Scientific publications

The article presents the results of the first comprehensive study of the content of the main elements and the particle-size composition of sediments in six small lakes (Karhu, Pityevoe, Poropellon, Skorbeevskoe, Krainee, Lohi) located on the Rybachy and Sredny peninsulas in the northern part of the Murmansk Region (Arctic zone of the Russian Federation). The results show that SiO₂ prevails among the main elements in precipitation (41.4–59.7 %). This, together with data on the loss on ignition (7.2–35.2 %), characterizes the deposits as organosiliceous. The amount of SiO2 in sediments corresponds to its content in land rocks entering the reservoir during coastal abrasion and weathering. The mechanical destruction of rocks of the catchment area and subsequent sedimentation occurred in a cold humid climate, as confirmed by the estimates of the chemical weathering index, the hydrolysate modulus, and the titanium modulus. Sediments of lakes Krainee, Skorbeevskoye and Lohi are shown to be associated with argillaceous shale, the composition of sediments of lakes Poropellon and Karhu aligns with hydrousmica pelite, and Lake Pityevoe sediments are similar to hydrous-mica clay. The concentrations of Al₂O₃, K₂O , and Na₂O in most of the studied lakes grow with sampling depth, which is due to an increase in the proportion of silt particles (<0.05–0.005 mm). The sediments in general are mainly represented by psammites (1–0.05 mm), pointing to a sandy type of sedimentation. The study highlights the role of the geomorphological features of lakes, lithological composition of rocks in the catchment area, and their weathering conditions in shaping the particle-size and geochemical composition of bottom sediments in small Arctic lakes.