Browsing by Author "Sealy, Judith"

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    A study of indigenous sorghum agriculture in Southern Africa: combining isotope and indigenous knowledge systems approaches
    (2023) Masemula, Nandi; Sealy, Judith
    Sorghum and millets were the principal grain crops of sub-Saharan African farming societies. Enquiry into their isotopic variability is scant and some of the work that has been done is based on studies in highly controlled, artificial environments. To help fill this gap, the present study investigates the variation in δ13C and δ15N in three varieties of sorghum, mshalane, 236 and 308. These were cultivated at four localities in different regions of Eswatini and South Africa, either by small-scale traditional farmers or in accordance with their methods. In addition, this study includes carbon and nitrogen isotopic analysis of archaeological sorghum grains from the mid-19th century Historic Cave siege site. The study also explores the impact that choice of agricultural practices and methods of grain storage and food preparation may have on the δ13C and δ15N values of sorghum. To this end, semi-structured interviews were conducted with 18 contemporary small-scale agriculturalists from eastern Eswatini. The range of δ13C values in the contemporary-grown sorghum from summerrainfall regions of South Africa is 1.7‰ (n=90), and the mshalane variety shows the greatest sensitivity to environmental variation. Archaeological sorghum grains from Historic Cave yield δ13C values approximately 1.1‰ less negative than contemporary-grown sorghum (after correction for variation in atmospheric δ13C), which likely reflects particular agricultural practices and/or the cultivation of sorghum varieties with characteristically higher δ13C values by the Kekana Ndebele. The range of δ15N values in both contemporary (5.4‰, n=90) and archaeological (8.7‰, n=11) sorghum is larger than that usually attributed to a single trophic level, with significant implications for the interpretation of δ15N in consumers. Some methods of sorghum storage and preparation involve fermentation, which may increase isotopic variation further. These results will contribute towards achieving improved isotope-based dietary reconstructions in African Iron Age farming communities.
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    Annals of ivory : perspectives on African elephant Loxodonta africana (Blumenbach 1797) feeding ecology from a multi-decadal record.
    (2008) Codron, Jacqueline; Lee-Thorp, Julia A; Sealy, Judith
    This thesis explores the dietary responses of African elephants (Loxodonta africana) to environmental change by testing the hypothesis that diet switching (from predominantly browse-based to more grass-rich diets) is driven by cyclical patterns of climate and habitat change in a southern African savanna. Elephants are thought to have substantial impacts on their environments, primarily because they consume large amounts of vegetation over sustained periods. However, the woody plant composition of their diet varies considerably across space and through time, so that in some instances they have been found to be almost pure grazers. Tracking these changes by traditional approaches (e.g. field observations) is difficult because of the geographical and temporal constraints inherent to these methods. Stable light isotope tracking of diet allows diet switching to be studied over multiple space/time scales. Here, I use stable isotope data from elephant faeces, tail hair, and ivory to record short- (monthly), medium- (seasonal to annual), and long-term (decadal) ecological variability, respectively, of elephant diets in the Kruger National Park, South Africa. Results from faeces collected at monthly resolution for one year confirm findings of a previous study (based on biannually-collected samples over two years) that elephants generally consume more grass in the more wooded habitats of the northern Kruger Park, but that there is a greater degree of seasonal diet switching in southern Kruger Park habitats. Moreover, diet changes also relate to changes in underlying bedrock across Kruger Park. Isotopic time-series produced by serial profiling of tail hairs confirm patterns observed in faeces. Long-term diet histories of individuals are derived from serial isotope sampling of ivory, yielding records that represent several decades of an animal’s life, at sub-annual (seasonal) resolution. Overlaying individual ivory series in time produces the first, to my knowledge, multidecadal record of African elephant diet, dating from 1903 to 1993. Contrary to expectations, stable carbon, nitrogen, and oxygen isotope records from ivory do not correlate well with cyclical climate trends for the study region. Rather, pronounced diet shifts are observed during extreme climatic events (floods and droughts), and the greatest levels of intra- and inter-annual variability coincide with significant changes in park management policy during the 20th century, i.e. the introduction of water provision programs after the mid 1930s, and the onset of elephant population control in 1967. It is proposed that such direct intervention has played the biggest role in disturbance of elephant-plant equilibria during the 20th century, and further studies to improve our understanding of this phenomenon will be instrumental to development of appropriate management strategies for the 21st century.
