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14C Calibration Curves for Modern Plant Material from Tropical Regions of South America

James R Ehleringer, John F Casale, Janet E Barnette, Xiaomei Xu, Michael J Lott, Janet Hurley

Abstract


Two Δ14C calibration curves have been produced that allow determination of the statistical average age of coca leaf and cocaine base specimens produced for the time period 1979–2009. These calibration curves are based on field collections of specimens in Bolivia, Colombia, Ecuador, and Peru. The coca leaf F14C and Δ14C calibration curves can be used to predict the ages of botanical tissues collected in tropical South America and possibly extended to other tropical locations. The cocaine F14C and Δ14C calibration curves can be used to predict the ages of seized cocaine specimens. Because the Δ14C of the atmosphere is diminishing, the precision of this approach for age determinations will continue to get less precise over time as atmospheric 14C content continues to decline.

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