Geologic History of the Mons Malapert and Mons Mouton Regions Near the Lunar South Pole: Basis for Future Exploration

Wueller, Lukas; Iqbal, Wajiha; Frueh, Thomas; Head, James W.; Kring, David A.; Oetting, Astrid; van der Bogert, Carolyn H.; Hiesinger, Harald

Abstract

This study presents a 1:100,000 scale geologic map of the region encompassing Mons Mouton, Mons Malapert, and Cabeus crater, highlighting the region's geologic diversity. Based on location and topography, Mons Mouton and Mons Malapert are interpreted as remnant massifs of the South Pole-Aitken (SPA) basin rim. Crater size-frequency distribution measurements of impact craters on Mons Mouton yield a formation age of 4.26 Ga, providing a chronological anchor point for the SPA impact event. Ejecta distribution models indicate that Mons Mouton and Mons Malapert are covered by hundreds of meters of post-SPA ejecta. Because massif lithologies and SPA ejecta blankets are not exposed at the surface and thus cannot be sampled directly, any sampling of them requires subsequent excavation to the surface by younger impacts. Stratigraphic subtraction of the ejecta deposits covering the massifs unveils their original configuration, strengthening the interpretation of Mons Mouton as an uplifted outer rim of the SPA basin that was subsequently reshaped by impact craters and covered by their ejecta. Our results indicate that volatile-rich deposits in Cabeus crater vary in thickness, suggesting that the fill material was emplaced from the southeast and that LCROSS-exposed volatiles were superposed later rather than initially contained. We provide geologic context for five Artemis III candidate landing regions, evaluating their temperature, volatile potential in permanently shadowed regions, and constraints on landing and surface operations, including slope, illumination, and Earth visibility. Additionally, we assess potential sample materials and science objectives to maximize the scientific return from future lunar exploration missions.