Electronic Theses and Dissertations (Masters)
Permanent URI for this collectionhttps://hdl.handle.net/10539/38012
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Item Assessing aquifer vulnerability to landfill pollution using drastic method in Gauteng, South Africa(University of the Witwatersrand, Johannesburg, 2023) Mphaphuli, Idah; Abiye, TamiruThis study integrated the DRASTIC method and field investigations into mapping the degree of vulnerability of aquifers to landfill pollution in the Gauteng Province, which is one of the most populated provinces in South Africa. In order to investigate the aquifer vulnerability of Gauteng's heterogeneous and complex geology, the DRASTIC method was used to generate intrinsic and specific vulnerability maps. Three vulnerability classes were generated from the DRASTIC index, namely, low vulnerability, moderate vulnerability and high vulnerability, which covered 46%, 37% and 17% of the study area, respectively. The highly-vulnerable areas were associated with the karst aquifer of Malmani dolomite, permeable vadose zone, high hydraulic conductivity and loamy sand/sandy loam soil type, whilst moderately-vulnerable areas were associated with fractured/weathered aquifers, high recharge and low topography. The intrinsic vulnerability was validated using average NO3+NO2-N (nitrate + nitrite as nitrogen) and the results of water samples from field investigations conducted in Marie Louise and Robinson landfill sites. Elevated NO3+NO2-N concentration (9.85-16.03 mg/l) was observed in the highly-vulnerable areas. Water samples were collected, in order to analyse the water chemistry, stable isotopes and radioactive isotopes (tritium). Gibbs and Piper diagrams were used to evaluate the main mechanism controlling the groundwater chemistry and the dominant major ions that influence it. Pollution by leachate was detected in the Marie Louise landfill site, where the groundwater showed high tritium and ammonia concentration. The main hydrochemical facies detected in Marie Louise were Mg SO4, Ca-SO4, Na-SO4 and Na-Cl. The hydrochemical facies detected in Robinson were Na-SO4, Ca-HCO3, Na-Cl and Ca-Cl. The DRASTIC method was shown to be effective in assessing groundwater vulnerability on a regional scale, provided that there is adequate input data.Item The tectonic evolution of the Bredasdorp Basin and its implications for oil and gas formation(University of the Witwatersrand, Johannesburg, 2023-10) Tau, Rethabile; Enslin, Stephanie; Manzi, Musa; Saffou, EricThe Bredasdorp Basin is an offshore rift basin located in the southernmost tip of Africa, within the larger Outeniqua Basin. Previous studies have indicated the presence of hydrocarbons, as well as structures or evidence that allude to the presence of hydrocarbons, where the basin has not yet been extensively drilled or explored. In this study, seismic attributes applied to high resolution pre-stack time migrated 3D seismic data are analyzed, in conjunction with well logs, specifically the gamma ray logs. By employing these methods, the study aims to delineate the presence of hydrocarbons and their migration, as well as deduce the evolution of the basin based on the structures observed. Using artificial neural network (ANN) to predict the lithologies and analyzing the patterns in the gamma ray logs, the stratigraphic results show that the basin begins with a marine dominated environment from the Valanginian age to Aptian age. From the Aptian to Albian age, there are consistent changes in sea level and sedimentation, caused by thermal sag and uplift. Past the Albian age to present age, the deposition environment is dominated by sandstones and coarse sediments. This is due to the evolving basin moving from a distal to a proximal environment of deposition. Using seismic attributes such as envelope attribute, edge detection and variance attribute, structures such as paleo pockmarks and fluid escape structures are identified. These identified paleo pockmarks have diameters ranging from 400m to 900m. In addition to these structures, erosive features were observed which could be classified as submarine channels or slump structures, with the dominating channel having depths of up to 1585 m. Using variance and ant-tracking, the fault structures observed of the study areas revealed two dominating phases of rifting. The first phase has horsts and grabens bounded by normal faults trending E-W, with implications that the rifting propagated N-S in this phase of rifting. This phase of rifting ends during the Aptian age. The next phase of rifting begins during the Santonian age, with the fault bound horsts and grabens trending N-S, which indicate an E-W rifting direction.Item A Review of Mineral Exploration at the Karingarab Carbonatite, Southern Namibia(University of the Witwatersrand, Johannesburg, 