Composition of Late Holocene Deposits in the Southern Chukchi Sea

Abstract—The objective of the work was a comprehensive study of Late Holocene bottom sediments from the southern Chukchi Sea and reconstruction of their accumulation conditions. Analytical methods included macroscopic description with smear slides, ²¹⁰Pb dating of sediments, determination of biogenic components, magnetic susceptibility measurements, and grain size distribution, palynological, and mineral analyses. The modern sedimentation rate established at the study point is 8–10 mm/year. Sediments are mainly represented by silts. In the upper part of the core, there are elevated concentrations of SiO_2biog, C_org, and N_tot and decreased magnetic susceptibility values. This is probably due to the increased bioproductivity of the Chukchi Sea in recent years, caused by current climate warming. The palynological composition of the studied deposits reflects the tundra and forest–tundra vegetation on land adjacent to the Chukchi Sea. The presence of Neogene pollen in Late Holocene sediments is evidence of their transfer from eroded ancient sediments.