Radiocarbon dating is a technique that measures the concentration of naturally occurring radioactive carbon-14 (14C). The technique can date back to around 50,000 years ago and is commonly used by archaeologists as a dating tool. The main principle behind the technique is that all living things contain 14C in concentrations that are in equilibrium with their environment. When an organism dies, the amount of 14C begins to decay away at a known rate – after 5730 ± 40 years only half the amount of original 14C remains. Comparing the amount of 14C in a dead organism to modern levels gives us an estimate of when that organism died. Accelerator Mass Spectrometer (AMS) 14C dating is a recent advancement that enables us to date samples as small as a grain of rice (and sometimes smaller). This has the advantage of minimal damage to artwork and other artefacts.
The best way to establish the age of rock art is to combine radiocarbon dates with other dating evidence, such as stratigraphic sequences. AMS radiocarbon dating of carefully selected organic pigments, beeswax, excavated charcoal and compounds living above or below rock art (e.g. wasp nests) will provide a tight chronological framework for understanding the age and sequence of Jawoyn sites, artefacts and art styles. AMS radiocarbon dating of individual fragments of charcoal from excavated archaeological deposits, bone fragments from ritual sites and organic materials from pollen sequences will also be undertaken.
With all these sample types it is important that samples are screened and specialized pretreatments applied to ensure the accuracy of the dates. Research at the University of Waikato’s Radiocarbon Dating Laboratory in New Zealand has concentrated on the application of radiocarbon and chemical characterization techniques to improve the reliability of archaeological results and chronologies.
For more information on radiocarbon dating, see the Waikato Radiocarbon Dating Laboratory web page at http://www.radiocarbondating.com/.