KREEP

KREEP, an acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks.

As the crystallization of this liquid rock proceeded, minerals such as olivine and pyroxene precipitated and sank to the bottom to form the lunar mantle.

However, the measurements from the gamma-ray spectrometer on-board this satellite showed that the KREEP-containing rocks are primarily concentrated underneath the Oceanus Procellarum and the Mare Imbrium.

The enhancement of heat-producing radioactive elements within the crust (and/or the mantle) of the Procellarum KREEP Terrane is almost certainly responsible for the longevity and intensity of mare volcanism on the nearside of the Moon.

Potassium and phosphorus are important for plant growth (NPK fertilizer is used on earth) whereas uranium and thorium are potential fuels for nuclear power.