Shock compression of FeOOH and implications for iron-water interactions in super-earth magma oceans
Year: 2025
Type: article
Abstract: Iron(Fe)-water reactions in a magma ocean can influence water storage and density of planets. These reactions can form Fe-O-H phases, whose density, melting, and electronic properties at planetary interior conditions are important for informing planetary models. Here, we study natural goethite (α-FeOOH) that is shock-compressed along its principal Hugoniot. Analysis of our velocity interferometer system for any reflector (VISAR) results extends the equation of state to over 800 GPa. X-ray diffraction and VISAR reflectivity results indicate the onset of melting occurs at ~95 GPa with complete melting by 166 GPa, which may be relevant to low seismic velocity anomalies observed above the core-mantle boundary. Analysis of X-ray emission spectroscopy results up to 285 GPa shows the spin crossover of Fe, with dominantly low spin Fe above ~265 GPa in the melt, supporting formation of dense basal magma oceans in terrestrial planets. Using our measured FeOOH densities, we model planetary interiors up to 10 Earth masses. Assuming FeOOH forms via iron-water reactions, the radius decreases by up to 28%, while the density increases by up to 165% compared to the unreacted case, providing an avenue to investigate water storage and evolution in super-Earths and sub-Neptunes.
Source: Nature Communications
Authors: Yanyao Zhang, Komal Bali, Caroline Dorn, Alessandra Ravasio, Hong Yang, Silvia Pandolfi, Amanda J. Chen, Xuehui Wei, Lélia Libon, Qijun Che, Donghao Zheng, Eglantine Boulard, Alessandra Benuzzi-Mounaix, Hae Ja Lee, Eric Galtier, Nicholas A. Czapla, Dimosthenis Sokaras, Roberto Alonso-Mori, Arianna E. Gleason, Sang Heon Shim, Guillaume Morard, Wendy L. Mao
Institutions: Stanford University, ETH Zurich, Institute for Particle Physics and Astrophysics, Centre National de la Recherche Scientifique, École Polytechnique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Sorbonne Université, Laboratoire pour l'Utilisation des Lasers Intenses, Muséum national d'Histoire naturelle, Institut de minéralogie, de physique des matériaux et de cosmochimie, Arizona State University, Institut des Sciences de la Terre, Université Grenoble Alpes, SLAC National Accelerator Laboratory, Princeton University
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Deutsche Forschungsgemeinschaft, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Ministerio de Economía y Competitividad, Nuclear Safety and Security Commission, Centre National de la Recherche Scientifique, Sichuan University, Sorbonne Université, Office of Science, SLAC National Accelerator Laboratory
Awards: Collaborative Research: From Silicate Melts Properties to the Dynamics and Evolution of an Early Basal Magma Ocean, G210990444, NCCR PlanetS: Origin, evolution and characterisation of planets, G308902114, Untersuchung planetarer Eise mit Kompressionsexperimenten, G4817264520, G4927892525, FAte of the volatile COmponents at the galilean Moons, MINeralogical DIversity in (eXo)planets Interiors, G7088042312, G7973539974, Planets and their deep volatile reservoirs, G8505061131
OpenAlex ID: W7117366344