Using a two-dimensional construction for space-filling bearings (SFB) recently proposed by Herrmann et al. (1990), as an idealized description of the texture of gouge-like material, we study the effect of grain rotations in a shear band. The SFB model is by construction self-similar and the disk-size distribution follows a power-law in good agreement with the observed particle-size distribution of natural gouges. The kinematics of the model is described by a single degree of freedom, i.e., each disk can only rotate, with no slip at the contact points. We investigate the isothermal remanent magnetization (IRM) reduction during such a cataclastic shearing. The problem can be solved analytically for this model. The magnetization loss, due to a disorientation of the grains can be shown to be a power-law as a function of the shear. The exponent of the power law is simply related to the fractal dimension of the particle-size distribution in the gouge. This result may stimulate experimental investigations using IRM to gain new insight into the gouge texture and kinematics. ¿ American Geophysical Union 1993