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    Antiquity of stone-walled tidal fish traps on the Cape coast South African
    (2010) Hine, Phillip James; Sealy, Judith; Halkett, David; Hart, Tim
    This paper attempts to answer a long-standing question in South African archaeology: the age of stone-walled tidal fish traps generally believed to date back to pre-colonial times. Since the stone walls cannot be directly dated, we sought datable fish bone in nearby archaeological sites. Four open shell middens at Paapkuil Fontein, near Cape Agulhas, were excavated and analysed and the contents of two previously excavated middens at Still Bay were studied. Both areas are renowned for their numerous fish traps, but lack detailed archaeological studies. The middens yielded very little, if any fish bone, so are probably unrelated to the traps. There is, by contrast, a great deal of archival evidence for the building and use of stone fish traps by historical communities, with traps repeatedly built and dismantled in the late 19th and 20th centuries. Given the lack of any direct evidence in Later Stone Age sites, a pre-colonial age for the practice of fishing with stone-walled tidal fish traps can no longer be entertained.
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    The archaeology of the coastal desert of Namaqualand, South Africa : a regional synthesis
    (2007) Dewar, Genevieve Isabel; Sealy, Judith
    The purpose of this thesis was to study human adaptation in a desert environment during the Later Stone Age. Nine open-air sites from the coastal desert of Namaqualand, South Africa were excavated and analysed with the focus on identifying settlement patterns and subsistence strategies within the context of a desert environment. Using radiocarbon dates and palaeoenvironmental indices, it was noted that most occupation of the region is linked to periods that were cooler and wetter than today. There is more evidence for occupation after the mid-Holocene warm phase, although there is a notable dearth of sites dating to the Medieval Warm Epoch, and a significant increase during the Little Ice Age. Using faunal and stable isotope analysis, it was found that people ate mixed diets that included both marine and terrestrial species; there is little evidence of heavy reliance on marine food as documented elsewhere along the South African coastline in the late Holocene. The overwhelming dominance of short-stay sites with limited ranges of artefacts suggest that settlement patterns were very mobile, with the paucity of water as a potential catalyst. While people from other areas dealt with increasing population pressure in recent millennia by becoming more sedentary and perhaps utilising delayed-returns strategies, there is little evidence to suggest that the carrying capacity of Namaqualand was being tested. In addition, this region has been suggested as one of the points of entry for pastoralism and pottery into South Africa. There is, however, no evidence for substantial changes in economy or material culture in the last 2000 years, so these items probably arrived at the Namaqualand coast through diffusion rather than migration. In addition, this research has, for the first time, identified special-purpose sites where people mass harvested springbok (Antidorcas marsupia/is), African penguins (Spheniscus demersus) and angulate tortoises (Chersina angulata). There is also evidence for intentional human hunting/collecting of micromammals, so that humans should be included in the classification system developed by Andrews (1990) as a category 5 predator. Finally, the locations of a prehistoric Cape fur seal (Arctocephalus pusillus) rookery and an African penguin hatchery were identified, which will be of value to long-term ecological studies.
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    Assessment and improvement of current sex estimation standards for application in Holocene San and Khoekhoe populations
    (2022) Malek, Sadiyah; Gibbon, Victoria; Sealy, Judith
    Skeletal sex estimation is important in biological anthropology. Population-specific sex estimation standards do not exist for southern African Holocene San and Khoekhoe (HS-K) population. Due to their markedly small stature, skeletal gracility, and physically active lifestyle, they exhibit reduced sexual dimorphism. In this study I aimed to assess the accuracy of current sex estimation methods, and to optimise the assessed methods for population-specific application in the HS-K population. Seven morphological traits (cranial and mandibular) and six metrical parameters (mandibular, humeral, and femoral) were analysed in 175 adult HS-K skeletons. Accuracy was determined by comparison with pelvic sex estimates. Results were analysed using chi-squared tests, univariate statistics, and cross-validated discriminant function analysis. Trait/parameter preservation rates were assessed and reported: Of the traits, supra-orbital margin and glabella were best preserved (90% and 88% respectively), and mandibular shape least (71%). Of the metrical parameters assessed, femoral and humeral vertical head diameters (FVHD and HVHD) were best preserved (89% and 80% respectively), and bicondylar breadth (BB) least (44%). The highest sex classification accuracies obtained were for mastoid process (73%) and mandibular shape (72%), whilst the lowest were for mental eminence (53%) and nuchal crest (53%). Following categorisation by pelvic sex, the highest accuracies in females were for nuchal crest (98%) and mental eminence (95%), and in males, mandibular shape (80%) and gonial eversion/flaring (81%), illustrating differential sexual dimorphic expression for certain traits. All six metrical parameters were sexually dimorphic, with dimensions of FVHD and HVHD being the most discriminatory. The highest discriminant function accuracy for a single measurement (univariate) was 75% for FVHD, and for combined measurements (multivariate) were 77% for direct combination of BB, FVHD and HVHD, and 73% for stepwise combination of FVHD and HVHD. Whilst all traits/parameters assessed were sexually dimorphic, they produced lower accuracy rates than in other populations. This confirms that the range of sexual dimorphism exhibited by the HS-K does not conform to existing standards, illustrating the need for methodological adjustments. This study identified the most accurate areas to target for sex estimation in the HS-K and generated the first population-specific discriminant functions for sex estimation with known accuracies.
