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The analysis of a computer music network and the implementation of essential subsystems

  • Authors: Wilks, Antony John
  • Date: 1995
  • Subjects: Computer networks , Computer music , MIDI (Standard)
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4666 , http://hdl.handle.net/10962/d1006682 , Computer networks , Computer music , MIDI (Standard)
  • Description: The inability to share resources in commercial and institutional computer music studios results in non-optimal resource utilisation. The use of computers to process, store and communicate data can be extended within these studios, to provide the capability of sharing resources amongst their users. This thesis describes a computer music network which was designed for this purpose. Certain devices had to be custom built for the implementation of the network. The thesis discusses the design and construction of these devices.
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  • Date Issued: 1995

The Children of Pierrette

The Children of Pierrette

The collapse of the 'tribal authority' system and the rise of civic organisations

  • Authors: Manona, Cecil W , Paper presented at an ISER Seminar, March 1995
  • Date: 1995
  • Subjects: Civic associations -- South Africa Local government -- South Africa -- Ciskei Local government -- South Africa Tribal government -- South Africa
  • Language: English
  • Type: Manuscript , Text
  • Identifier: http://hdl.handle.net/10962/2454 , vital:20293
  • Description: The paper examines the performance of a local ('tribal') authority which existed in the Keiskammahoek district up to 1993 and accounts for the rise of civic organisations which challenged tribal authorities virtually everywhere in the former Ciskei. It suggests that the problems of this local authority which included inefficiency, corruption and lack of democracy were manifestations of the limitations of the Black Authorities Act of 1951 which attempted to revive traditional authority in the rural areas in south Africa even though this was incompatible with political developments in many other African states, particularly in a period during which the process of decolonisation was at its peak. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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  • Date Issued: 1995

The conflict between adaptation and constraint : the case of the Siphonariid limpets

  • Authors: Chambers, Richard Jonathan
  • Date: 1995
  • Subjects: Siphonaria -- Adaptation Limpets -- Adaptation Pulmonata
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5657 , http://hdl.handle.net/10962/d1005340
  • Description: The reproductive strategies of marine invertebrates have been related to various aspects of both their ecology, and their phylogenetic history. It has been the purpose of this thesis to try and separate these components among Siphonaria, a group of marine pulmonates. The taxonomy of these species is revised and I conclude that nine species are valid. All species deposit benthic egg masses and development may be either direct (S. anneae, S. compressa, S. dayi, S. nigerrima, S. serrata and S. tenuicostulata) or planktonic (S. capensis, S.concinna and S. oculus). Data on distribution and life-history relating to mode of larval development is then presented for 26 species of Siphonaria worldwide. Fifteen species are direct developers, nine are planktonic developers and a further two appear to have a dual developmental capacity, retaining both the velar swimming apparatus of a planktonic developer and the crawling foot of a direct developer. Direct developing species hatch from larger egg capsules, and generally occur higher on the shore than planktonic developers. Worldwide, planktonic developers are more widespread than direct developers, and individual planktonic species may have a greater latitudinal range. In most S~honaria subgenera, mode of larval development appears to be constant, although two subgenera (Patel/opsis and Sacculosiphonaria) include both developmental types. Locally, the intertidal zonation of three sympatric species (S. capensis, S. concinna and S. serrata) does not support a model which predicts direct development on the high shore and planktonic development on the low shore. However, distributions do correspond to particular intertidal microhabitats, and while there may be no, direct relationship between mode of larval development and intertidal height, the physical structure of egg masses, and the microhabitats used for spawning appear adaptive with regards to desiccation in the intertidal. S. concinna (planktonic development) and S. serrata (direct development) occur in similar microhabitats and are likely to be under similar selection pressures. In having different modes of larval development, there appears to be more than one optimal solution in a particular selective regime. In addition, both species seem to apportion similar amounts of energy to reproduction for each spawning episode, and also annually suggesting an optimum allocation of resources to reproduction. Genetic investigations using PolyAcrylamide Gel Electrophoresis (PAGE) confirm the status of the southern African species initially described, and indicate greater genetic variability associated with planktonic developing species than direct developing species. The systematic relationships revealed by DNA fingerprinting support the current classification systems, and also have implications with regards the evolution of larval development: direct development may be the plesiomorphic condition in, and among, some Siphonaria groups. There are both phylogenetic and adaptive explanations for the distribution of reproductive mode among benthic marine invertebrates. An evolutionary question, however, is not just a matter of either adaptation or constraint, it is a combination of these. Both contribute to the distribution of developmental mode among Siphonaria.
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  • Date Issued: 1995

