Horizontal transport of the regolith,modification of features,and erosion rates on the lunar surface

New lunar soils, freshly deposited as impact ejecta, evolve into more mature soils by a complex set of processes involving both near-surface effects and mixing. Poor vertical mixing statistics and interregional exchange by impact ejection complicate the interpretation of soil maturization. Impact ejecta systematics are developed for the smaller cratering events which, with cumulative crater populations observed in young mare regions and on Copernicus ejecta fields, yield rates and a range distribution for the horizontal transport of material by impact processes. The deposition rate for material originating more than 1 m away is found to be about 8 mm m.y.^?1 Material from 10 km away accumulates at a rate of about 0.08 mm m.y.^?1, providing a steady influx of foreign material. From the degradation of boulder tracks, a rate of 5±3 cm m.y.^?1 is computed for the filling of shallow lunar depressions on slopes. Mass wastage and downslope movement of bedrock outcroppings on Hadley Rille seems to be proceeding at a rate of about 8 mm m.y.^?1 The Camelot profile is suggestive of a secondary impact feature.