Abstract We present six newly identified examples of lobate ejecta in Mercury's south polar quadrangle (H15), providing the first evidence of syn‐impact formation through our observation of perched impact melt at Nairne and Magritte craters. This finding challenges the idea that lobate forms could have developed post‐impact via mass wasting or landslide processes, suggesting instead that many, if not all, lobate ejecta deposits formed contemporaneously with the impact event. We present detailed morphostratigraphic…

Abstract Lobate forms emanate from impact craters and have morphologies indicating ground‐hugging emplacement via flow. We present global surveys of lobate forms on the Moon and Mercury. Very few examples have previously been reported on either body, with debate over their interpretation as either crater rim landslides or ejecta flows. We identify 92 lobate forms on the Moon, and 98 on Mercury, a significant increase on previously reported examples. 98% extend downslope into an adjacent or overlapped antecedent cr…

Mercury's Bach quadrangle (H15) is the area poleward of 65°S. We mapped this geologically using remote sensing-based observations of surface morphology revealed on MESSENGER data products. This map contributes to a series of quadrangle maps providing geological context forthe ESA-JAXA BepiColombo mission to Mercury. We performed digitisation at ∼1:400,000 scale and final publication scale is 1:3,000,000. There are four morphologically distinct plains units: intercrater, intermediate, smooth, and very smooth. Impac…

Abstract NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission has revealed that about 27% of the surface of Mercury is covered by smooth plains, which are mostly volcanic in origin. These plains are mainly located in the northern hemisphere, as well as within and around major impact basins. We used Mercury Atmospheric and Surface Composition Spectrometer data to perform an exhaustive spectral analysis of five major impact basins: Caloris, Rembrandt, Beethoven, Tolstoj, and Rachmaninoff. We …

Abstract The observed geochemical heterogeneity on the surface of Mercury is key to understanding the planet's volcanic activity and mantle conditions. The Caloris basin shows a diversity in elemental composition, spectral properties, and geomorphology, both within and around it. However, the relationship among these characteristics has not been well understood due to the mismatch in spatial resolutions of the available observation data. This study investigates the geochemical end‐members around the Caloris basin,…