Asymmetry distribution of craters on north and south poles of Mercury

Mercury, the innermost planet in our solar system, offers a unique natural laboratory for planetary science, particularly with its unexpectedly high concentration of volatile elements and the presence of volatile-related geological features. This study investigates the morphology and ages of craters at Mercury's north and south poles to understand the distribution of water ice within these regions. Utilizing high-resolution images from the MESSENGER mission and various digital elevation models, we measured crater depth and diameter and conducted crater size-frequency distribution analyses. Our findings reveal significant differences in the depth-to-diameter (d/D) ratios and absolute ages of craters between the poles. North Pole craters are generally younger, deeper, and smaller in diameter, while South Pole craters are older, shallower, and larger in diameter. The Northern Smooth Plains at the North Pole, formed by extensive volcanic activity, exhibit fewer impact craters, suggesting a younger surface. In contrast, the South Pole's heavily cratered terrain displays significant weathering and thicker regolith layers. The study also highlights the uneven distribution of water ice, likely influenced by crater morphology and the presence of insulating layers. This research provides insights into the geological history of Mercury and the processes shaping its polar regions, enhancing our understanding of the planet's volatile content and its implications for habitability in the inner solar system.