Slide 9 of 50

(Note this is indicated by the size-frequency crater distribution, the number of craters as a function of size. This is discussed in Wayne Spencer's ICC 1994 paper on the origin of the solar system as well as other researchers.) [See R.A.F. Grieve, and M.R. Dence, The Terrestrial Cratering Record, II, the crater production rate, Icarus, Vol. 38, 1979, pp 230-242.]