The geology and metallogeny of the Otavi mountain land, Damara orogen, SWA/Namibia, with particular reference to the Berg Aukas Zn-Pb-V deposit a model of ore genesis
- Authors: Misiewicz, Julian Edward
- Date: 1988
- Subjects: Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4959 , http://hdl.handle.net/10962/d1005571 , Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
- Description: The Olavi Mountain Land is a 10 000 km2 mineral province located at the eastern extremity of the exposed Northern Platform of the Damara Pan African orogenic belt. The Olavi Mountain Land is tbe most important mineral province on the Northern Platform. Exploitation of tbe Cu-Pb-Zn-V province has been on-going since the possession of the territory by the German colonial authority in 1890. Production has been mostly from four mines which in order of importance are Tsumeb, Kombat, Berg Aukas and Abeoab. A second mineral province on the Northern Platform located in the west is centred on Sesfontein where as yet only insignificant mineralization has been noted. Besides these localities, the Northern Platform is conspicuously devoid of notable mineralization. The aim of this thesis has been to document tbe Berg Aukas deposit, an important end-member type of mineralization in the Otavi Mountain Land. The basic premise bas been to show tbat the derivation and localization of the mineralization is a consequence of two broad controls which can be simply summarised as features of the basement and of the carbonate sequences. The geodynamic evolution of the Damara Belt commenced with intra-continental rifting approximately 900 Ma ago. Rift grabens trending north-east were filled by the Nosib Group which comprises mostly clastic lithologies but also some volcanics. The earliest and largest rift is referred to as the Northern Rift. Separation of the Congo, Kalahari, and proto-South American cratons resulted in rifting and rapid downwarping so that an encroaching sea and an Olavi Group carbonate shelf developed along the northern margin of the Northern Rift. Significantly, the carbonates only covered the Northern Rift in the area of the Otavi Mountain Land where a basinal dome, referred to as the Grootfontein Basement High, marked the basin edge. In the west, the carbonates covered the less important Sesfonfein Rift, and it is only in these two areas where Nosib sequences underlie the carbonate platform. Carbonate sedimentation was interrupted by a major period of crustal readjustment and the deposition of an extensive mixtite throughout the geosynclinal Swakop Trough and Northern Platform. This is referred to as the Chuos Formation and subdivides the Olavi Group into a lower Abenab and an upper Tsumeb Subgroup. Reversal of spreading led to plate collision and subduction of tbe Kalahari craton beneath the Congo craton. It was accompanied by orogenesis which resulted in F1 folding of the Northern Platform into a series of north-easterly trending intermontane basins into which a molasse sequence known as the Mulden Group was unconformably deposited. Following this major north-south deformation mild east-west compression initiated F2 folding and the formation of doubly plunging synclines. The Berg Aukas Syncline represents a primary depositional basin which was subsequently folded. The original basin was formed by late Nosib rifting wben spreading caused the Swakop geosynclinal Trough to form. Carbonates of the basal Berg Aukas Formation were deposited in a lagoonal setting typified by reef and fore-reef facies witb peri-platform conditions. Rapid subsidence caused these sediments to be overlain by deep water carbonates of the Gauss Formation. Two styles of mineralization known as the Tsumeb-type and Berg Aukas-type are stratigraphically, isotopically, and mineralogically distinct. The Tsumeb-type is a cupriferous variety of discordant bodies confined to the upper sequences beneath the Mulden unconformity. The Berg Aukas-type is a Zn-Pb variety confined to tbe basal unconformity. The Berg Aukas deposit comprises three ore bodies known as the Northern Ore Horizon, the Central Ore Body, and the Hanging Wall Ore Body. Sphalerite and galena constitute the bypogene ore. Willemite, smithsonite, cerussite, and descloizite are important supergene ores. A review of genetic models concludes that a magmatic origin initially proposed for tbe Tsumeb deposit is entirely rejected and a basin dewatering model in line with Mississippi Valley-type deposits is proposed. The syntectonic nature of mineralization at Berg Aukas and elsewhere in the Otavi Mountain Land indicates that orogenesis encouraged dewatering and leaching of metals from a broad mineralizing front along the margin of the Swakop Trough. These were transported by acidic saline brines which migrated along the clastic aquifers and structural conduits provided by the Northern Rift. Fluid inclusion studies indicate that the hydrothermal fluids at Berg Aukas were very saline (23% TDS) and were transported at temperatures ranging between 92° to 210°C. Hydrothermal fluids which mineralized Berg AukaS-type deposits migrated along the basal unconformity towards the basement high and were responsible for hydrothermally altering the basement granites and gabbros and the Nosib clastic rocks. Tsumeb-type deposits resulted by migration of fluids through the carbonate pile and along north-easterly trending basement geofractures. As a consequence of variation in transport, the Berg Aukas-type and Tsumeb-type fluids leached different sources and therefore derived mineralogically and isotopically seperable characteristics. The localization of the Berg Aukas ores was controlled by the carbonate stratigraphy and structure. Hydrothermal karsting and ore deposition took place on the contact between Massive Grey and Light Grey Dolostones which represents a permeability contrast. The movement of the hydrothermal fluids was controlled by north-south trending vertical fractures caused by F2 folding which resulted in a peric1inal structure. Hydrothermal karsting was accompanied by ca1citic, dolomitic and silicic alteration. The heated acidic fluids initiated solution collapse and a variety of breccia types. Supergene processes resulted in oxidation and upgrading of the ore. Vanadium derived indirectly from gabbros in the basement complex were transported as calcium metavanadate complexes and deposited on contact with the oxidizing base metal sulphides.
- Full Text:
- Date Issued: 1988
- Authors: Misiewicz, Julian Edward
- Date: 1988
- Subjects: Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4959 , http://hdl.handle.net/10962/d1005571 , Geology -- Namibia -- Damaraland , Ore deposits -- Namibia , Orogeny , Metallogeny , Geodynamics
- Description: The Olavi Mountain Land is a 10 000 km2 mineral province located at the eastern extremity of the exposed Northern Platform of the Damara Pan African orogenic belt. The Olavi Mountain Land is tbe most important mineral province on the Northern Platform. Exploitation of tbe Cu-Pb-Zn-V province has been on-going since the possession of the territory by the German colonial authority in 1890. Production has been mostly from four mines which in order of importance are Tsumeb, Kombat, Berg Aukas and Abeoab. A second mineral province on the Northern Platform located in the west is centred on Sesfontein where as yet only insignificant mineralization has been noted. Besides these localities, the Northern Platform is conspicuously devoid of notable mineralization. The aim of this thesis has been to document tbe Berg Aukas deposit, an important end-member type of mineralization in the Otavi Mountain Land. The basic premise bas been to show tbat the derivation and localization of the mineralization is a consequence of two broad controls which can be simply summarised as features of the basement and of the carbonate sequences. The geodynamic evolution of the Damara Belt commenced with intra-continental rifting approximately 900 Ma ago. Rift grabens trending north-east were filled by the Nosib Group which comprises mostly clastic lithologies but also some volcanics. The earliest and largest rift is referred to as the Northern Rift. Separation of the Congo, Kalahari, and proto-South American cratons resulted in rifting and rapid downwarping so that an encroaching sea and an Olavi Group carbonate shelf developed along the northern margin of the Northern Rift. Significantly, the carbonates only covered the Northern Rift in the area of the Otavi Mountain Land where a basinal dome, referred to as the Grootfontein Basement High, marked the basin edge. In the west, the carbonates covered the less important Sesfonfein Rift, and it is only in these two areas where Nosib sequences underlie the carbonate platform. Carbonate sedimentation was interrupted by a major period of crustal readjustment and the deposition of an extensive mixtite throughout the geosynclinal Swakop Trough and Northern Platform. This is referred to as the Chuos Formation and subdivides the Olavi Group into a lower Abenab and an upper Tsumeb Subgroup. Reversal of spreading led to plate collision and subduction of tbe Kalahari craton beneath the Congo craton. It was accompanied by orogenesis which resulted in F1 folding of the Northern Platform into a series of north-easterly trending intermontane basins into which a molasse sequence known as the Mulden Group was unconformably deposited. Following this major north-south deformation mild east-west compression initiated F2 folding and the formation of doubly plunging synclines. The Berg Aukas Syncline represents a primary depositional basin which was subsequently folded. The original basin was formed by late Nosib rifting wben spreading caused the Swakop geosynclinal Trough to form. Carbonates of the basal Berg Aukas Formation were deposited in a lagoonal setting typified by reef and fore-reef facies witb peri-platform conditions. Rapid subsidence caused these sediments to be overlain by deep water carbonates of the Gauss Formation. Two styles of mineralization known as the Tsumeb-type and Berg Aukas-type are stratigraphically, isotopically, and mineralogically distinct. The Tsumeb-type is a cupriferous variety of discordant bodies confined to the upper sequences beneath the Mulden unconformity. The Berg Aukas-type is a Zn-Pb variety confined to tbe basal unconformity. The Berg Aukas deposit