Grain Size Properties of Surface Bottom Sediments from the Chaun Bay

Based on the results of analysis of 174 samples of bottom sediments collected at 48 stations in the Chaun Bay during the 60th cruise of R/V “Academic Oparin” (October 2020), it was found that their particle size composition varies from poorly sorted silty clay to good sorted sand. The results of the study led to conclude that the main sedimentation mechanisms in the Chaun Bay are thermoabrasion, riverine runoff and abrasion, as well as ice and aeolian transport. The zoning of grain size types of the bottom sediments is related to the bottom topography and consistent with areas affected by river discharge, abrasion and thermoabrasion, as well as with the direction of currents. High occurrence of coarse clastic matter in sediments indicates abrasion of the coastal zone and active ice transport of large (up to 15 cm) rock fragments. The vertical variability of the granulometric parameters of the studied bottom sediments within the upper 20 cm layer reflects gradual Late Holocene intensification of terrigenous (fluvial and thermoabrasion) fluxes under the current climate changes in the Arctic.