The petrogenetic relationships of the different varieties of kimberlite in the De Beers Mine and Letseng-Ia-terai composite diatremes have been investigated using petrographic and chemical methods. Kimberlites in the Letseng-Ia-terai diatreme were found to be strongly contaminated by crustal material, mainly basalt. A method to correct for the effects of the contamination has been developed and applied to these kimberlites. Using the corrected data, the four kimberlite types in each group appear to be related to each other by crystal/liquid fractionation models. However the two groups cannot be related to each other. The De Beer Mine has two varieties of kimberlite, a monticellite apatite and calcite rich variety which intruded first, and a phlogopite rich type forming a discrete cylindrical body within the earlier kimberlite. These two kimberlites do not appear to be related by any of the fractionation models discussed. An examination of the data from this work and published sources, suggests that kimberlites are derived from below the low velocity zone by small degrees of partial melting involving garnet lherzolite with subordinate phlogopite and carbonate. Diamonds are probably incorporated as xenocrysts in the magma. Upward movement and emplacement of kimberlite appears to have been very rapid. The diatremes were probably eroded and shaped by gas, derived from the kimberlite magma, escaping to surface along weak zones in the earth's crust. Xenoliths of crustal material incorporated in the kimberlite on intrusion have also been studied and various features due to alteration by the magma are described, including the formation of natrolite and cebollite. The latter is a rare mineral that has not been described from kimberlite before. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Water is recognised as a key driver for social and economic development in the Zambezi basin. The basin is riparian to eight southern African countries and the transboundary nature of the basin’s water resources can be viewed as an agent of cooperation between the basin countries. It is possible, however, that the same water resource can lead to conflicts between water users. The southern African Water Vision for ‘equitable and sustainable utilisation of water for social, environmental justice and economic benefits for the present and future generations’ calls for an integrated and efficient management of water resources within the basin. Ensuring water and food security in the Zambezi basin is, however, faced with challenges due to high variability in climate and the available water resources. Water resources are under continuous threat from pollution, increased population growth, development and urbanisation as well as global climate change. These factors increase the demand for freshwater resources and have resulted in water being one of the major driving forces for development. The basin is also vulnerable due to lack of adequate financial resources and appropriate water resources infrastructure to enable viable, equitable and sustainable distribution of the water resources. This is in addition to the fact that the basin’s economic mainstay and social well-being are largely dependent on rainfed agriculture. There is also competition among the different water users and this has the potential to generate conflicts, which further hinder the development of water resources in the basin. This thesis has focused on the Zambezi River basin emphasising climate variability and climate change. It is now considered common knowledge that the global climate is changing and that many of the impacts will be felt through water resources. If these predictions are correct then the Zambezi basin is most likely to suffer under such impacts since its economic mainstay is largely determined by the availability of rainfall. It is the belief of this study that in order to ascertain the impacts of climate change, there should be a basis against which this change is evaluated. If we do not know the historical patterns of variability it may be difficult to predict changes in the future climate and in the hydrological resources and it will certainly be difficult to develop appropriate management strategies. Reliable quantitative estimates of water availability are a prerequisite for successful water resource plans. However, such initiatives have been hindered by paucity in data especially in a basin where gauging networks are inadequate and some of them have deteriorated. This is further compounded by shortages in resources, both human and financial, to ensure adequate monitoring. To address the data problems, this study largely relied on global data sets and the CRU TS2.1 rainfall grids were used for a large part of this study. The study starts by assessing the historical variability of rainfall and streamflow in the Zambezi basin and the results are used to inform the prediction of change in the future. Various methods of assessing historical trends were employed and regional drought indices were generated and evaluated against the historical rainfall trends. The study clearly demonstrates that the basin has a high degree of temporal and spatial variability in rainfall and streamflow at inter-annual and multi-decadal scales. The Standardised Precipitation Index, a rainfall based drought index, is used to assess historical drought events in the basin and it is shown that most of the droughts that have occurred were influenced by climatic and hydrological variability. It is concluded, through the evaluation of agricultural maize yields, that the basin’s food security is mostly constrained by the availability of rainfall. Comparing the viability of using a rainfall based index to a soil moisture based index as an agricultural drought indicator, this study concluded that a soil moisture based index is a better indicator since all of the water balance components are considered in the generation of the index. This index presents the actual amount of water available for the plant unlike purely rainfall based indices, that do not account for other components of the water budget that cause water losses. A number of challenges