2023) Nehoya, Jennifer Ndapanda; Nex, PaulThis research report reviews the Karingarab Carbonatite, which is one of several alkaline and carbonatite occurrences in Namibia targeted for rare earth element (REE) potential which are used in medical, renewable energy, technology and military applications. Several exploration campaigns have occurred at the Karingarab Carbonatite since 1977 and all indicate positive concentrations of REEs at the deposit. The Karingarab Carbonatite (68 Ma) is one of 41 alkaline and carbonatite occurrences in Namibia which is documented in this report and is very similar in terms of composition, age and emplacement to the Dicker Willem (49 Ma) and the Gross Brukkaros carbonatites (77 Ma) all located along south-west to north-east trending structures on the west coast of southern Namibia. The Karingarab Carbonatite lies in the center of a 2.5 km diameter circular vent raise 300 m above sea level, the edges of the vent are brecciated extrusive phonolites and other alkali silicate rocks with country rock fragments of phyllites and schists of the Oranjemund group, crosscut with late stage dykes of varying compositions in the alkaline and carbonatite series. Four main lithology types are identified through their distinct geochemical signatures with varying degrees of weathering and alteration. The target and main lithology is a layered extrusive carbonatite with lapilli of various shapes and sizes diluted in parts with mostly phonolites, schists and phyllites. The second more common lithology is extrusive phonolites which are mostly brecciated with cross cutting carbonatite dykes. The third lithology type is formed by clay rich autoclastic volcanic breccias which are a mixture of all the proximal and local rock types of the Oranjemund group, lastly the fourth lithology is formed by overburden which includes wind-blown dune sands and calcrete. The extrusive carbonatite lapilli is the dominant ore type, with deeper, fresh and unaltered carbonatites still mineralized and carrying lower grades while the shallower, weathered and altered carbonatite shows supergene enrichment and extremely high grades. This enrichment was upgraded by events in the early Paleogene which included deep erosion and surface weathering events along with a regional surface silcretization event capping and trapping mineralization. Preliminary findings following the first two drilling campaigns indicate a potential to produce from the carbonatite, 181 million tonnes of ore with 3.5 million tonnes of total rare earth oxides (REOs) at an average grade of 1.9% total REEs. The deposit remains partly open at depth, with satellite concealed volcanic occurrences still to be explored. Should the target become an operational mine, responsible sourcing will need to be considered particularly how to extract, refine, transport and process REEs in a manner which satisfies environmental, social and governance requirements (ESG) while ensuring the mineral value chain and potential industry spill-over is managed sustainably. Major risks to the target involve the criticality of supply which may be managed through monitoring geopolitics in supply, and technology improvements in substitution and recycling for the REEs and their products. Apart from these economic interests, the observations and studies on the subsurface lithologies at Karingarab will be invaluable to academia through improved literature on carbonatites, REE deposit genesis and the regional geology where much is covered by sandItem The Equidae from Gladysvale, a Hominin locality in the Cradle of Humankind, South Africa(University of the Witwatersrand, Johannesburg, 2023-10) Van der Merwe, Daniel Jean; Badenhorst, ShawThe later Pleistocene compared to modern census data indicated that Equidae are represented lower than comparably sized bovids (BOV III & IV). The reason for this may be due to numerous factors that have been previously investigated such as, landscape usage, carnivore and prey relationships and accumulation factors. However, a largely unexplored factor that may also have played a vital role in their lower representation may have been the difference and effectiveness of predator avoidance behaviours utilized by Equidae. The Equidae remains from the external and internal deposits of Gladysvale (730 to 580 Kya and 257 to 195 Kya) in the Cradle of Humankind, may provide insight into the predatory avoidance behaviours of two different Equidae species, Equus capensis and Equus quagga. This study aimed to create and renew an understanding of the role of these animals within larger faunal communities in the Cradle of Humankind. Equidae fossil material mostly from Gladysvale along with supporting material from Sterkfontein, Kromdraai and Coopers were examined, measured and photographed, in an attempt to broaden the understanding of