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Sarma, Diganta. "Assessment of sustainable groundwater utilization with case studies from semi-arid Namibia." University of the Western Cape, 2016. http://hdl.handle.net/11394/5649.
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Philosophiae Doctor - PhDThe thesis addresses sustainability of groundwater utilization in arid and semiarid regions of Namibia. Recharge in this hydrogeological setting occurs as discrete events to aquifers that are bounded in extent. Case studies involving fractured hardrock and alluvial aquifers with aquifer-ephemeral river interaction were considered. The nature of recharge to arid region bounded aquifers was explored. In arid region aquifers, roundwater storage is depleted during extended dry periods due to pumping and natural discharge. Steady state conditions are rarely achieved. With lowering of the water table, evapotranspiration is reduced thus decreasing aquifer discharge. However, depletion of ephemeral river flow is the primary source of water to boreholes. Physical constraints such as river bed and aquifer hydraulic properties set a limit to the degree of natural replenishment possible during flow events. An approach to assessing sustainable yield of a fractured rock aquifer associated with ephemeral river flow is discussed using a case study from rural semi-arid Namibia. Limited data required the simulation results to be verified against geological and hydrogeological constraints. The aquifer’s gain in storage is estimated through numerical simulation. It provides a basis for groundwater scheme management that rely on limited data in semi-arid conditions in sub-Saharan Africa. Aspects related to ephemeral river flow and groundwater recharge to strip alluvial aquifers was addressed in the second case study. The processes controlling infiltration, significance of surface water and groundwater losses, and possible artificial recharge options were investigated through numerical simulation. It was concluded that recharge processes in arid alluvial aquifers differ significantly from those in humid systems. Conjunctive use of surface and groundwater resources require artificial augmentation of aquifer recharge due to constrains in natural infiltration rates. The study provides a reference for sustainable management of alluvial aquifer systems in similar regions. It is seen from the study that high rates of groundwater exploitation deplete surface water resources needed downstream while failure to capture surface flow during flood events cause loss of potential recharge. It is concluded that as water demand in Namibia increases, basin wide combined surface water and groundwater resource evaluation and management have become a necessity.
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De, Almeida Louise. "The effect of sewage effluent from De Beers marine diamond mining operations on the expression of cytochrome P450 (CYP1A) and vitellogenin (vtg)." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1009440.
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Sewage effluents disposed into the marine environment from De Beers Marine Namibia diamond mining vessels have the potential to cause endocrine disruptive effects in marine organisms. Endocrine disruption refers to the alteration of the normal functioning of the endocrine system and various chemicals have the ability to mimic hormones, effecting endogenous hormone synthesis, transport, receptor interaction and intracellular signaling. The potential endocrine disruptive effects, caused by the release of different types of sewage effluents into the ocean, on fish species is a concern due to the commercial importance of fish species found in the mining area e.g. hake, sole, horse mackerel. Increased awareness of marine environmental degradation due to the presence of chemical contaminants has resulted in research being done on early warning systems, in the form of biomarkers. Cytochrome P450 monooxygenase 1A (CYP1A) and vitellogenin (vtg) are important proteins found in fish liver and blood, that have been used as biomarkers for the detection of pollutants in fish. CYP1A is a subfamily of the P450 superfamily of enzymes and catalyzes the oxidation, hydrolysis and reduction of exogenous and endogenous compounds (phase I reactions) and thus has the capacity to regulate the metabolism of several organic contaminants. CYP1A expression is altered by exposure to planar xenobiotic compounds e.g. polyaromatic hydrocarbons. Vtg is an important precursor for egg yolk proteins and plays a role in the growth and development of an oocyte. Expression of this protein is altered upon exposure to estrogenic compounds. The aim of this project was to isolate CYP1A from fish liver by