Rare earth distribution and its correlation with clay mineralogy in the clay-sized fraction of Cretaceous and Pliocene sediments (central Portugal)

Abstract

Abstract The REE contents in the clay-sized fractions of nineteen Cretaceous and Pliocene continental sediments, Portugal, were found to be correlated with kaolinite. No correlation is apparent between clay mineralogy and La/Lu or Eu/Sm ratios. The Eu anomaly is generally smaller (or even absent) in the clay-sized fraction than in the corresponding whole sediment, probably due to a greater ability of the clay minerals to accommodate Eu (as Eu 2+ ) rather than the other REE released during weathering.