The Moon is composed of two major geologic provinces that have a unique origin, composition, and thermal evolution. The Procellarum KREEP Terrane is a large province on the near side of the Moon that has high abundances of KREEP. The Felspathic Highlands Terrane, in contrast is composed predominantly of ancient anorthositic materials. A third terrane, the South Pole–Aitken Terrane, may simply represent deep crustal materials of the feldspathic highlands terrane.