Lunar terrane
A lunar terrane is a major geological province on the Moon. Three terranes have been identified on the Moon: the Procellarum KREEP Terrane, the Feldspathic Highlands Terrane, and the South Pole–Aitken Terrane. Each terrane has a unique origin, composition, and thermal evolution. Procellarum KREEP Terrane The Procellarum KREEP Terrane, or PKT, is a large province on the near side of the Moon that has high abundances of KREEP. KREEP is an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), and is a geochemical component of some lunar impact breccia and basaltic rocks. Notably, it is high in the KREEP element thorium, at a level of 4.8 ppm. This is a major factor distinguishing it from the other terranes. The PKT is on the near side of the moon, and covers 10% of the lunar surface, or 16% if one includes the maria lying within the FHT. Despite this, it contains 60% of all basaltic flows. KREEP has been shown to lower the melting point of rocks similar to those found on the Moon, and is expected to have contributed to volcanism in the region. The Oceanus Procellarum and Mare Imbrium