Determinación de fábricas mediante la anisotropía de la susceptibilidad magnética (ASM) en rocas con diferente grado de deformación. Ejemplo de materiales eocenos de la cuenca de Ainsa (Pirineo Central)

Abstract

The anisotropy of magnetic susceptibility (AMS) has been used to establish the petrofabric of some Eocene grey marls from the southern Pyrenees. The rocks are affected by increasing deformation conditions fron wakly to non-deformed rocks to the south, to the cleaved ones to the north, where a N-S axial plane cleavage is observed. It can be seen that there is a change on both the directional data and the shape of the anisotropy changes first from the flattening field to the constriction field and finally back again to the flattening one. Thus the AMS is revealed as a powerful method in structural geology for estimating preferred alignments of mine¬ral fabrics