Map of the Moon (left: nearside; right: farside), generated from gamma-spectrometric data collected by the Lunar Prospector vessel. The map shows the global distribution of the element Thorium in surface rocks, with high Thorium concentrations indicating the occurence of the so-called KREEP rocks, which have high contents in Potassium, Rare Earth Elements and Phosphorus. The heterogeneous distribution of KREEP rocks at the moon’s surface implies fundamentally different geological histories of the individual lunar regions (terranes). For further information see Jolliff et al. (2000).^[1]

1. ↑ Bradley Jolliff, Jeffrey Gillis, Larry Haskin, Randy Korotev, and Mark Wieczorek (2000): Major lunar crustal terranes: Surface expressions and crust-mantle origins. Journal of Geophysical Research. 105(E2): 4197–4216, doi:10.1029/1999JE001103.