New knowledge of Holocene hydroclimate and freshwater availability at Murujuga

Extensive rock art engravings and archaeological evidence of human occupation are documented around waterholes at Murujuga, highlighting their cultural significance and importance as sources of freshwater. Frequently, these waterholes have thick deposits of tufa (carbonate): evidence of the past environment and climatic conditions under which the carbonate precipitated. Here we discuss how we have refined our knowledge of the hydrology and water permanence of the waterholes at Murujuga using tufa as geo-archives of environmental and hydroclimatic change over time. Rainfall, surface water levels and geochemistry demonstrate that some waterholes are long-lasting (semi-permanent) and fed by perched seepage after large recharge events: other ephemeral waterholes evaporate quickly after rainfall events. Semi-permanent waterholes on Murujuga’s islands would be important for supporting humans as well as plant and animal life. The formation of tufa is dependent on moderate to large rainfall events that recharge the landscape and can generate significant surface water flows and allow for precipitation of calcium carbonate. Radiocarbon ages of Murujuga tufas range from 0.5 to 9.7 cal ka BP and constrain tufa formation to the Holocene. The initiation of tufa formation in the early- to mid-Holocene coincides with changing hydroclimatic conditions, following sea level rise and formation of the archipelago since the Last Glacial Maximum. Further insights from stable isotope and geochemical data from tufa will enhance our knowledge of hydroclimatic variability throughout the Holocene. This tufa palaeoenvironmental proxy record allows us to understand at what times during the Holocene water resources were abundant or sparse, meaning we can better contextualise the archaeological record at Murujuga. © The Authors

Keywords

Quaternary Period, Fresh water, Archaeological sites, Carbonates, Climates, Rain, Geochemistry, Western Australia, Carbon 14, Stable isotopes

Citation

Mather, C., Tucker, M., Leopold, M., Levchenko, V., Skrzypek, G., O'Leary, M., McDonald, J. (2024). New knowledge of Holocene hydroclimate and freshwater availability at Murujuga. Presentation to the Australian Archaeological Association Annual Conference 2024, Cairns, Queensland, 3-6 December 2024. In AAA 2024 Sharing Archaeological Narratives Abstract Booklet, (pp. 71). Retrieved from: https://www.aaaconference.com.au/2024/wp-content/uploads/2024/11/AbstractBooklet.pdf

URI

https://apo.ansto.gov.au/handle/10238/16105

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