LANTHANUM, CERIUM, SAMARIUM, AND EUROPIUM IN THE FOREST STEPPE SOILS OF THE VOLGA UPLAND

The content and distribution of lanthanum, cerium, samarium, and europ ium in the main soil groups of the Volga Upland are studied. The main factor responsible for the differentiation of these elements within a single physiographic region is the lithogeochemistry of the parent mat erial. All the examined elements participate in sorption and humus acc umulation, and samarium and lanthanum are involved in eluvial-illuvial redistribution. Soil formation leads to the convergence of these elem ents in soils on different parent materials.