Faculty of Science

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Osteopathology and insect traces in the Australopithecus africanus skeleton StW 431
(Academy of Science of South Africa (ASSAf), 2017-01) Zipfel, B.; Jakata, K.; Bonney, H.; Odes, E.J.; Parkinson, A.H.; Randolph-Quinney, P.S.; Berger, L.R.
We present the first application of high-resolution micro computed tomography in an analysis of both the internal and external morphology of the lumbar region of StW 431 - a hominin skeleton recovered from Member 4 infill of the Sterkfontein Caves (South Africa) in 1987. The lumbar vertebrae of the individual present a number of proliferative and erosive bony processes, which were investigated in this study. Investigations suggest a complex history of taphonomic alteration to pre-existing spinal degenerative joint disease (SDJD) as well as post-mortem modification by an unknown insect. This study is in agreement with previous pathological diagnoses of SDJD which affected StW 431 and is the first time insect traces on this hominin are described. The results of this analysis attest to the complex series of post-mortem processes affecting the Sterkfontein site and its fossil assemblages.
Attenuation of pollution arising from acid mine drainage by a natural wetland on the Witwatersrand
(Academy of Science of South Africa (ASSAf), 2017-01) Humphries, M.S.; McCarthy, T.S.; Pillay, L.
Wetlands are well known to be efficient at sequestering pollutants from contaminated water. We investigated metal accumulation in the peats of the Klip River, a natural wetland that has received contaminated water from gold mining operations in Johannesburg for over 130 years. Previous work conducted in the downstream portion identified the wetland as an important system for sequestering metals. We focused on the upstream section of the wetland, more proximal to the source of acid mine drainage, to provide a better understanding of the pollutant sources and the role of the wetland in pollutant attenuation. Geochemical and mineralogical analyses of peat cores revealed considerable metal enrichments in the peat ash, particularly in Co, Ni, Zn, Pb, Cu and U. Metal concentrations are typically between 4 to 8 times higher than those previously reported for the downstream, more distal portion of the wetland. The distribution of metal accumulation within the peat profiles suggests that contamination arises from a combination of sources and processes. Elevated concentrations in the shallow peat are attributed to the input of contaminated surface water via tributaries that drain the Central Rand Goldfield, whereas enrichments in the deeper peat suggest significant sub-surface inflow of contaminated water through the underlying dolomitic rocks. Metal immobilisation occurs through a combination of mechanisms, which include the precipitation of gypsum, metal sulfides, Fe-Mn oxyhydroxides and phosphates. Our study highlights the environmental and economic importance of natural wetland systems which have the ability to accumulate large quantities of metals and thus remediate polluted waters.
An Acheulean handaxe from Gladysvale Cave site, Gauteng, South Africa.
(Academy of Science of South Africa (ASSAf), 2006-03) Hall, G.; Pickering, R.; Lacruz, R.; Hancox, J.; Berger, L.R.; Schmid, P.
WE DESCRIBE A SINGLE HANDAXE FROM fossiliferous breccias at Gladysvale Cave, South Africa. The artefact is the only known tool so far discovered during the controlled excavations conducted at this site over the last decade, and was recovered from decalcified sediments near the stratigraphic interface of two breccia units, making it difficult to assign it with confidence to either. The morphology of the handaxe indicates a middle-late Acheulean industry, and preliminary electron spin resonance and palaeomagnetic dating suggest an age of greater than 780 000 years.
A study of inter-analyst variability in the classification of stone-walled structures in southern Gauteng, South Africa
(2013-04-18) MacRoberts, Rebecca
The study of stone-walled structures within the last 1000 years in southern Africa can help archaeologists to understand how the landscape was peopled. Google Earth and GIS can make data capture easier, but when diferent analysts are involved, there can be significant variability in their results. By comparing data classified by three researchers in the same study area, it was possible to quantify inter-analyst variability and to query where and why it occured. The quality of Google Earth imagery had much influence in introducing inter-analyst variability. Subjective decisions on classification also introduced high amounts of variability. With more intensive training on classification and better imagery, inter-analyst variability can be reduced.

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