Pulsed Volcanic Sulfur Emissions Linked to the End-Triassic Terrestrial Crisis

The end-Triassic mass extinction (ETE, ~201.6 Ma) is widely attributed to eruptions of the Central Atlantic Magmatic Province (CAMP), which released large volumes of CO₂, SO₂, and halogens into the atmosphere and disrupted global ecosystems. However, the mechanism linking CAMP volcanism to the terrestrial ecological crisis remains insufficiently constrained, particularly in continental successions located far from eruptive centers. Here we investigate two terrestrial Triassic–Jurassic boundary sections from inland basins at high and middle to low paleolatitudes, both situated far from CAMP eruptive centers. These sections record synchronous anomalies in Hg concentrations, sulfur isotopes, sulfur-associated molecular fossils, and wildfire-related biomarkers including retene, pimanthrene, and coronene. The results indicate that peak volcanic sulfur deposition coincided with intervals of floral diversity decline, fern spikes, and intensified high-temperature wildfire activity over an interval of approximately 60 kyr. We propose that a pulse of maximum CAMP eruptive activity rapidly increased volcanic sulfur influx to continental basins, triggering widespread acid rain and catastrophic vegetation dieback during the ETE. The resulting accumulation of dry biomass likely promoted increasingly frequent and widespread intense wildfires across terrestrial ecosystems. The recognition of synchronous pulsed sulfur-cycle perturbations across continental successions demonstrates that volcanic sulfur deposition may provide a robust stratigraphic marker for correlating terrestrial environmental change across the Triassic–Jurassic transition and refining the temporal structure of the end-Triassic terrestrial crisis.