ГЕОХИМИЯ ФОСФОРА В ОСАДКАХ ПРЕСНОВОДНЫХ ОЗЕР СЕВЕРО-ВОСТОКА РОССИИ

The phosphorus distribution in lake sediments, deluvium deposits, and bedrock was investigated. In deluvium deposits formed by acidic and basic rocks, phosphorus, like iron and manganese, is concentrated in fine grain-size fractions. The main supply of phosphorus to lake basins is associated with detrital material input from the catchment area. In bottom samples from the surface layer of lakes, as well as in deluvial sediments, fine clay sediments in deep parts of basins are enriched in phosphorus. Zones with high concentrations of P2O5, Fe2O3, MnO, and sometimes CaO have been identified in lake sections. The zones are characterized by an accumulation of vivianite. It is assumed that phosphorus was also sorbed by iron hydroxides, iron-manganese aggregates, and clay minerals. Peaks in phosphorus concentrations are observed in sediments of both cold and warm climatic stages.