Drainage dynamics of the entire South American continent during the Andean Orogeny: Results from tectono-sedimentary numerical models

During the Cenozoic, the formation of the Andean Cordillera had a profound effect on the drainage evolution in the South America continent. The load of the Andes induced the bending of the lithosphere, creating foreland basins adjacent to the cordillera. Additionally, an increase in orographic precipitation along the eastern flank of the Andes amplified the erosion of the cordillera and the sedimentation rate in the foreland and other interior basins. As a result, the drainage pattern changed from parallel to the cordillera to a system perpendicular to the orogen. This led to the development of the Amazon drainage system in northern South America and guided the formation of the present Paraguay-Paraná Basin in southern South America. Concurrently, dynamic topography induced by the subduction of the Nazca plate under the western margin of the continent created long-wavelength topographic perturbations throughout the continent, partially modulating the generation of accommodation space in interior sedimentary basins and allowing intermittent marine incursions in lowland regions. In this work, we present this complex evolution based on numerical models dedicated to simulating the tectono-sedimentary evolution of the entire South America continent, coupling surface processes, lithospheric flexure, sea-level oscillations, and dynamic topography. This project represents an expansion of the works developed in our research group, previously focused only on the drainage dynamics of northern South America.