The PI has developed an analytical technique for delta 18O of sulfate, based on barite delta 18O analyses. The main focus of the study will be to use the delta 18O of barite as a recorder for the d18O of seawater sulfate through the last 100 m.y., with particular attention to anoxic events in the mid-Cretaceous, with additional attention to the Permian-Triassic boundary. Effort will also be devoted to two related projects: studies of the delta 18O of dissolved sulfate in modern pore waters to better understand the factors that control the delta 18O of sulfate, and a comparison of the delta 18O values of barite and the trace sulfate in biogenic carbonates. Together these objectives will provide an improvement in our understanding of the global sulfur cycle and its interactions with the Earth's carbon and oxygen cycles. This research has the potential to broaden our understanding of carbon and sulfur cycles over Earth's history. The research will result in training of a post-doctoral scientist and a graduate student. The work will also serve as a basis for creating stronger interactions between geochemists and microbiologists at Harvard.
