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phaneritic texture, ranging between fine- and coarse- grained, and showed either equigranular or porphyritic terms (more common in felsic granitoids). Varied combi- nations of these primary end-members plus heteroge- neous strain explain the microstructural variety observed in the metagranitoids of this unit, in which it can be recognized felsic through to mafic metagrani- toids with vaguely defined planar fabric up to gneisses with well-developed compositional banding or even augen (K-Feldspar) structure. Some metagranitoids of this unit have yielded protolith crystallization ages at c. 573 Ma (Bandrés et al . 2004), but the age of metagra- nitoids s.l . included into the Serie Negra Group ranges between Ediacaran and Ordovician (e.g. Ordóñez Casado 1998; Martínez Poyatos 2002; Galindo and Casquet 2004; Navidad and Bea 2004; Talavera et al . 2008; Díez Fernández et al . 2015; Abati et al . 2018). Being the most heterogeneous in lithological compo- sition, this unit gathers variably strained lithologies that resulted from metamorphic transformation of a rock ensemble that included sedimentary and felsic to inter- mediate intrusive igneous rocks. None of the lithologies Figure 7. (a) Felsic orthogneisses from the Upper Schist-Metagranitoid Unit. (b) Highly strained marble at the base of the Carija Unit (Carija detachment). Note top-to-the-NW kinematic criteria such as sigma and boudinaged structures after stretched lighter limestone bands (red indicators) as well as later extensional shear bands (C’-planes in black). (c) Quartzite and slate beds of the Ordovician series in the northern part of the Mérida Massif. White lines indicate bedding (S 0 ), while red lines indicate oblique Variscan foliation (S V ). (d) High-angle Alpine thrust juxtaposing the crystalline basement of the Mérida Massif (hanging wall to the right) onto its Cenozoic sedimentary cover (footwall to the left). (e) Protomylonite after granitoid deformed by the Trujillanos detachment. Note sigma structures indicating top-to-the-SSE shear sense (blue arrows) (crossed polarizers view). (f) Protomylonite after granitoid deformed in the Magdalena thrust. Note quartz ribbons, C’-planes (red lines), and sigma structures (blue arrows) in subidiomorphic feldspar porphyroclasts (left) and white mica (right) indicating non-coaxial deformation (polarized light view). 8 R. D. FERNÁNDEZ ET AL. &KDSWHU