Seismic evidence of lithospheric delamination in North America that caused the termination of basin subsidence

The existence of cratonic basins indicates protracted periods of tectonic modification inside continental interiors. An enigmatic aspect of this global process is the inversion of cratonic basins with the cessation of subsidence. However, the driving force and mechanical process for subsidence termination in cratonic basins are unclear. Here, using full-wave ambient noise tomography, we reveal distinct seismic low-velocity anomalies below 60 km beneath the Illinois and Michigan Basins, where subsidence terminated in the latest Paleozoic to earliest Mesozoic. These low-velocity volumes, surrounded by distinctly higher velocities, reflect infiltrated asthenospheric materials after lithospheric delamination. Geodynamic modeling shows that the emplacement of these buoyant asthenospheric materials would lead to an uplift of about 3.5 km, sufficient to terminate and reverse basin subsidence. The findings in this study document delamination in the North American midcontinent and demonstrate the important role of lithospheric delamination in the evolution of cratonic basins.