were, however, faced in assessing the variability and historical drought conditions, mainly due to the fact that most parts of the Zambezi basin are ungauged and available data are sparse, short and not continuous (with missing gaps). Hydrological modelling is frequently used to bridge the data gap and to facilitate the quantification of a basin’s hydrology for both gauged and ungauged catchments. The trend has been to use various methods of regionalisation to transfer information from gauged basins, or from basins with adequate physical basin data, to ungauged basins. All this is done to ensure that water resources are accounted for and that the future can be well planned. A number of approaches leading to the evaluation of the basin’s hydrological response to future climate change scenarios are taken. The Pitman rainfall-runoff model has enjoyed wide use as a water resources estimation tool in southern Africa. The model has been calibrated for the Zambezi basin but it should be acknowledged that any hydrological modelling process is characterised by many uncertainties arising from limitations in input data and inherent model structural uncertainty. The calibration process is thus carried out in a manner that embraces some of the uncertainties. Initial ranges of parameter values (maximum and minimum) that incorporate the possible parameter uncertainties are assigned in relation to physical basin properties. These parameter sets are used as input to the uncertainty version of the model to generate behavioural parameter space which is then further modified through manual calibration. The use of parameter ranges initially guided by the basin physical properties generates streamflows that adequately represent the historically observed amounts. This study concludes that the uncertainty framework and the Pitman model perform quite well in the Zambezi basin. Based on assumptions of an intensifying hydrological cycle, climate changes are frequently expected to result in negative impacts on water resources. However, it is important that basin scale assessments are undertaken so that appropriate future management strategies can be developed. To assess the likely changes in the Zambezi basin, the calibrated Pitman model was forced with downscaled and bias corrected GCM data. Three GCMs were used for this study, namely; ECHAM, GFDL and IPSL. The general observation made in this study is that the near future (2046-2065) conditions of the Zambezi basin are expected to remain within the ranges of historically observed variability. The differences between the predictions for the three GCMs are an indication of the uncertainties in the future and it has not been possible to make any firm conclusions about directions of change. It is therefore recommended that future water resources management strategies account for historical patterns of variability, but also for increased uncertainty. Any management strategies that are able to satisfactorily deal with the large variability that is evident from the historical data should be robust enough to account for the near future patterns of water availability predicted by this study. However, the uncertainties in these predictions suggest that improved monitoring systems are required to provide additional data against which future model outputs can be assessed.

M.Phil. (Energy Studies) / Southern Africa is a major source of regional aerosols and trace gases from biomass burning, and this creates a need for experimental validation and systematics of the magnitude and frequency of aerosol transport episodes affecting the atmosphere of the region. This study links surface measurements of biomass burning atmospheric aerosols and trace gases with air mass trajectory analysis to determine transport pathways for periods of high and low concentrations. The hypothesis of this study is that from chemical signatures of trace gases and aerosols, as well as trajectory analyses, it is possible to identify sources of these emissions from industrial, traffic, marine and biomass burning activities. Consequently, frequencies, durations, intensities and seasonal variations of trace gases can be established. The study aims to interpret the long-term atmospheric monitoring record from a remote monitoring station at Botsalano (North West Province, South Africa) to determine the origin, frequencies, durations, intensities and seasonal occurrences of aerosol/haze episodes influencing the atmosphere of southern Africa. A suite of trace gas analysers and a Differential Mobility Particle Sizer (DMPS®) were used to measure ground level trace gas and aerosol quantities. MATLAB® scripts were used in performing quality assurance and processing to provide a working set of data from which different fire periods could be selected. Fire signatures, based on excess CO above average tropospheric levels and episodes of enhanced particulate matter concentrations in the 10 to 200 nm range, were identified using MATLAB® scripts and Excel®. Altogether 36 plumes were accepted as biomass burning plumes. Twenty-nine fire plumes had weak signals with excess CO ratios ranging between 0.07 and 0.32; seven plumes had strong signals ranging between 0.41 and 0.64. The occurrence of identified biomass burning plumes was high in the dry season from May to October (83%) and low (17%) during the wet season from November to April. Four pathways were identified for the long-range transportation of biomass burning aerosols to the site: easterly, south-westerly, re-circulation and northerly modes, with occurrence frequencies of 39%, 31%, 22% and 8%, respectively. Anti-cyclonic circulation was observed over southern Africa and was evident in the re-circulation and Indian Ocean slow modes. CO and Aitken-mode aerosol number intensities were generally larger for fire emissions arriving in the easterly and south-westerly air masses when compared with those arriving in re-circulation and northerly air masses. Easterly and south-westerly flows were dominated by Aitken-mode aerosol, whereas accumulation mode particles dominated in the re-circulation and northerly modes. Consequently, easterly and south-westerly flows transported