differential centrifugation and optimize conditions for the CYP1A-mediated ethoxyresorufin-Odeethylase (EROD) assay and western blot analysis (to assess CYP1A expression). Another aim of this study was to evaluate the potential effects of biologically disruptive chemicals from sewage effluents, discharged into the marine environment, on the expression of CYP1A in two species of hake, Merluccius capensis and M. paradoxus (Cape hake). CYP1A in Cape hake is approximately a 60 kDa protein and the highest EROD activity was detected in the microsomal fraction after differential centrifugation. Optimal EROD assay conditions were observed at pH 7.5, a temperature of 25 °C, 10 μl of sample and a reaction time of 30 seconds. Enzyme stability assays indicated a drastic decrease in enzyme activity after 30 seconds. The EROD assay was not NADPH dependent but was limited by NADPH supply, with an increase of 300% in EROD activity being observed with the addition of 0.1 M exogenous NADPH. The addition of dicumarol (40 μM), a phase II enzyme inhibitor, showed a 232% increase in EROD activity. This is because dicumarol inhibited enzymes with the capacity to metabolize the product (resorufin) of the EROD reaction. With regard to western blot analysis, the optimal primary (rabbit antifish CYP1A peptide) and secondary (anti-mouse/rabbit antibody-horseradish peroxidase conjugate (POD)) antibody dilutions were determined to be 1:1000 and 1:5000, respectively. The comparison of CYP1A expression in Cape hake samples from De Beers Marine mining area and reference sites showed higher EROD activity (16.29 ± 0.91 pmol/min) in fish samples from the mining area in comparison to the reference site (10.42 ± 2.65 pmol/min). Western blot analysis was in agreement with the EROD assay results and a higher CYP1A expression was observed in fish from the mining sites. The increased CYP1A expression observed in fish from the mining area is not definitively an indication of a pollutant effect in the environment, as several environmental and biological factors (e.g. photoperiod and age) must also be considered before reaching this conclusion. Another aim of this study was to purify vtg from Cape hake blood samples. Cape hake vtg was purified from fish plasma by selective precipitation with MgCl2 and EDTA. Precipitated sample was subjected to anion exchange chromatography using fast protein liquid chromatography (FPLC). Vtg eluted as two broad peaks and had a molecular weight above 200 kDa. SDS-PAGE analysis also resolved smaller molecular weight proteins below 70 kDa, which were thought to be vitellogenin cleavage proteins, lipovitellin and phosphovitins. Western blot analysis was performed; however, it did not produce any conclusive results. The purification of vtg enables further studies in characterizing this protein and developing assay aimed at detecting estrogenic pollutants in the marine environment
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Krapf, Carmen. "Ephemeral river systems at the Skeleton Coast, NW-Namibia sedimentological and geomorphological studies on the braided river dominated Koigab Fan, the cenozoic succession in the Uniabmond area and comparative studies on fluvio-aeolian interaction between ephemeral rivers and the Skeleton Coast erg /." Doctoral thesis, [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968609740.
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Matengu, Brian Munihango. "Groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, Namibia: Omdel Aquifer as case study." University of Western Cape, 2020. http://hdl.handle.net/11394/7852.
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Philosophiae Doctor - PhDThe study addressed the groundwater assessment and sustainable management of the coastal alluvial aquifers in Namib Desert, the Omaruru River Delta Aquifer (Omdel Aquifer) was used as a case study. Sustainable utilization of groundwater in parts of hyper-arid Sub-Saharan Africa, like the Namib Desert, is always a challenge due to lack of resources and data. Understanding of hydrogeological characteristics of the Omaruru Delta Aquifer System is a pre-requisite for the management of groundwater supply in the Central Namib area (Namib Desert). For the Omdel Aquifer in the Omaruru catchment, Namibia, issues to investigate include the lack of information on the geology and hydrogeological setting, the hydraulic properties and geometry of the aquifer at the inflow and outflow sections, groundwater recharge conditions upstream of the aquifer, and the impact of artificial recharge.
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Jobst, Petra. "Investigating water problems of F. albida along the Kuiseb river, Namibia." Thesis, University of Cape Town, 1996. http://hdl.handle.net/11427/25898.
