Marine radiocarbon reservoir effects for the Mesolithic and Medieval Periods in the Western Isles of Scotland

Ascough, P. L. , Church, M. J. and Cook, G. T. (2017) Marine radiocarbon reservoir effects for the Mesolithic and Medieval Periods in the Western Isles of Scotland. Radiocarbon, 59(1), pp. 17-31. (doi: 10.1017/RDC.2016.99)

Abstract

This article presents new values for the Scottish marine radiocarbon reservoir effect (MRE) during the Mesolithic at 4540–4240 BC (6490–6190 BP) and the Medieval period at AD 1460–1630 (490–320 BP). The results give a ΔR of –126±39 14C yr for the Mesolithic and of –130±36 14C yr for the Medieval. We recalculate previously published MRE values for the earlier Holocene in this region, at 6480–6290 BC (8430–8180 BP). Here, MRE values are slightly elevated, with a ΔR of 64±41 14C yr, possibly relating to the 8.2ka BP cold event. New values for the Mesolithic and Medieval indicate lower MRE values, broadly consistent with an existing data set of 37 mid- to late Holocene assessments for Scottish waters, indicating stable ocean conditions. We compare the intercept and probability density function (PDF) methods for assessing ΔR. The ΔR values are indistinguishable, but confidence intervals are slightly larger with the PDF method. We therefore apply this more conservative method to calculate ΔR. The MRE values presented fill important gaps in understanding Scottish marine 14C dynamics, providing confidence when calibrating material from critical periods in Scotland’s prehistory, particularly the Mesolithic, when the use of marine resources by coastal populations was high.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cook, Professor Gordon and Ascough, Dr Philippa
• Authors: Ascough, P. L., Church, M. J., and Cook, G. T.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Radiocarbon
• Publisher: Cambridge University Press
• ISSN: 0033-8222
• ISSN (Online): 1945-5755
• Published Online: 28 December 2016
• Copyright Holders: Copyright © 2016 Cambridge University Press
• First Published: First published in Radiocarbon 59(1):17-31
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher