Oral Presentation Freshwater Sciences 2023

Environmental change and fire management over 50,000 years in a freshwater spring in the Central Queensland Coast (#24)

Seadín Gallagher 1
  1. University of Queensland, Brisbane, QUEENSLAND, Australia

The Pleistocene and Holocene palaeoenvironments of Australia have undergone considerable amounts of change. Not only did Indigenous Australians adapt to these changes, but they in turn had active roles in modifying and maintaining their landscape. Detailed palaeoenvironmental records are vital in understanding this relationship but are largely lacking in many regions of Australia. One such region is the Central Queensland coast. Despite the archaeological work that has so far been conducted in this area, past interactions between Indigenous Australians and the palaeoenvironment remain poorly understood, particularly in terms of freshwater springs.

Abercorn Springs is a freshwater spring mound of the Great Artesian Basin. A 5m peat core was taken from the mound, and the extracted record is one of the few known paleoenvironmental sequences from the region, and with a basal date of almost 50,000 BP is the oldest Quaternary sequence in inland Central Queensland Coast. Using a multi-proxy approach including pollen, phytoliths, charcoal, and XRF analyses, this presentation explores the relationship between humans, fire, and freshwater systems. Several charcoal peaks throughout the core demonstrate continued human interactions with the landscape, with modifications for a more open environment and maintenance of grasslands, starting from perhaps c. 40,000 BP. An extended dry period appears to match with propositions of an extended Last Glacial Maximum (LGM), dating to ~30,000 BP. Post-LGM, the site’s surroundings changing from a lake to a wetland. Environmental and floral variability is high throughout, with a marked difference in the record post European contact, likely due to the cessation of Indigenous fire management and the degradation of the spring by European pastoral practices. Abercorn Springs demonstrates human agency on past environments, the interactions with freshwater springs, and a temporal scale demonstrating how this relationship has changed through time and through important changes in climate such as the LGM.