45-1 Assessing Mercury’s Geologic History through Crater Counting

Session: Surface Processes Across the Solar System (Posters)

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The MESSENGER mission (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) was launched in 2004 with the goal of orbiting Mercury in order to study its geology, and other aspects. Using image data from the MESSENGER Mercury Dual Imaging System (MDIS) and Mercury Laser Altimeter (MLA) instruments,  the project will aim to assess Mercury’s geologic evolution through CSFDs (crater size frequency distributions) and crater counting in order to understand surface age variations in Mercury’s volcanic smooth plains. Crater counting is used to estimate the age of a planet by looking at the relative density of impacts across surfaces. Older surfaces have a higher crater density (more craters) because there was more time for craters to form, and overlap. Comparing the CSFD across different surfaces allows for a better understanding of a planet's geologic evolution.

Through the crater counting process most of the CSFDs did not follow the production function curve, showing that the data was inflated. This may have been due to secondary craters being counted along with the genuine (primary) craters, so we identified and removed obvious chains or clusters of secondary craters from each of the previous counts. However, the removal of secondary craters did not significantly improve the fit of the CSFDs to the production function. The results from removing the secondary craters indicates some level of saturation within the specific regions of Mercury’s surface; it could also imply that some primary craters were eradicated by secondaries. Overall, since the removal of secondary craters has not affected the CSFDs as expected, more crater counting is needed to understand why the counts are still inflated. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

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