The Amundsen-Ganswindt basin: An overlooked lunar peak-ring basin with multiple exploration opportunities

Abstract

The ∼ 355 km diameter Amundsen-Ganswindt impact basin (81°S, 120°E) has been stratigraphically constrained as the oldest large basin in the South Pole-Aitken basin terrane. It partly overlaps the Artemis Exploration Zone, across which it deposited significant volumes of impact ejecta deposits. The basin is highly degraded and partially superposed by the similar-sized Schrödinger peak-ring impact basin, leading previous workers to question whether it contains any remnants of an original peak-ring. We have conducted a detailed geologic study of the Amundsen-Ganswindt basin and evaluated the scientific potential of this ancient structure in the context of global lunar exploration objectives that underpin future crewed and robotic exploration missions to the lunar south polar region. We have mapped the basin at a scale of 1:1,000,000 and identified high-value exploration targets, including remnants of an original peak ring and opportunities to sample this uplifted material. Given its age, both Amundsen-Ganswindt's peak ring and ejecta deposits will contain a high proportion of material from the South Pole-Aitken basin. In addition, material from the Schrödinger peak-ring impact basin — the second youngest basin on the Moon — are also available for sampling. Morphological evidence suggests that the Amundsen-Ganswindt basin influenced the final morphology of Schrödinger's rim and peak ring. The Amundsen-Ganswindt basin is also host to large, accessible permanently shadowed regions with orbital detections of water ice. Thus, we propose that the overlooked Amundsen-Ganswindt basin is an exceptional exploration target for future robotic and human exploration missions.