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Spaggiari, Renato Igino. "Sedimentology of plio-pleistocene gravel barrier deposits in the palaeo-Orange River mouth, Namibia : depositional history and diamond mineralisation." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1004636.
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The largest known marine diamond placer, the Namibian mega-placer, lies along the Atlantic coast of south-western Africa from the Orange River mouth 1,000 km northwards to the Namibian-Angolan border. The most economically viable portion of the Namibian mega-placer (>75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa.KMBT_363
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Nakashole, Albertina Ndahafifwa. "Heavy minerals in the palaeo and modern Orange River and offshore southern Namibia." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/20057/.
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Linking the erosional record of drainage basins with the depositional record of sedimentary basins is a major challenge in geosciences. Thick diamondiferous gravel terrace deposits along the lower Orange River and their coeval downstream offshore deposits provide a rare opportunity for understating source-to-sink relationships. Two distinct gravel terrace deposits are recognised, based on clast and heavy mineral assemblage analysis at Boom, Lorelei, Sendelingsdrif, Daberas, Auchas Major, Auchas Lower and Arrisdrif, referred to as the Proto and Meso Orange River deposits. These are compared to offshore sample sites. The Proto Orange River deposits are coarser and characterised by a dominance of Karoo Supergroup shale and sandstone clasts whereas the younger Meso Orange River gravels exhibit a banded iron formation dominance. Differences in clast assemblage between the Proto and Meso deposits are ascribed to a more powerful river system during Proto-Orange River time, driven by a changing drainage basin geomorphology, rather than reworking of older deposits or changes in clast provenance. This is accompanied by an increase in local bedrock sources, including amphibole-epidote in the heavy mineral assemblages. The fluvial and marine gravels have similar detrital heavy mineral assemblage derived from the Namaqua Metamorphic Complex and Gariep Belt. Offshore, the eastern regions show a higher amphibole-epidote content similar to that of the Meso Orange River gravel. Therefore, offshore amphibole-epidote distribution is a function of the relative amount of Namaqua Metamorphic Complex derived sediments and also decay of these two minerals over time and is neither a function of northward longshore drift nor geomorphology of the seabed or sea level. Diamond indicator minerals derived from kimberlites do not persist into the heavy mineral assemblage of the study area. In Atlantic 1, a weak positive correlation of coarse magnetite with diamond grade for gravels that are closer to the Orange River mouth could be explained by their hydrodynamic similarities.
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Kamwi, Innocent Silibelo. "Fitting extreme value distributions to the Zambezi river flood water levels recorded at Katima Mulilo in Namibia." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The aim of this research project was to estimate parameters for the distribution of annual maximum flood levels for the Zambezi River at Katima Mulilo. The estimation of parameters was done by using the maximum likelihood method. The study aimed to explore data of the Zambezi's annual maximum flood heights at Katima Mulilo by means of fitting the Gumbel, Weibull and the generalized extreme value distributions and evaluated their goodness of fit.
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Van, der Merwe Schalk. "Is commercial livestock farming environmentally viable within the Orange and Fish River catchment area (OFCA) of Southern Namibia?" Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/4811.
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Includes bibliographical references.There are neither historical nor current baseline information relating to the productivity of the OFCA veld and a definite link between the current crisis and the possibly that it is suffering from the effects of having farmed the OFCA veld into a state of durable suboptimal productivity remains to be conclusively established. This current study has been undertaken in order to investigate such a possible link, and to reach a more definite conclusion with regards to the contribution of negative environmental feedback which may have arisen from commercial farming. Specifically, the study investigates the relationship between commercial livestock grazing regimes, possible associated resource degradation (losses in veld productivity and adverse structuring of botanical communities due to livestock grazing effects), and the current productive crisis within the sector.
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Jacobson, Peter James. "An ephemeral perspective of fluvial ecosystems: Viewing ephemeral rivers in the context of current lotic ecology." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30582.
