Abstract
Marine reservoir age is reported for Foxe Basin, Canada, during deglaciation of the Laurentide Ice Sheet. Radiocarbon ( 14 C) measurements were made on pairs of contemporaneous molluscs and Salix (willow) macrofossils, yielding a mean marine reservoir age of 985 ± 10 14 C a. Mean regional Δ R is calculated to be 615 ± 20 14 C a relative to a mean global reservoir age of ca. 400 14 C a. Previous studies in the Canadian Arctic that have been conducted on modern pre‐bomb molluscs give Δ R values of ca. 100–300 14 C a. The difference between modern and deglacial reservoir ages indicates that Δ R in Foxe Basin has changed over time, which has implications for the reconstruction of past events based on marine 14 C dates. We recalculate the timing of deglaciation of Hudson Strait with this new reservoir age and relate this to the 8.2 cal. ka event. We recommend that local Δ R be determined for the time period being examined whenever possible, and that in cases where this is impossible a Δ R value of 615 14 C a be applied when calibrating marine samples from Foxe Basin and vicinity during deglaciation. Copyright © 2010 John Wiley & Sons, Ltd.