Potential pitfalls of pollen dating

Type Article
Date 2013
Language English
Author(s) Neulieb Thomas1, 2, Levac Elisabeth1, 2, 3, Southon John4, Lewis Michael5, Pendea I. Florin6, Chmura Gail L.1, 2
Affiliation(s) 1 : McGill Univ, Dept Geog, Montreal, PQ H3A 0B9, Canada.
2 : McGill Univ, Global Environm & Climate Change Ctr, Montreal, PQ H3A 0B9, Canada.
3 : Bishops Univ, Dept Environm Studies, Sherbrooke, PQ J1M 1Z7, Canada.
4 : Univ Calif Irvine, Earth Syst Sci Dept, Irvine, CA 92697 USA.
5 : Geol Survey Canada Atlantic, Nat Resources Canada, Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada.
6 : Lakehead Univ, Dept Interdisciplinary Studies, Orillia, ON L3V 0B9, Canada.
Meeting Proceedings of the 21st International Radiocarbon Conference edited by A J T Jull & C Hatté
Source Radiocarbon (0033-8222) (Univ Arizona Dept Geosciences), 2013 , Vol. 55 , N. 2-3 , P. 1142-1155
DOI 10.2458/azu_js_rc.55.16274
WOS© Times Cited 12
Abstract Pollen extracted from ocean and wetland sediments cored from the eastern Canadian Margin, James Bay region, and Atlantic provinces of Canada have been radiocarbon dated and results are reported here. Pollen dates from ocean sediments were compared with marine carbonate (mollusk shells or foraminifera) dates from the same core levels, dates for which validity was assessed via correlations with other cores, and for which reworking has been excluded. Pollen samples from 3 tidal wetlands were taken from levels dated with Cs-137 and Pb-210 profiles. Pollen dates from 2 additional wetlands were compared with C-14 dates of botanical macrofossils. Most pollen dates disagree with C-14 dates based on macrofossils or carbonates, with age differences typically exceeding 250 yr and reaching 4000 yr in one instance. In some cores, pollen dates show age reversals. Significant proportions of reworked pollen grains in ocean and wetland samples are associated with pollen dates that are too old. Prolonged core storage could result in pollen C-14 ages that are too young, possibly because of growth of fungi or other microbes, but more work is needed to verify this hypothesis. Despite the problems we encountered, some pollen dates are consistent with other C-14 dates from the same core levels, suggesting this dating method can work, but at present, more work is needed to understand the conflicting results obtained.
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