10:30 AM - 10:45 AM
[BPT27-07] Sulfur and carbon isotope study for understanding environmental changes across the Middle/Late Permian boundary
Keywords:Guadalupian-Lopingian boundary, mass extinction, oceanic anoxia, carbonate-associated sulfate, Panthalassan paleoatoll carbonates
Negative correlations were observed between δ34SCAS and δ13Ccarbonate values for Guadalupian and Lopingian carbonates, respectively. These correlations imply that the bottom water anoxia expanded to the open oceans before and after the G-L boundary. In such environments, organic matter was oxidized by sulfate-reducing bacteria in the water column, which produced negative δ34SCAS-δ13Ccarbonate correlations.
The slopes of the negative correlations varied at the G-L boundary. This implies that the supply processes of carbon and sulfur into the oceans changed at the boundary. This finding suggests that the magmatic chemistry changed at the boundary from sulfur-rich type to CO2-rich type.