1 |
By the campfire. Pyrotechnology and Middle Stone Age hearths at Sibudu CaveBentsen, Silje Evjenth 01 September 2014 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2014. / The Middle Stone Age rock shelter site Sibudu contains abundant evidence of pyrotechnology (the controlled use of fire) such as combustion features, ashy layers and lenses and burned bone. I study the use, reuse and discard of fire at Sibudu and the layers Brown/Grey mix and Brown under Yellow Ash 2(i) from the post-Howiesons Poort (post-HP) industry (c. 58 000 years BP) and the layers Pinkish Grey Sand and Pinkish Grey Sand 2 from the Howiesons Poort (HP) techno-tradition (c. 65 000 years BP) are selected for detailed studies. I describe properties of selected combustion features, such as size, form, number of hearth strata, contents (bone, charcoal and stone) and pH values. The post-HP combustion features generally contain a higher proportion of charcoal and are more acidic than the HP 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 and the second cycle of experiments burned Dichrostachys cinerea exclusively. Variables such as wood mass, topsoil horizon and number of sequential fires were carefully controlled. The surface and subsurface temperatures of the experimental fires were recorded. The experimental hearths were excavated using similar techniques as those used at Sibudu. Surface temperatures vary greatly even under similar environmental conditions, but subsurface temperatures are more predictable. Five kilograms of wood is 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 with charcoal, but experimental fires do not. Instead they produced 2 – 5 distinct strata, and long-burning fires produced more strata than short-burning ones. Experimental ash dumps lack strata. Areal extent of a hearth is
dependent on the wood mass burned, but its depth is dependent on the wood taxon burned.
I present spatial analysis of charcoal, bone and knapped stone from the selected Sibudu layers using Kernel density estimation. Higher densities of bone, charcoal and stone are present in the post-HP layers than in the HP. 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 than in the HP combustion features; this could be caused by different 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 I cannot explain this difference. Thus it is 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 surface temperatures of campfires. Amongst the experiments described here, experimental fires burning five 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 straight-forward 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.
|
2 |
Physico-chemical characterisation of a one hundred thousand year old ochre processing toolkit from Blombos Cave, South AfricaMphuthi, Dikeledi Salamina January 2016 (has links)
A Masters Dissertation submitted to the faculty of Science, University of the Witwatersrand in fulfillment of the requirements for the Masters` degree. Johannesburg 2016. / The Middle Stone Age (MSA) levels (c. 100 – 72 ka) (thousand years) at Blombos Cave, South Africa, contain buried remnants of human existence and their activities (these include ochre-stained shell beads, processed ochre pieces, bone tools, stone tools, and ochre processing toolkits). A preliminary study on the occupation layers at Blombos Cave was done in order to chemically and physically characterise the sediment deposits. The interpretation of the information preserved in these sediments, as a result of human activities, was achieved by using the following characterisation techniques: FT-IR, ICP-OES/MS, CHNS analysis as well as pH and EC measurements.
Fluctuations in the bio-essential trace elements (K, P, Mg, Ca, S, Fe, Al, Cr, Na, Cu and C) and in the markers of in situ burning (P, K, C, Ca and Mg) through the MSA levels suggested a non-contiunous anthropogenic occupation of the cave. Further, the dark coloured layers were indicative of periods when heavy human activities, such as fire use, were encoutered. These layers were characterised by high levels of P, K, C, Ca and Mg, also elevated pH and EC levels were observed. The calcite origin for these sediment deposits was confirmed to be pyrogenic. The layers found to contain large bone, ochre and shell densities (with no evidence of fire use) had high levels of Fe, P high Ca and low EC. The calcite origin for these sediment deposits was geogenic. Biogenic calcite was only observed in the more recent CA and CC layers.
Substantial amounts of ochre assemblages were recovered from the MSA levels at Blombos Cave. Among these was an ochre processing toolkit recovered from the CP layer (c.100 ka). Ochre is abundant in African archaeological sites after 165 ka and is likely to have played a symbolic role in the lives of prehistoric people. It contains an iron-oxide mineral as well as accessory minerals. When mixed with a binder (such as fat or water) ochre can be used as a pigment. A large number of fragmented bone remains were found in the M1 and M2 levels. It is suggested that the majority of the fragmentation occurred while the bones were in a fresh state; implying marrow extraction by the site occupants. The exploitation of bone
marrow was crucial in order to extract the fat and use it as a binder during the pigment production. Some of the broken and marrow-extracted bones were heated and used as fuel during seasons when wood was scarce while the other bones were deliberately engraved for symbolic intent.
The characterisation of the ochre processing toolkit was achieved by mineralogical analysis and elemental fingerprinting. FT-IR analysis revealed that the general matrix of the ochre samples comprised of hematite (Fe2O3) or goethite (α-FeO(OH)) as the main chromophores and clay minerals (such as kaolinite (Al2Si2O5(OH)4), muscovite [(KF)2(Al2O3)3(SiO2)6(H2O)] and illite [K(Al4Si2O9(OH)3)]), calcite (CaCO3) and quartz (SiO2) as the main accessory minerals. PXRD analysis confirmed Fe2O3, Al2Si2O5 (OH)4, [K(Al4Si2O9(OH)3)] and SiO2 to be the predominant mineral phases in the ochre, implying this specific type of ochre was preferred during the production of the pigment. Fe2O3 contributed the red hue and the aluminosilicates their clayey properties making them good extenders of the pigment.
Multivariate statistics and Fe ratios made it possible to identify elements important for differentiating the ochre recovered from the CP layer. Analysis of variance (ANOVA one-way) showed a statistically significant difference between the ochre residues in terms of trace elemental profiling. The variance suggested different geological origins for the ochre.
FT-IR was used as a screening technique for any organic residues associated with the toolkit and GC-MS was used to identify the preserved organic residues. These were mostly lipids and terpenes. The identified bio-molecular markers; stearic acid and dehydroabietic acid were exploited to give insight on the origin of the residues. Stearic acid suggested the use of animal fat while dehydroabietic acid implied the use of a resin (potentially as a binder in the pigment).
The characterisation investigations revealed that the prehistoric populations at Blombos Cave specifically sourced hematite and aluminosilicate- containing ochre pigments in order to fulfil their social and cultural demands. The MSA site
occupants’ chemical understanding of these materials suggested they were technologically advanced.
Keywords: Blombos Cave, MSA levels, ochre, mineralogical analysis and elemental fingerprinting. / LG2017
|
3 |
Temporal, spatial and structural analysis of LSA burials in the Western Cape province, South AfricaLazarides, Maria January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, August 2015. / Burials within the Western Cape provide a valuable opportunity to understand past social practices during the Later Stone Age. The aim of this dissertation is to specifically study Western Cape LSA burials in such a way as to understand the social and cognitive processes of hunter-gatherers in that region. In order to do this the burials will be approached and studied from a social and cultural perspective. This will include applying a theoretical approach which lends itself to materiality. Certain techniques will be employed to aid the study of this research question, such as a temporal, spatial and structural analysis of the Western Cape burials. Once the temporal analysis is done, certain sections within time can more closely be studied and analysed. The spatial analysis will examine the sites on a regional scale. The interpretative discussion will concentrate on specific patterns and structural aspects of the burials. The above may illuminate a possible array of questions to be asked surrounding the Western Cape burials. This in turn will help in aiding a discussion surrounding the cognitive and social processes of hunter-gatherers in the Western Cape.
|
Page generated in 0.0737 seconds