Identifying taxa from highly degraded shell micro-fragments in anthropogenic soils from Waterfall Bluff, South Africa
- 1Max Planck Institute for the Science of Human History, Jena, Germany (annetteoertle@gmail.com)
- 2Pre-Construct Archaeology, Cambridge, UK
- 3Department of Chemistry, Nelson Mandela University, Port Elizabeth, South Africa
- 4Geophysics and Remote Sensing Unit, Council for Geoscience, Cape Town, South Africa
- 5African Centre for Coastal Palaeoscience, Nelson Mandela University, Port Elizabeth, South Africa
- 6ERAAUB. Dept. Història I Arqueologia, Universitat de Barcelona, Barcelona, Spain
- 7Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
- 8African Centre for Coastal Palaeoscience, Nelson Mandela University, Port Elizabeth, South Africa
- 9Department of Anthropology, New York University, New York, USA
- 10Palaeo-Research Institute, University of Johannesburg, Johannesburg, South Africa
- 11Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, USA
- 12Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
- 13Interdisciplinary Center for Archaeology and Evolution of Human Behaviour (ICArEHB), Universidade do Algarve, Faro, Portugal
Archaeomalacological analysis is generally undertaken on recovered macro-remains to characterize the overall composition of faunal remains in a deposit. Given the susceptibility of shell middens to a variety of taphonomic processes, it is assumed that the prior presence of shell in deposits may therefore occasionally be missed. Deteriorated micro-remains can mix indistinguishably into surrounding sediments and make their analyses and identification difficult, particularly in older deposits and in environments that experience rapid rates of weathering. This paper explores whether microscopic remains of deteriorated molluscs can be distinguished from other microscopic remains at the coastal rock shelter site of Waterfall Bluff in Mpondoland, South Africa. The methodology uses a multi-scalar approach integrating shell mineralogy and microstructure using the taxonomic distinctiveness of these features. The diagnostic features (e.g. morphology, hinges, spires, and apertures) used for identifying macro-remains are absent in micro-remains, therefore unique methods of identification are needed to identify these microscopic mollusc fragments. Through mineralogical analyses and scanning electron microscope (SEM) imaging, the nacreous remains of mussel shell were identified from previously unidentified degraded shell remains as well as sediment samples from Waterfall Bluff. These highly degraded remains were located under the dripline in the oldest deposits (LBCS) which are sharply comparable to the more well-preserved macro mollusc evidence in the younger (SRCS) deposits. These methods recovered ‘invisible’ evidence of shellfish remains, which led to additional and clearer evidence of continued coastal foraging from Marine Isotope Stage 3 to the early Holocene (40 ka to 10 ka) on the South African coast.
How to cite: Oertle, A., Szabó, K., Gaqa, S., Cawthra, H., Esteban, I., Pargeter, J., and Fisher, E.: Identifying taxa from highly degraded shell micro-fragments in anthropogenic soils from Waterfall Bluff, South Africa, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4341, https://doi.org/10.5194/egusphere-egu22-4341, 2022.