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Hydrologic and material dynamics of ephemeral rivers were investigated in the Namib Desert to assess how hydrologic regimes shape the physical habitat template of these river ecosystems. An analysis of long-term hydrologic records revealed that the variation in mean annual runoff and peak discharge were nearly four times higher than the global average, rendering the rivers among the most variable fluvial systems yet described. Further, a pronounced downstream hydrologic decay characterized all of the rivers. The high spatio-temporal variability in flow was reflected in patterns of material transport. Retention of woody debris increased downstream, in contrast to patterns typically reported from more mesic systems, largely attributable to hydrologic decay. Woody debris piles were the principal retentive obstacles and played an important role in channel dynamics. They were also key microhabitats for various organisms, forming "hotspots" of heterotrophic activity analogous to patterns reported from perennial streams. Large amounts of fine particulate and dissolved organic matter (FPOM and DOM) deposited in the lower reaches of the rivers serve to fuel this heterotrophic biota. As a result of the hydrologic decay, sediment concentration (both organic and inorganic) increased downstream and the lower reaches of these rivers acted as sinks for material exported from their catchments. FPOM and DOM concentrations were among the highest reported for any aquatic system, and, contrary to patterns reported from more mesic systems, FPOM dominated the total organic load transported in these rivers. Inorganic solute concentration also increased downstream, resulting in a downstream increase in soluble salt content in floodplain soils. Soils within the river's lower reaches served as effective long-term integrators of hydrologic variability. The mean extent of floods entering the lower river was defined by an alluviation zone, evident from the convexity exhibited in the lower section of the rivers' longitudinal profiles. A downstream increase in the proportion of silt within floodplain soils is associated with increased sediment deposition. Silt deposition had a positive influence on moisture availability, plant rooting, and habitat suitability for various organisms, including fungi and invertebrates. In addition, a strong positive correlation was observed between silt, organic matter, and macronutrients. Thus, the hydrologic control of transport and deposition patterns has important implications for the structure and function of ephemeral river ecosystems. Finally, an examination of the influence of elephants upon riverine vegetation highlighted the importance of these systems as isolated resource patches interspersed in an arid and hostile landscape. Further, it illustrated that flooding was a key ecological process and that hydrologic alterations would affect the fluvial ecosystem as well as the regional landscape they drain.Ph. D.
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Kose, Eileen [Verfasser], Jürgen [Gutachter] Richter, and Ünsal [Gutachter] Yalçin. "Early And Late Ironworking Groups Along The Middle Kavango River In Northern Namibia During The First And Second Millennium AD. / Eileen Kose ; Gutachter: Jürgen Richter, Ünsal Yalçin." Köln : Universitäts- und Stadtbibliothek Köln, 2016. http://d-nb.info/121064259X/34.
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Noli, Hans Dieter. "An archaeological investigation of the Koichab River region of the south-western Namib Desert centred on the activities of Holocene hunter-gatherers." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/21816.
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Bibliography: pages 107-116.The 1986-1988 archaeological investigations of the previously largely unresearched Koichab River region the south-western Namib Desert are described. The sites studied are those of Holocene hunter-gatherers. Included are the analyses of archaeological remains from two excavations and three surface collections. The investigations resulted in the recovery of the oldest dated archaeological material from the entire Namib coast, and the halving of the duration of the previously established Holocene hiatus for the southern Namib. It is suggested that the resources of the Koichab River reion were subjected to opportunistic utilization, a subsistence strategy which may have been more extensively resorted to in all of southern Africa than has so far suspected.
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Koekemoer, Johannes Hendrik. "A fish ecological study of rivers and floodplains in the Eastern Caprivi, Namibia." Thesis, 2008. http://hdl.handle.net/10210/1025.
