¹Romain Tartèsea,²Paolo A. Sossi,³Frédéric Moynier
Proceedings of the National Academy of Sciences of teh United States of America (PNAS) (in Press) Link to Article [DOI: https://doi.org/10.1073/pnas.2023023118]
¹Department of Earth and Environmental Sciences, The University of Manchester, M13 9PL Manchester, United Kingdom;
²Institute of Geochemistry and Petrology, ETH Zürich, CH-8092 Zürich, Switzerland;
³Université de Paris, Institut de Physique du Globe de Paris, CNRS UMR 7154, 75005 Paris, France

Rocks from the lunar interior are depleted in moderately volatile elements (MVEs) compared to terrestrial rocks. Most MVEs are also enriched in their heavier isotopes compared to those in terrestrial rocks. Such elemental depletion and heavy isotope enrichments have been attributed to liquid–vapor exchange and vapor loss from the protolunar disk, incomplete accretion of MVEs during condensation of the Moon, and degassing of MVEs during lunar magma ocean crystallization. New Monte Carlo simulation results suggest that the lunar MVE depletion is consistent with evaporative loss at 1,670 ± 129 K and an oxygen fugacity +2.3 ± 2.1 log units above the fayalite-magnetite-quartz buffer. Here, we propose that these chemical and isotopic features could have resulted from the formation of the putative Procellarum basin early in the Moon’s history, during which nearside magma ocean melts would have been exposed at the surface, allowing equilibration with any primitive atmosphere together with MVE loss and isotopic fractionation.