Contribution of Impact Material to the Lunar Magma Ocean Liquid and Solid Cumulates

Abstract

During its accretion and early evolution, the Moon experienced an ongoing bombardment by impacting material. As a consequence, the lunar magma ocean (LMO) did not crystallize as a closed system but was influenced by the influx of accreting material that modified its thermal state and chemical composition. Depending on the size, density and degree of melting of the projectiles, impacting material could either have been mixed into the LMO or sunken through the LMO and contributed to the bottom cumulate. By combining impact and LMO solidification models, we aim to obtain quantitative information on how much of the material that accreted during LMO solidification has been mixed into the LMO liquid and how much in the solid cumulate, how the relation of these contributions changed with time and how this affected the thermochemical evolution of the LMO and the composition of lunar mantle reservoirs.