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A pre-requisite for the formulation of a responsible fisheries management programme for an aquatic ecosystem is a comprehensive fish ecological study, which focuses on the various ecological and biological aspects of the fish population and related fisheries data. The fish ecological and fisheries data must be considered during the decision making process of management. The freshwater fish of the Eastern Caprivi, Namibia, has enormous value in terms of the local subsistence fishery. Fish is an affordable protein source in this region, and is of socioeconomic importance, as it generates income for up to 82% of the local households. Unfortunately commercialisation of the resource is becoming more and more prevalent in this region, as local commercial fishermen take advantage of the readily available fish resource, by the callous use of non-selective fishing gears such as drag nets. Unregulated fishing methods, such as the use of drag nets, is detrimental to the fish population and ecology of an aquatic ecosystem. The Ministry of Fisheries and Marine Resources (MFMR), Namibia, recognised the need for a fisheries management programme in the Eastern Caprivi region. Proper fisheries legislation, in terms of the recommended fishing gears which may be used by local fishermen, is however needed to achieve the goals set by such a management programme. The MFMR realised the need for a comprehensive fish ecological study in the Eastern Caprivi, which would thus aid in the formulation of legislation measures. Five, flood related, fish ecological surveys were consequently conducted in the Eastern Caprivi, between 1997 to 1999. The relevant ecological, biological, and fisheries data was gathered. This data will lay the basis for future studies in this region, and will aid management in their decision making process. Results derived from the experimental gill net data is of the most importance in the formulation of fisheries legislation. The data collected in the Eastern Caprivi was processed and the results presented and discussed in this study. Conclusions are made concerning the biological and ecological aspects of the fish species and the fish population. Recommendations, concerning the fisheries data, are made to the management of the Ministry of Fisheries and Marine Resources in aid of their legislation process. The Eastern Caprivi is a productive and intricate wetland system, consisting of rivers, floodplains, canals, lakes, swamps and marshlands. Three perennial rivers, the Zambezi, Chobe, and Kwando Rivers with their associated floodplains were studied. A total of 82 fish species occur in the Eastern Caprivi, of which 69 were recorded during this studyProf. G.J. Steyn
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Paterson, John Richard Bernard. "The Kunene River mouth : managing a unique environment." Thesis, 2007. http://hdl.handle.net/10413/1025.
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The Kunene River Mouth (KRM) is one of only two river mouths in Namibia. The Kunene river and river mouth is bisected by the international border between Namibia and Angola, and lies between two protected areas, Iona National Park in Angola and Skeleton Coast Park in Namibia. The governments of Namibia and Angola have signed a Memorandum of Understanding (MoU) to link these two parks as a transfrontier park. This study further proposes a transfrontier Marine Protected Area to protect the marine environment surrounding the KRM and the Angola Benguela Front. The KRM is a fluvially dominated freshwater river mouth. The area is a biogeographically important biodiversity hotspot. The remoteness and pristine character contribute to the aesthetic appeal of the area. This study provides a profile of the KRM addressing its conservation value in terms of both biodiversity and aesthetic value, making use of the concept of “sense of place”. An analysis of all current and potential stakeholders is presented and their interests, activities and potential threats are evaluated. The main stakeholders are Government: the Ministry of Environment and Tourism, the Angolan Government, Ministry of Fisheries and Marine Resources, Namwater, Ministry of Mines and Energy, and the Kunene Regional Council. The private sector presently has a small stake in the area, with the exception of the Northern Namibia Development Corporation who is prospecting for diamonds at the KRM. Although the area has great tourism potential there is no tourism development currently underway or planned. The threat analysis suggests that the KRM is under severe threat from inappropriate development, both locally as well as within the catchment. Mining and prospecting were identified as the greatest threat, whereas tourism poses the least threat to the area. It is suggested that appropriate tourism is the most suitable development for this sensitive area. There is currently no coherent management strategy in place for the KRM. The current environmental legislation is ineffective. The need for a stringent adaptive management regime is identified and management goals for the area are suggested. It is further suggested that the concepts of “Thresholds of Potential Concern” and “Limits of Acceptable Change” are useful to monitor indicators for biophysical components and development activities respectively and to maintain a “Desired State” for the area. This “Desired State” must be the result of a participatory process. To be effective stakeholders must reach consensus on the “Desired State”. An eight step participatory process is proposed to develop and implement an adaptive management and development strategy for the KRM.Thesis (M.Env.Dev.) - University of KwaZulu-Natal, Pietermaritzburg, 2007.
