A comparison of the first results of a comprehensive micropaleontological analysis (pollen, spores, organic-walled microfossils, diatoms, ostracods) and radiocarbon ages (AMS14C) from sediment core recovered in the northeastern outer shelf of the Laptev Sea (51 m water depth) revealed a temporal coincidence between terrestrial and marine environmental changes that occurred between 11.2–10.3 cal ka. This interval provided evidence for a landscape transition from grass tundra to shrub tundra and the development of a freshwater estuarine basin with the strong influence of riverine discharge and a minor advection of North Atlantic waters. The establishment of a warmer and wetter climate promoted the expansion of shrub tundra habitats. The interval of 9.5–7.5 cal ka recorded a transition from a shrub tundra environment to forest-tundra vegetation. This interval also revealed a series of short-term temperature fluctuations, when summer temperatures were 3–4°C higher than today. The active advection of North Atlantic waters and the increase in salinity were also recorded by this interval.