Speaker: Dr. Clara Blattler (Princeton University)
Abstract: It is surprising that we cannot robustly answer the question: “Why is the sea salty?” The major-element composition of seawater acts as an important boundary condition that shapes how we interpret marine records, environments, and evolution. Its composition has undoubtedly changed over time, but why, and by how much, remain outstanding questions. I will present a new method for reconstructing ancient seawater chemistry, in particular the relative concentrations of SO4, Ca, and DIC. This method relies on calcium isotope analyses of carbonate and sulfate minerals in marine evaporites, and provides important constraints on seawater chemistry during broad periods of geological time, including intervals where few other data exist.