A Holocene Record of Changing Arctic Ocean Ice Drift Analogous to the Effects of the Arctic Oscillation

The Arctic Oscillation (AO) controls the configuration of the Transpolar Drift (TPD). If thicker ice from the Beaufort Gyre were exported, the volume of fresh water/sea ice in the Nordic seas would significantly increase, decreasing the formation of North Atlantic deep water. This would cool large parts of the Northern Hemisphere and affect global climate. Therefore, in order to understand how the global climate system functions, it is imperative to know how the TPD changed over the last millennium or more. The provenance of grains in a sediment core located near the confluence of the TPD and the Beaufort Gyre provides a direct proxy for changes in seaice drift owing to these circulation systems. The core has more than 200 cm of Holocene sediment, with intervals dominated by grains from the Russian shelves alternating with intervals of abundant grains from North American sources. Grains matched to Russian shelves indicate that the TPD was shifted toward North America, similar to what occurs during a more positive phase of the AO. This condition alternated with intervals where few grains matched to Russian sources, presumably because the TPD was restricted to the Russian half of the Arctic, far from the core site. During the last 1300 years, increased influx of Russian grains occurred approximately every 50-150 years. This fluctuation might represent the long-term oscillation of the AO, which modulates the same TPD shift today