Hi,
I recently cores a site in the Snowy Mountains in Australia and got AMS dating done on three depths (51, 61, 67 cm). 51 cm and 61 cm came out with what I would think of as normal ages, as in 757 +-16 for 51 cm and 591+-18 for 61 cm. However, the sample at 67 cm came back as 114.7 +- 0.3%, which I found means it has a percentage of modern carbon in it(not sure how to explain it exactly). When I looked this up it was suggested that I put it into the modern carbon function of Rbacon pMC.Age to get a 'real age'. Rbacon pumped out -1102 +- 21, then they packed up and called it a night, leaving me to wonder what exactly that number means. My guess is that I should subtract it from 1950, giving me the age 848. I've talked to others who said this is completely wrong and I have no room to dispute that. Could someone give me a definitive answer on what to do with this type of data?
Thanks!
Mark
Hi Mark
Your radiocarbon measurement 114.7 +- 0.3% pMC calibrates to cal AD 1816-1830 (32% probability) or cal AD 1893-1922 (63% probability).
I would exclude it from your age-depth model as the sample is clearly modern and must have been contaminated.
Peter
You can use the Oxcal program for date calibration. For the correct interpretation of the results, it is advisable that you personally study the articles on dating stratigraphic columns in Radiocarbon magazine. This reading will lead you to understand how organic matter moves through the earth's layers and how this phenomenon modifies its apparent age. Once you understand the phenomenon, you can apply it to your research.
44/5000
Check the links before using OxCal
https://www.hic.ch.ntu.edu.tw/AMS/A%20guide%20to%20radiocarbon%20units%20and%20calculations.pdf
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/B026333C73B2E92AE90F2BA774CF2081/S0033822200033154a.pdf/discussion_reporting_and_calibration_of_postbomb_14c_data.pdf
before you use OxCal
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