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, K-max greater than or equal to K-int greater than or equal to K-min, 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 K-min, 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 K-max, and the stretching lineation present a similar trend, but different values of plunge. Copyright (C) 1996 Elsevier Science Ltd.