A simple toolbox for evaluating the combined contributions to the whole-rock magnetic fabric

The interpretation of magnetic fabric (studied mainly by means of anisotropy of magnetic susceptibility) has become one of the well-established, fast, and reliable rock fabric proxies used in many branches of the Earth science. In the usual case, the magnetic fabric ellipsoid reflects the crystallographic or shape preferred orientation of the grains of the main rock-constituent mineral. If two (or more) sets of mineral grains are present, their combined contribution towards the whole-rock magnetic fabric is proportional to their relative content, their value of bulk susceptibility and their degree of anisotropy. This can be the case of, for example, combined contribution of differently oriented paramagnetic and ferromagnetic sub-fabrics, normal and inverse magnetic fabric, or anisotropic fabric and isotropic matrix. In order to overcome some misconception on how various magnetic fabrics can contribute to the overall rock fabric, we present a simple toolbox for visualizing a combined contribution of two pre-defined end-member magnetic sub-fabrics. These end-member fabrics are defined by their bulk susceptibility, degree of anisotropy, shape of anisotropy ellipsoid and the orientations of its principal directions. The toolbox is part of Anisoft software which enables the instant visualization how magnetic fabric changes as a function of the relative content of the end-member sub-fabrics.