Equidae relations within the Cradle of Humankind. Furthermore, to also elaborate on the potential differences between Equus capensis and Equus quagga. Past research has usually assigned Equus capensis to the larger version of Equus quagga during the later Pleistocene, with other studies based on DNA analysis suggesting the two species have very little intraspecific diversity. However as seen in this study it would appear that there is a notable difference in size between the two Equidae species, but also a difference in overall representation within the Cradle of Humankind. This could imply that not only are the two species different in size but that they also employed different predatory avoidance behaviours.Item Hydrogeological assessments and investigation of inflow sources at Lumwana Copper Mine, Zambia(University of the Witwatersrand, Johannesburg, 2023) Mbilima, Mike; Abiye, TamiruThis Research Report presents results of integrated field and desktop-based hydrogeological investigations at the Lumwana Mine, Zambia. Groundwater occurrence in the mine poses challenges with effective mining operations and slope stability. The primary aim of this study was to establish the sources of groundwater inflows and to establish the nature of surface water and groundwater interaction within the Lumwana Mine hydro-geotechnical units. The Lumwana hydrogeological investigation has been achieved through the integration of multi-disciplinary data types, which include geology, structures, hydrochemistry, meteorological data (rainfall, temperature, humidity and evapotranspiration), environmental isotopes, dewatering pumping records, groundwater level monitoring, water temperature, general hydrogeological data and surface hydrology. The investigation has confirmed the presence of hydraulic connections between different surface water bodies such as dams, diversion channels, streams and open pit excavation, and has proven to be a useful approach in tracing the source of mine inflows. Rainfall, groundwater and surface water samples have similar δ18O and δ2H isotopic signatures thus lamenting the existence of a hydraulic link between groundwater and surface water. Recharge estimation through Water Table Fluctuation method (WTF) determined 8% of mean annual precipitation (MAP). The dominant hydrochemical facies are Ca-Mg-HCO3 and Ca-Mg-SO4. The local geology and geochemistry of the tailings are the main controllers of groundwater chemistry through rock-water interaction. The geology of the study area consists of older metamorphosed gneisses, schists, migmatites, amphibolites and granitoids. Integrated assessment of the Lumwana hydrogeological environment has enabled the development of the Lumwana Mine hydrogeological conceptual model. In the shallow, highly to moderately weathered zones, groundwater flows from south towards low topographic regions in the northwest mimicking the general topography. The hydraulic test conducted at Lumwana Mine has revealed the saprock units have higher hydraulic conductivity by several orders compared to the saprolites and the fresh bedrock, where groundwater flow is mainly controlled by the occurrence and distribution of the fracture network.Item Reconstructing locomotor behaviour of Southern African plio-pleistocene cercopithecoids: evidence from functionally-related inner structural arrangement of the trabecular bone(University of the Witwatersrand, Johannesburg, 2023-07) Babutsi, Mosarwa; Beaudet, Amélie; Zipfel, Bernhard; Jakata, KudakwasheBecause of their abundance in African Plio-Pleistocene hominin-bearing sites and their stratigraphic association with fossil hominins, cercopithecoids represent a relevant “control group” for contextualising hominin evolution. often considered as ecological and biochronological indicators, particularly their ecological sensitivity is valuable in reconstructing southern African hominin bearing site’s palaeoenvironment and environmental changes. Since biomechanical loadings on trabecular bone produced throughout locomotor activities shape the structure of the skeleton, particularly at locomotor key joints, the expectation is that investigation of the trabecular bone of fossil cercopithecoids key joints like femur, humerus, Tibia and calcaneus would provide further evidence for eloquent discreet disparity in their locomotor behaviour and reconstructing their paleohabitats. This study used trabecular bone, described as meshwork or sponge with porous network within long bones joints and inside footbones contains red bone marrow. Its preferred orientation in is the basis of Wolff’s law, relating bone structures and its ability to adapt to mechanical load alignment in the direction of loading stress, as such recoding informative locomotor signals. Forty one (41) fossil cercopithecids from the Cradle of Humankind World Heritage