comprises three ore bodies known as the Northern Ore Horizon, the Central Ore Body, and the Hanging Wall Ore Body. Sphalerite and galena constitute the bypogene ore. Willemite, smithsonite, cerussite, and descloizite are important supergene ores. A review of genetic models concludes that a magmatic origin initially proposed for tbe Tsumeb deposit is entirely rejected and a basin dewatering model in line with Mississippi Valley-type deposits is proposed. The syntectonic nature of mineralization at Berg Aukas and elsewhere in the Otavi Mountain Land indicates that orogenesis encouraged dewatering and leaching of metals from a broad mineralizing front along the margin of the Swakop Trough. These were transported by acidic saline brines which migrated along the clastic aquifers and structural conduits provided by the Northern Rift. Fluid inclusion studies indicate that the hydrothermal fluids at Berg Aukas were very saline (23% TDS) and were transported at temperatures ranging between 92° to 210°C. Hydrothermal fluids which mineralized Berg AukaS-type deposits migrated along the basal unconformity towards the basement high and were responsible for hydrothermally altering the basement granites and gabbros and the Nosib clastic rocks. Tsumeb-type deposits resulted by migration of fluids through the carbonate pile and along north-easterly trending basement geofractures. As a consequence of variation in transport, the Berg Aukas-type and Tsumeb-type fluids leached different sources and therefore derived mineralogically and isotopically seperable characteristics. The localization of the Berg Aukas ores was controlled by the carbonate stratigraphy and structure. Hydrothermal karsting and ore deposition took place on the contact between Massive Grey and Light Grey Dolostones which represents a permeability contrast. The movement of the hydrothermal fluids was controlled by north-south trending vertical fractures caused by F2 folding which resulted in a peric1inal structure. Hydrothermal karsting was accompanied by ca1citic, dolomitic and silicic alteration. The heated acidic fluids initiated solution collapse and a variety of breccia types. Supergene processes resulted in oxidation and upgrading of the ore. Vanadium derived indirectly from gabbros in the basement complex were transported as calcium metavanadate complexes and deposited on contact with the oxidizing base metal sulphides.
- Full Text:
- Date Issued: 1988
The hydrogeology of a Karoo basalt/sandstone contact aquifer moretele II district Republic of Bophuthatswana southern Africa
- Authors: Martinelli, Giorgio Luigi
- Date: 1988
- Subjects: Basalt -- South Africa -- Bophuthatswana Sandstone -- South Africa -- Bophuthatswana Aquifers -- South Africa -- Bophuthatswana Hydrogeology -- South Africa -- Bophuthatswana
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4802 , http://hdl.handle.net/10962/d1001902
- Description: As part of a development programme in the Moretele II District, the Government of the Republic of Bophuthatswana, commissioned in 1983 the building of a dry system coal-fired power station. The lack of local surface water to cool the power station resulted in a decision to investigate the potential of the ground water resources. The resources will be required to supply an anticipated 30 year water demand. Because of the high capital investment and the importance of establishing an accurate assessement of the ground water potential there was a need for a comprehensive and detailed hydrogeological study. The specific aim of the investigation is to assess and quantify the long term reliability of the ground water resources. The very limited data for the area necessitated a particularly thorough and detailed investigation. This thesis describes the hydrogeological investigation carried out to define the ground water resource potential of this area. The main objectives of the study are to identify, recognize and evaluate the hydrogeological processes operating on this previously ill-defined Karoo aquifer. To achieve the research objectives the hydrogeological investigation was formulated to make use of various traditional geological, hydrogeological, geophysical and hydrochemical techniques in a logical framework. More specifically, the work involved a hydrocensus, a geophysical survey, the drilling of exploratory boreholes, aquifer tests to determine the intrinsic hydraulic parameters, water level measurements and the collection and analysis of water samples. The combined results of these various techniques provided data to quantify, evaluate and then propose management strategies for the identified resources. The study provided an understanding of the local hydrogeological conditions and has allowed for a conceptual model of the aquifer system to be derived
- Full Text:
- Date Issued: 1988
- Authors: Martinelli, Giorgio Luigi
- Date: 1988
- Subjects: Basalt -- South Africa -- Bophuthatswana Sandstone -- South Africa -- Bophuthatswana Aquifers -- South Africa -- Bophuthatswana Hydrogeology -- South Africa -- Bophuthatswana
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4802 , http://hdl.handle.net/10962/d1001902
- Description: As part of a development programme in the Moretele II District, the Government of the Republic of Bophuthatswana, commissioned in 1983 the building of a dry system coal-fired power station. The lack of local surface water to cool the power station resulted in a decision to investigate the potential of the ground water resources. The resources will be required to supply an anticipated 30 year water demand. Because of the high capital investment and the importance of establishing an accurate assessement of the ground water potential there was a need for a comprehensive and detailed hydrogeological study. The specific aim of the investigation is to assess and quantify the long term reliability of the ground water resources. The very limited data for the area necessitated a particularly thorough and detailed investigation. This thesis describes the hydrogeological investigation carried out to define the ground water resource potential of this area. The main objectives of the study are to identify, recognize and evaluate the hydrogeological processes operating on this previously ill-defined Karoo aquifer. To achieve the research objectives the hydrogeological investigation was formulated to make use of various traditional geological, hydrogeological, geophysical and hydrochemical techniques in a logical framework. More specifically, the work involved a hydrocensus, a geophysical survey, the drilling of exploratory boreholes, aquifer tests to determine the intrinsic hydraulic parameters, water level measurements and the collection and analysis of water samples. The combined results of these various techniques provided data to quantify, evaluate and then propose management strategies for the identified resources. The study provided an understanding of the local hydrogeological conditions and has allowed for a conceptual model of the aquifer system to be derived
- Full Text:
- Date Issued: 1988
The integrative nature of the synoptic weather map in relation to adolescent cognitive structures and the teaching of senior secondary meteorology-climatology
- Authors: Van Jaarsveld, Pieter Paul
- Date: 1988
- Subjects: Meteorology -- Study and teaching (Secondary) Climatology -- Study and teaching (Secondary) Cognition in children
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1843 , http://hdl.handle.net/10962/d1004377
- Description: A poorly consolidated concept base creates considerable difficulty amongst adolescents when it comes to the higher order task of analyzing complex, abstract and scientific weather phenomena as they appear on synoptic charts. The nature of the difficulties which they experience tends to encourage them to resort to the rote memorisation of concepts rather than understanding them. Kuhn (1962) avers that concepts, not enquiry methods, are at the core of rational thought. A well taught concept becomes a well developed mental construct which encourages understanding. It is the author's firm belief that in order for pupils to come to a thorough understanding of senior secondary meteorology - climatology and the synoptic chart, teaching of basic concepts should be graded and sequential. This thesis attempts to show the difficulties inherent in synoptic climatology. It relates these difficulties to adolescent cognitive development. Within this framework, the syllabus and past examinations of the Cape Education Department, and textbooks are examined. Teachers' views and pupils' understanding are gauged through the analyses of questionnaires and worksheets respectively. Conclusions are drawn and the problems which teachers and pupils encounter are addressed.
- Full Text:
- Date Issued: 1988
- Authors: Van Jaarsveld, Pieter Paul
- Date: 1988
- Subjects: Meteorology -- Study and teaching (Secondary) Climatology -- Study and teaching (Secondary) Cognition in children
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1843 , http://hdl.handle.net/10962/d1004377
- Description: A poorly consolidated concept base creates considerable difficulty amongst adolescents when it comes to the higher order task of analyzing complex, abstract and scientific weather phenomena as they appear on synoptic charts. The nature of the difficulties which they experience tends to encourage them to resort to the rote memorisation of concepts rather than understanding them. Kuhn (1962) avers that concepts, not enquiry methods, are at the core of rational thought. A well taught concept becomes a well developed mental construct which encourages understanding. It is the author's firm belief that in order for pupils to come to a thorough understanding of senior secondary meteorology - climatology and the synoptic chart, teaching of basic concepts should be graded and sequential. This thesis attempts to show the difficulties inherent in synoptic climatology. It relates these difficulties to adolescent cognitive development. Within this framework, the syllabus and past examinations of the Cape Education Department, and textbooks are examined. Teachers' views and pupils' understanding are gauged through the analyses of questionnaires and worksheets respectively. Conclusions are drawn and the problems which teachers and pupils encounter are addressed.
