<b>Directional dependence of magneti</b><b>zation and coercivity in hematite ore experimentally deformed in torsion</b>

Rock-magnetic methods are widely used to resolve the composition, concentration, size, shape and alignment of iron oxides in rock samples. Although anisotropy of magnetic susceptibility is measured routinely, acquisition of remanent magnetization as well as hysteresis loops are usually measured in one direction only. This may lead to biased interpretation of the results. In our study, observation of strong directional dependence of remanence acquisition curves and hysteresis loops in experimentally deformed samples of hematite ore is reported. Subpopulations of grains with different magnetic coercivities are expressed in different way, depending on the measurement direction, the anisotropy of induced magnetization being of several tens of per cent. These findings have significant impact on the remanent and induced magnetization measurement protocols and interpretation of the data. Anisotropy of these parameters should be checked at least in cases when hematite is assumed to be present in the samples, or the samples underwent deformation.