Contrastes estructurales entre el plutonismo varisco precoz y el tardío del centro-oeste de España

Abstract

Meso - and megascopic structural contrasts between early and late Variscan plutonism are shown in Central -Western Spain (Central Iberian Zone). A contrasted architecture of batholiths on both sides of the Juzbado-Penalva do Castelo Shear Zone is revealed: the early batholiths (Sayago, Tormes Dome and Lumbrales) without gravimetric minimum anomalies and the late ones (Guarda and minor plutons) showing a concentric gravimetric pattern, which points to a rooted geometry. The presence of early leucogranite belts are also a distinctive structural feature, the amalgamation of which can account for the co nstruction of the Anatectic Tormes Dome. Phase -3 Variscan mega-structures deforming a subhorizontal foliation can be traced inside the early granodioritic Sayago batholith, in contrast with a weak mineral preferent orientation in the Spanish area of the Guarda batholith . Gneissic and metapelitic alternating belts could have led to the repetition of low-melting degree leucogranitic melts generated from these metamorphic materials, whereas a more localized magma generation accounts for zonation and re-used magma condu its in late pluto