Irina Evgenyevna Smirnova

The study of the mineralogical composition of sand (0,25-0,05 mm) and coarse silt (0,05-0,01 mm) fractions revealed a significant lithological heterogeneity of soil forming material on the territory of the Zvenigorod biostation. The predominance of ore minerals in the heavy fractions (up to 42% of the grains) and, to a lesser extent, hornblende and biotite, explains the ironing (significant presence of iron oxides, hydroxides) of the profiles and the brown color of sandy loam soils. This feature, along with the insignificant presence of the clay fraction, admit us to classify texturally undifferentiated soils as ferric-metamorphic soils, and more differentiated - as eluvial soils.