Published online by Cambridge University Press: 20 January 2017
AMS radiocarbon dates were obtained from Salix herbacea leaves, Carex seeds, and bulk organic detritus from a lake sediment profile of Wisconsinan (Weichselian) Lateglacial age in SW Ireland. There is a systematic age difference between the dated series from the two types of macrofossils, with ages obtained from Salix herbacea leaves being 900 to 1500 14C years younger than those obtained from Carex seeds. The latter tend to be more in accord with dates from the total organic detritus in the lake sediment, although the bulk organic fraction invariably registered the older ages. Intact survival of the fragile Salix leaves indicates that they are unlikely to have been physically transferred within the sediment matrix and/or otherwise reworked from the surrounding catchment. Hence, these macrofossils are the more likely to be contemporaneous with the time of deposition. However, there is no significant correlation between measured 14C age and depth in the Salix values, which scatter over a range of 700 14C years. In contrast, the age/depth relationship for Carex shows a significant reversal, possibly reflecting the redeposition of these macrofossils, and therefore giving radiocarbon ages that are anomalously old. The data have important implications for the dating of lake sediment sequences by AMS radiocarbon measurement of terrestrial plant macrofossils.
To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.