Sulfur isotopes link atmospheric sulfate aerosols from the Siberian Traps outgassing to the end-Permian extinction on land

Abstract

Throughout Earth history, large volcanic eruptions that inject sulfur-bearing gases are believed to have imparted strong forcings on global climates and ecosystems. Sulfur outgassing by the Siberian Traps Large Igneous Province (STLIP) is hypothesized to have catalyzed environmental catastrophe associated with the end-Permian extinction (EPE). However, there is as yet only sparse evidence for dispersal of atmospheric sulfate aerosols that precisely coincided with the EPE on land. Here we report S-isotopic compositions of pyrite (δ34S) from the Sydney Basin in SE Australia, where we find a sharp δ34S decrease from 0.04‰ to −21.52‰ coinciding with the stratigraphic level of the terrestrial extinction. The negative δ34S values in the extinction interval provide new evidence for a significant increase in atmospheric sulfate concentrations linked to fallout of sulfate aerosols originating from the Siberian Traps eruptions. We suggest that climatic perturbations of short-term cooling caused by the sulfate aerosols, along with longer-term global warming, and their interactions, may have contributed to the EPE on land. Our data suggest that sulfuric acid rain and ozone depletion may have greatly deteriorated global environments, leading to the terrestrial EPE.