Late Cretaceous glaciations in a hyper-arid plateau desert of the South China Coastal Mountains

Abstract Increasing evidence indicates the existence of a cryosphere during the Cretaceous supergreenhouse. However, current understanding of a potential link between lithosphere dynamics and cryospheric processes in the Cretaceous plateau desert successions of China remains limited. We report the occurrence of ice-rafted dropstones and diamictites from the Upper Cretaceous Chishan Formation of the Subei Basin at the East Asian continental margin. Our provenance results indicate that fluvial deposits of the Lower Chishan Formation were mainly derived from the Sulu Orogen to the north and the Zhangbaling Uplift to the west, whereas aeolian deposits of the Upper Chishan Formation were largely recycled from the two sources with an additionally notable contribution from the post-Cretaceous basement of the Yangtze Block. Combined with previous evidence, provenance analysis indicates that Late Cretaceous collision between the Okhotomorsk Block and the East Asian continent led to the growth of the South China Coastal Mountains via crustal thickening, which generated an arid, high-altitude basin region that experienced desertification and paleohydrological variability, and that was supplied with additional clastic sediment sources from the basement of the South China Block. Our results provide evidence of Late Cretaceous cryospheric processes in a continental mid-latitude plateau desert linked to the northwestward subduction and collision of the paleo-Pacific realm. Global cooling from the late Turonian to Maastrichtian drove the establishment of glaciers in high-altitude mountains leading to the development of ice-related deposits in the plateau deserts, as recorded in the Subei desert basin of the South China Coastal Mountains. The record of ice-rafted debris and the provenance signature reveal an active Cretaceous plateau cryosphere linked to lithosphere dynamics.