnetic minerals in a rock although the ellipsoid determined depends also on magnetocrystalline anisotropy and on factors of instrumental technique [Ellwood et al., in press, 1987], The challenge for the geoscientist in analyzing AMS data is first to identify the origin of the AMS geometry, then second to relate that geometry to the natural processes which produced the inferred or measured distribution of magnetic materials.