Continental weathering linked to climate warming at the Sakmarian to Artinskian transition

Abstract

Assessing the patterns of climate change and their complex interactions with continental weathering throughout geological history offers profound insights into the mechanisms of the Earth's dynamic climate system. The Artinskian Warming Event (AWE) was characterized by a progressive rise in paleotemperatures during the late Paleozoic Ice Age (LPIA), coinciding with the retreat of large-scale Gondwanan ice sheets and profound transformations in the terrestrial ecosystems of Euramerica. Despite these observations, the exact chronology, nature, and geographical extent of the AWE are yet to be precisely defined. The contribution of continental weathering to the accumulation of atmospheric pCO₂ concentrations, which subsequently facilitated the melting of major LPIA ice centers by the mid-late Cisuralian, remains a topic of ongoing debate. To comprehensively trace the global extent of the AWE and to examine the potential causal link between climate and weathering processes during the Sakmarian to Artinskian transition, a detailed record of weathering trends in low-latitude mudstones has been established from the Dacheng coalfield in Hebei Province, North China. This far-field dataset, along with the near-field sedimentological record from eastern Australia, as well as published weathering trends and additional climate records from a spectrum of low to high latitude regions, has been compiled and synthesized for comprehensive analysis. The results reveal a globally notable rise in chemical weathering intensities and mean surface temperatures across the Sakmarian to Artinskian transition, while chemical weathering intensities significantly decreased in the earliest Artinskian within the Dacheng coalfield and parts of North China, consistent with the AWE-recorded aridification. These patterns are in alignment with the processes of deglaciation, increased sea surface temperature, and sea-level high-stand, along with shifts in biodiversity and changes in the abundance of marine and terrestrial ecosystems. The perturbations in the carbon cycle across a wide geographical area further substantiate the AWE as a global event. LIP volcanism supplied an initial CO₂ pulse, while the subsequent sustained decline in silicate weatherability during the earliest Artinskian, driven by low-latitude aridification, enabled prolonged escalation of atmospheric pCO₂ levels. This phenomenon is believed to have contributed to the onset of the AWE. The findings of this study will enhance our understanding of the AWE and the climate-weathering relationship during the demise of the LPIA.