Tectonometamorphic evolution and structural overprinting of a Cadomian suture zone in SW Iberia

The Cadomian Orogeny, an accretionary orogen around Gondwana, was extensively reworked during the Paleozoic Variscan Orogeny. In SW Iberia, a structural, geochronological and tectonometamorphic study of the Mina Afortunada Massif identified two Cadomian deformation phases. The first phase (DC1; ~586 Ma, U-Pb dating of inherited garnet) represents the ophiolite acrection during the closure of a back-arc or intra-arc basin, identified as the Cuartel Ophiolite. This phase is preserved as internal foliation in Ediacaran metasedimentary rocks. The second deformation phase (D_C2; 515–485 Ma) is marked by a penetrative foliation in the Mina Afortunada Gneiss (~515 Ma) and the absence of deformation in overlying Ordovician sediments (~485 Ma). Extensional tectonics during D_C2 facilitated early exhumation of the Cadomian suture zone, evidenced by telescoped metamorphic isograds and low-angle normal faults. Later Variscan deformation overprinted Cadomian structures and played a significant role in further exhumation. Geochronological and structural correlations link the Cuartel Ophiolite to the Mérida ophiolite (SW Iberian Massif), being fragments of a single Cadomian suture zone located at the northern margin of Gondwana. This work highlights the potential duplication of suture zones in reworked orogens, especially after ophiolite accretion.