emissions from young/fresh fire plumes, with source regions probably close to Botsalano. Re-circulation and northerly flows were responsible for transport of rather aged plumes from more distant regional fires. Based on forward trajectories, this study revealed that the 2006/2007 measurement period exhibited transport features of a La Niña ENSO during which transport of biomass v burning aerosols towards the south in the Indian Ocean slow and Indian Ocean fast modes was most frequent. This study is significant in that it complements earlier studies of regional aerosol transport over the sub-continent and adds to the understanding of the regional scale generation and transport of trace substances through the atmosphere. Furthermore, the study combines a technique for identifying enhanced CO concentrations as a unique identifier of large scale biomass combustion events with the use of the Aitken-mode particle number densities and size distributions. This technique reveals aspects of aerosol growth dynamics through the changing size distributions, thereby adding fresh insights normally not available through conventional particle volume/mass concentrations measurements.

Regional community in southern Africa has been limited to the region’s states. As a result, deeper notions of community emanating from non-state actors, particularly transnational social movements, continue to be ignored. In an attempt to transcend state centrism, this thesis highlights alternative forms of regional community by exploring the Zion Christian Church (ZCC), one of southern Africa’s biggest and fastest growing cross-border movements. The ZCC is a potential agent for developing regional community from the bottom-up, driving a people-oriented regional integration approach in southern Africa. The ZCC, with its extensive following among the region’s poor, offers a compelling example of a grassroots and truly bottom-up approach to regional community. This thesis explores the possibility of the ZCC as a model of alternative community and identity centred on people’s daily experiences and grounded in a shared history and solidarity. It seeks to highlight the significance of transnational movements like the ZCC to policy makers in the region and it argues that grassroots communities are marching ahead of SADC member states and politicians in the area of integration. There exists a transnational cooperation amongst followers of the ZCC and other grassroots communities across the region and this cooperation transcends the traditional notion of state sovereignty, thereby highlighting deeper notions of what it means to be a community at regional level.

Climate change and a growing demand for freshwater resources due to population increases and socio-economic changes will make water a limiting factor (in terms of both quantity and quality) in development. The need for reliable quantitative estimates of water availability cannot be over-emphasised. However, there is frequently a paucity of the data required for this quantification as many basins, especially in the developing world, are inadequately equipped with monitoring networks. Existing networks are also shrinking due mainly to shortages in human and financial resources. Over the past few decades mathematical models have been used to bridge the data gap by generating datasets for use in management and policy making. In southern Africa, the Pitman monthly rainfall-runoff model has enjoyed relatively popular use as a water resources estimation tool. However, it is acknowledged that models are abstractions of reality and the data used to drive them is imperfect, making the model outputs uncertain. While there is acknowledgement of the limitations of modelled data in the southern African region among water practitioners, there has been little effort to explicitly quantify and account for this uncertainty in water resources estimation tools and explore how it affects the decision making process. Uncertainty manifests itself in three major areas of the modelling chain; the input data used to force the model, the parameter estimation process and the model structural errors. A previous study concluded that the parameter estimation process for the Pitman model contributed more to the global uncertainty of the model than other sources. While the literature abounds with uncertainty estimation techniques, many of these are dependent on observations and are therefore unlikely to be easily applicable to the southern African region where there is an acute shortage of such data. This study focuses on two aspects of making hydrologic predictions in ungauged basins. Firstly, the study advocates the development of an a priori parameter estimation process for the Pitman model and secondly, uses indices of hydrological functional behaviour to condition and reduce predictive uncertainty in both gauged and ungauged basins. In this approach all the basins are treated as ungauged, while the historical records in the gauged basins are used to develop regional indices of expected hydrological behaviour and assess the applicability of these methods. Incorporating uncertainty into the hydrologic estimation tools used in southern Africa entails rethinking the way the uncertain results can be used in further analysis and how they will be interpreted by stakeholders. An uncertainty framework is proposed. The framework is made up of a number of components related to the estimation of the prior distribution of the parameters, used to generate output ensembles which are then assessed and constrained using regionalised indices of basin behavioural responses. This is premised on such indices being based on the best available knowledge covering different regions. This framework is flexible enough to be used with any model structure to ensure consistent and comparable results. While the aim is to eventually apply the uncertainty framework in the southern African region, this study reports on the preliminary work on the development and testing of the framework components based on South African basins. This is necessitated by the variations in the availability and quality of the data across the