- Full Text:
- Date Issued: 1988
The lack of resources as a contributory factor to the high failure rate in Standard 10 History examinations in the Alice circuit
- Sobahle, Wellington Mkhululi
- Authors: Sobahle, Wellington Mkhululi
- Date: 1988
- Subjects: History -- Study and teaching (Secondary) -- South Africa Black people -- Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1867 , http://hdl.handle.net/10962/d1004677
- Description: As the title of this thesis indicates, the researcher was concerned at the high failure rate in the Standard 10 history examinations in the Alice circuit. This problem is confined neither to history as a subject nor to a single area in the Ciskei.
- Full Text:
- Date Issued: 1988
- Authors: Sobahle, Wellington Mkhululi
- Date: 1988
- Subjects: History -- Study and teaching (Secondary) -- South Africa Black people -- Education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1867 , http://hdl.handle.net/10962/d1004677
- Description: As the title of this thesis indicates, the researcher was concerned at the high failure rate in the Standard 10 history examinations in the Alice circuit. This problem is confined neither to history as a subject nor to a single area in the Ciskei.
- Full Text:
- Date Issued: 1988
The orientation of the standard six pupil transferring from primary to secondary schooling
- Authors: Pollock, Graeme Mackenzie
- Date: 1988
- Subjects: Student adjustment , Students, Transfer of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1377 , http://hdl.handle.net/10962/d1001443
- Description: Pupils entering High School for the first time experience many problems of orientation and adjustment. This study arose from the conviction that something could be done to alleviate this time of stress to the benefit of both pupil and school alike. A brief review of literature showed that despite a fair amount of research having been done in Britain and the United States, there is still a dearth of information relating directly to the South African situation. Most transition studies differentiate between factors affecting academic adjustment, those relating to personal adjustment after transfer, and those which involve adjustment to environmental factors. In general studies approached orientation pogrammes from two perspectives - those that handled orientation as an event with its concomitant administrative and practical advantages, and those that saw it to be a process which has more person-focussed advantages. Most researchers agree that each school has its own needs and that the orientation programme should reflect those needs. Many favour a problem-solving approach to the design of any programme and emphasize the need for constant evaluation of the programme to maintain relevance and effectiveness. A low-key investigation into adjustment problems faced by new pupils in the High School was conducted by means of a questionnaire. Three main areas of information were investigated: attitude to school; personal adjustment as indicated by the self-concept; and general impression of Secondary School. The results confirmed that problems of orientation and adjustment are experienced by pupils in the South African Education System and revealed a framework upon which an orientation programme could be based. An overview of existing orientation programme objectives stresses the fact that orientation must be concerned with the total adjustment of the child - personal, academic and environmental - and that, of necessity, it involves the whole family. An orientation programme is outlined and expanded upon in order to provide a framework upon which other programmes could be designed, specific to the particular needs of the schools involved. Finally, certain observations are offered which may lead to a better understanding of the demands of the orientation process
- Full Text:
- Date Issued: 1988
- Authors: Pollock, Graeme Mackenzie
- Date: 1988
- Subjects: Student adjustment , Students, Transfer of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1377 , http://hdl.handle.net/10962/d1001443
- Description: Pupils entering High School for the first time experience many problems of orientation and adjustment. This study arose from the conviction that something could be done to alleviate this time of stress to the benefit of both pupil and school alike. A brief review of literature showed that despite a fair amount of research having been done in Britain and the United States, there is still a dearth of information relating directly to the South African situation. Most transition studies differentiate between factors affecting academic adjustment, those relating to personal adjustment after transfer, and those which involve adjustment to environmental factors. In general studies approached orientation pogrammes from two perspectives - those that handled orientation as an event with its concomitant administrative and practical advantages, and those that saw it to be a process which has more person-focussed advantages. Most researchers agree that each school has its own needs and that the orientation programme should reflect those needs. Many favour a problem-solving approach to the design of any programme and emphasize the need for constant evaluation of the programme to maintain relevance and effectiveness. A low-key investigation into adjustment problems faced by new pupils in the High School was conducted by means of a questionnaire. Three main areas of information were investigated: attitude to school; personal adjustment as indicated by the self-concept; and general impression of Secondary School. The results confirmed that problems of orientation and adjustment are experienced by pupils in the South African Education System and revealed a framework upon which an orientation programme could be based. An overview of existing orientation programme objectives stresses the fact that orientation must be concerned with the total adjustment of the child - personal, academic and environmental - and that, of necessity, it involves the whole family. An orientation programme is outlined and expanded upon in order to provide a framework upon which other programmes could be designed, specific to the particular needs of the schools involved. Finally, certain observations are offered which may lead to a better understanding of the demands of the orientation process
- Full Text:
- Date Issued: 1988
The petrology, mineralogy and geochemistry of the main zone of the Bushveld Complex at Rustenburg Platinum Mines, Union Section
- Authors: Mitchell, Andrew Alexander
- Date: 1988
- Subjects: Mineralogy -- South Africa Petrology -- South Africa Rustenburg Platinum Mines Geochemistry -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4903 , http://hdl.handle.net/10962/d1001563
- Description: Union Section of Rustenburg Patinum Mines is situated in the northwestern part of the Bushveld Complex, some twenty kilometres north of the Pilanesberg Alkaline Complex. The mining lease area covers a roughly triangular segment of Lower, Critical and Main Zone rocks, transgressed to the north and south by magnetite-bearing ferrogabbro of the Upper Zone. The Main Zone at Union Section is the focus of this study. The prime source of sample material for the study is the deep exploration borehole SK2, but additional, supplementary samples were collected on surface and underground, as well as from a second surface exploration borehole, SK4. In line with the recommendations of SACS (1980), the top of the Critical Zone, and therefore the base of the Main Zone, is taken to be the top of the Bastard Cyclic Unit. Sharpe (1985) suggested that the succession from the base of the Main is an isotopically separate entity Zone up to the Pyroxenite Marker from the rest of the Bushveld layered succession. This is not strictly true, as there is evidence that more than one parental magma was involved in the formation of this interval. It is, however, true that there are fundamental differences, particularly in isotopic makeup, between the Main Zone rocks below the pyroxenite Marker and those above (the latter having been assigned by Molyneux (1970) to subzone C of the Main Zone). Kruger et al. (1986, in press) suggested that the Pyroxenite Marker marks the base of the Upper Zone, and this convention is adhered to here. The implication of this is that the rocks which formerly constituted subzone C of the Main Zone are now considered part of the Upper Zone. The Main Zone rocks below the pyroxenite Marker were originally subdivided by Molyneux (1970) into two subzones, A and B. The results of the present study indicate that this subdivision is not justified. Instead, eight units have been distinguished in the Main Zone on geochemical, petrological and mineralogical bases. Each of these units is characterized by a coherent set, or progression, of chemical and petrological characteristics. The specific assignment of genetic connotations to these units has been deliberately avoided , at least until further studies of the Main Zone prove this to be justified. The demarcation of the eight units is illustrated in the composite diagram (Fig. 34) in the back pocket of this work, and the reasons for the subdivisions are listed in Table 6 (at the end of chapter 7 of this thesis). Until the late 1970's, it was thought that most layered cumulates formed by crystal settling (Wager and Brown, 1968). More recently, there has been a fundamental conceptual change, and many workers now believe that most cumulate rocks formed by in situ crystallization at the floor and walls of the magma chamber (McBirney and Noyes, 1979, Irvine, 1980a; Campbell, 1987). There is, however, some evidence for the physical separation of phases undergoing cotectic crystallization, particularly in the Upper Critical Zone and lower part of the Main Zone (Eales et al., 1986). This process, which has been alluded to in the past by various authors (Ferguson and Botha, 1963; Vermaak, 1976) involves the flotation of early-formed plagioclase crystals due to their positive bouyancy in tholeiitic liquids. The result is an apparent decoupling of the chemistry of pyroxene and plagioclase, as in unit IV of the Main Zone, where plagioclase becomes more anorthitic upwards, whilst pyroxene becomes more iron-rich. There is some substantial evidence, particularly in reversals in the strontium isotope initial ratio and the orthopyroxene Mg/(Mg+Fe) ratio , for multiple intrusion in the Main Zone. Although the largest and most important magma influx in the Main Zone was a high-R₀ aluminous tholeiite, as suggested by Sharpe (1985), the intrusive history of the Main Zone is believed to be far more complex than Sharpe (op. cit.) suggested. Significantly, there is strong evidence for small influxes of Upper Zone-type (Fe-rich tholeiite) magma in the upper reaches of the Main Zone. These are believed to be precursors to the major influx of Upper Zone-type magma at the pyroxenite Marker (Kruger et al, 1986, in press). The fate of intercumulus liquids in cumulate rocks has recently recieved substantial attention (Sparks et al., 1985; Morse, 1986; Barnes, 1986: Campbell, 1987). It is believed that the migration, or at least redistribution, of intercumulus liquids has played a vital role in modifying fractionation trends in the Main Zone. More importantly, the accumulation of late-stage intercumulus liquids is believed to be responsible for the formation of the Fe-rich ultramafic pegmatite bodies that interrupt the layered cumulates in borehole SK2 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1988
