The freshwater reservoir and radiocarbon dates on cooking residues: Old apparent ages or a single outlier? Comments on Fischer and Heinemeier (2003)

Fischer and Heinemeier (2003) present a hypothesis that the freshwater reservoir effect produces old apparent ages for radiocarbon dates run on charred cooking residues in regions where fossil carbon is present in groundwater. The hypothesis is based in part on their analysis of dates on charred cooking residues from 3 inland archaeological sites in Denmark in relation to contextual dates from those sites on other materials. A critical assessment of the dates from these sites suggests that rather than a pattern of old apparent dates, there is a single outlying date-not sufficient evidence on which to build a case for the freshwater reservoir effect.