This $118,260 federal Project Grant awarded by the National Science Foundation's Geosciences Program (CFDA 47.050) supports a collaborative research project at Purdue University to investigate the effects of lithospheric foundering on mountain building in the Southern Puna Plateau of Argentina. The research employs field work, stratigraphic analysis, and numerical modeling to better understand the processes by which the lower crust and mantle lithosphere are removed through detachment and subsidence, and how this impacts the geologic record and deformation of the overlying crust. The project will engage 2 PhD students, 7 undergraduate researchers from underrepresented minority groups, 2 postdoctoral researchers, and 3 early-career PIs, while also building connections between North American and Argentinian scientists. This multi-disciplinary effort aims to provide new insights into the effects of density variations on the evolution of major mountain belts and high plateaus.