- Authors: Mitchell, Andrew Alexander
- Date: 1988
- Subjects: Mineralogy -- South Africa Petrology -- South Africa Rustenburg Platinum Mines Geochemistry -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4903 , http://hdl.handle.net/10962/d1001563
- Description: Union Section of Rustenburg Patinum Mines is situated in the northwestern part of the Bushveld Complex, some twenty kilometres north of the Pilanesberg Alkaline Complex. The mining lease area covers a roughly triangular segment of Lower, Critical and Main Zone rocks, transgressed to the north and south by magnetite-bearing ferrogabbro of the Upper Zone. The Main Zone at Union Section is the focus of this study. The prime source of sample material for the study is the deep exploration borehole SK2, but additional, supplementary samples were collected on surface and underground, as well as from a second surface exploration borehole, SK4. In line with the recommendations of SACS (1980), the top of the Critical Zone, and therefore the base of the Main Zone, is taken to be the top of the Bastard Cyclic Unit. Sharpe (1985) suggested that the succession from the base of the Main is an isotopically separate entity Zone up to the Pyroxenite Marker from the rest of the Bushveld layered succession. This is not strictly true, as there is evidence that more than one parental magma was involved in the formation of this interval. It is, however, true that there are fundamental differences, particularly in isotopic makeup, between the Main Zone rocks below the pyroxenite Marker and those above (the latter having been assigned by Molyneux (1970) to subzone C of the Main Zone). Kruger et al. (1986, in press) suggested that the Pyroxenite Marker marks the base of the Upper Zone, and this convention is adhered to here. The implication of this is that the rocks which formerly constituted subzone C of the Main Zone are now considered part of the Upper Zone. The Main Zone rocks below the pyroxenite Marker were originally subdivided by Molyneux (1970) into two subzones, A and B. The results of the present study indicate that this subdivision is not justified. Instead, eight units have been distinguished in the Main Zone on geochemical, petrological and mineralogical bases. Each of these units is characterized by a coherent set, or progression, of chemical and petrological characteristics. The specific assignment of genetic connotations to these units has been deliberately avoided , at least until further studies of the Main Zone prove this to be justified. The demarcation of the eight units is illustrated in the composite diagram (Fig. 34) in the back pocket of this work, and the reasons for the subdivisions are listed in Table 6 (at the end of chapter 7 of this thesis). Until the late 1970's, it was thought that most layered cumulates formed by crystal settling (Wager and Brown, 1968). More recently, there has been a fundamental conceptual change, and many workers now believe that most cumulate rocks formed by in situ crystallization at the floor and walls of the magma chamber (McBirney and Noyes, 1979, Irvine, 1980a; Campbell, 1987). There is, however, some evidence for the physical separation of phases undergoing cotectic crystallization, particularly in the Upper Critical Zone and lower part of the Main Zone (Eales et al., 1986). This process, which has been alluded to in the past by various authors (Ferguson and Botha, 1963; Vermaak, 1976) involves the flotation of early-formed plagioclase crystals due to their positive bouyancy in tholeiitic liquids. The result is an apparent decoupling of the chemistry of pyroxene and plagioclase, as in unit IV of the Main Zone, where plagioclase becomes more anorthitic upwards, whilst pyroxene becomes more iron-rich. There is some substantial evidence, particularly in reversals in the strontium isotope initial ratio and the orthopyroxene Mg/(Mg+Fe) ratio , for multiple intrusion in the Main Zone. Although the largest and most important magma influx in the Main Zone was a high-R₀ aluminous tholeiite, as suggested by Sharpe (1985), the intrusive history of the Main Zone is believed to be far more complex than Sharpe (op. cit.) suggested. Significantly, there is strong evidence for small influxes of Upper Zone-type (Fe-rich tholeiite) magma in the upper reaches of the Main Zone. These are believed to be precursors to the major influx of Upper Zone-type magma at the pyroxenite Marker (Kruger et al, 1986, in press). The fate of intercumulus liquids in cumulate rocks has recently recieved substantial attention (Sparks et al., 1985; Morse, 1986; Barnes, 1986: Campbell, 1987). It is believed that the migration, or at least redistribution, of intercumulus liquids has played a vital role in modifying fractionation trends in the Main Zone. More importantly, the accumulation of late-stage intercumulus liquids is believed to be responsible for the formation of the Fe-rich ultramafic pegmatite bodies that interrupt the layered cumulates in borehole SK2 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 1988
The political department and the retraction of paramountcy in India 1935-1947
- Authors: Moëd, Madeleine
- Date: 1988
- Subjects: India , India -- Politics and government -- 1919-1947
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2526 , http://hdl.handle.net/10962/d1001855
- Description: The Political Department and the Indian Political Service stand accused of sins of omission and commission. The evidence suggests that they were badly hampered by ill-conceived training prodecures, a lack of manpower and above all the incoherent policy of the British government towards the Indian states. The failure of the 1935 Federation Act which formally established the Political Department was not due to princely intransigence inspired by political officers. Between 1935 and 1947 the Political Department embarked on a vigorous programme of combining the resources of the smaller states to strengthen them as viable partners in a new India. Their lack of success in effecting the federation of the states with India in 1947 was not a result of the disinclination of political officers to implement reform as much as their inability to do so. Many princes were also unwilling to sacrifice a measure of sovereignty for efficient government and paramountcy precluded forcing internal reform on the princes. Paramountcy was never clearly defined and thus its retraction in 1947 took place amidst confusion and misunderstanding on all sides. The Indian Political Service was always treated as secondary to the Indian Civil Service and the states to British India. Britain's emphasis on constitutional change in British India, reflected in the Cripps Mission of 1942, the Cabinet Mission of 1946 and the rush towards independence in 1947 resulted in her inattention to the Political Department and the princes which culminated in the abandonment of both in 1947.
- Full Text:
- Date Issued: 1988
- Authors: Moëd, Madeleine
- Date: 1988
- Subjects: India , India -- Politics and government -- 1919-1947
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2526 , http://hdl.handle.net/10962/d1001855
- Description: The Political Department and the Indian Political Service stand accused of sins of omission and commission. The evidence suggests that they were badly hampered by ill-conceived training prodecures, a lack of manpower and above all the incoherent policy of the British government towards the Indian states. The failure of the 1935 Federation Act which formally established the Political Department was not due to princely intransigence inspired by political officers. Between 1935 and 1947 the Political Department embarked on a vigorous programme of combining the resources of the smaller states to strengthen them as viable partners in a new India. Their lack of success in effecting the federation of the states with India in 1947 was not a result of the disinclination of political officers to implement reform as much as their inability to do so. Many princes were also unwilling to sacrifice a measure of sovereignty for efficient government and paramountcy precluded forcing internal reform on the princes. Paramountcy was never clearly defined and thus its retraction in 1947 took place amidst confusion and misunderstanding on all sides. The Indian Political Service was always treated as secondary to the Indian Civil Service and the states to British India. Britain's emphasis on constitutional change in British India, reflected in the Cripps Mission of 1942, the Cabinet Mission of 1946 and the rush towards independence in 1947 resulted in her inattention to the Political Department and the princes which culminated in the abandonment of both in 1947.