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Krapf, Carmen [Verfasser]. "Ephemeral river systems at the Skeleton Coast, NW-Namibia : sedimentological and geomorphological studies on the braided river dominated Koigab Fan, the cenozoic succession in the Uniabmond area and comparative studies on fluvio-aeolian interaction between ephemeral rivers and the Skeleton Coast erg / vorgelegt von Carmen Krapf." 2003. http://d-nb.info/968609740/34.
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Geiger, Markus. "An Explanation of the Geological Map 1:10000 of the Namibian borderland along the Orange River at Zwartbas - Warmbad District - Karas Region - Namibia." Master's thesis, 1999. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-46269.
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The locality of Zwartbas is situated at the border of Namibia and South Africa about 15 km west of Noordoewer. The mapped area is confined by the Tandjieskoppe Mountains in the north and the Orange River in the south. Outcropping rocks are predominantly sediments of the Nama Group and of the Karoo Supergroup. During the compilation of this paper doubts arose about the correct classification of the Nama rocks as it is found in literature. Since no certain clues were found to revise the classification of the Nama rocks, the original classification remains still valid. Thus the Kuibis and Schwarzrand Subgroup constitute the Nama succession and date it to Vendian age. A glacial unconformity represents a hiatus for about 260 Ma. This is covered by sediments of the Karoo Supergroup. Late Carboniferous and early Permian glacial deposits of diamictitic shale of the Dwyka and shales of the Ecca Group overlie the unconformity. The shales of the Dwyka Group contain fossiliferous units and volcanic ash-layers. A sill of the Jurassic Tandjiesberg Dolerite Complex (also Karoo Supergroup) intruded rocks at the Dwyka-Ecca-boundary. Finally fluvial and aeolian deposits and calcretes of the Cretaceous to Tertiary Kalahari Group and recent depositionary events cover the older rocks occasionallyDie Lokalität Zwartbas liegt an der namibisch-südafrikanischen Grenze, etwa 15 km westlich von Noordoewer. Das Kartiergebiet wird durch die Tandjiesberge im Norden und den Oranje Fluß im Süden begrenzt. Die anstehenden Gesteine bestehen hauptsächlich aus Sedimenten der Nama Gruppe und der Karoo Supergruppe. Während der Erarbeitung dieser Abhandlung entstanden Zweifel an der Klassifikation der Nama Gesteine, so wie sie in der Literatur zu finden ist. Da keine sicheren Hinweise zur Revision der Klassifikation der Nama Gesteine gefunden wurden, bleibt die ursprünglich Klassifikation jedoch gültig. Die Kuibis und Schwarzrand Untergruppe bilden also die Nama Abfolge und datieren sie ins Vendian. Eine glaziale Diskontinuität repräsentiert einen Hiatus von etwa 260 Mio Jahren. Sie wird überlagert von Sedimenten der Karoo Supergruppe. Spät-karbone und früh-permische glaziale Ablagerungen von diamiktitischen Tonsteinen der Dwyka Gruppe und Tonsteine der Ecca Gruppe liegen über dieser Diskontinuität. Die Sedimente der Dwyka Gruppe sind fossilführend und enthalten Tufflagen. Ein Sill des jurassischen Tandjiesberg Dolerit Komplex (auch Karoo Supergruppe) intrudierte in die Gesteine an der Dwyka-Ecca Grenze. Schließlich bedecken lokal fluviatile und äolische Ablagerungen und Kalkkrusten der kretazischen und tertiären Kalahari Gruppe und jüngerer Ablagerungsereignisse die älteren Gesteine
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Unandapo, Lazarus Pendapala. "Longitudinal modelling of water levels of the Okavango River." Thesis, 2016. http://hdl.handle.net/10539/21273.
