Fábrica magnética del plutón de Marimanha (Pirineo central)

Abstract

The structural and magnetic fabric study of the Marimanha granite (Axial zone of the Pyrenees, Catalonia), provides new data to characterize the zonation and the internal structure of the pluton. The Marimanha granite intrudes Cambro-Devonian metasediments of the Axial zone of the Pyrenees. The zonation of low field magnetic susceptibility is consistent with the petrological zonation of the igneous body and indicates a concentric arrangement of rock types, with more basic compositions at the external areas. By means of measurements of the anisotropy of the magnetic susceptibility, we have inferred the magmatic fabric of this pluton. Magnetic foliations and magnetic lineations are concentric and parallel to petrografic contacts in map view. The dominant strike of magnetic foliation is NE-SW with steep dips. The dominant magnetic lineation also trends NE-SW with shallow plunges to the NE and SW. This orientation agrees with the slightly elongated shape of the pluton in the NE-SW direction. This relationship suggests an intrusion contemporary with a E-W transpressional regime