A new approach to the calculation of the cratering rate of the Earth over the last 125 ± 20 Myr

Abstract

The recent cratering record of the surface of the Earth is re-examined using a new technique that concentrates on estimating the mean areas occupied by individual craters, together with the gradients of linear plots of crater numbers versus crater ages. This analysis indicates that the lower limit of the rate at which craters have been produced over the last 125±20 Myr is, for example, (12.0±0.7)×10−15 km−2 yr−1 for D ⩾ 2.4 km craters, (9.5±0.6)×10−15 km−2 yr−1 for D ⩾ 5.0 km craters, (6.5±0.5)×10−15 km−2 yr−1 for D ⩾ 12 km craters, and (3.0±0.3)×10−15 km−2 yr−1 for D ⩾ 22 km craters. These figures indicate that previous researchers have considerably overestimated the rate at which small (2.4<D<20 km) craters are being produced. It is also found that the relationship between crater production rate and crater diameter is not a simple power law in the 2.4<D<40 km diameter range. On the most stable areas of the Earth's continents, and over the last 125±20 Myr it seems that the rate at which craters are eroded below the detection limit does not depend on crater diameter throughout the above size range.