Crater studies in the Apollo 17 region

As part of crater analysis in the Apollo 17 region, cumulative size-frequency curves were constructed, the density distribution of small craters was determined, and the effects of secondary crater clusters near the landing site were studied. The cumulative curves indicate that the old dark-mantled mare is similar in age to Apollo 11 mare, and that the adjacent young light mare of Central Serenitatis is similar in age to Apollo 15 mare. The old dark-mantled surface is markedly deficient in craters between 100 and 200 m in diameter, and the analysis suggests that this deficiency is a consequence of the old dark mantle which gives rise to an unusually thick unconsolidated layer that causes abnormally rapid degradation of small craters.