An integrated study of Rutherfurd crater: Composition, morphology, and chronology

The youngest era in the lunar geological timescale, the Copernican period, is estimated to have commenced approximately 1.1 billion years ago and is named after the prominent 95 km-diameter Copernicus crater. Copernican craters represent the youngest and best-preserved impact craters on the Moon. This study presents the first high-resolution geological and morphological map of the ∼48 km diameter Copernican-age Rutherfurd crater, produced through the integration of optical, radar, and hyperspectral datasets. Observations reveal significant asymmetry in the crater's structure, particularly in terms of slumping, terracing, and rim preservation, which we interpret as being due to the effects of pre-existing topography. Spectral analysis indicates the dominance of high-calcium pyroxene (HCP) within the central peak, rim, and isolated mounds, suggesting excavation of a buried HCP-rich plagioclase layer. Crater Size-Frequency Distribution (CSFD) analysis of the continuous ejecta blanket yields an age of ∼1-1.1 Ga, confirming Rutherfurd as the youngest crater in the Clavius crater arching chain. In contrast, CSFDs from the impact melt ponds yield anomalously younger apparent ages (∼200–510 Myr), likely reflecting statistical uncertainties arising from their limited surface area and the paucity of large craters, rather than true differences in formation age. Distinct asymmetries in ejecta distribution and secondary crater patterns are interpreted to reflect the oblique nature of the impact and interactions with local topographic variations. Ejecta morphology and secondary crater orientations suggest an oblique impact from the southeast to northwest at an angle of ∼20–30°. This study not only refines our understanding of Rutherfurd's formation and evolution but also highlights its significance as a target for future lunar exploration, particularly due to its exposure of deeper crustal materials and proximity to regions with potential hydration signatures.