KREEP

Thorium concentrations on the Moon, as mapped by Lunar Prospector. Thorium correlates with the location of 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. Its most significant feature is somewhat enhanced concentration of a majority of so-called "incompatible" elements[1] (those that are concentrated in the liquid phase during magma crystallization) and the heat-producing elements, namely radioactive uranium, thorium, and potassium (due to presence of the radioactive 40K).[2]

  1. ^ Taylor, G. Jeffrey (August 31, 2000). "A New Moon for the Twenty-First Century". Planetary Science Research Discoveries. University of Hawaii. Retrieved August 11, 2009.
  2. ^ Shearer, Charles K.; Hess, Paul C.; Wieczorek, Mark A.; et al. (2006). "Thermal and Magmatic Evolution of the Moon". Reviews in Mineralogy and Geochemistry. 60 (1). Mineralogical Society of America and Geochemical Society: 365–518. Bibcode:2006RvMG...60..365S. doi:10.2138/rmg.2006.60.4. Retrieved August 11, 2009.