Uranium-series and radiocarbon dating of speleothems – methods and limitations

Abstract

¹⁴C ages of speleothems are usually younger than the Uranium-Series ages. The difference is often explained by changes of atmospheric radiocarbon concentration in the past, and in fact, speleothems have been used as a material for radiocarbon time scale calibration. However in other works large spread of data points has been obtained. Comparison with the ¹⁴C calibration data suggests that many ¹⁴C of speleothems ages are too young or the Uranium-Series ages too old. ¹⁴C dates of speleothems are commonly treated with caution, because of the reservoir effect, producing an apparent age, which is usually not accurately known. However, the reservoir effect may be of minor importance when compared to contamination with younger carbon.