sites that include Sterkfontein, Swartkrans, Makapansgat, Taung and Bolt’s Farm as well as forty (40) extant cercopithecoids specimens were scanned using a micro-focus X-ray computed tomography (CT) scanner. Trabecular bone parameters that include trabecular bone fabric anisotropy, volume fraction, thickness and spacing were quantified in ImageJ. These Plio-Pleistocene cercopithecoids recorded more arboreal locomotor signals with occasional terrestrial locomotion, suggesting transitional palaeoenvironment from long trees with cool climatic conditions to a more open grass land savanna type with dry climatic conditions believed contributed significantly to extinct of archaic humans and the emergence of the successful Homo.Item Cranial orientation and the lateral semicircular canal in primates: implications for palaeobiological reconstructions and the evolution of locomotor repertoires(University of the Witwatersrand, Johannesburg, 2023) Pestana, Christopher; Benoit, Julien; Beaudet, AmélieThe lateral semicircular canal and its predicted relation to head posture have been used in reconstructions of locomotion and posture of contemporary and extinct species, and in the evolution of bipedalism. Inferences of head posture in fossil species sometimes assume that the lateral semicircular canal is held near the earth’s horizontal when the head is at rest. Despite the physiological importance of the vestibular system, the relationship between head posture and lateral semicircular canal orientation in primates has not been explored on a statistically significant sample, using phylogenetically corrected methods. This study tests the hypothesised relationship between lateral semicircular canal orientation and head posture in primates, and investigates potential links to locomotor categories. This study finds that lateral canal orientation is not significantly correlated to positional repertoires. Significant differences in canal orientation are detected between terrestrial and arboreal species. Neutral head posture distinguishes several locomotor categories, and explains a moderate proportion of the variance in positional behaviour. Brain mass is found to correlate with positional behaviour when correcting for the effects of the phylogeny. The implications of the evolution of head posture in fossil species are discussed.Item The relationship between dental complexity and mandibular shape: implications for dietary inference in stem mammals(University of the Witwatersrand, Johannesburg, 2024) Harris, Wade; Choiniere, Jonah N.Non-mammalian cynodonts exhibit some of the first major morphological innovations that contributed to the success of their descendent lineage, mammals. This includes features that are hypothesized to enable adaptation to a highly varied suite of diets such as specialized tooth crowns with complex occlusal surfaces and a jaw muscle configuration where two major muscles contribute to jaw closing. Surprisingly, inferences on cynodont diets so far have been based on qualitative evidence, and the quantification of these dietary adaptations could assist in testing these inferences. Here, I evaluate the relationships of mandibular shape, dental complexity and the combined data on body mass and relative mandible size, to known diets in living mammals, to assess the utility of these ecomorphological proxies for inferring the diets of extinct non-mammalian cynodonts. To assess relationships between diet and jaw shape, I collected 12 fixed landmarks (type 2) and four sliding landmarks (type 3) for six non- mammalian cynodonts, 51 marsupial mammals and 211 placental mammals. Dental complexity (OPCR) values were collected using the R package molaR, for a sample of 19 non-mammalian cynodonts, 47 marsupial mammals and 193 placental mammals. Procrustes-aligned shape coordinates, OPCR values, body mass estimates and relative mandible size data were then subjected to phylogenetic Procrustes ANOVA regressions and phylogenetic regressions. Neither mandible shape nor OPCR are strongly correlated to diet (carnivory, frugivory, granivory, herbivory, nectivory, invertivory), but the combination of these variables are a somewhat reliable predictor of diet, particularly mandible shape. Extinct non-mammalian cynodonts have mandible shapes that are comparable to those of mammals, however they occupy a narrow morphospace and their OPCR scores are generally much lower than those of mammals. Consequently, when these variables were entered into a predictive framework for diet, I observed limited inferential power since non-mammalian cynodonts do not strongly resemble mammals.Item Potential Source for the Alluvial Gold Deposit in the Kapoeta Area, Eastern Equatoria State, South Sudan(University of the Witwatersrand, Johannesburg, 2023-10) Bali, Francis Khamis Alex; Woldai, Tsehaie; Kinnaird, Judith