Rare-earth distribution patterns in eight terrestrial materials

Abstract

The rare-earth element contents and relative abundances in a phosphorite, two coals, a composite mixture of sea shells, two corals, and two carbonatites have been determined by neutron activation analysis. The abundance distribution patterns in the phosphorites and calcareous marine materials are close to that of well-differentiated sediments. The coals are extra-abundant in Eu and depleted in the heavier and lighter lanthanides, relative to sediments. The distributions in the carbonatites resemble each other, but vary quite markedly from the sediment pattern, as is characteristic of most other materials with igneous origins. Considerable latitude was found in the rare-earth element concentrations. The La content of the phosphorite was 160 ppm; of the coals 4·9 and 3·3 ppm; of the shells and corals 0·13, 0·08 and 0·052 ppm; and of the carbonatites 181 and 76 ppm.