Foreland basin evolution in response to thin-skinned vs. basement-involved (Laramide-style) deformation: a case study from the southern Central Andes, Argentina (28−29°S)

CHELSEA MACKAMAN-LOFLAND; PAOLA OROZCO; PATRICIA ALVARADO; BRIAN K. HORTON; RICHARD A. KETCHAM; TOMAS N. CAPALDI; DANIEL F. STOCKLI

Encuentro; AGU 2019 session T049: Structure, sedimentation, and dynamics of fold-and-thrust belts and associated basins on Earth and other planets; 2020

Retroarc deformation above the Argentina-Chile flat-slab subduction segment (28−33°S) is characterized by type examples of (1) thin-skinned thrusting along the eastern flank of the high Andes (Precordillera fold-thrust belt), and (2) basement uplifts that expand >700 km towards the craton (Sierras Pampeanas structural domain). The Precordillera and Sierras Pampeanas intersect near the flat- to normal-slab transition zone at ~29°S, providing an excellent location to study structural interactions and basin architecture in response to thin- and thick-skinned deformation. We integrate new geo- and thermochronological data for bedrock and Neogene foreland basin fill with structural, stratigraphic, and sediment provenance results to reconstruct development of the broken foreland basin system. Zircon U-Pb maximum depositional ages and published magnetostratigraphic ages constrain synorogenic deposition in the La Flecha depocenter from ~23 to