title: Extensive volatile loss during formation and differentiation of the Moon.
abstract: Low estimated lunar volatile contents, compared with Earth, are a fundamental observation for Earth-Moon system formation and lunar evolution. Here we present zinc isotope and abundance data for lunar crustal rocks to constrain the abundance of volatiles during the final stages of lunar differentiation. We find that ferroan anorthosites are isotopically heterogeneous, with some samples exhibiting high δ(66)Zn, along with alkali and magnesian suite samples. Since the plutonic samples were formed in the lunar crust, they were not subjected to degassing into vacuum. Instead, their compositions are consistent with enrichment of the silicate portions of the Moon in the heavier Zn isotopes. Because of the difference in δ(66)Zn between bulk silicate Earth and lunar basalts and crustal rocks, the volatile loss likely occurred in two stages: during the proto-lunar disk stage, where a fraction of lunar volatiles accreted onto Earth, and from degassing of a differentiating lunar magma ocean, implying the possibility of isolated, volatile-rich regions in the Moon's interior.
authors.affiliation: Institut de Physique du Globe de Paris, Université Paris Diderot, CNRS UMR 7154, Paris 75005, France.|Department of Earth and Planetary Sciences and McDonnell Center for Space Sciences, Washington University in St Louis, St Louis, Missouri 63130, USA.
authors.forename: Chizu
authors.initials: C
authors.lastname: Kato
authors.affiliation: Institut de Physique du Globe de Paris, Université Paris Diderot, CNRS UMR 7154, Paris 75005, France.|Institut Universitaire de France, Paris 75005, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Moynier
authors.affiliation: Department of Earth and Planetary Sciences and McDonnell Center for Space Sciences, Washington University in St Louis, St Louis, Missouri 63130, USA.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Valdes
authors.affiliation: Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, California 92093-0244, USA.
authors.forename: Jasmeet K
authors.initials: JK
authors.lastname: Dhaliwal
authors.affiliation: Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, California 92093-0244, USA.
authors.forename: James M D
authors.initials: JMD
authors.lastname: Day