Marine radiocarbon reservoir corrections for the mid- to late Holocene in the eastern subpolar North Atlantic

The time dependency of the regional difference DeltaR in the marine radiocarbon reservoir correction is an important issue for the calibration of marine radiocarbon ages and also provides information about past ocean circulation changes, Few measurements of Holocene reservoir corrections are available for the climatically important North Atlantic. We determined DeltaR for intervals during the past 6100 years before present (BP) by comparing radiocarbon ages of 31 marine and terrestrial sample pairs from 14 archaeological sites from the coast of Ireland, Scotland and the Orkney Islands. We find that, while a time dependency in DeltaR for this region cannot be ruled out, within the error of the determinations, the DeltaR appears, to have been constant for at least the last 2000 and possibly the last 6000 years. This work results in a recommendation for DeltaR of -33 +/- 93 for the region.