Some erroneous radiocarbon dates of lacustrine sediments

Abstract

In some cases radiocarbon dating of both the NaOH soluble fraction and the insoluble fractionof lacustine sediments give different ages as a result of dating errors : (1) the insoluble fraction is too old, due probably to contamination by old inactive carbon, either bedrock-derived graphite or carbonate; (2) the soluble part is also too old, due probably to hard-water effect or contamination by redeposited interstadial organic carbon.