Untangling Earth's archive of multiple sulfur isotope anomalies

Dr Mark Claire, University of St Andrews. Part of the Physical Seminar Series.

Abstract: Multiple sulfur isotope anomalies are only known to arise via gas phase chemical reactions, making them a key tracer of atmospheric chemistry. Over the past 20 years, the geologic record has yielded rich datasets ranging in scale from smog aerosols, to polar ice records, to Earth's earliest sediments - all hinting at dramatic changes in atmospheric chemistry involving sulfur gases.

In tandem, a number of experimental and theoretical attempts have been made to isolate the mechanisms that give rise to anomalous sulfur isotope fractionation, but the ability to generate data still far exceeds our ability to interpret it.

This talk will summarize this field from my perspective as an atmospheric geochemist interested in using photochemical models to quantify changes in paleo-atmospheric composition. Ultimately, I aim to provide a charge for the collaboration on the necessary fundamental work in kinetics, theory, and modeling that is needed to move forward in this exciting field.