The Fuegian thrust-fold belt: From arc-continent collision to thrust-related deformation in the southernmost Andes

TORRES CARBONELL, PABLO J.; CAO, SEBASTIÁN J.; GUILLOT, MAURICIO GONZÁLEZ; GONZÁLEZ, VICTORIA MOSQUEIRA; DIMIERI, LUIS V.; DUVAL, FLORIAN; SCAILLET, STÉPHANE

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020

0895-9811

New detailed structural data from the Fuegian Andes including new ages and cross27 cutting relationships with intrusive rocks, as well as an appraisal of published structural28 data, support that this orogen evolved as a basement-involved thrust-fold belt after29 initial formation in an arc-continent collision scenario. New structural data from a30 deformed 84 Ma intrusive indicate that structures from the collisional event in the31 Argentine Fuegian Andes are of Campanian age, comprising only the youngest and less32 intense deformation of the orogenic wedge. In the internal thrust-fold belt, these33 structures are cut by intrusives with new ages of 74 Ma (Ar/Ar on hornblende). The34 superposition of thrusts on these early structures indicates a subsequent event in35 which a thrust-fold belt formed since the Maastrichtian-Danian. Additional new data36 confirm brittle-ductile thrusting in the central belt, with thrusts joining a common37 upper detachment in the base of the Lower Cretaceous rocks. These thrusts formed a38 first-order duplex system that transferred the shortening accommodated in the39 foreland until the Miocene.