By the Campfire: Pyrotechnology and Middle Stone Age Hearths at Sibudu Cave.
University of the Witwatersrand, 2014.
The Middle Stone Age rockshelter site of Sibudu, South Africa, contains abundant evidence of pyrotechnology (the controlled use of fire) such as combustion features, ashy layers and lenses and burned bone. This thesis studied the use, reuse and discard of fire at
Sibudu and the layers Brown/Grey mix and Brown under Yellow Ash 2(i) from the postHowiesons Poort industry (c. 58,000 BP) and Pinkish Grey Sand and Pinkish Grey Sand 2 from the Howiesons Poort techno-tradition (c. 65,000 BP) were selected for detailed studies. The thesis describes the properties of selected combustion features, such as size, form, the number of hearth strata, contents (bone, charcoal and stone) and pH values. The post-Howiesons Poort combustion features generally contain a higher proportion of charcoal and are more acidic than the Howiesons Poort combustion features, suggesting post-depositional differences.
Twenty actualistic experiments including 39 experimental fires constitute the largest component and contribution of this thesis. The experiments were conducted in two cycles: the first cycle of experiments burned (in different fires) one each of the wood taxa
Casuarina equisetifolia, Dichrostachys cinerea, Eucalyptus globulus or Acacia erioloba, while the second cycle of experiments burned Dichrostachys cinerea exclusively.
Variables such as wood mass, topsoil horizon and the number of sequential fires were carefully controlled. The surface and sub-surface temperatures of the experimental fires were recorded. The experimental hearths were excavated using similar techniques to those used at Sibudu. Surface temperatures vary greatly even under similar environmental conditions, but sub-surface temperatures are more predictable. Five kilograms of wood are sufficient to produce high temperatures for several hours and slowly adding logs to a fire ensures even temperatures.
Sibudu’s hearths have a basal black layer, but experimental fires do not. Instead, they produced between two and five distinct strata, and long-burning fires produced more strata than short burning ones. Experimental ash dumps lack strata. The areal extent of a hearth is dependent upon the wood mass burned, but its depth is dependent upon the wood taxon burned. Using Kernel density estimation, a spatial analysis of charcoal, bone and knapped stone from the selected Sibudu layers is presented. Higher densities of bone, charcoal and stone are present in the post-Howiesons Poort layers than in those belonging to the Howiesons Poort. Specialist studies of wood taxa, micromorphology and organic petrology are also included. No specific firewood taxa were preferred, but herbaceous plants were burned at 65,000 years ago, suggesting short fires.
This thesis provides a foundation for future research on fire-related behaviour at Sibudu and other Middle Stone Age sites. For example, higher acidity was recorded in the post-HP
Azania: Archaeological Research in Africa, 2014
Vol. 50, No. 1, 147–153 than in the HP combustion features; this could be caused by differential diagenesis and geoarchaeological studies need to be conducted to resolve the issue. In addition, all the primarily deposited archaeological combustion features in this study were underlain by a basal black layer rich in charcoal, but such layers did not develop in the experimental combustion features and this difference cannot currently be explained. It is thus necessary to conduct more studies of the variables affecting the formation and preservation of combustion features. One aspect to study experimentally is the range of attributes controlling the surface temperatures of campfires. Among the experiments described here, experimental fires burning 5 kg wood produced maximum surface temperatures in the range of 132–848°C, which demonstrates that surface temperatures are unpredictable. The implication is that producing particular temperatures of a fire is not straightforward and that prehistoric fire users needed planning abilities and a thorough knowledge of pyrotechnology. Both these skills require mental abilities like those of modern people and they also require a sophisticated understanding of environmental conditions.
This work was supported by a grant from PAST - Palaeontological Scientific Trust and their
Scatterlings of Africa programme.
Silje Evjenth Bentsen
Evolutionary Studies Institute, University of the Witwatersrand
Johannesburg, South Africa
Silje.Bentsen@wits.ac.za © 2014, Silje Evjenth Bentsen
Pointed Bone Tool Technology in Southern Africa. University of Johannesburg, 2014. http://dx.doi.org/10.1080/0067270X.2014.993222
Stone Age societies are understood largely in terms of their technology. The way in which we frame our research and understanding of these past societies is based almost exclusively on stone tools and ceramics, yet these materials represent only a small percentage of recent hunter-gatherer paraphernalia and may not necessarily reflect the complexity of cultural adaptations and technological achievements of the past. Pointed bone tools are present in the archaeological record of almost every ancient society and time-period; yet, for various reasons, they have seldom been afforded the same attention as their stone equivalents. Unless all aspects of past technological systems are acknowledged and understood we risk providing a distorted image of the past.
This thesis begins to explore the variable and diverse functions of pointed bone artefacts in southern Africa during the Later Stone Age from approximately 18,000 years ago until a few hundred years ago when the hunter-gatherer societies practising a Stone Age economy came under the influence of immigrant Iron Age farmers. A comprehensive study of bone tools has the potential to provide information about past societies that is simply not available from stone tools and ceramics. This thesis looks at one aspect of past technology, namely pointed bone tools, that has seldom formed the focus of research. It presents the results of a metrical analysis and three use-trace analyses (micro-residue, use-wear and macrofracture), each designed to provide complementary information about the past function/s of pointed bone tools. Over 300 tools are examined from 12 archaeological sites. 148 PhD Abstracts