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Single-grain versus distribution anisotropy: a simple three-dimensional model

1996; Elsevier BV; Volume: 94; Issue: 1-2 Linguagem: Inglês

10.1016/0031-9201(95)03072-7

1872-7395

Edgardo Cañón‐Tapia,

Geophysical and Geoelectrical Methods

The effects of individual-grain anisotropies are combined in a three-dimensional model used to study the anisotropy of magnetic susceptibility (AMS) of magnetically interacting particles. The examples examined show that whenever magnetic interaction takes place, the measured AMS is dominated by the distribution of grains rather than by their individual orientations. The combined effects of individual-grain anisotropy and magnetic interaction, however, may result in a magnetic fabric that does not bear a simple relationship with neither the orientation of individual grains nor their distribution, clearly indicating that it is not possible to establish a unique relationship between the fabric observed in thin sections and that measured by magnetic methods. A mechanism explaining how a strong remanent magnetization may influence the measured AMS of a rock specimen owing to magnetic interaction between particles is also delineated. Stability of the magnetic fabric during magnetic cleaning can be used as an argument to eliminate the influence of the remanence as a factor defining the measured AMS, but can not rule out the possibility of magnetic interaction related to induced magnetization.