DISTRIBUTION ANISOTROPY - 2 SIMPLE-MODELS FOR MAGNETIC LINEATION AND FOLIATION

In a recent paper, Hargraves et al. (1991) have carried out experiment s on synthetic samples containing magnetite particles distributed in l ayers. They show that anisotropy of susceptibility arises from such an arrangement and suggest that anisotropy in rocks may sometimes be a r esult of similar non-uniform distributions of interacting isotropic pa rticles rather than to preferential orientation of anisotropic particl es. In this paper two simple models involving either lines or planes o f interacting spherical particles are used to show that non-uniform di stributions of spherical particles can give rise to large anisotropies . Using the models, the separation between particles within a line (or plane) can be found directly from the measured anisotropy of suscepti bility and if the average susceptibility is also measured, the separat ion between lines (or planes) of particles can also be determined in p rinciple.