Reliability of radiocarbon dating of pedogenic carbonate in the Australian arid zone

Abstract Radiocarbon dates from pedogenic carbonate in the southern Strzelecki Desert of South Australia are several thousand years too young, a conclusion contrary to previous work which suggested dates on such material were reasonably reliable within the semi-arid zone, or several thousand years too old in the arid zone. Multiple dates from the same horizon, and from carbonates in vertical sequence in the same exposure, were used to test the reliability of those dates. These revealed that there were reversals and inconsistencies along single horizons, and it was found that carbonate fragments in cores of nodules gave older dates; also some recrystallization of carbonate had taken place and more than one generation of micrite was present. Dates from soil carbonates in the arid zone are not reliable estimates of the age of pedogenesis, but can be useful if their limitations are recognized.