Transition from orogenic plateau to thinning reveals mesozoic North China craton dynamics
Yanjing Chen, Zhenju Zhou, Xu Chen
Abstract
The North China Craton underwent extensive lithospheric thinning and crustal reworking during the Mesozoic, challenging classic views of craton stability. This period marks a transition from tectonic quiescence to widespread reactivation, but timing and magnitude remain poorly constrained. Here we reconstruct crustal thickness evolution along the southern margin of the North China Craton using strontium to yttrium and lanthanum to ytterbium ratios, plus neodymium isotopic data from granitoids. Thickening began in the Jurassic and peaked around 130 Ma, when crustal thickness exceeded 70 km and palaeoelevation surpassed 5 km, forming a plateau comparable to the Tibetan Plateau. After ~128 Ma, thickness and elevation decreased to 30–40 km and <3 km by 125–110 Ma. These shifts parallel sedimentary, structural and geophysical evidence. We interpret this evolution as two stages: initial thickening from North China–Yangtze collision, followed by extensional collapse and lithospheric thinning likely driven by Paleo-Pacific plate rollback. The North China Craton underwent two distinct crustal stages, characterized by thickening due to Mesozoic collision, followed by extensional collapse and lithospheric thinning likely driven by PaleoPacific plate rollback, according to a crustal thickness reconstruction using Sr/Y and La/Yb ratios as well as εNd isotopic data of granitoids.