The development of a typology of science teachers' views on the nature of science and science practical work: an evaluative pilot study

  • Authors: Meiring, Leslie Frank
  • Date: 1995
  • Subjects: Science -- Study and teaching -- Research Science -- Study and teaching -- South Africa Science teachers -- Attitudes Science -- Philosoph
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1931 , http://hdl.handle.net/10962/d1007607
  • Description: Many theories on the nature of science and the nature of learning have been proposed. In particular, two theoretical orientations have been identified as having a decisive impact on activities in the school science classroom, namely "Inductivism" and "Constructivism". Inductivism views observations as objective, facts as constants and knowledge as being obtained from a fixed external reality. The constructivist view sees all knowledge as "reality" reconstructed in the mind of the learner. Each view predisposes certain orientations towards the science curriculum and within it particularly to assessment. It is postulated that teachers' views on science will influence how they teach and assess it. An "inductivist" teacher is more likely to reward certain approved responses from learners whereas a "constructivist" teacher is more likely to attend to learners' unique observations as evidence of their thinking. In this study a questionnaire was developed in an attempt classify science teachers according to their views on the nature of science and learning, and during this process encourage them to reflect on these views. It is hoped that the instrument could measure any changes in teacher's views as a result of the teachers becoming more reflective practitioners over time. Research indicates that the majority of teachers have a predominantly inductivist view of science. The study confirmed the results of other researchers by showing that a majority of non-tertiary science educators could be classified as being strongly inductivist. However, the overall proportion of these teachers was not as high as expected. Of possible concern was the indication that the strongly constructivist group showed very strong inductivist tendencies when assessing written tests which involved pupils' responses to laboratory observations.
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  • Date Issued: 1995

The discourse of postgraduate seminars

  • Authors: De Klerk, Vivian A
  • Date: 1995
  • Language: English
  • Type: Article
  • Identifier: vital:6132 , http://hdl.handle.net/10962/d1011584
  • Description: Video recordings of a range of postgraduate seminars in the Arts Faculty at a South African university were made and analyzed, in order to define the current nature of this particular form of educational practice in South African tertiary institutions. Recent demographic changes in formerly White universities are having a significant effect on the nature of interaction in formal discussion groups. Despite a common perception that at a tertiary level tutors and students are equally entitled to speak and all contributions equally valued, this article reveals that postgraduate seminars are sites of competition for the floor and that there are significant imbalances in participation by different groups in this competitive speaking environment; it is further argued that these imbalances reflect different (culture- and gender-specific) assumptions about what constitutes appropriate participation and also, to some degree, previous learned discourse patterns associated with schooling experience.
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  • Date Issued: 1995

The effect of fluctuating substrate salinity on the yield and flag leaf photosynthesis of wheat

  • Authors: Beckett, R P , Drennan, P M , Botha, Christiaan E J
  • Date: 1995
  • Language: English
  • Type: Article
  • Identifier: vital:6501 , http://hdl.handle.net/10962/d1005922
  • Description: The effects of constant and fluctuating substrate salinity on flag leaf photosynthesis and grain yield of wheat were investigated. Plants exposed to salinity fluctuating around a mean integrated value of 25 mol m-3 NaCl (0-50 mol m-3) and around 50 mol m-3 NaCl (25-75 mol m-3) had yields 36 and 38% higher, respectively, than those receiving the corresponding constant salinity. Plants treated with salinity fluctuating from 50-100 mol m-3 NaCl had a 14% lower yield than those receiving 75 mol m-3 NaCl. Flag leaf photosynthesis did not vary between treatments and during salinity fluctuations, suggesting that differences in flag leaf longevity caused the observed differences in yield. Results suggest plants grown under constant salinity are unlikely to behave as those in field situations, where fluctuating rather than constant salinity occurs.
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  • Date Issued: 1995