A.This study concentrates on the integrated approach of applying geochemical, and remote sensing data combined with field investigation to understand the source of the alluvial gold deposit in the Kapoeta area. The use of an integrated technique approach proves effective in mapping and outlining areas of potential gold mineralisation in Kapoeta. Kapoeta has been known for its endowment of gold deposits for quite some time. Landsat-8 (OLI) and SRTM-DEM satellite images were employed during this study to map lithological units and highlight areas of hydrothermal alteration and structural trends in Kapoeta to understand the potential source for the widely distributed alluvial gold in the area. The several image-processing techniques employed were effective in mapping the lithological units and outlining the major structural trends in the area. Mapping the hydrothermal alteration zones was challenging because of the overburden that masks most parts of the Neoproterozoic juvenile metavolcano-sedimentary sequences. Secondly, the vegetation cover is another factor affecting the mapping of the lithological units around the Didinga Hills and Dongotona mountains. Structural mapping identified four main trends N-S, NNW-SSE, NW-SE, and NE-SW. The image interpretation, together with geochemical occurrence and anomaly map showing Cu, Co, Ni, and Cr, shows that N-S and NNW-SSE are the potential controls on mineralisation in the area. The whole-rock geochemical data plotted on the TAS discrimination diagrams shows that the rocks analysed are dominantly tholeiitic with minor calc-alkaline units. Trace elements normalised to the primitive mantle show low concentrations of Zr, Hf, Nb and Ta. The REE normalised chondrite values indicates general enrichment of LREE elements relative to HREE with a negative Eu anomaly. On the tectonic discrimination diagrams, the results indicate that the rocks of Greater Kapoeta belong in a marine environment related to a spreading centre, oceanic island, oceanic ridges, and floor. The distribution of Cu, Co, Cr and Ni and their high concentration suggest that these elements are the potential pathfinders for gold in the area. The study concludes the following: Based on the remote sensing, field observations and geochemical data indicates that the gold mineralisation of Kapoeta is orogenic in nature with a strong element of epigenetic characteristics, however, a syngenetic origin cannot be ruled out. The host lithologies may vary from quartz veins to schists, amphibolites, quartzo-feldspathic gneisses, and ultramafics and the marbles related to the N-S, NNS-W-SSE and NW-SE trending shear zones that limit the greenstone belt.Item An investigation into high gear and low gear propulsion in human gait and its relation to metatarsal diaphyseal geometric cross-sectional properties(University of the Witwatersrand, Johannesburg, 2023-06) Reyneker, Mark Brenden; Carlson, Kristian J.; Zipfel, BernhardThis study investigates the relationship between metatarsal bone form, as quantified by cross-sectional geometric properties, and its relationship to high (medial forefoot loading) versus low gear (lateral forefoot loading) push-off during the propulsion phase of the gait cycle. The objective being to assess whether forefoot loading may be variable or whether high gear loading occurs in higher frequencies, as depicted in theoretical foot function models. The study sample (n=53), made up of three broad groups, include Later Stone Age southern Africans, post-industrial individuals from South Africa, and the Jomon of Japan. Metatarsals 1-5 cross-sectional geometric properties (CSA, Ix, Iy, Imin, Imax, Zx, Zy, Zp, Zmin, Zmax) taken from CT scans at 25%, 35%, 50% and 65% metatarsal diaphyseal biomechanical lengths are grouped into high gear (metatarsal 1-2) and low gear (metatarsal 2-5) for comparison. The combined population analysis reveals that the high gear metatarsal diaphysis exhibit significantly higher strength and rigidity driven mainly by the post-industrial individuals from South Africa and the Later Stone Age southern Africans. In contrast, the Jomon of Japan, exhibit no significant differences between high and low gear metatarsals except for CSA, Imax, and Zmax. Furthermore, metatarsal 1 and 5 differ far less in cross-sectional geometric properties in the Jomon of Japan compared to the other populations except for medial-lateral strength (Zy) and torsional and average bending strength (Zp) where metatarsal 5 is significantly higher. The study findings indicate that forefoot loading demonstrates variability during the propulsion phase of gait, while also suggesting a higher frequency of occurrence for high gear push-off. This challenges current theoretical models of foot function that emphasise high gear push-off as typical and normal for striding bipedalism.