EEPS Colloquium: Liam Peterson

 

Hydrogen (H) is the most abundant element in the universe and exerts a significant control on the habitability and physicochemical evolution of Earth and other bodies. Considering the Earth likely accreted from a mix of thermally primitive (e.g., chondrites, ice, dust), incompletely melted (e.g., primitive achondritic), and fully melted (achondritic) materials/bodies, it is necessary to constrain the H budget at each stage of thermal processing. In this talk, I will present the first constraints on the H budgets of small, incompletely melted bodies. I found that these small, incompletely melted bodies are essentially anhydrous. Assuming that precursor materials resemble primitive chondrites, this requires effective dehydration prior to or at the onset of melting on meteoritic parent bodies. Furthermore, this requires that Earth’s H budget be primarily accounted for by thermally primitive materials (e.g., chondrites, ice, dust) or capture or nebular gas. I will also present my experimental constraints on the partitioning of H between olivine and melt at low pressures (10 – 200 MPa), which show that, at low pressures, the olivine-melt H partition coefficient is controlled by H speciation in the melt.