CONICET | Buscador de Institutos y Recursos Humanos

New detailed structural data from the Fuegian Andes including new ages and cross-cutting relationships withintrusive rocks, as well as an appraisal of published structural data, support that this orogen evolved as abasement-involved thrust-fold belt after initial formation in an arc-continent collision scenario. New structuraldata from a deformed 84 Ma intrusive indicate that structures from the collisional event in the Argentine FuegianAndes are of Campanian age, comprising only the youngest and less intense deformation of the orogenic wedge.In the internal thrust-fold belt, these structures are cut by intrusives with new ages of 74 Ma (Ar/Ar on hornblende).The superposition of thrusts on these early structures indicates a subsequent event in which a thrust-foldbelt formed since the Maastrichtian-Danian. Additional new data confirm brittle-ductile thrusting in the centralbelt, with thrusts joining a common upper detachment in the base of the Lower Cretaceous rocks. These thrustsformed a first-order duplex system that transferred the shortening accommodated in the foreland until theMiocene.