- Full Text:
- Date Issued: 1988
The Port Elizabeth disturbances of October, 1920
- Authors: Baines, Gary F, 1955-
- Date: 1988
- Subjects: Black people -- South Africa -- Port Elizabeth -- Social conditions , Police shootings -- South Africa -- Port Elizabeth , Labor movement -- South Africa -- Port Elizabeth -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2529 , http://hdl.handle.net/10962/d1001858
- Description: Chapter one suggests thet trade and merchant capital, which were crucial to Port Elizabeth's economic development during the nineteenth century, was subsumed by the rise of manufactures and industrial capital after the First World War. Industrial expansion was cut short by the post-war recession, which caused un- and underemployment. The black worker, who experienced a severe loss in real earnings on account of the increased cost of living, became involved in a struggle with employers for wage increases. Chapter two shows how the policy of segregation was applied in Port Elizabeth, which meant that the workers were subjected to an increasing degree of control and regulation of their daily lives. The conditions of reproduction in the black townships fostered inter-racial and cross-class mobilisation which culminated in the formation of a general labour union, the Port Elizabeth Industrial and Commercial Workers' Union (PEICWU). Chapter three will suggest links between the tradition in Port Elizabeth of worker resistance and the unionisation of black workers in the post-war period. Thus, the first three chapters attempt to provide a historical perspective for analysing the underlying causes of the 1920 Port Elizabeth disturbances. The immediate cause of the disturbances was the arrest of the Union leader, Masabalala, after he called for a general strike. Chapter four will show how the intervention of the local authorities provoked a spontaneous act of defiance on the part of Union members. A demonstration outside the Baakens Street Police Station to demand the release of Masabalala, precipitated the tragic shootings of 23 October 1920. The repressive violence which left 22 dead (with two further deaths resulting indirectly from the incident) was unprecedented in South African history. The resolution of the crisis brought the workers no nearer to obtaining a reasonable settlement of the wage issue. If anything, the resolve of employers to deny wage demands was hardened by the actions of the local authorities, who attributed the disturbances to ' agitation '. Such thinly-disguised justifications of the shootings by the dominant classes, however, provoked recriminations from other quarters. Chapter five examines the legal and political ramifications of the Port Elizabeth shootings. The circumstances of the shootings prompted the Smuts Government to appoint a Commission of Enquiry in the face of public pressure. The Commission found that the Police and vigilantes were largely to blame for the high death toll. But the Government's 'whitewash' of the findings could not absolve the Police from culpability entirely, nor could it sidestep its own responsibility and liability to victims of the shootings. Finally, in Chapter six, an attempt will be made to assess the long term impact of the shootings on the PElCU and the black labour movement in Port Elizabeth generally. The outcome of the episode was a victory for employers, which dealt a body blow to worker organisation which only became resurgent in the 1950s.
- Full Text:
- Date Issued: 1988
- Authors: Baines, Gary F, 1955-
- Date: 1988
- Subjects: Black people -- South Africa -- Port Elizabeth -- Social conditions , Police shootings -- South Africa -- Port Elizabeth , Labor movement -- South Africa -- Port Elizabeth -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2529 , http://hdl.handle.net/10962/d1001858
- Description: Chapter one suggests thet trade and merchant capital, which were crucial to Port Elizabeth's economic development during the nineteenth century, was subsumed by the rise of manufactures and industrial capital after the First World War. Industrial expansion was cut short by the post-war recession, which caused un- and underemployment. The black worker, who experienced a severe loss in real earnings on account of the increased cost of living, became involved in a struggle with employers for wage increases. Chapter two shows how the policy of segregation was applied in Port Elizabeth, which meant that the workers were subjected to an increasing degree of control and regulation of their daily lives. The conditions of reproduction in the black townships fostered inter-racial and cross-class mobilisation which culminated in the formation of a general labour union, the Port Elizabeth Industrial and Commercial Workers' Union (PEICWU). Chapter three will suggest links between the tradition in Port Elizabeth of worker resistance and the unionisation of black workers in the post-war period. Thus, the first three chapters attempt to provide a historical perspective for analysing the underlying causes of the 1920 Port Elizabeth disturbances. The immediate cause of the disturbances was the arrest of the Union leader, Masabalala, after he called for a general strike. Chapter four will show how the intervention of the local authorities provoked a spontaneous act of defiance on the part of Union members. A demonstration outside the Baakens Street Police Station to demand the release of Masabalala, precipitated the tragic shootings of 23 October 1920. The repressive violence which left 22 dead (with two further deaths resulting indirectly from the incident) was unprecedented in South African history. The resolution of the crisis brought the workers no nearer to obtaining a reasonable settlement of the wage issue. If anything, the resolve of employers to deny wage demands was hardened by the actions of the local authorities, who attributed the disturbances to ' agitation '. Such thinly-disguised justifications of the shootings by the dominant classes, however, provoked recriminations from other quarters. Chapter five examines the legal and political ramifications of the Port Elizabeth shootings. The circumstances of the shootings prompted the Smuts Government to appoint a Commission of Enquiry in the face of public pressure. The Commission found that the Police and vigilantes were largely to blame for the high death toll. But the Government's 'whitewash' of the findings could not absolve the Police from culpability entirely, nor could it sidestep its own responsibility and liability to victims of the shootings. Finally, in Chapter six, an attempt will be made to assess the long term impact of the shootings on the PElCU and the black labour movement in Port Elizabeth generally. The outcome of the episode was a victory for employers, which dealt a body blow to worker organisation which only became resurgent in the 1950s.
- Full Text:
- Date Issued: 1988
The presented case study aims to demonstrate the efficacy of psychotherapy with a child previously treated with medication
- Authors: Cheesman, C
- Date: 1988
- Subjects: Child psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3167 , http://hdl.handle.net/10962/d1007730 , Child psychotherapy
- Description: The impetus for using the therapy with J.B. for this study was primarily the challenge inherent in the situation from the moment the parents and J.B. arrived for their family interview and assessment. They had been through many professionals by then, and much medication. They were sceptical of our intervention, since nothing to date had relieved the situation, and J.B. still had outbursts of rage towards his mother, he was still expressing suicidal ideation and anxiety. The challenge was particularly in relation to the mother, who had great difficulty conceptualising J.B. 's problems as being emotional and relational in nature - she was infinitely more comfortable with physiological interpretations of everything. This had the effect on the therapist and the supervisor of frequently reassuring their belief in psychotherapy as the treatment of choice in this case, or if in fact there was a lurking 'disease ' or organic cause to the child's behaviour. The pressure was thus considerable in this respect, despite the fact that the child had been examined physically and nothing found. This study aims to demonstrate the efficacy of psychotherapy, and the changes that took place, with this patient who was previously treated with medication.
- Full Text:
- Date Issued: 1988
- Authors: Cheesman, C
- Date: 1988
- Subjects: Child psychotherapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3167 , http://hdl.handle.net/10962/d1007730 , Child psychotherapy
- Description: The impetus for using the therapy with J.B. for this study was primarily the challenge inherent in the situation from the moment the parents and J.B. arrived for their family interview and assessment. They had been through many professionals by then, and much medication. They were sceptical of our intervention, since nothing to date had relieved the situation, and J.B. still had outbursts of rage towards his mother, he was still expressing suicidal ideation and anxiety. The challenge was particularly in relation to the mother, who had great difficulty conceptualising J.B. 's problems as being emotional and relational in nature - she was infinitely more comfortable with physiological interpretations of everything. This had the effect on the therapist and the supervisor of frequently reassuring their belief in psychotherapy as the treatment of choice in this case, or if in fact there was a lurking 'disease ' or organic cause to the child's behaviour. The pressure was thus considerable in this respect, despite the fact that the child had been examined physically and nothing found. This study aims to demonstrate the efficacy of psychotherapy, and the changes that took place, with this patient who was previously treated with medication.
