La
Lanthanum is one of many chemical elements that geochemists
call "incompatible elements." Others that commonly appear
in reports of rock analyses are Y, Zr, Nb, Ce, Pr, Nd, Sm, Gd,
Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Th, and U. Incompatible elements
tend to be in higher concentrations in Earth rocks than in meteorites.
Among meteorites, only some from the Moon have concentrations
in the range of typical terrestrial igneous rocks.
See Notes,
Caveats, and References