Colloquium: Rita Parai

Rita Parai, Postdoctoral Fellow, Department of Terrestrial Magnetism, Carnegie Institution for Science

Abstract - Noble gases in mantle-derived rocks provide unique insights into the evolution of planetary volatile budgets. Volatiles are outgassed from the mantle in association with volcanism, and are potentially recycled at subduction zones. We measured noble gas isotopic compositions in a suite of mid-ocean ridge basalts with sufficient precision to demonstrate that atmospheric heavy noble gases are recycled to the deep mantle over time. Although significant atmospheric Xe recycling occurs, the Xe isotopic compositions of mantle sources have not been entirely overprinted, but rather preserve a record of very early differentiation of the upper mantle from the mantle plume source. I will discuss new constraints from noble gases on the nature of the plume source and upper mantle, volatile cycling between deep Earth and surface reservoirs, and the timing of the Moon-forming giant impact.