ENVIRONMENTAL OF LAKE SEDIMENT FORMATION IN THE SOUTH-WESTERN PART OF THE MURMANSK REGION IN THE HOLOCENE
To reconstruct the environmental in the Late and Post-Glacial period was carried out study of the bottom sediments of several lakes in the south-western part of the Murmansk region. The sediments of 6 lake basins located at elevations from 102.0 m to 136.4 m above sea level were studied. A detailed lithological description and photo documentation of complete sections of lakes were carried out, samples for diatom, granulometric analyses and radiocarbon dating were taken. Sediment horizons with and without hydrotroillite, as well as with Fe-Mn concretion, have been found within Lake Girvas. The formation of such horizons is associated with certain physico-chemical conditions that depend on the hydrological regime in the basin and climate change. In the area of Upoloksha, horizons of disturbed sediments have been found in sections of some lakes. The area of their occurrence is limited according to lithological data from several lakes.