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    Capitalizing on the Potential of South African Indigenous Beef Cattle Breeds: A Review
    (2021-04-15) Van Marle-Köster, Este; Visser, Carina; Sealy, Judith; Frantz, Laurent
    Cattle populations arrived in Southern Africa almost 2000 years ago, brought by farming communities migrating southwards. For centuries, cattle have been an integral component of livestock production to meet the animal protein needs of a growing population and they are also important in many cultural and religious events, as repositories of wealth and signifiers of social status. Selection within these cattle populations led to the development of breeds such as the Nguni, Afrikaner and Drakensberger that are well adapted to the local production environment. Genetic information has been generated for most of these populations, providing new insights into their ancestry and indicating moderate levels of diversity and relatively low inbreeding. Indigenous cattle breeds are present in both the well-developed commercial sector as well as the developing South African livestock sector. These breeds have been included in several research studies, mostly focusing on their production and adaptive potential. Genetic improvement of the local cattle populations and breeds, which are often more resilient to local environmental conditions, has the potential to improve the productivity of the small-scale production developing sector and contribute to the alleviation of poverty.
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    Cobern Street burial ground : investigating the identity and life histories of the underclass of eighteenth century Cape Town
    (1999) Cox, Glenda; Sealy, Judith
    The Cobern Street site was shown to be a burial ground only in 1994, when a number of skeletons were disinterred prior to building operations. Attempts to locate documentary records of the burials have been unsuccessful, and we do not know who these people were. The lack of documentary records is unusual, and suggests that Cobern Street may have been the burial ground for lower-class citizens. From the history of the site, and the few items buried with the bodies, we can deduce that they are eighteenth century burials. As part of the investigation into the identity of these people five techniques of dietary tracing have been applied to 53 of the excavated skeletons, and are reported in this thesis. Analysis of different skeletal elements has allowed us to reconstruct the life histories of some of these people. Of particular interest are several skeletons with filed teeth. This practice is not known from the Cape, but is common further north in Africa. Isotopic analysis of teeth and long bones from the skeletons with decorated teeth show that these individuals were of tropical origin, from diverse areas, and are likely to be slaves brought to the Cape.
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    A comparison of hunter-gatherer material culture from Matjes River Rock Shelter and Nelson Bay Cave
    (2005) Ludwig, Ben; Sealy, Judith
    This thesis investigates whether or not there is a material cultural expression of the economic (and by inference, social) difference seen in the stable isotope values of human skeletons from Robberg/Plettenberg Bay and Matjes River Rock Shelter between 4500 and 2000 B.P. After 2000 B.P. the introduction of pastoral subsistence in the area changed existing modes of production in such a way as to alter Ձ15N values. The two major excavated archaeological sites in this region are Nelson Bay Cave and Matjes River Rock Shelter, which lie only 15 kilometres apart. For this thesis, previously published descriptions of the artefact assemblages from these two sites were studied, and selected categories of artefacts were re-examined. More original work was necessary on the Matjes River collection, due to the poor quality of previous reports. The thesis focuses on the Wilton and pre-ceramic post-Wilton. In general, the same types of artefacts were found at both sites, but a number of types that were common in Layer C (i.e. in the Wilton) at Matjes River were not a feature of the Wilton levels at Nelson Bay Cave, although they became common in the post-Wilton. Backed scrapers were much more common in the Wilton levels of Matjes River than in any levels at Nelson Bay Cave, and chalcedony was more strongly favoured. Stone sinkers and perforated turtle carapace were present at Nelson Bay but were very rare at Matjes River. Several of the differences noted are not readily explained in terms of different functions or activities at the two sites. The contrast in the proportions of backed scrapers is best understood in terms of different traditions of artefact manufacture. Similarly, differences between the two sites in highly visible decorative items such as shell pendants are likely related to the negotiation of group or personal identity. These differences are consistent with a territorial separation between the groups that occupied the two sites, as postulated on the basis of the isotopic evidence.