The effects of elevated and ambient temperature conditions on dilutions of fluocinolone acetonide ointment assessed using the human skin-blanching assay

  • Authors: Haigh, John M , Smith, Eric W
  • Date: 1995
  • Language: English
  • Type: text , Article
  • Identifier: vital:6380 , http://hdl.handle.net/10962/d1006298
  • Description: Topical corticosteroid formulations have been in use now for some 30 years and many methods are available for the in vivo assessment of these preparations. Of all the assays described in the literature, the one first advocated by McKenzie and Stoughton, the so-called vasoconstrictor assay, is one of the most reliable if performed by experienced researchers using - the optimised methodology. Topical application of corticosteroids produces a whitening (blanching) of the skin, the intensity of which is directly proportional to the clinical efficacy of the formulation. Assessment of the degree of blanching produced is therefore of use in determining the rate and extent of corticosteroid release' from the semi-solid base through the stratum corneum. Since it is the degree of blanching which is measured, we prefer to call this test the human skin blanching assay. Some of the main advantages of this assay technique are that normal healthy skin is used therefore persons with dermatological complaints are not compromised, it is not painful for the volunteers, it is non-invasive and several formulations can be evaluated simultaneously. Most commercially available topical corticosteroid preparations have been formulated in such a way as to provide optimum release of the active ingredient from the base through the stratum corneum. Despite this fact, many practitioners often prescribe dilutions of topical corticosteroid formulations, presumably in an effort to reduce the unwanted side effects. This could be problematic; dilution with an incompatible base could destroy the delivery environment thus considerably reducing the efficacy of the formulation. The method of dilution could also play a role in the suitability of the final preparation. The objective of this work was to determine the effects of two different dilutions of fluocinolone ointment at both ambient and elevated temperature on the blanching produced by the dilutions and, by inference, the relative clinical efficacies of these dilutions compared to the full strength product.
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  • Date Issued: 1995

The effects of trade policy on the development of the South African petrochemical industry

  • Authors: Giantsos, John
  • Date: 1995
  • Subjects: Petroleum chemicals industry -- South Africa , Petroleum industry and trade -- Government policy -- South Africa , Petroleum chemicals industry , South Africa -- Commerce
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:1014 , http://hdl.handle.net/10962/d1002749 , Petroleum chemicals industry -- South Africa , Petroleum industry and trade -- Government policy -- South Africa , Petroleum chemicals industry , South Africa -- Commerce
  • Description: The objective of the research was to determine the role which South African trade policy played in shaping the development of the domestic petrochemical industry. The focus of the study falls on the domestic development of the petrochemical industry in general, and the polymer industry in particular. Three broad stages are distinguished in the domestic development of the petrochemical industry. Prior to the early 1970's development occurred primarily on an ad hoc basis, with the establishment of domestic production plants for most major petrochemicals. The development of the domestic petrochemical industry over the period from the early 1970's to the early 1980's was characterised by rapid growth in the domestic production of petrochemicals, while the period from the early 1980's to the early 1990's saw a significant slowdown in the annual growth rate for the domestic production of petrochemicals. The role of trade policy in the industry's development over each of these three periods could not be established conclusively. In each period a number of factors were identified which may have impacted on the industry's development. However, two factors do appear to have played particularly important roles in the industry's development prior to the early 1980's, namely strong growth in domestic petrochemical demand and the provision of a substantial degree of protection through quantitative import controls and tariffs. with regard to the industry's development over the period from the early 1980's to the early 1990's, a number of factors were identified which may have influenced trends in domestic petrochemical production, including the withdrawal of quantitative import controls and the progressive lowering of import tariffs, the depreciation of the rand in the mid-1980's, a slowdown in the growth of the domestic demand for petrochemicals, the fall in the international prices of petrochemicals in the early 1980's, and the fall in the international oil price in the mid-1980's. In view of the small size of the domestic petrochemical market it is recommended that local petrochemical producers should continue to expand their focus beyond that of producing solely for the requirements of the domestic market. In light of the key role played by the petrochemical industry in a modern economy, it is also recommended that the industry in South Africa receive more attention from policy makers than it has in the past.
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  • Date Issued: 1995

