Middle-Late Triassic metamorphism of the Guajira Arch-basement: Insights from zircon U–Pb and Lu–Hf systematics

The Guajira Arch is located in the northernmost portion of South America and holds record several stages magmatism metamorphism. We performed LA-ICP-MS U–Pb zircon geochronology coupled with Lu–Hf isotope geochemistry on 11 samples from a high-grade gneissic basement hosting interleaved complexes younger meta-granitoids meta-sediments to unravel its tectono-metamorphic evolution. oldest rocks correspond Rodinia-type at ca. 1100-880 Ma, affected by mafic during Permian 272 anatexis Carnian 230 updoming formation an extensional detachment fault Norian 224 Ma concluding Jurassic since 190 Ma. Trace element shows that Triassic zircons are depleted HREE yield lower Th/U ratios than enriched both HREE, Yb, Y. Hf systematics indicates evolution towards more radiogenic compositions. lithological associations, structural setting, ages, Triassic-Jurassic characterize active margin setting hot orogenic belt NW-Gondwana, comprising Central Cordillera Colombia, Santa Marta Massif, Merida Andes, Perijá Range, Santander Massif para-autochthonous terranes south Ouachita-Marathon Suture (Oaxaquia, Acatlán, Maya), thus vindicate existence conjugate Laurentia until Late Triassic, preceding breakup western Pangaea. anatectites granitoids Proterozoic TDMi ages which indistinguishable autochthonous render allochthonous origin terrane accretion highly improbable. Instead, these data point melting continental crust incorporation primitive material reflecting two-stage process boundary large underlying mantle convection cell (i) slab steepening, subduction arrest, 230-223 (ii) Early arc-magmatism 190-165 due renewed convergence. Furthermore, we propose lithology, units, fit into style cordilleran core-complex emplaced roll-back Pangaea break-up.