The significance of microgranular enclaves in assessing the magmatic evolution of a high-level composite batholith: A case on the Los Pedroches Batholith, Iberian Massif, Spain

Abstract

To evaluate the origin and significance of microgranular enclaves hosted by granites, we present new data on two granitoid series belonging to the Los Pedroches Batholith (LPB), SW Iberian Massif, Spain. The two series in the LPB show a distinct contrast in terms of field, petrographic, mineralogical and geochemical data. This contrast also extends to the enclaves, differing in abundance and other features in each of the series considered. Isotopic measurements, however, including 87 Sr/ 86 Sr, e Nd and δ 18 O data, show no significant, inter- or intra-series contrast throughout the LPB. These data lend additional support to an origin of all the granitoid rocks in the LPB from a single, isotopically homogeneous, lower crustal source. We also suggest that differences between microgranular enclaves in the two LPB granitoid series cannot be related to a different degree of participation of mafic rocks in the genesis of the respective groups: in both cases, microgranular enclaves are better interpreted as autoliths.