High strain peralkaline orthogneisses within orogenic scale shear zones: geological and structural mapping in the Arronches region (Tomar-Badajoz-Córdoba shear zone, Ossa-Morena Zone)

Abstract

The lithological units in the Arronches region (included within the Arronches tectonic unit, Tomar-Badajoz-Córdoba Shear Zone, northernmost Ossa-Morena Zone) and in particular the peralkaline orthogneisses therein, have been the target for petrological, geochemical and structural studies in order to constrain its petrogenesis and tectono-metamorphic contextualization within the broader regional geology. Two detailed geological-structural maps of the Arronches region (from the Arronches village and the Fialha area), as well as the structural analysis allow the description of two mylonitic high strain fabrics found in different peralkaline orthogneiss bodies (the dominantly Arronches-type S fabric and the dominantly Fialha-type S-L fabric), which provide better insights about the internal architecture of the Tomar-Badajoz-Córdoba Shear Zone.