Chronologies for Recent Peat Deposits Using Wiggle-Matched Radiocarbon Ages

Problems with Old Carbon Contamination

Bibliographic Data

ID9244608
AuthorsDan J Charman, Mark H Garnett
Year2005
Volume47
Issue1
Pages135-145
Publication date2005-01-01
Open AccessYes
TypeARTICLE
VenueRadiocarbon (JOURNAL)
Journal identifiersISSN: 0033-8222 • E-ISSN: 1945-5755
PublisherCambridge University Press (CUP) (PUBLISHER)
DOI10.1017/s0033822200052255
OpenAlexW155508180
LanguageEN
Citations received11
References cited24

Dating sediments which have accumulated over the last few hundred years is critical to the calibration of longer-term paleoclimate records with instrumental climate data. We attempted to use wiggle-matched radiocarbon ages to date 2 peat profiles from northern England which have high-resolution records of paleomoisture variability over the last ∼300 yr. A total of 65 14 C accelerator mass spectrometry (AMS) measurements were made on 33 macrofossil samples. A number of the age estimates were older than expected and some of the oldest ages occurred in the upper parts of the sequence, which had been dated to the late 19th and early 20th century using other techniques. We suggest that the older 14 C ages are the result of contamination by industrial pollution. Based on counts of spheroidal carbonaceous particles (SCPs), the potential aging effect for SCP carbon was calculated and shown to be appreciable for samples from the early 20th century. Ages corrected for this effect were still too old in some cases, which could be a result of fossil CO 2 fixation, non-SCP particulate carbon, contamination due to imperfect cleaning of samples, or the “reservoir effect” from fixation of fossil carbon emanating from deeper peat layers. Wiggle matches based on the overall shape of the depth- 14 C relationship and the 14 C minima in the calibration curve could still be identified. These were tested against other age estimates ( 210 Pb, pollen, and SCPs) to provide new age-depth models for the profiles. New approaches are needed to measure the impact of industrially derived carbon on recent sediment ages to provide more secure chronologies over the last few hundred years

Accelerator mass spectrometry · Archaeology · Carbon fibers · Chronology · Climate change · Geochronology · Geography · Geomorphology · Holocene · Macrofossil · Paleoclimatology · Peat · Physical geography · Radiocarbon dating · Snow · Coastal wetland ecosystem dynamics · Environmental Science · Geological formations and processes · Geology and Paleoclimatology Research · Geology · Oceanography · Paleontology

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