My research develops our understanding of the evolution of early Earth’s marine environments. To do this I integrate sedimentology, stratigraphy and geochemistry in both field and lab work. I am a strong advocate for having a thorough understanding of paleoenvironments and diagenesis prior to any geochemical analysis. In this regard I am working on component-specific geochemistry (trace metals, metal isotopes) of both marine and burial carbonates. I also aim to improve our knowledge of Precambrian carbonate formation and sedimentology, and additionally have recently been working on early diagenetic silicification. I am particularly interested in reef evolution, primary carbonate mineralogy, marine cementation and syn-sedimentary dolomitisation in Precambrian sequences. Much of my research centres around the “Precambrian dolomite problem”, as it now appears that marine dolomitisation was widespread in the these anoxic oceans.
Carbonate sediments play a key role in unlocking the secrets of the early Earth. Precambrian carbonates of North America, Australia and Africa contain newly discovered, primary marine carbonate precipitates that can reveal the redox chemistry of seawater over time. The development of these marine cements as a reliable proxy for ocean oxygenation forms part of my research at Yale. I hope to better constrain the redox state and associated chemical depth gradients of Precambrian seawater by geochemical and sedimentological examination of these marine cements. Geochemical analysis includes Laser Ablation- ICPMS of these components, and the application of several different isotope systems (U, Cr, Sr, C,O). Additionally, when analysed in a stratigraphic framework, basic variations in carbonate mineralogy provides a record of ocean Mg/Ca during the Precambrian “dolomite seas”.
These carbonates are beginning to reveal just how unusual the oceans were during the Precambrian, highlight the complexity of the evolution of the ocean-atmosphere in the early Earth.