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    Dental morphology and variation across holocene Khoesan people of Southern Africa
    (2014) Black, Wendy; Ackermann, Rebecca Rogers; Sealy, Judith
    Dental analyses of the Holocene Khoesan populations of southern Africa can provide insight into the biological evolution of an anthropologically important people. There have been many studies of dental variation in Holocene populations of Europe and the Americas, but few of African populations. Despite the Khoesan being the focus of much osteological research over the last two decades, their dental morphology is understudied and we know little about their dental evolution. Here, I assess the metric and non-metric dental morphology and variation of Holocene Khoesan individuals across southern Africa (N=487). Due to the fragmentary nature of many archaeological skeletons, most previous work on Khoesan osteology has focused on the second half of the Holocene, because more recent skeletons tend to be better preserved. There are, however, relatively abundant and well-preserved dental remains from the early Holocene. These are studied in detail for the first time in this dissertation, adding to our understanding of the emergence of Holocene Khoesan dentition and providing insight into phenotypic (and presumably genetic) continuity in this region. In addition to examining similarities/differences among the Khoesan through space and time, comparisons are made between the teeth of Khoesan and those of Holocene archaeological skeletons from East Africa (Kenya) to provide a broader context for interpreting the Khoesan dentition. Comparisons are also made between Holocene Khoesan and Mid-Late Pleistocene teeth from southern Africa in order to provide insights into dental relationships deeper in time. There are six aims of this thesis: (1) to construct the population's dental map and with it, (2) evaluate the significance of Khoesan Late mid-Holocene body size fluctuations and (3) assess the question of population continuity or replacement ca. 2000 BP with the introduction of herding in South Africa, (4) to explore possible geographic differences among Khoesan dentitions (5) to investigate temporal differences within the Holocene, and also to compare Holocene and earlier hunter-gatherers to assess population continuity/discontinuity, and (6) to evaluate the position of Khoesan dentition in a global context. Up to 52 non-metric traits were scored using the Arizona State University Dental Anthropology System. To test for significant relationships between groups through time, chi-square statistics were employed on dichotomised data and the mean measure of divergence was assessed in order to identify phenetic similarities and dissimilarities between regions. Additionally, MANOVAs and Principal Components Analysis were used to investigate size and shape variation. Metric analyses demonstrate minor size/shape variation between temporal and regional groups. Increased metric variation is observed during the Late Holocene, coinciding with fluctuations in body size documented in previous studies. Although some differences in trait frequencies are observed during the Late Holocene, there is little variation in qualitative traits throughout the Khoesan sample. This suggests that the minor differences observed result from intrinsic factors such as geographic variation, rather than gene flow from outlying areas. Teeth from the Mid-Late Pleistocene demonstrate a degree of phenetic affinity to Holocene Khoesan dentition. Finally, the Khoesan dentition is significantly different from global dental complexes, as exemplified by a suite of twelve core Khoesan traits that distinguish Khoesan teeth from other dental patterns (including Afridonty). Taken together, these results support hypotheses of morphological and genetic continuity in southern African populations during the Holocene, with some evidence for continuity deeper in time. In addition, these results place the Khoesan dentition at the margins of the range of human dental variation and call into question the fit of this dental map into current sub-Saharan African dental models.
