Rare-earth elemental systematics of mixed-layered illite-smectite from sedimentary and hydrothermal environments of the Western Carpathians (Slovakia)

The mixed-layers illite-smectite of the shales yield a narrow span of total REE abundances from 17.3 to 36.5 μg/g, compared to those of the associated bentonites, from 1.20 to 93.7 μg/g, of the same basin. These differences result from varied origins of the original REE-carriers. The Eu anomaly relates to alteration of the authigenic minerals in the sedimentary bentonites acting as a closed system, or to the chemistry of the percolating hot fluids in the Dolná Ves hydrothermal deposit. The data also indicate that no-detectable zircon, apatite, monazite, or any other REE-carrier occurred in the size fractions, at least in the finest, and if any, these minerals had no significant impact on the REE contents and distribution patterns of the varied analyzed size fractions consisting mainly if not exclusively of mixed-layered illite-smectite.