We have developed a new model for diffusive erosion of airless bodies on which impact bombardment is the dominant surface evolution process. We use terrains in simple crater equilibrium to constrain an analytical model of diffusive erosion model. Using LROC observations of the Apollo 15 landing site as well as a numerical Monte Carlo code called the Cratered Terrain Evolution Model, we set constraints on the cratering processes that determine the diffusive erosion rate of lunar topography. Our results show that the majority of each new crater's contribution to diffusive topographic degradation occurs over a spatially heterogeneous region much larger than that bounded by the crater's proximal ejecta blanket, possibly as much as 50x larger than the final crater rim diameter. This is in contrast to previous studies that assumed that the majority of topographic degradation occurred by the direct excavation and preferential downslope deposition of proximal ejecta. We conclude that the dominant mechanism for topographic degradation on the Moon is therefore related to energetic distal ejecta deposition, and it is this distal process that sets the empirical equilibrium cumulative size-frequency distribution for simple post-mare craters.
Cite this work
Researchers should cite this work as follows:
- Minton, D. A., Fassett, C. I., Hirabayashi, M., Howl, B., Richardson, J. (2017). Topographic degradation by impact cratering on airless bodies is dominated by diffusive erosion from distal ejecta. Purdue University Research Repository. doi:10.4231/R79C6VMX
Data to reproduce figures and movies for first submission to Icarus.
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