Out of the woods: Driftwood insights into Holocene pan‐Arctic sea ice dynamics

Abstract

AbstractThe collation of 913 driftwood samples from across the western Arctic, with spatiotemporal distribution and available provenance data, enabled the production of a high‐resolution proxy‐based reconstruction of Holocene Arctic Ocean surface current and sea ice dynamics. Regionally bounded, driftwood‐based sea ice reconstructions studies suggest spatiotemporally complex past Arctic sea ice extent and movement; however, a large‐scale compilation of Holocene Arctic driftwood has not previously been developed. Sparse driftwood in the early Holocene (≥8.2 cal ka B.P.) deglacial period was followed by increased driftwood deposition in the warmer mid‐Holocene (8.2–4.2 cal ka B.P.); characterized by an enhanced Transpolar Drift (TPD) ∼7 cal ka B.P., leading to sea ice loss through the Fram Strait. Driftwood incursion peaks show spatial E‐W progression from the Eurasian Archipelagos to Greenland and the Canadian Arctic Archipelago, suggesting a progressive shift in the orientation of the TPD on centennial‐millennial time scales and intermediate phases in the Arctic Oscillation. Late Holocene cooling (≤4.2 cal ka B.P.) is indicated by increased influx of probably North American Picea via a strengthened Beaufort Gyre (BG) which enhanced sea ice recirculation, starting in the western Arctic and progressing eastward. In recent millennia (<2 cal ka B.P.), a more variable driftwood record alternates between BG and TPD dominance on centennial time scales. To further constrain a spatiotemporal reconstruction of variations in Holocene ocean current and sea ice dynamics, a more definitive determination of driftwood provenance is recommended to build upon the current framework, such as through radiogenic isotope tracing and aDNA analysis.