Rare Earth Elements in Soils of the Central Forest State Nature Biosphere Reserve

The total content of rare earth elements (REEs) and the content of their oxalate-soluble fraction were studied in four soil profiles (Gleyic Umbrisols, Albic Gleyic Folic Retisols (Raptic), Dystric Albic Retisol) of the Central Forest Nature Reserve. The REE content was normalized to a local standard (the Russian Platform clay), and the cerium and europium anomalies were quantified [ 8 ]. In addition to the initial redistribution of REEs during the formation of rocks, REEs in the studied soils undergo geochemical fractionation, which results in the depletion of soil horizons of heavy lanthanides and europium. The negative europium anomaly is maximal in eluvial horizons and is weaker or absent in organic horizons. The oxalate-soluble REE fraction affects the redistribution of heavy lanthanides and cerium in the studied soils, and also results in the development of a positive cerium anomaly in some horizons.