Geochemistry of Titanium in Lake Sediments of the Russian Far East

The element distribution was analyzed in the surface bottom sediments of the lakes of the Kuril archipelago (Maloe and Pernatoe lakes), Magadan district (Grand, Chernoe, Chistoe, Bezymyanka, Chukcha, Ui, and Forel lakes), and Chukotka (Lake Elgygytgyn). The distribution of TiO2, SiO2/TiO2, Al2O3/TiO2, and Fe2O3/TiO2 in the sediments of the lakes depends on the size of deluvium fractions and composition of bedrocks and reflect sedimentation conditions. The SiO2/TiO2 ratio and the SiO2 content show simultaneous variations throughout cores, which are indicative of biogenic silica accumulation and productivity of basins. The Al2O3/TiO2 ratio is an indicator of grain-size composition, with lower values for fine sediments. The peaks of Fe2O3/TiO2 and TiO2 values are in some cases an indicator of chemogenic iron accumulation. These levels may indicate the presence of autigenic iron-bearing minerals.