The external dimension in the transformation of Afrikaner Nationalism

  • Authors: Botha, André Pedro
  • Date: 1995
  • Subjects: Afrikaners -- Ethnic identity , Afrikaners -- Politics and government , Nationalism -- South Africa -- History , Economic sanctions -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2763 , http://hdl.handle.net/10962/d1002973 , Afrikaners -- Ethnic identity , Afrikaners -- Politics and government , Nationalism -- South Africa -- History , Economic sanctions -- South Africa
  • Description: This work looks at Afrikaner Nationalism, and more closely the changes it has undergone in years since external pressure has been applied against it from as early as 1946. This has been accomplished by placing it against the background of the international context ego as in relation to India and the British Commonwealth. Following a discussion of the ideology of nationalism in general, the thesis examines the specific case of Afrikaner Nationalism, which it portrays as an example of ethnonationalism. This latter is distinguished by familial ties and other stereotypes. After outlining the changing characteristics of Afrikaner Nationalism over time by reference to pronounciations by its leaders and other prominent spokesmen, this process of change is analysed with particular regard to the role played by international and other external pressures upon Afrikaner Nationalism. By carefully describing the changing attitudes of elite groups within Afrikaner Nationalism, the thesis assesses the impact of external factors. Then it is reasonably stated in this work that Afrikaner elites have become less exclusive under external pressure. The writer of this study is of the opinion that, give the fact that the doors of the National Party were thrown open, Afrikaner Nationalism and its aforementioned ideological organ are no longer identical.
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  • Date Issued: 1995

The foreign policy orientation and national role conceptions of a post-apartheid South Africa: options and scenarios

  • Authors: Landsberg, Chris
  • Date: 1995
  • Subjects: South Africa -- Foreign relations -- 1989-1994 , Apartheid -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2793 , http://hdl.handle.net/10962/d1003003 , South Africa -- Foreign relations -- 1989-1994 , Apartheid -- South Africa
  • Description: This thesis should essentially be considered as an exposition of the foreign policy of a "new", apartheid-free South Africa in a post-Cold War international arena, arguing for a pro-active and prudent foreign policy. An important goal of the study is to make as dispassionate and rational as possible a contribution to the debate on South Africa's future foreign policy, national roles and external relations. A further aim of the study shall be to deduce relevant results of perpetual and viable foreign policy orientations and national role models within the framework of policy alternatives to South Africa's decision-makers in the future.
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  • Date Issued: 1995

The geomorphological evolution of the area between Grahamstown and the Indian Ocean

  • Authors: Lewis, Colin A
  • Date: 1995
  • Language: English
  • Type: Book
  • Identifier: vital:6709 , http://hdl.handle.net/10962/d1006746 , ISBN 0868102776
  • Description: [From the introduction]: The landforms of the Albany, Alexandria and Bathurst Districts in the area between Grahamstown and the sea are the product of many different geomorphological processes that have operated for well over 150 million years. The evolution of landforms normally occurs over a very long time and is usually highly complex. As a result it is difficult for a human being, whose allocated span on Earth is of the order of three score years and ten, to appreciate the time involved in their formation. The purpose of this booklet is to indicate the ways in which the present landforms of the area may have evolved. Much research is still needed in order to determine exactly how and when various features developed. In some cases a number of hypotheses exist in order to explain the evolution of a particular feature or region. Consequently it has proved necessary to present more than one interpretation of the devlopment of certain phenomena. This booklet must therefore be regarded as an introduction to the geomorphological development of the area between Grahamstown and the Indian Ocean rather than a definitive statement of the geomorphological evolution of that area.
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  • Date Issued: 1995

The human soul (jivatma) and its ultimate goal (moksa) in the context of Taittiriya Upanisad (3.10.5): a study in an aspect of Hindu eschatology

