Coevolution of craton margins and interiors during continental break-up

• Published in: Nature (London) 2024-08, Vol.632 (8024), p.327-335
• Main Authors: Gernon, Thomas M., Hincks, Thea K., Brune, Sascha, Braun, Jean, Jones, Stephen M., Keir, Derek, Cunningham, Alice, Glerum, Anne
• Format: Article
• Language: English
• Subjects: 704/2151/210; 704/2151/213; 704/2151/215; 704/2151/562; Boundaries; Coevolution; Cratons; Denudation; Drainage; Escarpments; Exhumation; Fault lines; Geology; Gondwana; Humanities and Social Sciences; Interiors; Landforms; Lithosphere; multidisciplinary; Plateaus; Regions; Rifting; Science; Science (multidisciplinary); Simulation; Statistical analysis; Statistical models; Topography
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/s41586-024-07717-1

Many cratonic continental fragments dispersed during the rifting and break-up of Gondwana are bound by steep topographic landforms known as ‘great escarpments’ 1 – 4 , which rim elevated plateaus in the craton interior 5 , 6 . In terms of formation, escarpments and plateaus are traditionally considered distinct owing to their spatial separation, occasionally spanning more than a thousand kilometres. Here we integrate geological observations, statistical analysis, geodynamic simulations and landscape-evolution models to develop a physical model that mechanistically links both phenomena to continental rifting. Escarpments primarily initiate at rift-border faults and slowly retreat at about 1 km Myr −1 through headward erosion. Simultaneously, rifting generates convective instabilities in the mantle 7 – 10 that migrate cratonward at a faster rate of about 15–20 km Myr −1 along the lithospheric root, progressively removing cratonic keels 11 , driving isostatic uplift of craton interiors and forming a stable, elevated plateau. This process forces a synchronized wave of denudation, documented in thermochronology studies, which persists for tens of millions of years and migrates across the craton at a comparable or slower pace. We interpret the observed sequence of rifting, escarpment formation and exhumation of craton interiors as an evolving record of geodynamic mantle processes tied to continental break-up, upending the prevailing notion of cratons as geologically stable terrains. By integrating geological observations, statistical analysis, geodynamic simulations and landscape-evolution models, a physical model is proposed to link the coevolution of craton margins and interiors with continental rifting.