Preliminary palaeomagnetic results from the Subbetic Zone (Betic Cordillera, southern Spain): kinematic and structural implications

Abstract

Abstract We present palaeomagnetic evidence from Jurassic limestones and basic submarine volcanic rocks (sills, pillow lavas, and intrusive material) from the central part of the Subbetic Zone of the Betic Cordillera. Isothermal remanent magnetization acquisition experiments performed on limestones and thermomagnetic curves and measurements of the magnetic susceptibility determined for the volcanic rocks demonstrate strong dependence of rock magnetic properties on lithology. In most cases a stable magnetization could be isolated after thermal and/or alternating field demagnetization. Locally, declinations of the characteristic remanent magnetization from interbedded limestones and volcanics are similar, but inclinations tend to vary. Regionally, declinations for both limestones and volcanics show significant clockwise rotation. These results cannot be explained by the anticlockwise rotation of Iberia during the Cretaceous opening of the Bay of Biscay. Considering the long and complex history of large-scale shear between Africa and Europe accommodated in southern Spain, the anomalous declinations can be explained by a model with rotation of crustal blocks within a zone of wrench tectonics.