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

Abstract

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 U-Pb dating on paleosols and adjacent tuffs, the onset and the termination of the intense weathering are constrained to similar to 259.6 Ma and similar to 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 similar to 253.4 Ma