The relationship between thermal inertia and degradation state of craters in areas of low surface dust cover on Mars

On Mars, impact craters that are proximal can exhibit vastly different thermal inertia values on their rims, even where the target lithology appears to be the same. Degradation of crater rims produces fine-grained regolith over time through comminution, and we investigated whether this process affects crater rim thermal inertia in regions with low dust cover. We used a series of regression analyses to test for correlations between crater rim thermal inertia and rim irregularity, an indicator of degradation state, in three martian study locations. The results of these analyses support the interpretation that crater rim thermal inertia is a function of crater degradation state in all three study areas. Therefore, rim thermal inertia could be used as a quick way to estimate impact crater degradation states and relative ages in areas on Mars with low dust cover and similar target properties. In contrast, crater rim thermal inertia in regions with high dust cover is a function of the amount of dust mantling the crater rims.