Sophie Benaroya

Sophie Benaroya completed her BSc and MSc at Rutgers University (USA). During her MSc, she investigated the formation history of the martian meteorite NWA 13227 under the supervision of Dr. Juliane Gross. This project deepened her interest in planetary petrology, leading her to pursue a Ph.D. at the University of Alberta under the supervision of Dr. Chris Herd. Her research focuses on refining our understanding of redox processes in martian meteorites and the redox state of the martian mantle by developing an experimentally calibrated vanadium (V) oxybarometer.

The redox state of planetary materials is important because it influences mineral formation and volatile speciation. Oxygen fugacity (fO₂) is a measure of redox state, and studying how fO₂ changes throughout a sample’s crystallization history can provide insights into the fO₂ of the martian mantle and the occurrence of open-system processes. Currently, Fe oxybarometers are used to estimate the magmatic fO₂ of martian samples, but these require multiple minerals (olivine, pyroxene, and spinel or ilmenite and magnetite) to be present within a sample and be in chemical equilibrium. Additionally, as Fe is present in many minerals within samples, variations in melt composition and the effects of subsolidus re-equilibration of Fe introduce uncertainties as to what these barometers are measuring.

To address this, Sophie is calibrating a V-oxybarometer that can be used to estimate fO₂ with a single mineral: olivine or pyroxene. To achieve this, she conducts high-temperature experiments with vanadium-doped synthetic martian compositions, which she analyzes using EPMA and LA-ICP-MS. Initial experimental results are currently being applied to various martian meteorites to evaluate a debated link between Incompatible-Trace-Element (ITE) enrichment and redox state. She is also using thermodynamic modeling to investigate the effects of volatile degassing on the redox evolution of martian meteorites.