region. Uncertainty in the parameter estimation process was incorporated by assuming uncertainty in the physical and hydro-meteorological data used to directly quantify the parameter. This uncertainty was represented by the range of variability of these basin characteristics and probability distribution functions were developed to account for this uncertainty and propagate it through the estimation process to generate posterior distributions for the parameters. The results show that the framework has a great deal of potential but can still be improved. In general, the estimated uncertain parameters managed to produce hydrologically realistic model outputs capturing the expected regimes across the different hydro-climatic and geo-physical gradients examined. The regional relationships for the three indices developed and tested in this study were in general agreement with existing knowledge and managed to successfully provide a multi-criteria conditioning of the model output ensembles. The feedback loop included in the framework enabled a systematic re-examination of the estimation procedures for both the parameters and the indices when inconsistencies in the results were identified. This improved results. However, there is need to carefully examine the issues and problems that may arise within other basins outside South Africa and develop guidelines for the use of the framework. / iText 1.4.6 (by lowagie.com)

Please read the abstract in the 00front part of this document / Dissertation (MSc Agric (Agricultural Economics))--University of Pretoria, 2006. / Agricultural Economics, Extension and Rural Development / unrestricted

From May 1994 until the end of August 1994, pieces of decomposing wood and twigs were collected from different locations in the Northern Cape Province, Gauteng, Mpumalanga and in the Western Cape. Fifty-nine taxa were recorded (one new genus, one new species and 43 new records from southern Africa). This study reviews the development of the taxonomy of the mitosporic fungi, in particular the Huyphomycetes, makes some comments on the structure-function relationships and functional diversity that occur and describes a large number of new Hyphomycete records for southern Africa. The classification of these micro-fungi has been controversial since inception. As the asexual phase of a sexually reproducing organism (the ascomycete or basidiomycete states), the taxonomy is covered by a dualistic nomenclature whidh is an exception of Principle IV (one organism: one name) of the International Code of Botanical Nomenclature (ICBN). Alth9ough the role of morphological features in the development of anamorph taxonomic theory has evolved as microscopic image technology has advanced, inadequately defined characters, obscure distinctions between morphologically similar species and a weak theoretical base undermine the usefulness of this system. Molecular systematic studies are yielding a wealth of new fungal taxonomic characters. Molecular technology can generate the data required to verify phylogenetic relationships in this artificial classification system, but is subject of the constraints of time, money and expertise. Neither morphological nor molecular based taxonomy is inherently superior. The utilitarian aspect of morphological systematics, in fact, is the great advantage over molecular methods. However, from the viewpoint of applied mycology, the biochemical profiles of these organisms offer the most useful identification system. The taxonomic significance of the results from such investigations and their contribution to a better understanding of the complex situation are undeniable. All earlier views and systems were based on the knowledge and technology available at that time. Current students of this group can similarly only base their views and proposals on the information available. Current knowledge is advanced to what was known then. This will also be true about today’s concepts and those still to come. The now redundant systems were created to serve science and not because of human inadequacies. The nature of these fungi dictates to scientists an arbitrary species concept and user-friendly taxonomic systems. Various opinions about terms, and especially the conidiogenic processes, appear to be confusing, but led to a functional, although phylogenetically inadequate, system. What Kananaskis could not do for phylogenetics, it did for standardization of terms. / Thesis (PhD (Botany))--University of Pretoria, 2005. / Plant Science / unrestricted

Africa’s international marginalization is preponderantly conceptualized through world systems approaches, particularly structural dependency. Consequently, the region’s socioeconomic quagmire, characterized by economic stagnation, abysmal poverty, inequality and foreign dependency, is often attributed to its colonial heritage. Particular reference is made to the small size of the African state and its structural specialization in primary production. Collective self reliance based on mutual interdependence (regional integration) thus suggests itself as a logical way to overcome the structural constraints imposed by the small size of the state, while at the same time representing a viable alternative to asymmetric trade with developed countries. It is within the context of this theoretical framework that this study critiques the predisposition of the regional body in Southern Africa, the Southern African Development Community (SADC), towards a trade biased approach to regional integration (market integration). This critique is based on theoretical and empirical findings showing that trade led strategies are primarily suited for developed countries with robust manufacturing industries and complimentary production structures. Countries in Southern Africa are however characterized by a near absence of manufacturing industries, are at different levels of development and show low levels of trade complementarities. This study therefore concludes that market integration is an inappropriate strategy for regional integration in Southern Africa and in the process suggests development integration – a political economy approach, as an alternative.

