Evolution of Mercury’s Volatile-bearing Crust within Raditladi Basin

Abstract Mercury’s surface presents significant challenges for understanding planetary volatile distribution. Previous studies have identified features including hollows, flows, and chaotic terrains as associated with the presence of volatiles. Their formation and connection to Mercury’s volatile inventory remain incompletely characterized. Using Hapke’s radiative transfer model, we conducted detailed photometric analyses of three distinct regions within Mercury’s Raditladi basin that display hollows and flow-like morphologies to quantify regolith properties and their relationship to volatile-driven processes, revealing three key findings. (1) The basin floor regolith exhibits distinct structural characteristics indicating a separate evolutionary pathway. (2) Hollows and surrounding halos demonstrate regolith properties (higher porosity, finer-grained) consistent with slow, low-energy sublimation processes that minimally disrupt intergrain relationships. (3) Areas within the peak ring display photometric signatures indicative of volatile-rich mass wasting flows. The hollows and halos exhibit significantly higher single-scattering albedos compared to other units, suggesting the presence of a unique residual material that remains after volatile sublimation that appears intimately mixed with common regolith components. Previously mapped flow-like features share regolith structural similarities with hollows supporting their derivation from a common volatile-rich layer (VRL). Regions along peak walls display distinctive photometric properties that likely represent remnants of VRL flow sources within the peak ring structure, suggesting that peak rings maintained their volatile composition throughout the flow process. The excavation of hollow-like regolith from impacts on the basin floor suggests either differentiation of the impact melt or burial of volatiles outgassed from the peak ring, deposited on the basin floor, and later buried.