Pulsed volcanic sulfur emissions linked to the end-Triassic terrestrial crisis.

Abstract

The end-Triassic mass extinction (ETE) was triggered by Central Atlantic Magmatic Province (CAMP) volcanism, which released voluminous carbon dioxide, sulfur dioxide, and halogens into the atmosphere, affecting marine and terrestrial ecosystems, but the mechanism driving terrestrial crisis remains unclear. Here, we investigate two terrestrial Triassic-Jurassic sections in high- and low/middle- paleolatitudes, finding synchronous anomalies of mercury concentration, sulfur (S) isotopes, S-associated molecular fossils, and biomarkers (retene, pimanthrene, and coronene), indicating that peak volcanic sulfur deposition coincided with floral diversity loss and fern spikes, and intensified high-temperature wildfires over an interval of ~60,000 years. We propose that the pulse of maximum CAMP eruptions rapidly increased volcanic-S influxes (acid rain) to terrestrial basins, leading to catastrophic plant dieback during the ETE. The consequent creation of moisture-free biomass supplied fuel for increasingly frequent and widespread intense wildfires, occurring even on a global scale.