Protracted post-eruptive basaltic weathering of the Emeishan large igneous province constrained by UPb CA–ID–TIMS geochronology

The post eruptive basaltic weathering of the Emeishan large igneous province is proposed to cause early Wuchiapingian cooling globally. However, the endpoint of this cooling event has not been evaluated yet, preventing the further understanding of long-term interaction between climate and weathering. In this study, abundant thick and highly weathered basaltic paleosols at the Emeishan volcanic landscapes have been identified, providing direct evidence for intense post-eruptive basaltic weathering. By using CA-TIMS zircon UPb dating on paleosols and adjacent tuffs, the onset and the termination of the intense weathering are constrained to ∼259.6 Ma and ∼ 253.4 Ma, respectively. The onset of intense weathering is coincident with the early Wuchiapingian cooling, supporting the CO₂-forced cooling model triggered by the post-eruptive basaltic weathering of the Emeishan large igneous province. Moreover, the temporal correlation between the long-term weathering and the paleoclimate and carbon isotope records indicate that this cooling is possible persisting until at ∼253.4 Ma.