Geoarchaeological and chronological investigations of combustion features at Lake Mungo, NSW

Lake Mungo is home to some of the earliest and most significant archaeological sites in Australia and contains a sedimentary archive that charts environmental change throughout the Willandra Lakes Region. This thesis sets out to provide a methodological approach to integrate the archaeological and environmental record of Lake Mungo. This study had 3 aims: to assess the stratigraphic integrity of these hearth features using soil micromorphology and Fourier transform infrared (FTIR) spectroscopy; to integrate these archaeological traces into the wider landscape by analysing the stratigraphic record of a gully system located in the southern end of the lunette; and finally to provide chronological context using optically stimulated luminescence (OSL) dating. A total of 8 stratigraphic units were identified that range in age from 65 ± 4 to 19 ± 1 ka ago. Although parallels could be drawn between these units with the classic units of previous studies at Lake Mungo, some variation was found to exist. One major variation was found in the sedimentary composition of SU4 (~34–26 ka), which showed micromorpholgical evidence at odds with the suggested high lake levels of previous work. Micromorphological analysis and FTIR spectroscopy of the sediments from the two combustion features showed evidence of both anthropogenic rake out and dumping, and geogenic reworking via aeolian activity. Furthermore, the presence of a disconformity surface above the combusted materials in both sediment blocks implicates the integrity of unburnt archaeological materials from above this surface. OSL age estimates from both combustion features place the formation of these features with the SU6 depositional phase (~23–20 ka). Structures observed in thin section from the combustion and sediment blocks along with wider palaeoenvironmental indicators pointed towards a harsh, cold and windy environment during this time. Further experimental and empirical work into identifying in situ combustion features is required to fully realise the potential of FTIR in this sphere. However, the use of micromorphology was shown to be invaluable in assessing the association between combustion features and the associated archaeological materials, without which would otherwise be considered to be spatially and temporally secure. The techniques outlined in this thesis ultimately provide a geoanalytical framework to support on-going archaeological investigations of the Lake Mungo lunette.