Investigating the Sources and Timing of Projectiles Striking the Lunar Surface
The lunar surface is exposed to bombardment by asteroids, comets, and debris from them. Surviving fragments of those projectiles in the lunar regolith provide a direct measure of the sources of exogenous material delivered to the Moon. Con-straining the temporal flux of their delivery will directly address key questions about the bombardment history of the inner Solar System. Regolith breccias, which are consolidated samples of the lunar regolith, were closed to further impact processing at the time they were assembled into rocks [1]. They are, therefore, time capsules of impact bombardment at different times through lunar history. Here we investigate the impact archive preserved in the Apollo 16 regolith breccias and compare this record to evidence of projectile species in other lunar samples.