Stepwise aridification of the Late Paleozoic North China Craton

Abstract

The Late Paleozoic marked Earth’s most recent icehouse–greenhouse transition, providing valuable insights into future climate and environmental changes. Although the aridification of the North China Craton (NCC) during the Late Paleozoic is well established, its pattern and causes remain unclear. Here, we identify four aridification intervals from the late Gzhelian to Lopingian by analyzing continuous records of elemental climate proxies (MgO/CaO, Sr/Cu), a volcanism proxy (Hg/TOC), and spore–pollen assemblages. Interval I (∼303–295 Ma), during which the NCC was located at low paleolatitudes, was characterized by humid conditions and a predominance of ferns, associated with weak volcanism. Interval II (∼295–286 Ma) was subhumid, with increasing gymnosperm presence, and significant climate fluctuations linked to volcanism. CO₂ emissions from the Tarim LIP and Panjal Traps drove aridification from the late Asselian to late Artinskian, contributing to the decline of the Late Paleozoic Ice Age. As a result, aridification in the NCC lagged behind that of Pangea. Interval III (∼286–280.98 Ma) marked the transition to subarid conditions and the onset of dominance by gymnosperms, associated with a rapid northward drift of the NCC and an increase in atmospheric ρCO₂. Interval IV (∼259.51–251.902 Ma), separated from the underlying Interval III by a major regional unconformity (∼280.98–259.51), coincided with global aridification and intensified volcanism. These findings highlight the significant influences of both tectonic plate motion and volcanism on the climate evolution of the NCC, with shifts in the dominant controlling factors through time. This study provides new insights into the distinct trajectories of global and regional climate dynamics.