  • Authors: Saradananda, Swami
  • Date: 1995
  • Subjects: Upanishads -- History and criticism , Hindu eschatology , Soul -- Hinduism , Suicide -- Religious aspects -- Hinduism
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:1304 , http://hdl.handle.net/10962/d1016396
  • Description: This research was stimulated by pastoral concerns regarding the high rate of suicide in the South African Hindu community. On the one hand it was found that traumatized individuals contemplating suicide were woefully ill-equipped with helpful religious guidelines and on the other it is known that the primary and authoritative scriptures of Hinduism possess a wealth of information that can promote healing. This work uses the Taittiriya Upanishad (3.10.5) to address this challenge. The early Vedic writings are not systematized nor are they fully explicable except through commentaries. This research surveys the early Vedic and Upanisadic Writings in order to show the literary, social and philosophical conditions under which the texts were produced. The Taittiriya Upanisad is the culminating part of several strands of thought that emerged from the earlier Taittiriya School. In order to interpret the text of this Upanisad it was necessary to link its key concepts with other Upanisads of this period. Further interpretations emerged from later Upanisads. These texts were viewed in the light of several commentators - Shaukara (medieval period), and Vivekananda, Aurobindo and Radhakrishuan of the Neo-Vedanta movements. In the early Vedic period the soul is a metaphysical entity. Upon death it is judged and in accordance with its good or bad actions, heavenly rewards or the punishments of hell are meted out to it. Heaven and hell are final eschatological goals for the soul in the Vedic period. In the later Vedic or Upanisadic period it is found that heaven and hell are temporary eschatological goals. The ultimate goal becomes Liberation which implies the cessation of duality and the realization of non-duality. Correspondingly the Taittiriya Upauisad defines the soul in a manner in which its components have the potential to achieve this later goal. Here the soul is a formulation of five sheaths: body, vital energy, mind, intellect and bliss with an immortal consciousness as its focus. Functioning under the effects of ignorance each sheath binds the soul to suffering and rebiiths either on earth or on other planes (heaven or hell). However, each sheath also possesses an intrinsic capacity to liberate the soul from suffering. Tills work explores these negative and positive capabilities of the sheaths and points out the path by which the soul's divine potential may be realized. The ultimate healing or liberation occurs when the 'focus-consciousness' of the soul is intuitively realized. This consciousness is one with the universal consciousness. This achievement produces the 'liberated soul' who experiences ecstasy at this knowledge of oneness. This research also points out that the Neo-Vedanta movements, unlike their medieval counterparts, have a life-affirming and positive social attitude that seeks to draw from ancient texts for the purposes of healing and social upliftment.
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  • Date Issued: 1995

The impact of the mentally retarded child on the family living in the rural areas of the Transkei

  • Authors: Sipambo, Sindiswa
  • Date: 1995
  • Subjects: Children with mental disabilities -- South Africa -- Eastern Cape -- Family relationships , Children with mental disabilities -- Family relationships
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3281 , http://hdl.handle.net/10962/d1006502 , Children with mental disabilities -- South Africa -- Eastern Cape -- Family relationships , Children with mental disabilities -- Family relationships
  • Description: This research was designed to do four things: first to discover what problems face caregivers who bring up handicapped children in their own homes; second, what community resources are available or which should be available to assist the mentally retarded and his family to cope with the problem; third, social policy measures available through the Transkei government, e.g. single care grant and disability grant and under what conditions are they available and whether other resources/services are available, and fourth, to find out from caregivers themselves how well the social services, although limited which are intended to help them and their children work in practice, more specifically in rural areas especially when community and public sector measures are highly circumscribed. The lack of resources for mentally retarded children and their families in Transkei and particularly the Sterkspruit district raised some questions in the researcher's mind on how to rear a mentally retarded child in this area. Data was gathered from a sample of all mentally retarded children who are single care grant recipients. The subjects were the mothers of these children or the present custodian about the time of the study. Information was also gathered from the social workers in the district mainly from their case files in the office. The sample was sufficient for the study to be meaningful and well represented and to eliminate guesses and assumptions about the lives of mentally handicapped children and their families. Findings reveal that caring for a mentally retarded child is a demanding task with varying levels of stress. Families of the retarded, in general, tend to have more problems in individual and marital adjustment, child-rearing practices, and sibling relationship. They are significantly affected - socially, economically and emotionally - by mental retardation. Support systems both formal and informal, were a great single source of help for these families for them to cope with these children. Recommendations for better quality of life for both the handicapped child and his family are given in the last chapter, and they are most suitable for undertaking by the Welfare and Education Departments. It is not the purpose of this study to give advice to parents on how to bring up their handicapped children. Often using the mothers' own words, the researcher only presents the picture given by the parents themselves of how they actually learn to live with a handicapped child
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  • Date Issued: 1995

