ИСТИНА

The case study object is a small U-shaped dry valley (balka in Russian) with the catchment area 32.8 ha and the length of 400 m located in the middle part of the river Protva basin, 100 km to the southwest from Moscow. The sampling was performed from topsoil horizons along three cross-sections and additionally along the bottom of the landform and its detrital fan. In total 50 samples were collected from various tlandform’s geomorphic units and analyzed for Mn, Cu, Ni, Co, Cr, Zn, Pb, Ti, Zr, Fe contents. 11 samples were chosen for physical fractionation into 5 grain-size fractions (1-0.25mm, 0.25-0.05mm, 0.05-0.01mm, 0.01-0.001mm and <0.001mm) with their further analysis for the metals’ contents. Across the grain-size fractions the maximum Zr content was observed in the coarse silt fraction and Ti − in the medium and fine silt fraction, while other metals, such as Fe, Mn, Co, Ni, Cr, Pb, Zn, revealed the highest concentrations in the clay fraction. For Fe, Mn, Co and Ni the second concentration peak was observed in the coarse and medium sand fraction. Due to probably eolian genesis and(or) the transformation during weathering, the coarse silt fraction in comparison to other fractions showed the depletion of the majority of metals while the minimum concentrations of Ti, Zr and Cr were limited to the coarse and medium sand.