Estructura magnética del plutón granítico de Villavieja de Yeltes (Salamanca)

Resumo

The Villavieja de Yeltes granitic pluton is located in the western Salamanca province, within the Centro-Iberian Zone of the Iberian Variscan Belt. This pluton belongs to the traditionally considered late Variscan granites. An study of the magnetic properties shows that the granite is paramagnetic and the phillosilicates (biotite, chlorite, muscovite) are the main magnetic holders. Magnetic lineations show a dominant N-S to NNE-SSW orientation, with sub-horizontal lines. The magnetic foliation has a sunvertical N-S orientation that follows the contour of the pluton in the east, south and west edges. The core of the intrusion is characterized by the presence of sub-horizontal foliations that coincides with an increase of the anisotropy and planarity. All these data suggest that the emplacement took place during the fourth Variscan phase of deformation, along an extensional structure related to a N-S shear zone. The Armorican Quartzite, located sout of the pluton, probably acted as a rheological barrier that inhibited its ascent to shallower levels, and the Villares de Yeltes syncline should form a roof zone in the core of the intrusion. Probably, the final emplacement took place in a extensional local context with the lateral expanding of the magma.