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    Diet and subsistence patterns in the later iron age of South Africa : an analysis of stable carbon and nitrogen isotopes and the incidence of dental caries
    (1995) Gilbert, Cheryl Lee; Sealy, Judith
    Current archaeological perspectives on the change in Later Iron Age diet and subsistence patterns and the subsequent affect on the economy, are re-examined using isotopic and caries analyses. Existing perspectives have focused mainly on material archaeological evidence and are not reflective of diet at the individual level. Consequently, the focus of archaeological research has been biased towards the importance of cattle in subsistence patterns and the economy, and the role of agriculture has not been as thoroughly investigated. In order to address this problem the isotopic signatures of 72skeletal remains, and the pattern of carious lesions of 44 of those individuals, were examined. The samples were drawn from different ethnic groups and geographical/climatic regions. Skeletons were analysed for both ᵟ¹³C and ᵟ¹⁵ N values in order to better reflect both the level of cultigen consumption and the relative importance of animal protein in the diet. The results were initially examined at an individual level, within the biomes from which they were drawn, to determine subsistence type. The diets of persons and ethnic groups was then compared to archaeological and ethnographical research. Combination of results demonstrates a trend towards more enriched ᵟ¹³C values over time. Although there were differences between individuals diets, there is an overall increasing consumption (and therefore reliance) on domesticated grains, whilst the consumptive levels of animal protein remain relatively constant over the last 1000 years. Consequently, the context of previously undated skeletal material was founded on the trend towards increasing ᵟ¹³C values during the second millennium. The creation of a set of criteria based on pattern, type and extent on carious lesions, has provided a further means of assessing the carbohydrate intake level of individuals. An increase in both ᵟ¹³C values and the incidence of caries during the 18th century, may reflect the introduction of maize in the interior of South Africa, via Delagoa Bay. It is suggested that population growth and increased demand resulted in maize replacing indigenous African cultigens to become a staple food source after this period. In conclusion it is postulated that further re-examination of the current outlook should be undertaken as it is clear from this study that the Later Iron Age is heterogenous with comparable but distinct dietary levels.
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    The ecological and evolutionary significance of browsing and grazing in savanna ungulates
    (2006) Codron, Daryl; Lee-Thorp, Julia A; Sealy, Judith; Sponheimer, Matt
    Includes bibliographical references (leaves 175-208).
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    Excavations at Melkbosstrand: Variability among herder sites on Table Bay, South Africa
    (2004) Sealy, Judith; Maggs, Tim; Jerardino, Antonieta; Kaplan, Jonatha
    During an archaeological impact assessment in 1997, three shell middens were identified along a dune ridge 1.5 km from the shore at Melkbosstrand, about 22 km north of central Cape Town. They were subsequently excavated and yielded evidence of occupation beginning c. AD 700. Remains consisted mostly of shell and bone, with a very informal stone artefact assemblage. All three sites yielded ceramics and sheep bone; at one site sheep was the animal most frequently identified to species level. On the edge of one midden, a stone hearth 1.8 m in diameter was uncovered This site cluster was almost certainly occupied by herders and, as such, constitutes the closest herder sites to Cape Town investigated to date
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    Groundwater hydrogen, oxygen, and strontium isotope variation of Hout Bay Valley, Cape Town
    (2022) Daws, Warrick; Harris, Chris; Sealy, Judith
    Accessible groundwater can be an alternative water supply to meet water demands and elevate stress from existing water supply systems in semi-arid regions. Monitoring stable isotope compositions (δD and δ18O) in the hydrosphere can aid hydrogeologists in understanding groundwater processes. The δD and δ18O of 148 water samples (groundwater, rainwater, and stream water) from Hout Bay, a coastal valley 20 km south-west of Cape Town are considered in this study. Groundwater samples from 65 boreholes/wellpoints is presented over two distinct phases (February/March 2020, and November 2020) with groundwater electrical conductivity and groundwater temperature measurements. Hout Bay groundwater δD and δ18O range from -16.5‰ to -6.4‰ and -3.90‰ to -2.14‰ respectively and show no strong correlation with seasonality or elevation above sea level. Electrical conductivity of Hout Bay 2020 groundwater is relatively low ranging from 126 µS/cm to 2370 µS/cm. Hout Bay monthly rainwater amount, δD, and δ18O were measured from March 2020 to February 2021. The weighted mean δD and δ18O values of Hout Bay monthly rainwater from March 2020 to February 2021 are - 6.2‰ and -2.38‰ respectively. The δD and δ18O values of Hout Bay rainwater cluster around the local meteoric water line established for UCT, and show a strong amount effect (r = -0.92 for δD vs amount). Three possible explanations are proposed for the δD and δ18O difference between Hout Bay monthly rainwater weighted mean from March 2020 to February 2021, and Hout Bay February/March 2020 and November 2020 groundwater. The first is that intense rainfall events preferentially recharge groundwater with low δD and δ18O values. The second explanation is that Hout Bay groundwater might have retained more negative δD and δ18O values from rainwater recharge prior to March 2020. Lastly, recharge from mountain peaks at higher elevation than the Hout Bay groundwater sample locations add a component of more negative δD and δ18O to Hout Bay groundwater than proximal rainwater. Nine samples from Hout Bay February/March 2020 groundwater sample collection were analysed for strontium isotope composition (87Sr/86Sr) to determine the applicability of strontium to trace the source of groundwater. The 87Sr/86Sr ratios in Hout Bay groundwater vary from 0.710 to 0.731. There is a strong negative correlation between 87Sr/86Sr and δ18O (r = -0.91). The low end of the 87Sr/86Sr data array appears to be of marine origin but the corresponding δ18O values of ~-2.9‰ do not reflect that of seawater. Minor interactions of Hout Bay groundwater with Cape Granite produce relatively high 87Sr/86Sr ratios while lower 87Sr/86Sr ratios similar to that of modern seawater are attributed to dissolution of the marine sediments of the Quaternary Witzand Formation and marine aerosols in sea spray. Higher rainwater amounts are proposed to increase 87Sr/86Sr ratios of higher elevation groundwater sample locations by diluting the dissolution of marine aerosols in rainwater.
