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

Abstract

The 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.

Short communication: Driftwood provides reliable chronological markers in Arctic coastal deposits

“…Age control on Holocene driftwood is commonly obtained by radiocarbon ( 14 C) dating and the reported uncalibrated ages may have uncertainties in the order of decades to centuries (e.g. Funder et al, 2010;Hole and Macias-Fauria, 2017). Modern AMS facilities, however, can provide substantially lower methodological dating uncertainties (Wacker et al, 2010;Nixon et al, 2016;Mason et al, 2020;Fig.…”

A driftwood-based record of Arctic sea ice during the last 500 years from northern Svalbard reveals sea ice dynamics in the Arctic Ocean and Arctic peripheral seas

“…are being increasingly examined for their impact on ocean circulation and sea ice dynamics (e.g. Barnes & Screen, 2015;Comiso & Hall, 2014;Ding et al, 2017;Hole & Macias-Fauria, 2017;Rigor et al, 2002). Data on past conditions are needed to understand the region's abiotic and biotic responses to various climatic processes and forcings and their resulting impacts on a global scale (Dieckmann & Hellmer, 2010;Armand et al, 2017).…”

“…These involve lateral shifts from a) an eastward route toward Fram Strait, with sea ice (and any driftwood entrained in it) advection to the European Arctic; b) a westward route toward Greenland with sea ice advection to the Canadian Arctic Archipelago (CAA); and c) a split route with sea ice transport divided between the east and west. A driftwood-based reconstruction of the dynamics of Holocene sea ice extent and dynamics shows that there has been a progression from millennial to centennial shifts in the relative position of the TPD and BG throughout the Holocene, with indications of alignment with concurrent dynamics of the AO (Hole & Macias-Fauria, 2017). The AO Index is characterised as the variable atmospheric mass exchange between the Arctic Ocean and temperate latitudes (Rigor et al, 2002), with positive or negative polarity determined by anomalies in Sea Level Pressures (SLPs) over the polar regions and mid-latitudes (c. 55°-60°N; Kwok et al, 2013).…”

“…All rights reserved. Fauria (2017), including evidence of late Holocene centennial fluctuations in AO index polarity and ocean circulation patterns.…”

“…Deposits of driftwood on Arctic shorelines reveal the transport by sea ice within large-scale Arctic Ocean circulations, which enables the reconstruction of past surface-current dynamics and sea ice conditions in the Arctic (Häggblom, 1982;Dyke et al, 1997;Funder et al, 2011;Hole & Macias-Fauria, 2017). Up to now, driftwood-inferred sea ice conditions have not been directly compared with the observational record.…”