Impact of the freshwater reservoir effect on the radiocarbon dating of shells from the lower and Central Murray River

Since the 1950s, archaeological research conducted along the lower and central Murray River, on Ngintait, Latji Latji, Barkandji, Yorta Yorta, and Ngaiawang Countries, has relied on radiocarbon dating of freshwater mollusc shell to help confirm the chronology of human occupation in this region as well as support larger models of human occupation timing in Australia. The popularity of freshwater mollusc shell for radiocarbon dating in this region is partially due to the prevalence of shell in a variety of Aboriginal cultural sites. However, radiocarbon dating of freshwater organisms, such as molluscs, is complex as the carbon reservoir of the water bodies in which they live may differ from atmospheric values. Therefore, radiocarbon dates which do not consider this freshwater reservoir effect may be inaccurate. While Gillespie and colleagues (2009) investigated the freshwater reservoir effect in the Murray-Darling Basin around Willandra Lakes World Heritage Area, the effect present in the Murray River has yet to be explored. Therefore, this research analysed historically live-collected freshwater mussel samples collected from Ngintait, Latji Latji, Barkandji, Yorta Yorta, and Ngaiawang Countries, near Mildura (VIC), Echuca (VIC), and Morgan (SA), to establish a freshwater reservoir effect for the lower and central Murray River. We also dated modern water and freshwater shell samples from across this region to better understand the source of this offset. The calculated average offset of approximately 136-56 years will have an impact on chronologically recent sites and improve overall precision. These results will help us improve chronologies in the region and better understand the important relationship between people, molluscs, and Country. © The Authors

Keywords

Fresh water, Carbon 14, Shells, Rivers, Australia, Archaeological sites, Molluscs, Cultural objects

Citation

Stringer, C., Prendergast, A., Garvey, J., May., J.-H., & Levchenko, V. (2024). Impact of the freshwater reservoir effect on the radiocarbon dating of shells from the lower and Central Murray River. Poster presentation to the Australian Archaeological Association Annual Conference 2024, Cairns, Queensland, 3-6 December 2024. In AAA 2024 Sharing Archaeological Narratives Abstract Booklet, (pp. 114). Retrieved from: https://www.aaaconference.com.au/2024/wp-content/uploads/2024/11/AbstractBooklet.pdf

URI

https://apo.ansto.gov.au/handle/10238/16103

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