- Full Text:
- Date Issued: 1988
The profit maximising pricing model
- Authors: Jackson, Cecil Wilfred
- Date: 1988
- Subjects: Profit -- Mathematical models , Pricing -- Mathematical models
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:899 , http://hdl.handle.net/10962/d1004597 , Profit -- Mathematical models , Pricing -- Mathematical models
- Full Text:
- Date Issued: 1988
- Authors: Jackson, Cecil Wilfred
- Date: 1988
- Subjects: Profit -- Mathematical models , Pricing -- Mathematical models
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:899 , http://hdl.handle.net/10962/d1004597 , Profit -- Mathematical models , Pricing -- Mathematical models
- Full Text:
- Date Issued: 1988
The promotion of a racially integrated Catholic community at King William's Town : challenges and opportunities
- Authors: Fahy, Paul
- Date: 1988
- Subjects: Apartheid -- South Africa -- Religious aspects -- Catholic Church
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:1218 , http://hdl.handle.net/10962/d1001548
- Description: Taking as its point of departure the model of the Church as a sacrament of unity, this study explores its implications for the fostering of a racially integrated Catholic community within an apartheid society. The particular context within which the investigation is conducted is the Sacred Heart Church, King William's Town, where the writer is pastor to a multiracial congregation. A dialogical approach is adopted between theology and praxis, in terms of which the data from a social analysis of the community are brought into a creative dialogue with the Vatican II vision of the Church. Findings from the analysis show that the attitudes of congregants to a racially integrated community are generally ambivalent. Historical, theological, psychosocial and political factors are seen to play an important role in shaping these attitudes. Arising from the dialogue between theology and praxis, the model of a pilgrim Church suggests itself as more relevant and realistic. This model constitutes a proximate goal. The sacrament model of the Church provides direction and focus for the pilgrim Church and is viewed as the ultimate goal. These models must be seen as complementary. The study concludes with a pastoral plan aimed at attaining the goals described. The main thrust of this plan is directed at changing congregants' attitudes to a racially integrated community. The strategies suggested involve the motivation of congregants to become actively involved, the transformation of congregants' attitudes, the promotion of a positive attitude to conflict and the challenging of apartheid structures. A differential approach is suggested in the pursuit of these objectives. A final conclusion to be drawn from this study is that the search for community is never-ending and that the fostering of a racially integrated Catholic community is a slow and painful process.
- Full Text:
- Date Issued: 1988
- Authors: Fahy, Paul
- Date: 1988
- Subjects: Apartheid -- South Africa -- Religious aspects -- Catholic Church
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:1218 , http://hdl.handle.net/10962/d1001548
- Description: Taking as its point of departure the model of the Church as a sacrament of unity, this study explores its implications for the fostering of a racially integrated Catholic community within an apartheid society. The particular context within which the investigation is conducted is the Sacred Heart Church, King William's Town, where the writer is pastor to a multiracial congregation. A dialogical approach is adopted between theology and praxis, in terms of which the data from a social analysis of the community are brought into a creative dialogue with the Vatican II vision of the Church. Findings from the analysis show that the attitudes of congregants to a racially integrated community are generally ambivalent. Historical, theological, psychosocial and political factors are seen to play an important role in shaping these attitudes. Arising from the dialogue between theology and praxis, the model of a pilgrim Church suggests itself as more relevant and realistic. This model constitutes a proximate goal. The sacrament model of the Church provides direction and focus for the pilgrim Church and is viewed as the ultimate goal. These models must be seen as complementary. The study concludes with a pastoral plan aimed at attaining the goals described. The main thrust of this plan is directed at changing congregants' attitudes to a racially integrated community. The strategies suggested involve the motivation of congregants to become actively involved, the transformation of congregants' attitudes, the promotion of a positive attitude to conflict and the challenging of apartheid structures. A differential approach is suggested in the pursuit of these objectives. A final conclusion to be drawn from this study is that the search for community is never-ending and that the fostering of a racially integrated Catholic community is a slow and painful process.
- Full Text:
- Date Issued: 1988
The psychological experience of being in hiding against the background of political repression in South Africa during the 1986 general State of Emergency: a phenomenological explication
- Authors: Scheepers, Esca
- Date: 1988
- Subjects: Violence -- South Africa -- Psychological aspects , South Africa -- Politics and government -- 1989-1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3111 , http://hdl.handle.net/10962/d1004586 , Violence -- South Africa -- Psychological aspects , South Africa -- Politics and government -- 1989-1994
- Description: This is a study in Critical Psychology which examines the psychological costs of one of the direct outcomes of political repression - the experience of being in hiding. The aims of the study can be depicted on two levels: it is first and foremost an attempt to provide a true account of the phenomenon of being in hiding. On a second level of equal importance it is an implicit and overt critique of the social order in which this phenomenon takes place. The psychological experience of being in hiding is examined and discussed in its proper socio-political context. Therefore, the theoretical part of the mini-thesis has a strong political bearing, focusing on the State, and extra-parliamentary opposition in South Africa. repression The empirical part of the mini-thesis explicates the psychological experience of being in hiding with the aid of the phenomenological method of investigation. Due to the lack of research on this or similar topics, it is discussed within the framework of the experience of a stressful life event. For the five subjects being in hiding was an extreme intervention which was imposed upon their existences and which brought about a qualitative transformation in the individual subjects mode of being-in-the-world - not only in terms of practicalities, but also on a deep experiential level. It was a phenomenon which touched on fundamental parts of their experience of themselves and their individual worlds and the way in which they actualized themselves. For them it essentially entailed a loss of relationships and roles which resulted in an experience of a measure of encapsulation or separation from the world of others . It was a profound, multi - dimensional disruption of the structure of the subject ' s existence which infused a rich emotional experience .
- Full Text:
- Date Issued: 1988
- Authors: Scheepers, Esca
- Date: 1988
- Subjects: Violence -- South Africa -- Psychological aspects , South Africa -- Politics and government -- 1989-1994
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3111 , http://hdl.handle.net/10962/d1004586 , Violence -- South Africa -- Psychological aspects , South Africa -- Politics and government -- 1989-1994
- Description: This is a study in Critical Psychology which examines the psychological costs of one of the direct outcomes of political repression - the experience of being in hiding. The aims of the study can be depicted on two levels: it is first and foremost an attempt to provide a true account of the phenomenon of being in hiding. On a second level of equal importance it is an implicit and overt critique of the social order in which this phenomenon takes place. The psychological experience of being in hiding is examined and discussed in its proper socio-political context. Therefore, the theoretical part of the mini-thesis has a strong political bearing, focusing on the State, and extra-parliamentary opposition in South Africa. repression The empirical part of the mini-thesis explicates the psychological experience of being in hiding with the aid of the phenomenological method of investigation. Due to the lack of research on this or similar topics, it is discussed within the framework of the experience of a stressful life event. For the five subjects being in hiding was an extreme intervention which was imposed upon their existences and which brought about a qualitative transformation in the individual subjects mode of being-in-the-world - not only in terms of practicalities, but also on a deep experiential level. It was a phenomenon which touched on fundamental parts of their experience of themselves and their individual worlds and the way in which they actualized themselves. For them it essentially entailed a loss of relationships and roles which resulted in an experience of a measure of encapsulation or separation from the world of others . It was a profound, multi - dimensional disruption of the structure of the subject ' s existence which infused a rich emotional experience .
