Roger Bryant is a Postdoctoral Scholar who studies sedimentary geochemistry. Specifically, he studies how post-depositional processes (collectively termed “diagenesis”) affect the chemical and mineralogical composition of marine sediments and sedimentary rocks. He conducts chemical analyses of minerals (e.g., iron sulfides, sulfates, carbonates) or chromatographically separated elements (e.g., calcium, magnesium, sulfur) using mass spectrometry, to reconstruct the past chemistry of Earth’s ocean. Previously, he has published work that used the sulfur isotopic composition of iron sulfide minerals to track the response of the marine sulfur and iron cycles to sudden environmental perturbations such as rapid terrigenous sediment exportand ocean anoxic events (OAEs). Currently, he is working with Prof. Clara Blättler to understand the effects of diagenesis on the sulfur isotopic composition of carbonate-associated sulfate (CAS). The long-term goal is to generate a filtered CAS sulfur isotope record that can be used to quantitatively reconstruct Earth’s oxidation history, with a focus on Earth’s Great Oxidation Events (GOEs).