Fábricas magnéticas y su relación con la tectónica en el límite NE de Cameros (NO Cordillera Ibérica)

The anisotropy of magnetic susceptibility (AMS) is studied in units from the Cameros Basin (NW Iberian Range) deposited during its last Late Jurassic-Early Cretaceous rifting stages (Olivan and Enciso Groups, Aptian and Albian in age) in outcrops located near the NE limit of the Massif. The magnetic carriers identified are paramagnetic minerals (phyllosilicates) and a ferromagnetic phase, identified as hematite in the Olivan Group and magnetite in Enciso. The presence of magnetite seems to originate inverse fabrics in two sites, as inferred from the magnetic subfabrics analysis. The other sites from the Enciso Group show girdles interchanging the intermediate and minimum axes, which point to the influence in the magnetic fabric of the axial-plane cleavage developed in the basin during the Mesozoic. The NW-SE magnetic lineation in two sites from the Olivan Group is also associated with the influence of compression. In the third outcrop from the Olivan Group, the magnetic lineation associated with extension in the basin could have been preserved (NE-SW).