STATE OF IRON IN BROWN FOREST SOILS OF THE MIDDLE URALS BASED ON EVIDENCE OF NMR-SPECTROSCOPY AND MAGNETIC MEASUREMENTS

The magnetic properties (by the Faraday method) and the spectra of ori ginal and calcined samples of fine earth and clay from two profiles of brown forest soil in the middle Urals were studied. The iron content in the Tamm (Fe-o) and Mehra-Jackson (Fe-d) extracts was determined. I ron is present in the forms of silicate and roentgen-amorphous compoun ds constituting no less than 99% of the total iron content. The share of silicate iron constitutes 62-70% of the total iron in the fine eart h of profile I and 43-77% in profile 13. Its content in the clay fract ion is less than 50% of the total iron in profile 1, while it reaches 80% in profile 13. The soil horizons are differentiated by the content of iron compounds, being more closely related to the modern burozem ( brown forest soil) formation in the upper parts (composed of silty cla y loam) and determined by rock lithology (soil paleogenesis) in the lo wer parts (composed of sandstone with clayey interlayers in profile 1 and red-brown solifluction clay in profile 13).