‘An Ear to the Ground’: Fish Otolith Geochemistry, Environmental Conditions and Human Eccupation at Lake Mungo

21st April 2013

Kelsie E. Long

BA(Hons), School of Archaeology and Anthropology in conjunction with the Research School of Earth Sciences, The Australian National University, October 2012

Fish otoliths are calcium carbonate structures that form within the inner ear of teleost fish. They are usually employed in archaeological studies as indicators of human diet and resource use. Recently, however, they have been investigated for their geochemical properties and how these can be used for dating and as palaeoenvironmental indicators. This study analyses the geochemical composition of otoliths collected from a series of hearth sites at Lake Mungo in the Willandra Lakes World Heritage Area of New South Wales. Radiocarbon and amino acid racemisation were tested as methods of dating the otoliths. Oxygen isotope, strontium isotope and elemental abundance ratios were measured across the banded growth lines in order to assess the use of otoliths as high resolution recorders of past environmental conditions and to identify fish migration. Fish otoliths from the same hearth site are assumed to have been killed and eaten at the same time, a theory which is backed up by radiocarbon dating and the similarities of geochemical assays. Difficulties in identifying age lines and associating each with the sampled areas caused slight offsets in the dataset. Nevertheless, evaporative trends experienced by fish were able to be identified as were potential points of migration and seasonal temperature fluctuations. Otoliths are an ideal tool for multidisciplinary research providing links between their internal geochemical records, the archaeology of the hearth sites and the geology of the surrounding sediment layer.

Kelsie E. Long
‘An ear to the ground’: Fish otolith geochemistry, environmental conditions and human occupation at Lake Mungo
June 2013
Thesis Abstracts
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