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    An investigation of skeletons from Type-R settlements along the Riet and Orange Rivers, South Africa, using stable isotope analysis
    (2015) Masemula, Nandi; Sealy, Judith
    In the last centuries before incorporation into the Cape Colony, the Riet and Orange River areas of the Northern Cape, South Africa were inhabited by communities of hunter-gatherers and herders whose life ways are little understood. These people were primarily of Khoesan descent, but their large stone-built stock pens attest to the presence of substantial herds of livestock, very likely for trade. This region was too dry for agriculture, although we know that there were links with Tswana-speaking agricultural communities to the north, because of the presence of characteristic styles of copper artefacts in Riet River graves. This was a frontier region at a turbulent time in South African history, so one of the questions about these societies is the extent to which they were homogeneous or heterogeneous - were many outsiders incorporated into these communities? What was the relative importance of herding compared with hunting in the local economy? Did connections with farming communities extend to the trading of cereal foods?
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    An investigation of stable sulphur isotopes as a palaeodietary indicator in South Africa
    (2011) Johnson, Malia; Sealy, Judith
    The purpose of this thesis is to assess the use of stable sulphur isotope analysis as a tool for studying the diet and mobility of Later Stone Age people in the Western Cape Province of South Africa.
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    Lead isotopes as a palaeodietary tracer in southwestern South Africa
    (2018) Scott, Mari; Le Roux, Petrus; Sealy, Judith; Pickering, Robyn
    This thesis evaluates the utility of lead (Pb) isotopes, in combination with strontium (Sr) isotopes, as a geochemical tracer for studying the palaeodiets and palaeo-landscape usage in southwestern South Africa. Isotopes of light elements, carbon (C), nitrogen (N), oxygen (O), and sulphur (S), are widely used as (palaeo) environmental tracers, but do not yield information on the geological substrates on which individuals have lived. Sr isotopes in bones and teeth are useful in distinguishing between areas of distinct bedrock geology, however, the efficiency of Sr is limited at near-coastal areas, which forms a major part of this study area. This is because Sr has a relatively high concentration and long residence time in seawater. In addition, coastal soils contain not only aerosol-derived marine Sr, but frequently also include fragments of shells and other marine carbonates, so their 87Sr/86Sr is like the ocean. This study analysed Pb and Sr concentrations and isotopic compositions of animals and plants derived from the various geological substrates of southwestern South Africa. In order to do this, a detailed Sr-Pb separation scheme was developed, involving the separation and pre-concentration of Sr and Pb from a single digested sample by means of ion-exchange chromatography. Elemental concentrations were measured with a Thermo X-series II quadrupole ICP-MS instrument. Sr concentrations ranged between 111 ppm and 1862 ppm, while Pb concentrations were lower, ranging between 0.012 ppm and 2.30 ppm. Isotopic ratios were determined by means of a Nu Instruments high resolution multi-collector inductively-coupled plasma mass spectrometry (HR-MC-ICP-MS). Samples were introduced into the system as solutions, producing an order of magnitude more precise results than laser ablation analysis on the same material. Sr isotopes are useful for distinguishing between individuals living in near-coastal environments and those living further inland, while Pb isotopes could differentiate between granites and shales/sandstones. Pb isotopes proved to be a valuable palaeodietary tracer and can be used in combination with Sr isotopes to extent our knowledge of palaeo-landscape usage at coastal-marine environments.
