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The Sanabria appinitic rocks and host migmatites form an unusual, non-peri-batholithic complex in which all the typical members of the appinite suite are present. It differs from most appinitic complexes in the deeper level of emplacement and the close temporal and spatial association with migmatites. Consequently, many in situ relationships that resulted from the invasion of mafic magma into a crustal anatectic zone are extremely well preserved. The complex shows unequivocal relations between members of the appinitic suite and between these and migmatites derived by anatexis of a gneissic formation (Ollo de Sapo gneiss). These relations point to derivation of monzodiorites and biotite diorites by hydrous basalt fractionation combined with fluid-assisted melting of the crustal rocks surrounding the appinitic intrusions. This hydrous basic magma may be derived from an enriched region of the mantle associated with subduction. Petrogenetic models have been tested using a combination of field relations and geochemical data. Despite the complexity of the processes involved, it is concluded that water played an important role in the petrogenesis of the intermediate and mafic magmas. Reaction between monzodiorite melts and the host migmatites was responsible for the generation of a range of intermediate rocks within the complex. The need for water to facilitate magma generation in both the mantle and the crust suggests that melting is linked with subduction. This interpretation has important implications because appinitic magmatism may be considered as indicative of subduction processes involved not only in the generation of the mafic end-members of the suite, but also in the generation of batholiths with which the appinitic rocks are spatially and temporally associated.

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The Zarza la Mayor and Zarza de Montánchez tonalites and Arroyo de la Luz granodiorite are part of a tonalitic–granodioritic belt located along the Schistose-Greywacke Domain of the Central Iberian Zone. These intrusions are also part of the Central Extremadura Batholith, a set of plutons ranging from tonalite to leucogranite that have been considered a prime example of Variscan syn-kinematic plutonism. New LA-ICP-MS and CA-ID-TIMS U–Pb dating reveals that the Zarza la Mayor tonalite–granodiorite is an Early Ordovician intrusion. The LA-ICP-MS data show that there is an absence of inherited cores, despite some complex internal zoning with obvious resorption features in some of the zircon crystals. Dating of monazite and zircon by CA-ID-TIMS provides a concordant age of 478.1 ± 0.8 Ma. This age coincides with electron microprobe analysis (EMPA) monazite chemical ages for the Zarza de Montánchez (482 ± 10 Ma) and Arroyo de la Luz (470 ± 15 Ma) intrusions. These new data indicate the presence of an Early Ordovician belt of calc-alkaline tonalite–granodiorite in the Schistose-Greywacke Domain – the Beira Baixa–Central Extremadura tonalite–granodiorite belt – which resembles a continental magmatic arc. This belt is contemporaneous with the Ollo de Sapo magmatic event further north in the Central Iberian Zone.

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