Composite magnetic fabrics from S-C mylonites

Magnetic anisotropy data are presented for samples of S-C mylonites from a shear zone developed in the Veiga granodiorite, a late-kinematic pluton located in the northern part of the Iberian Variscan belt (Spain). The magnetic susceptibility is geometrically represented by an ellipsoid whose principal axes, Kmax≥ Kint≥ Kmin, often show a one-to-one correlation with the principal directions—X,Y and Z—of finite strain. We report an exception to this rule, since our results reflect composite magnetic fabrics arising from the contribution of both the C- and S-structures. The magnetic foliation, defined as the plane normal to Kmin, shows an intermediate orientation between the C- and S-planes, and rotates towards the orientation of the C-planes as finite strain increases. The magnetic lineation, parallel to Kmax, and the stretching lineation present a similar trend, but different values of plunge.