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    Managing collections of human remains in South African museums and universities: Ethical policy-making and scientific value
    (2003) Sealy, Judith
    Several articles in this issue describe recent work on fossil hominid remains or on the emergence of modern humans (between 200 000 and 100 000 years ago) — major issues in archaeology and anthropology to which South African finds have made and continue to make a key contribution. Ancient human remains can be meaningfully assessed only in a comparative framework, by tracing the emergence or disappearance of features, or investigating relationships between lineages. The study of recent human skeletons (those from the last 10 000 or so years) plays an important role in such comparisons: a role that can be critical, as in the question of whether early modern humans in South Africa were or were not the direct ancestors of more recent Khoesan populations — an as yet unresolved question.
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    Marine fish exploitation during the middle and later Stone Age of South Africa
    (2011) Van Niekerk, Karen Loise; Sealy, Judith
    Marine fish remains are not common in Middle Stone Age (MSA) sites in Africa. There are currently only two known MSA sites with good organic preservation in South Africa that contain marine fish remains in relatively high numbers: Blombos Cave (BBC) and Klasies River main site (KR). Marine fish exploitation is considered by some researchers as a marker of modern human behaviour, requiring cognitive and technological capacities thought to have only appeared after 50 000 years ago, during the Later Stone Age (LSA).
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    New radiocarbon dates for Matjes River Rock Shelter
    (South African Archaeological Society, 2006) Sealy, Judith; Ludwig, Ben; Henderson, Zoe
    Matjes River Rock Shelter is a key site for the Later Stone Age in South Africa. Early excavations were, however, crude, and we have only a very broad picture of the sequence uncovered by Dreyer (1933) and Hoffman and Meiring (Hoffman 1958, 1962; Louw 1960). More detailed work by Hilary Deacon and Willemien Dockel in the early 1990s provided better resolution on the lower part of the sequence, but in the areas in which they worked, the upper layers were unfortunately no longer preserved (Dockel 1998). Nearly all the previously published radiocarbon dates for Matjes River are for the lower levels.We present here a series of recent radiocarbon determinations, most of them for materials derived from the upper levels. Some of these results have been published (Sealy and Pfeiffer 2000), but many are new. Here, we explore the implications of the suite of dates for the sequence at the site.
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    Of fish, pigs and cesspits : a comparative study of stable carbon and nitrogen isotope analyses on animal bone and soil samples from five medieval sites in Belguim
    (2003) Schietecatte, Liesbet; Sealy, Judith
    In medieval archaeology, diet is often inferred from excavated faunal remains. Recently, researchers have started to apply stable isotope techniques to diet reconstruction. Most studies have focused on the analysis of human bone collagen. In this research, human skeletal remains were not available, so ¹³C/¹²C and ¹⁵N/¹⁴N analyses were made on animal bones and soil samples from a medieval fisherman's village, Walraversijde. In addition, samples were analysed from four other late medieval sites: Ostend, Bruges, Aalst and Namur. Bone collagen samples fiorn Walraversijde showed an ocean-derived saline influence on the isotopic values of especially sheep/goats. Dogs, often used in prehistoric research as dietary proxies for humans, are unsuitable at this site because of huge variability in δ¹⁵N values. Pigs showed the most positive δ¹³C and δ¹⁵N values of all the terrestrial animal species. It seems likely that the residues after fish processing were collected and fed to them in pens, thus indicating that a waste management system existed. Analysis of sequential samples of pig teeth showed that piglets were probably bought at inland markets and brought to the village for fattening. These resuits call for an extended survey of animal isotopic values. δ¹³C and δ¹⁵N analysis was also carried out on soil samples, including a number taken from excavated cesspits. This is the first time that a study of this kind has been undertaken. The results are very promising as there seems to be less routing of dietary components than in human bone collagen. The cesspits at Narnur, the site furthest from the coast, yielded the lowest δ¹⁵N values, indicating a low trophic level diet with little influence from fish. The highest trophic level diet was recorded in the cesspit at Aalst. At Walraversijde, the low representation of marine foods was very surprising, apparently contradicting the abundance of fish remains found at the site. Fish seems to have been more important for its commercial value than as an item of diet. Clearly, more research is needed into the economy of the village and its organization.