  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 (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). ==typical composition== the typical composition of kreep includes about one percent, by mass, of potassium and phosphorus oxides, 20 to 25 parts per million of rubidium, and a concentration of the element lanthanum that is 300 to 350 times the concentrations found in carbonaceous chondrites. ==possible origin== indirectly, it has been deduced that the origin of kreep is contained in the origin of the moon. this is now commonly thought to be the result of a rocky object
Lunar_science Mineralogy