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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. May 30, 2016.In statistics, a model is as good as the data fed to it. Data about hydrological events continues to grow rapidly over the years, with different variables being recorded on a continuous scale. These variables can be interpreted and used in a different manner among disciplines. Thus, choosing the right variables and interactions among variables is an important statistical step in building a good and accurate model. This dissertation involved the development of a statistical model which can be used to predict weekly water level within the Okavango river in northern Namibia. The parameters of the statistical mixed model were estimated based on two methods for longitudinal data, the Generalised Estimating Equations (GEE) which is a well known method of parameter estimation in longitudinal data analysis when the observed variables are correlated, and the Restricted Maximum Likelihood Estimation (REML) which is a likelihood based approach method, unlike the GEE. Using cross-validation and a simulation study, the GEE method of estimation was found to be less accurate and inconsistent in terms of prediction of parameter estimation of water level while the well known REML was found to predict the water level with a good degree of accuracy, consistency and with lower variance. Parameters from a simulation study have also shown less bias in REML method and predicted the cross-validation test-set with less bias.
GR 2016
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Brain, Conrad. "The eco-physiology of baboons living in the Kuiseb river canyon, Namibia." Thesis, 2016. http://hdl.handle.net/10539/20897.
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A dissertation submitted to the Faculty of Science, University
of the Witwatersrand, Johannesburg, in fulfilment of the
requirements for the degree of Doctor of Philosophy
Okaukuejo 1993This study was designed to investigate the eco-physiology of baboons (Papio cynocephalus ursinus) in a troop living in the Kuiseb River canyon of the central Namib desert, Namibia. Answers were sought for two major questions: what Were the baboons prospects for survival and were there special adaptations allowing for their survival in their desert environment? To answer the former, life history phenomena of individuals and demographic changes within the troop were studied over a six year period. Results showed that the troop was not self-sustaining. Ectco-parasite infestations killed the majority of infants born to high ranking female baboons, while infant kidnapping by high ranking females killed most lower ranking females' infants. The high infant mortality appeared to affect the behaviour of adult male baboons in the troop, causing non-paternal males to fight harder to maintain a rank with reproductive opportunities, usually with serious wounding or death as a consequence. Answers to the latter question involved investigation into the baboons feeding patterns and diet, body temperature regulation, water flux rates and methods of body water conservation. Despite their desert environment, the baboons had access to plants of high water content and Were not dependent on free water intake. Plant foods also had low electrolyte concentrations. Body temparetures of three free-ranging baboons recorded by intraperitoneal radio tolemeters were remarkably labile, indicating an adaptive heterothermy. The baboons appeared to employ evaporative cooling only when water was available to drink and used cool sub-surface sand to slow their body temperature rises. water flux rates determined using tritiated water of three free-ranging baboons were not different to those of baboons from elsewhere. Acquisition of free water at times of water scarcity was strictly rank related. Body water conservation was apparently achieved through a combination of factors: urine concentration of Kuiseb baboons increased significantly when they were water deprived. The kidneys of the Kuiseb baboons, obtained from baboons that died naturally were anatomically significantly different and head greater urine concentrating abilities than the kidneys Of baboons from the northern Transvaal, South Africa. Kuiseb baboons showed efficient faecal water conservation, similar to other desert adapted mammals, Body water also was apparently conserved by engaging in water conservative behaviour, predominantly inactivity.
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Freemantle, Guy George. "Primary uranium mineralisation of the central Damara Orogen, Namibia: a petrographic, geochemical and mineralogical account of the granite - hosted uranium deposits situated along the Swakop- and Khan River valleys." Thesis, 2017. http://hdl.handle.net/10539/23612.