Bibliography: p. 206-228. / Understanding a widespread motif in San rock art - a human figure depicted in frontal perspective with distinctive bodily characteristics - is the aim of this study. A concentration of these figures in north eastern Zimbabwe was first described by researchers in the 1930s and subsequently, when one researcher, Elizabeth Goodall, described them as 'mythic women'. Markedly similar figures in the South African art have received little attention. On the basis of fieldwork in the KwaZulu-Natal Drakensberg, the south western Cape (South Africa) and Zimbabwe, and an extensive literature survey, a spectrum of these figures is described. In order to further understanding of the motif, existing interpretive methods and the traditions which inform them are examined, with a view to outlining a number of areas in need of attention. It is argued that analysis of rock art remains dependent on a range of dualistic notions which may be linked to retained structuralist ideas. It is suggested that the dominant model in rock art research, in which the rock art is seen as essentially shamanistic, perpetuates distinctions between mind and body, myth and ritual, and sacred and profane, while in its search for general truths concerning the rock art, and its central focus on iconography, the model retains traces of linguistic structuralism. It is proposed that the 'mythic woman' motif, with its gendered and sexual characteristics, is not well accounted for by reference to southern San ritual and religious practice alone. Drawing on contemporary theories concerning temporality and embodiment, it is argued that the motif is better understood in relation to recurrent themes of death and regeneration in San mythology and oral narratives, with shamanistic practice enacting related themes. The motif may be seen as representing San history in terms of culturally specific temporal schemes arising from San experience of the world. The 'ethnographic method', by means of which San accounts are used to illuminate features of the art, is reassessed and extended. Hermeneutic theories are drawn upon in order to address questions regarding the way in which ethnographies and art may be mutually illuminating, and to account for the inevitability of multiple interpretations arising from the situated process of reading or viewing. Prominent themes, images and devices in San myth and oral narrative are discussed in an attempt to move beyond a narrowly iconography-centred approach and in order to account for devices and stylistic features of San arts which are evident in both verbal and visual media. Implications of the research for investigating an archaeology of gender, and the writing of San history, are discussed.

In this study, the selection and breeding of Friesian horses in Southern Africa were evaluated. Literature was reviewed for sUbjective and objective selection criteria in horse breeding with special reference to the Friesian. 852 Pedigree records from Friesian horses registered at the FPSSA and SAFBA, were included for pedigree analyses and 232 horses were measured for eight different linear body measurements. Only 25,7% of the population was found to be inbred. A regression of average inbreeding on year of the whole population, indicated a relatively slow increase in the rate of inbreeding. It is, however, suspected that this could be a conservative estimation, because of the limited pedigree information. The results indicated that the Friesian horse is normally of rectangular (height at withers: body length) shape. A large average difference between wither height and back height was observed. The cannon length measurements were proportional to overall size, no obvious deviations were observed. Pearson correlation estimates between the eight body measurements were mostly in accordance with other studies on horses reported in the literature. A sire model was fitted for the estimation of heritability for wither-, back- and croup height, body length, cannon circumference and cannon length. Estimates ranged from 0.30 for wither height to 0.57 for cannon circumference. The results indicate that South African breeders can apply body measurements in their selection programs for Friesians. From the results, guidelines were provided for establishing a database for Friesian horses in Southern Africa to ensure a scientific approach to selection and breeding. / Dissertation (MSc (Agric))--University of Pretoria, 2003. / Animal and Wildlife Sciences / unrestricted