A recent study led by Professor Lijun Liu from the University of Illinois Urbana-Champaign challenges long-standing beliefs about the stability of Earth’s cratons, revealing that they have experienced repeated deformation beneath their crust since their formation. Traditionally seen as stable, cratons are now understood to be underpinned by dense, dynamic mantle keels that can change significantly over time. Analyzing previously collected data on the lithosphere, the research shows that the expected buoyancy of craton keels is misguided, as they are denser than once thought, affecting their elevation compared to sea level.
The study outlines how mantle upwellings, or plumes, can cause these dense keels to peel away from the lithosphere, similar to the movement in a lava lamp, impacting surface erosion and uplift processes. This cyclical deformation is pivotal in understanding the seismic behavior of the lithosphere and the historical geological events linked to supercontinent formations, particularly the significant erosion associated with the breakups of Rodinia and Pangea. The findings, published in Nature Geosciences, suggest a paradigm shift in how we view continental evolution and plate tectonics, highlighting the complex dynamics beneath seemingly stable cratonic regions.
