Earth-based radar data reveal extended deposits of the Moon's Orientale basin

Abstract

We present new Earth-based radar observations of ejecta associated with the lunar Orientale impact basin. We can distinguish (1) a block-poor ejecta facies composing a concentric halo of mantling material 10 m or greater in thickness that extends more than 1000 km from the basin center, and (2) a melt-rich deposit that forms a discontinuous but areally extensive stratigraphic marker across the southern highlands. The melt-rich component likely extends well into the South Pole-Aitken basin, a key target for future landed and sample return missions. The observation of these two ejecta facies and their distribution across the southern nearside yields new insight into the types and distribution of material contributed by large basin-forming impacts to the highlands megaregolith.