TOPOGRAPHIC-COMPOSITIONAL UNITS ON THE MOON AND THE EARLY EVOLUTION OF THE LUNAR CRUST

The distribution of elevations on the moon determined by Clementine de viates strongly from a normal distribution, suggesting that several ge ologic processes have influenced the topography. The hypsograms for th e near side and far side of the moon are distinctly different, and the se differences correlate with differences in composition as determined by Apollo orbital geochemistry, Clementine global multispectral imagi ng, and groundbased spectroscopy. The hypsograms and compositional dat a indicate the presence of at least five compositional-altimetric unit s. The lack of fill of the South Pole-Aitken Basin by mare basalts sug gests poor production efficiency of mare basalt in the mantle of this area of the moon.