Full textAbstract:
A thesis submitted to the Faculty of Science in fulfilment of the requirements for the degree of Doctor of Philosophy at the School of Geosciences University of the Witwatersrand, Johannesburg, 2017Namibia, the 6th largest producer of uranium globally, has produced uranium from Pan African granite-hosted (primary) deposits since 1976, and from palaeochannel deposits since 2007; exporting 3 472 tonnes U in 2016. The large granite-hosted deposits at the Husab Mine are expected to add over 5 700 tonnes U/year at peak, while three large primary-hosted deposits remain in various stages of development at Goanikontes, the Ida Dome, and Valencia. This study presents a comprehensive geological, geochemical and uranium mineralogical appraisal of four of the major primary-hosted uranium deposits, all situated within the southern Central Zone (sCZ) of the polydeformational (D1-D3) Damara Belt. The sCZ comprises highly deformed Neoproterozoic sediments, unconformably draped over rheologically competent granite-gneiss domes and inliers of a Palaeoproterozoic basement. A suite of fractionated sheeted leucogranites (SLGs) are a characteristic of the final stages of Orogenic deformation; while most SLGs appear to precede D3 deformation and metamorphism (ca. 510 Ma); most of the mineralised SLGs across the region invade reduced-facies sediments in pressure shadows formed in the hinges and limbs of upright D3 antiforms, proximal to basement inliers. A pre-existing, six-fold, alphabetised SLG classification scheme is revised and extended to categorise distinctive and consistent field and petrographic characteristics of the SLGs across the region. Discriminating SLG sub-types is less consistent in standard geochemical diagrams, except where high field-strength (HFS) and rare-earth elements (REE) are concerned. REE profiles in pre-D3 SLGs reflect abundances, or paucities, of characteristic accessory mineral assemblages; while REE profiles show relative REE enrichment, prominent REEfractionation and -ve Eu anomalies in the uraniferous SLGs, reflecting lower-percentage partial melts in the more uraniferous samples. The overwhelming majority of primary uranium mineralisation is in magmatic uraninite, followed by coffinite which predominate as a replacement phase of uraninite, and more rarely as solid solution with thorite. The refractory minerals betafite and brannerite are rare, but are locally abundant in discrete, magmatic textures within uraniferous SLGs of some deposits. Hydrated uranyl silicates predominate in the supergene portions of the orebodies across the region. An electron microprobe study presents the first comprehensive assessment of uraninite compositions in the region, while Husab deposit betafite and brannerite compositions allow for a well-rounded comparison with refractory minerals from the Rössing deposits. Key Words Primary Uranium, Granite, Orogenic, Damara, Namibia, Rare Earth Elements, Mineralisation, Fractionation, High-grade Metamorphism, Economic Geology, Mining, Processing, Uraninite, Coffinite, Etango, Goanikontes, Husab, Ida Dome, Rössing, Valencia
XL2018
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Ailonga, Chris Elungi. "Impact of the Daberas slimes dam in southern Namibia on the water quality of the Orange River." Thesis, 2011. http://hdl.handle.net/10539/10282.
Full textAbstract:
Daberas slimes dam has been seeping since 2004. As a result, seepage leachate
could have been passing through a permeable layer of gravel from the slimes dam
to an international river. This was a major concern especially from department of
Water Affairs and the Ministry of Mines and Energy in Namibia. The main
concern was the possible water contamination of the Orange River, which of
course leads to the Orange River mouth, which is a Ramsar protected site and the
other concern was that the trees along the riverbank section that is adjacent to the
Daberas tailings dam were dying.
This study has however revealed that the seepage leachate from the Daberas
slimes dam is actually reaching the Orange River. Given limited available results,
a minor impact on the water quality of the river has been recorded. All parameters
that were studied are well within the limit of excellent water quality, with respect
to the current water guidelines in Namibia. Iron and manganese which are
components of ferrosilicon which is used as Dense Medium Separation (DMS)
material at Daberas remains well within the limit of excellent water quality as per
Namibian water guidelines. Most interestingly, the latest sample analysis
confirms that iron concentration in water is actually declining near the Daberas
mine section, meaning that iron concentration is higher in the upstream section in
the latest samples taken in July 2007. The water quality in the Orange River section downstream of Daberas mine is Arated,
characterising water with excellent quality, as per Namibian water
guidelines. Despite that, an effective integrated water management plan and
concise water-monitoring plan is recommended for the Daberas mine.
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Van, Zyl Barend Johannes. "'n Visekologiese ondersoek van die Okavango- en Kuneneriviere met spesiale verwysing na visontginning." Thesis, 2014. http://hdl.handle.net/10210/10173.
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