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The longevity of cratons usually implies that the entire cratonic lithosphere remained unchanged over billions of years, which is traditionally attributed to their intrinsically buoyant and strong lithospheric roots. By reviewing relevant studies and recent observational constraints, we show that the present cratonic roots are notably denser than the ambient mantle, with the compositional buoyancy offsetting only one-fifth of the negative thermal buoyancy. In addition, the presence of a weak mid-lithospheric discontinuity could decouple the upper and lower lithosphere upon perturbation, allowing delamination of the lower portion, while most of the delaminated lithosphere would eventually relaminate to the base of the lithosphere after sufficient warming inside the convective mantle. This process generates enduring (>100 Myr) and prominent (>1 km) surface uplifts within continents, a mechanism more compatible with data, especially those reflecting lithospheric deformation, than the model of all continents climbing up a steady region of dynamic uplift. Subsequent lithospheric cooling gradually draws the surface down to below sea level, where the lithospheric mantle density reaches a maximum upon formation of the next supercontinent. We argue that such cratonic deformation has happened repeatedly over supercontinent cycles since the Neoproterozoic and has largely shaped the properties of the present cratonic lithosphere. A few new research directions are also suggested. 

Fundamental to plate tectonics is the subduction of cold and mechanically strong oceanic plates. While the subducted plates are conventionally regarded to be impermeable to mantle flow and separate the mantle wedge and the subslab region, isolated openings have been proposed. By combining new shear wave splitting measurements with results from geodynamic modeling and recent seismic tomography and geochemical observations, we show that the upper ~200 km of the Cocos slab in northern Central America is intensively fractured. The slab there is strong enough to produce typical arc volcanoes and Benioff Zone earthquakes but allows mantle flow to traverse from the subslab region to the mantle wedge. Upwelling of hot subslab mantle flow through the slab provides a viable explanation for the behind-the-volcanic-front volcanoes that are geochemically distinct from typical arc volcanoes, and for the puzzling high heat flow, high elevation, and low Bouguer gravity anomalies observed in northern Central America. 

Abstract Growth of the Andes has been attributed to Cenozoic subduction. Although climatic and tectonic processes have been proposed to be first-order mechanisms, their interaction and respective contributions remain largely unclear. Here, we apply three-dimensional, fully-dynamic subduction models to investigate the effect of trench-axial sediment transport and subduction on Andean growth, a mechanism that involves both climatic and tectonic processes. We find that the thickness of trench-fill sediments, a proxy of plate coupling (with less sediments causing stronger coupling), exerts an important influence on the pattern of crustal shortening along the Andes. The southward migrating Juan Fernandez Ridge acts as a barrier to the northward flowing trench sediments, thus expanding the zone of plate coupling southward through time. Consequently, the predicted history of Andean shortening is consistent with observations. Southward expanding crustal shortening matches the kinematic history of inferred compression. These results demonstrate the importance of climate-tectonic interaction on mountain building. 

Abstract Transient intraplate sedimentation like the widespread Late Cretaceous Western Interior Seaway, traditionally considered a flexural foreland basin of the Sevier orogeny, is now generally accepted to be a result of dynamic topography due to the viscous force from mantle downwelling. However, the relative contributions of flexural versus dynamic subsidence are poorly understood. Furthermore, both the detailed subsidence history and the underlying physical mechanisms remain largely unconstrained. Here, we considered both Sevier orogenic loading and three different dynamic topography models that correspond to different geodynamic configurations. We used forward landscape evolution simulations to investigate the surface manifestations of these tectonic scenarios on the regional sedimentation history. We found that surface processes alone are unable to explain Western Interior Seaway sedimentation in a purely orogenic loading system, and that sedimentation increases readily inland with the additional presence of dynamic subsidence. The findings suggest that dynamic subsidence was crucial to Western Interior Seaway formation and that the dominant control on sediment distribution in the Western Interior Seaway transitioned from flexural to dynamic subsidence during 90–84 Ma, coinciding with the proposed emplacement of the conjugate Shatsky oceanic plateau. Importantly, the sedimentation records require the underlying dynamic subsidence to have been landward migratory, which implies that the underlying mechanism was the regional-scale mantle downwelling induced by the sinking Farallon flat slab underneath the westward-moving North American plate. The simulated landscape evolution also implies that prominent regional-scale Laramide uplift in the western United States should have occurred no earlier than the latest Cretaceous.