- Full Text:
- Date Issued: 1988
The role of male competition and female choice in the mating success of a Lek-breeding Southern African Cichlid fish Pseudocrenilabrus Philander (Pisces: Cichlidae)
- Authors: Chan, Tin-Yam
- Date: 1988
- Subjects: Cichlids -- Africa, Southern -- Physiology Courtship in animals Fishes -- Reproduction Cichlids Pseudocrenilabrus philander Lek-breeding Courtship Reproduction Spawning Competition Rivalry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5599 , http://hdl.handle.net/10962/d1002049
- Description: A lek-breeding cichlid fish Pseudocrenilabrus philander was studied experimentally. Females in choice-chamber experiments showed no active choice for male size and colour, or for other male attributes, but preferred males which courted most actively. In a laboratory lek, the significant determinants of the strongly skewed mating success in males were territory size, side-shake and female chasing frequency. Together these three variables explained 79% of the variation in male mating success, with territory size alone accounting for 75% of the variation and the other two variables each accounting for 2% of the remaining variation. As there was no difference in territory quality in the laboratory lek, territory size became the principal measure of the effect of male-male competition since it was directly related to dominance. Both side-shake and female chasing could be identified as the basic factors influencing female choice, as they had an immediate effect on the display-response mating system of females. Thus, the relative importance of these three variables indicated that sexual selection in this particular lek mating species operated chiefly through the agency of intrasexual competition for dominance. However, both female behaviour and their requirement for a prolonged pre-spawning courtship had the effect of promoting male rivalry and favouring mating with dominant males. Although the intense male competition excluded subordinate males from practising normal courtship behaviour, competitively inferior males might "make the best of a bad situation" by facultatively adopting an alternative sneaking tactic to gain access to females. Spawning intrusions by females to steal freshly-laid eggs also occurred frequently. However, territorial males appeared to be relatively more tolerant of female intruders than male sneakers. Interference during spawning could lead to a longer pre-spawning courtship and even multiple-mating by females. The results of the present study and the behavioural evidence shown by males and females did not support the ʺrunaway selection modelʺ of the mating pattern in terms of sexual selection in leks, but conformed to the rival ʺwar propaganda modelʺ
- Full Text:
- Date Issued: 1988
- Authors: Chan, Tin-Yam
- Date: 1988
- Subjects: Cichlids -- Africa, Southern -- Physiology Courtship in animals Fishes -- Reproduction Cichlids Pseudocrenilabrus philander Lek-breeding Courtship Reproduction Spawning Competition Rivalry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5599 , http://hdl.handle.net/10962/d1002049
- Description: A lek-breeding cichlid fish Pseudocrenilabrus philander was studied experimentally. Females in choice-chamber experiments showed no active choice for male size and colour, or for other male attributes, but preferred males which courted most actively. In a laboratory lek, the significant determinants of the strongly skewed mating success in males were territory size, side-shake and female chasing frequency. Together these three variables explained 79% of the variation in male mating success, with territory size alone accounting for 75% of the variation and the other two variables each accounting for 2% of the remaining variation. As there was no difference in territory quality in the laboratory lek, territory size became the principal measure of the effect of male-male competition since it was directly related to dominance. Both side-shake and female chasing could be identified as the basic factors influencing female choice, as they had an immediate effect on the display-response mating system of females. Thus, the relative importance of these three variables indicated that sexual selection in this particular lek mating species operated chiefly through the agency of intrasexual competition for dominance. However, both female behaviour and their requirement for a prolonged pre-spawning courtship had the effect of promoting male rivalry and favouring mating with dominant males. Although the intense male competition excluded subordinate males from practising normal courtship behaviour, competitively inferior males might "make the best of a bad situation" by facultatively adopting an alternative sneaking tactic to gain access to females. Spawning intrusions by females to steal freshly-laid eggs also occurred frequently. However, territorial males appeared to be relatively more tolerant of female intruders than male sneakers. Interference during spawning could lead to a longer pre-spawning courtship and even multiple-mating by females. The results of the present study and the behavioural evidence shown by males and females did not support the ʺrunaway selection modelʺ of the mating pattern in terms of sexual selection in leks, but conformed to the rival ʺwar propaganda modelʺ
- Full Text:
- Date Issued: 1988
The selection and evaluation of grey-level thresholds applied to digital images
- Authors: Brink, Anton David
- Date: 1988
- Subjects: Image processing -- Digital techniques
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5443 , http://hdl.handle.net/10962/d1001996
- Description: Many applications of image processing require the initial segmentation of the image by means of grey-level thresholding. In this thesis, the problems of automatic threshold selection and evaluation are addressed in order to find a universally applicable thresholding method. Three previously proposed threshold selection techniques are investigated, and two new methods are introduced. The results of applying these methods to several different images are evaluated using two threshold evaluation techniques, one subjective and one quantitative. It is found that no threshold selection technique is universally acceptable, as different methods work best with different images and applications
- Full Text:
- Date Issued: 1988
- Authors: Brink, Anton David
- Date: 1988
- Subjects: Image processing -- Digital techniques
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5443 , http://hdl.handle.net/10962/d1001996
- Description: Many applications of image processing require the initial segmentation of the image by means of grey-level thresholding. In this thesis, the problems of automatic threshold selection and evaluation are addressed in order to find a universally applicable thresholding method. Three previously proposed threshold selection techniques are investigated, and two new methods are introduced. The results of applying these methods to several different images are evaluated using two threshold evaluation techniques, one subjective and one quantitative. It is found that no threshold selection technique is universally acceptable, as different methods work best with different images and applications
- Full Text:
- Date Issued: 1988
The sulphidization of mineral surfaces as applied to the froth flotation process
- Authors: Ramagwede, Mudzimba Hubert
- Date: 1988 , 2013-02-28
- Subjects: Sulfide minerals , Flotation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4296 , http://hdl.handle.net/10962/d1004590
- Description: This work constitutes a fundamental study of the interaction between soluble sulphide,copper (II) oxide and cerussite particles in the presence of Ca²⁺ ,Mg²⁺ starch , gum arabic and Triton X- IOO . A detailed investigation of the effect of pH of the system on the rate of sulphide uptake was made . In addition , the structural form of the surface precipitat.es were determined with the aid of scanning electron microscopy . On the basis of these results , it was concluded that adsorption of sulphide on cerussite in the presence or absence of Ca²⁺ starch, gum arabic and Triton X-IOO could either lead to the formation of a non-uniform or a uniform sulphide layer depending on the experimental conditions . However , the interaction of copper (II) · oxide wi th soluble sulphide in the presence or absence of the above mentioned species always led to the formation or a non-uniform sulphide layer . Preliminary experiments of the interaction between xanthate and sulphidized surface showed that oxide surface covered with metal sulphide layer reacts with less xanthate than the free oxide surface.
- Full Text:
- Date Issued: 1988
- Authors: Ramagwede, Mudzimba Hubert
- Date: 1988 , 2013-02-28
- Subjects: Sulfide minerals , Flotation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4296 , http://hdl.handle.net/10962/d1004590
- Description: This work constitutes a fundamental study of the interaction between soluble sulphide,copper (II) oxide and cerussite particles in the presence of Ca²⁺ ,Mg²⁺ starch , gum arabic and Triton X- IOO . A detailed investigation of the effect of pH of the system on the rate of sulphide uptake was made . In addition , the structural form of the surface precipitat.es were determined with the aid of scanning electron microscopy . On the basis of these results , it was concluded that adsorption of sulphide on cerussite in the presence or absence of Ca²⁺ starch, gum arabic and Triton X-IOO could either lead to the formation of a non-uniform or a uniform sulphide layer depending on the experimental conditions . However , the interaction of copper (II) · oxide wi th soluble sulphide in the presence or absence of the above mentioned species always led to the formation or a non-uniform sulphide layer . Preliminary experiments of the interaction between xanthate and sulphidized surface showed that oxide surface covered with metal sulphide layer reacts with less xanthate than the free oxide surface.
- Full Text:
- Date Issued: 1988
Theory in interpretive psychology - with special reference to Paul Ricoeur's interpretation of Freud
- Authors: Du Toit, Barry
- Date: 1988
- Subjects: Freud, Sigmund, 1856-1939 , Ricœur, Paul , Psychoanalysis
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2906 , http://hdl.handle.net/10962/d1002071
- Description: The thesis aims to show that, while an interpretive psychology is not compatible with theory as it occurs in the predictive- causal explanation of the natural sciences, it is both possible and necessary to develop a concept of theory valid within an interpretive methodology. These claims are advanced in the course of an examination of Ricoeur 's interpretation of Freudian psychoanalysis. After examining some traditional ways in which phenomenological psychology has responded to the psychoanalytic challenge, the thesis presents an interpretation of Freudian psychoanalysis as a hermeneutic approach which utilized theoretical constructions in a productive way, although distorted by Freud's natural-scientific self- understanding. Freud's causal-explanatory language and natural- scientific meta theory are shown to be significant inasmuch as they provide a vehicle for theory construction in psychoanalysis. However, since the theory is modeled on that of the natural sciences, it proves incompatible with the interpretive aspects of Freud's approach. We then establish a concept of theory and of causal analysis which is different to that of the natural sciences, and is compatible with, and indeed founded in, an interpretive approach to psychology. These concepts are then illustrated in the context of psychoanalysis. In the final chapter the advantages of the use of theory in interpretive psychology are discussed.
- Full Text:
- Date Issued: 1988
Theory in interpretive psychology - with special reference to Paul Ricoeur's interpretation of Freud
- Authors: Du Toit, Barry
- Date: 1988
- Subjects: Freud, Sigmund, 1856-1939 , Ricœur, Paul , Psychoanalysis
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2906 , http://hdl.handle.net/10962/d1002071
- Description: The thesis aims to show that, while an interpretive psychology is not compatible with theory as it occurs in the predictive- causal explanation of the natural sciences, it is both possible and necessary to develop a concept of theory valid within an interpretive methodology. These claims are advanced in the course of an examination of Ricoeur 's interpretation of Freudian psychoanalysis. After examining some traditional ways in which phenomenological psychology has responded to the psychoanalytic challenge, the thesis presents an interpretation of Freudian psychoanalysis as a hermeneutic approach which utilized theoretical constructions in a productive way, although distorted by Freud's natural-scientific self- understanding. Freud's causal-explanatory language and natural- scientific meta theory are shown to be significant inasmuch as they provide a vehicle for theory construction in psychoanalysis. However, since the theory is modeled on that of the natural sciences, it proves incompatible with the interpretive aspects of Freud's approach. We then establish a concept of theory and of causal analysis which is different to that of the natural sciences, and is compatible with, and indeed founded in, an interpretive approach to psychology. These concepts are then illustrated in the context of psychoanalysis. In the final chapter the advantages of the use of theory in interpretive psychology are discussed.
