Fig. 1

a The Apollo (denoted as A) and Luna (denoted as L) sampling sites on the Moon. The base image is the global mosaic of the Moon that is obtained by the Lunar Orbiter missions and the Clementine spacecraft (59 m/pixel; equirectangular projection). b Crater size-frequency distributions at difference-aged lunar surfaces can be aligned after a same polynomial function. The labels of the counting areas can be read from the original plot in Neukum et al. (1975). c Calibration points used to construct the lunar crater chronology function (Stöffler et al. 2006). d Examples of isochrones of crater size-frequency distribution on different-aged lunar surfaces. The production and chronology functions are based on those proposed by Neukum et al. (2001)