宇宙線照射年代からみた月表層部の攪拌過程
1979 年 24 巻 1 号 p. 1-8
詳細
1979 年 24 巻 1 号 p. 1-8
From the cosmic-ray exposure age data, (time scale 107-108 years), of the lunar surface materials, we discuss the gardening process of the lunar surface layer caused by the meteoroid impact cratering. At steady state, it is calculated that, in the region within 10-50 m of the surface, a mixing rate of 10-4 to 10-5 mm/yr is necessary to match the exposure ages. Observed exposure ages of the lunar samples could be explained by the gardening effect calculated using a crater formation rate which is slightly modified from the current crater population data.
