Topographic-compositional units on the moon and the early evolution of the lunar crust.

The distribution of elevations on the moon determined by Clementine deviates strongly from a normal distribution, suggesting that several geologic processes have influenced the topography. The hypsograms for the near side and far side of the moon are distinctly different, and these differences correlate with differences in composition as determined by Apollo orbital geochemistry, Clementine global multispectral imaging, and ground-based spectroscopy. The hypsograms and compositional data indicate the presence of at least five compositional-altimetric units. The lack of fill of the South Pole-Aitken Basin by mare basalts suggests poor production efficiency of mare basalt in the mantle of this area of the moon.