Late Precambrian series and structures in the Navalpino Variscan Anticline (Central Iberian Peninsula)
The Navalpino Anticline is a major Variscan structure in the Central Iberian Zone of Spain. Three lithological groups are defined in the pre-Ordovician rocks of this anticline. The Rifean or Lower Vendian Extremeño Dome Group is unconformably overlain by the Upper Vendian Ibor-Navalpino Group. This latter group presents two different facies separated by a NW-SE trending synsedimentary fault. The Lower Cambrian Valdelacasa Group unconformably overlies both the Extremeno Dome and the Ibor-Navalpino Groups.Three pre-Variscan episodes of deformation have been defined in the area of the Navalpino Anticline. A major asymmetrical fold with a subvertical east-west-striking limb is the result of the first deformation event of pre-Late Vendian age. The second deformation event is of Cadomian (Late Precambrian) age and is composed of two stages; (i) an early extensional stage including NW - SE trending extensional fault and basin development in the north-eastern block; and (ii) a second compressive stage giving rise to north-south trending upright folds. This second compressive stage possibly inverted the basin. A final pre-Variscan deformation event took place between the Early Cambrian and the Early Ordovician resulting in a 5–10° tilting to the north-east.There are two main phases of Variscan deformation in the area. The first deformation event (Dv1) gave rise to a upright WNW - ESE trending folds on all scales, whereas the second (Dv2) gave rise to a brittle—ductile sinistral strike-slip shear zone tending subparallel to the axial trace of the Dv1 folds.