Linking accretionary orogens with continental crustal growth and stabilization: Lessons from Patagonia

ORIOLO, SEBASTIÁN; GONZÁLEZ, PABLO D.; RENDA, EMILIANO M.; A. S. BASEI, MIGUEL; OTAMENDI, JUAN; CORDENONS, PABLO; MARCOS, PAULO; BELÉN YOYA, MARÍA; BALLIVIÁN JUSTINIANO, CARLOS A.; SUÁREZ, RODRIGO

GONDWANA RESEARCH

ELSEVIER SCIENCE BV

Año: 2023

1342-937X

Theorigin of the continental crust and the tectonic significance of Paleozoicmagmatic rocks of Patagonia (southernmost South America) remain one of the mainenigmas in the history of the Gondwana supercontinent. Here, new whole-rockgeochemistry together with coupled zircon U-Pb and Lu-Hf isotopic data ofDevonian to Permian intrusive rocks of northern Patagonia are integrated with arevised geochemical and isotopic database of the region, providing a novelmodel for the tectonomagmatic evolution and related crustal growth mechanisms.The development of a Devonian retreating accretionary orogen associated withcrustal thinning was succeeded by a late Carboniferous to Permian advancingorogen and crustal shortening, resulting from slab shallowing. The latter wasrelated to the Gondwanide Orogeny, a major transpressional tectonic event thatled to the maturation and stabilization of the continental crust of Patagoniadue to widespread magmatism and crustal thickening, which culminated withPermian-Triassic slab break-off. Addition of juvenile mantle-derived magmas ismore significant during the Devonian, whereas a progressively increase in crustalreworking is documented from the late Carboniferous to the Permian due tocrustal thickening. Therefore, this non-collisional model favors an insitu middle to late Paleozoic crustal growth of Patagonia duringchanging dynamics of accretionary orogens at the proto-Pacific margin ofsouthwestern Gondwana.