Correlating continental flood basalt volcanism, environmental change, and mass extinction events at high resolution using novel geochemical proxies in sediments

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Continental flood basalt volcanism is thought to have played a role in all five of the largest mass extinctions in Earth history. However, our understanding of how volcanism causes environmental change leading to mass extinction is hampered by difficulty determining the precise timing of these events, which occurred over 10 to 100 thousand-year timescales. Volatile trace elements which are enriched in volcanic gas, injected into the atmosphere during flood basalt volcanism, and later deposited in sediments can potentially link these processes at timescales of less than a few tens of thousands of years, beyond the resolution of radiometric dating. Previously, mercury (Hg) concentrations in sediments have been used as a proxy for past volcanism. Our recent work has shown that tellurium (Te) and selenium (Se), in sedimentary rocks may be more sensitive and reliable proxies for volcanism. This project will measure trace elements (including Hg, Te and Se) in sediment profiles across the Permian – Triassic and Cretaceous – Paleogene boundaries, in order to link flood basalt volcanism in Siberia and in India (Deccan) respectively, with the record of environmental change and extinction preserved in the same sediments, at a resolution of a few tens of thousands of years. For the Cretaceous – Paleogene, we will also be able to determine the timing of Deccan volcanic pulses relative to the Chicxulub impact event, and test the recent hypothesis that the impact triggered the largest Deccan eruptions.