- Full Text:
- Date Issued: 1988
Tidal exchanges of carbon, nitrogen and phosphorus between a Sarcocornia salt-marsh and the Kariega estuary, and the role of salt-marsh brachyura in this transfer
- Authors: Taylor, David Ian
- Date: 1988
- Subjects: Salt marsh ecology -- South Africa -- Eastern Cape Salt marsh animals -- South Africa -- Eastern Cape Kariega River
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5623 , http://hdl.handle.net/10962/d1004524
- Description: Tidal exchanges of organic carbon, nitrogen and phosphorus between a south temperate Sarcocornia marsh and its associated estuary are examined. Subterranean water flow was small, and the hydraulic exchange between the two systems largely surficial. The dominant tidal signal was semi-diurnal, and the extent of inundation of the marsh varied considerably as a consequence of interactions of semi-lunar tidal cycles with changes in daily mean sea level. Annual net fluxes of organic carbon were directed from the marsh to the estuary, but amounted to less than 2% of marsh aerial net primary productivity. This indicates the incompatibility of E.P. Odum's outwelling hypothesis to this marsh-estuarine system. The direction of net flux of organic carbon switched on a time-scale of days. These directions were largely correlated with mesoscale oceanic events, which materially altered the extent of marsh inundation, and which provided evidence of the mutual exclusivity of outwelling of DOC from the marsh and oceanic upwelling. Laboratory mesocosm experiments using intact marsh blocks of sediment from the marsh were conducted to identify the proximate processes and interactions at the marsh-water interface responsible for the variability of marsh-estuarine exchanges. Patterns of fluxes of organic carbon, total nitrogen and phosphorus were markedly different in the structurally contrasted tidal creek and Sarcocornia Zone regions of the marsh. Both regions exported these components, but the fluxes of organic carbon and total phosphorus were significantly larger from the tidal creek than from the Sarcocornia zone, and the opposite applied to nitrogen. The presence of brachyuran crabs . the most numerous macrofauna on the marsh enhanced the flux of carbon, nitrogen and phosphorus from the marsh biocoenosis, largely as a result of the effect of their bioturbation. Evidence is examined which suggests that differential mobilization of nutrients in the two zones by crabs is responsible for biogeochemical coupling of these two regions , which may account for the elevated productivity of salt- marsh systems
- Full Text:
- Date Issued: 1988
- Authors: Taylor, David Ian
- Date: 1988
- Subjects: Salt marsh ecology -- South Africa -- Eastern Cape Salt marsh animals -- South Africa -- Eastern Cape Kariega River
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5623 , http://hdl.handle.net/10962/d1004524
- Description: Tidal exchanges of organic carbon, nitrogen and phosphorus between a south temperate Sarcocornia marsh and its associated estuary are examined. Subterranean water flow was small, and the hydraulic exchange between the two systems largely surficial. The dominant tidal signal was semi-diurnal, and the extent of inundation of the marsh varied considerably as a consequence of interactions of semi-lunar tidal cycles with changes in daily mean sea level. Annual net fluxes of organic carbon were directed from the marsh to the estuary, but amounted to less than 2% of marsh aerial net primary productivity. This indicates the incompatibility of E.P. Odum's outwelling hypothesis to this marsh-estuarine system. The direction of net flux of organic carbon switched on a time-scale of days. These directions were largely correlated with mesoscale oceanic events, which materially altered the extent of marsh inundation, and which provided evidence of the mutual exclusivity of outwelling of DOC from the marsh and oceanic upwelling. Laboratory mesocosm experiments using intact marsh blocks of sediment from the marsh were conducted to identify the proximate processes and interactions at the marsh-water interface responsible for the variability of marsh-estuarine exchanges. Patterns of fluxes of organic carbon, total nitrogen and phosphorus were markedly different in the structurally contrasted tidal creek and Sarcocornia Zone regions of the marsh. Both regions exported these components, but the fluxes of organic carbon and total phosphorus were significantly larger from the tidal creek than from the Sarcocornia zone, and the opposite applied to nitrogen. The presence of brachyuran crabs . the most numerous macrofauna on the marsh enhanced the flux of carbon, nitrogen and phosphorus from the marsh biocoenosis, largely as a result of the effect of their bioturbation. Evidence is examined which suggests that differential mobilization of nutrients in the two zones by crabs is responsible for biogeochemical coupling of these two regions , which may account for the elevated productivity of salt- marsh systems
- Full Text:
- Date Issued: 1988
Towards a portable occam
- Authors: Hill, David Timothy
- Date: 1988 , 2013-03-07
- Subjects: occam (Computer program language) , Transputers , Parallel programming (Computer science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4587 , http://hdl.handle.net/10962/d1004749 , occam (Computer program language) , Transputers , Parallel programming (Computer science)
- Description: Occam is designed for concurrent programming on a network of transputers. AIlocation and partitioning of the program is specified within the source code, binding the program to a specific network. An altemative approach is proposed which completely separates the source code from hardware considerations. Static allocation is performed as a separate phase and should, ideally, be automatic but at present is manual. Complete hardware abstraction requires that non-local, shared communication be provided for, introducing an efficiency overhead which can be minimised by the allocation. The proposal was implemented on a network of IBM PCs, modelled on a transputer network, and implementation issues are discussed
- Full Text:
- Date Issued: 1988
- Authors: Hill, David Timothy
- Date: 1988 , 2013-03-07
- Subjects: occam (Computer program language) , Transputers , Parallel programming (Computer science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4587 , http://hdl.handle.net/10962/d1004749 , occam (Computer program language) , Transputers , Parallel programming (Computer science)
- Description: Occam is designed for concurrent programming on a network of transputers. AIlocation and partitioning of the program is specified within the source code, binding the program to a specific network. An altemative approach is proposed which completely separates the source code from hardware considerations. Static allocation is performed as a separate phase and should, ideally, be automatic but at present is manual. Complete hardware abstraction requires that non-local, shared communication be provided for, introducing an efficiency overhead which can be minimised by the allocation. The proposal was implemented on a network of IBM PCs, modelled on a transputer network, and implementation issues are discussed
- Full Text:
- Date Issued: 1988
What makes a painting good?: an enquiry into the criteria used in evaluation
- Authors: Frost, Lola
- Date: 1988
- Subjects: Painting -- Appreciation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2461 , http://hdl.handle.net/10962/d1008542
- Description: From introduction: "To affirm that a work of art is good or bad is to commend or condemn, but not describe . Thus criticism does not, and cannot, have the impersonal character and strict rules applicable independently of time and place," .. . (Macdonald 1966: 111) "Criticism and appraisal, too, are more like creation than like demonstration and proof." (Macdonald 1966: 112) This essay articulates evaluatory criteria that are used by both critics and laymen and which are cross -culturally applicable. Thus it seeks to articulate relatively objective types of criteria which we all use when evaluating paintings. This essay articulates fixed and objective criteria, but within these categories recognizes that there is much room for skillful, sympathetic and knowledgeable criticism. Thus criticism is a creative act. These objectively- articulated criteria are best seen as aids to, rather than carbon copies, for evaluation.
- Full Text:
- Date Issued: 1988
- Authors: Frost, Lola
- Date: 1988
- Subjects: Painting -- Appreciation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2461 , http://hdl.handle.net/10962/d1008542
- Description: From introduction: "To affirm that a work of art is good or bad is to commend or condemn, but not describe . Thus criticism does not, and cannot, have the impersonal character and strict rules applicable independently of time and place," .. . (Macdonald 1966: 111) "Criticism and appraisal, too, are more like creation than like demonstration and proof." (Macdonald 1966: 112) This essay articulates evaluatory criteria that are used by both critics and laymen and which are cross -culturally applicable. Thus it seeks to articulate relatively objective types of criteria which we all use when evaluating paintings. This essay articulates fixed and objective criteria, but within these categories recognizes that there is much room for skillful, sympathetic and knowledgeable criticism. Thus criticism is a creative act. These objectively- articulated criteria are best seen as aids to, rather than carbon copies, for evaluation.
- Full Text:
- Date Issued: 1988