Catastrophic craton destruction via wholesale lithosphere delamination

Abstract

Abstract The nuclei of continents, manifested as cratons, are the most long-lived parts of Earth’s lithosphere. However, ancient cratons in some areas can be substantially destroyed through mechanisms that are not fully understood. We used experimentally calibrated geobarometers to calculate the equilibrium pressures of mafic magmas in the North China craton, which directly constrain the evolving depth of the lithosphere-asthenosphere boundary beneath the craton through time. We show that the lithospheric thickness of the eastern part of the craton decreased from ~200 km to ~35 km in the Early Cretaceous. This intense destruction took place within a short time interval of ~10 m.y., at least locally. Following this destruction, the lithosphere gradually rethickened and stabilized as the upwelling asthenosphere cooled and formed a juvenile lithosphere. We suggest that this catastrophic lithosphere thinning resulted from wholesale lithosphere delamination. As a consequence of this catastrophic loss of thick mantle roots, the eastern part of the North China craton may have undergone rapid crustal rebound and surface uplift, as recorded by the regional unconformities formed between 130 and 120 Ma in the destructed area.