Title: A phosphorus control on Earth's oxygenation history

Speaker: Professor Simon Poulton

Abstract:

Phosphorus is generally considered the ultimate limiting nutrient on geological timescales and likely played a major role in the history of Earth surface oxygenation through the Precambrian. Recent high profile reconstructions have attempted to address relationships between phosphorus bioavailability and oxygenation, but all suffer from poor constraints on our understanding of redox and mineralogical controls on phosphorus recycling in Precambrian settings. Here, I will review current understanding of the Precambrian phosphorus cycle, and will present case studies of phosphorus cycling in modern analogues for the Precambrian ocean. The new insight afforded by these modern case studies will then be considered in relation to the operation of the phosphorus cycle through the mid-Proterozoic, with a focus on the early Neoproterozoic prior to the first Cryogenian Snowball Earth glaciation.