Characteristics of the Shackleton-de Gerlache ridge and implications for lunar south polar geology and future sampling activities

The geology of the Shackleton-de Gerlache ridge at the lunar south pole is of interest to the planetary community due to its geologic history, ancient age, illumination conditions, and polar location. The precise origin, evolution, and lithology of the ridge is currently poorly understood, but data recently collected by instrumentation like ShadowCam provides new information that will support our understanding of the lunar highlands and the effects of impact cratering in this polar location. In this work, we evaluate the topographic extent of the ridge, and assess its physical and chemical makeup as exposed within the Shackleton crater. We find that the ridge is adorned by four peaks with saddles between them and a berm feature formed nearby Spudis crater. We also find that boulder distribution inside Shackleton indicates ongoing mass wasting processes, and that boulder density is not constant along the cross section of the ridge. Changing boulder distribution densities appear to correspond with varying modal mineralogy, potentially indicating that the ridge presents overturned layered material, or is brecciated. Ridge characteristics are consistent with a crustal origin where materials were deposited by the South Pole-Aitken impact. Future work should continue evaluating the subsurface exposed by large craters in this region to better understand the geologic evolution of similar ridges prior to exploration efforts.