Chronologies for recent peat deposits using wiggle-matched radiocarbon ages: problems with old carbon contamination

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Chronologies for recent peat deposits using wiggle-matched radiocarbon ages: problems with old carbon contamination

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dc.contributor.author Charman, Dan, J en_GB
dc.contributor.author Garnett, Mark, H en_GB
dc.date.accessioned 2010-04-20T13:47:37Z en_GB
dc.date.accessioned 2011-01-25T10:39:05Z en_US
dc.date.accessioned 2013-03-20T14:30:43Z
dc.date.issued 2005 en_GB
dc.description.abstract 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 14C 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 14C 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 CO2 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-14C relationship and the 14C minima in the calibration curve could still be identified. These were tested against other age estimates (210Pb, 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. en_GB
dc.identifier.citation Radiocarbon, 2005, 47 (1): pp. 135-145 en_GB
dc.identifier.uri http://hdl.handle.net/10036/96909 en_GB
dc.language.iso en en_GB
dc.publisher University of Arizona en_GB
dc.relation.url http://www.radiocarbon.org/ en_GB
dc.subject wiggle-matched en_GB
dc.subject radiocarbon ages en_GB
dc.subject peat en_GB
dc.subject carbon contamination en_GB
dc.title Chronologies for recent peat deposits using wiggle-matched radiocarbon ages: problems with old carbon contamination en_GB
dc.type Article en_GB
dc.date.available 2010-04-20T13:47:37Z en_GB
dc.date.available 2011-01-25T10:39:05Z en_US
dc.date.available 2013-03-20T14:30:43Z
dc.identifier.issn 0033-8222 en_GB
dc.description Reproduced with permission of the publisher. © 2005 by the Arizona Board of Regents of behalf of the University of Arizona. en_GB
dc.identifier.journal Radiocarbon en_GB


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