Revisiting the architecture of the Nico Pérez Terrane (Uruguay): insights into the evolution of a composite crustal block

The Neoproterozoic assembly of southwestern Gondwana involved prolonged collision and reorganization of cratons and crustal blocks, leading to extensive basement reworking. In the southern Dom Feliciano Belt, this history is recorded in the Nico Pérez Terrane, a collage of Archean to Mesoproterozoic gneissic blocks, whose origin and coherence remain debated. Proposed models interpret it as an assemblage of exotic terranes, a reworked cratonic margin, a fragment of the Congo Craton or Río de la Plata Craton, or a microplate. New cartographic, geochemical, zircon U–Pb, Sm–Nd, and Lu–Hf data indicate that the Nico Pérez Terrane represents a coherent polyphase crustal unit preserving a continuous but heterogeneous geological record. The Archean evolution was dominated by Mesoarchean (3.1–3.0 Ga) magmatic–metamorphic processes possibly linked with with continental arc evolution. Paleoproterozoic evolution included widespread Rhyacian–Orosirian magmatism and metamorphism (2.2–2.0 Ga), followed by crustal reworking and emplacement of crustally derived intrusions at c. 2.0 Ga. Newly identified occurrences of Statherian granitoids ( c. 1.75 Ga) and Mesoproterozoic magmatism demonstrate prolonged crustal evolution, the latter linked to extension-related juvenile magmatism. Widespread Neoprtoerozoic deformation, particularly along orogen-parallel shear zones, segmented the terrane into variably reworked blocks. Correlations with adjacent Precambrian domains support affinities with the Congo Craton.