Resumen
RT-AMS ellipsoids from Upper Cretaceous carbonate rocks in the Southwestern Pyreneesexhibit an unusual orientation for rocks within a well-cleavage domain: neither do all sites show themaximum axes in the intersection lineation nor are the minimum axes at the pole of the cleavage plane.The study of the subfabrics (LT-AMS and AARM) indicates that the paramagnetic grains (phyllosilicates)respond to a layer parallel shortening, with the minimum axis perpendicular to S0. On the otherhand, the ferromagnetic grains (magnetite) orient in relation to the strain field, which also producesthe cleavage domain. The maximum axes of the ferromagnetic ellipsoids have a horizontal NNE-SSWdirection. An extended version of this paper is published in Oliva-Urcia et al. (2009).