The metallogeny of the Upington and Kenhardt area, northern Cape

  • Authors: Boelema, Robert
  • Date: 1995
  • Subjects: Metallogeny -- South Africa , Metallogeny -- South Africa -- Northern Cape , Plate tectonics -- South Africa -- Northern Cape , Geology, Structural -- South Africa -- Northern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4975 , http://hdl.handle.net/10962/d1005587 , Metallogeny -- South Africa , Metallogeny -- South Africa -- Northern Cape , Plate tectonics -- South Africa -- Northern Cape , Geology, Structural -- South Africa -- Northern Cape
  • Description: In the Upington region, there are three major- tectonic crustal provinces; namely the Kaapvaal Craton, Kheis and Namaqua tectonic provinces. The Eburnian-aged (early Proterozoic) Kheis Province developed along the western flank of the Archaean Kaapvaal Craton while the Kibaran-aged (middle Proterozoic) Namaqua Metamorphic Province, superimposed on the Eburnian-aged basement, developed to the east of the Kheis Province. The Namaqua Metamorphic Province is divided into the Gordonia and Bushmanland Subprovinces, the former being further subdivided into various tectonostratigraphic terranes. These are termed, from west to east, the Kakamas, Areachap, and Upington Terranes. The Upington Terrane includes fault bounded grabens with accompanied bimodal volcanism and sedimentation of the Wilgenhoutsdrif and Koras Groups. The Areachap Terrane consists predominantly of amphibolites generated in an island arc environment while the Kakamas Terrane is characterised by volcano-sedimentary sequences which have been extensively intruded by syn to late-tectonic predominantly I-type Keimoes Suite granitoids. The main styles of mineralisation correlate well with the various tectonostratigraphic terranes. Sedimentary exhalative massive sulphide deposits are characteristic of the Bushmanland Subprovince and are thought to be associated with the deposits at Aggeneys and Putsberg to the west of the area under investigation. These deposits are considered to have been deposited in an east-west-elongated intracontinental basin. The Kakamas Terrane is typified by granite-related mineralisation. In the eastern portion of the Kakamas Terrane, Sn-Wand base metal-bearing veins occur while pegmatites are developed in the western portion. These two styles of granite-related mineralisation is considered to reflect differing depths of formation due mainly to varying degrees of thrusting. The Areachap Terrane consists of volcanogenic massive sulphide deposits of the Besshi-type and is considered to have formed in a back-arc environment. In the Upington Terrane, the Wilgenhoutsdrif and Koras Groups consists essentially of minor Cu occurrences mainly disseminated within basalts and in structural trap sites. The possibility for sediment-hosted Cu deposits is not ruled out. More recent surface processes have led to uranium and gypsum deposits in pans, river beds and calcretes. Eburnian aged tectonic setting remains enigmatic. Kibaran-aged tectonics which best fits the metallogeny of the area under investigation is considered to be of a subduction zone from west to east formed by the collision of the Bushmanland "microcontinent" against the Kaapvaal Craton. Subduction fbrmed an island arc setting in which the massive sulphide deposits were formed in the Areachap Terrane while the Wilgenhoutsdrif Groups developed in a marginal basin. Further convergence led to collision of the two continents and underriding of the Bushmanland "microcontinent" which generated predominantly I-type granitoids represented by the Keimoes Suite. The level of emplacement of these granitoids is a reflection of the degree of foreland thrusting and produced shallower level Sn-W and base metal vein-type mineralisation closer to the suture zone and deeper level pegmatites further from the suture zone to the west. The final period of deformation is represented by northward lateral movement which created "pull apart" fault-bounded basins into which the Koras Group was deposited.
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  • Date Issued: 1995

The mineralogy and geochemistry of the Voëlwater banded iron-formation, Northern Cape Province

  • Authors: Tsikos, Harilaos
  • Date: 1995
  • Subjects: Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4977 , http://hdl.handle.net/10962/d1005589 , Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
  • Description: Banded iron-formations (BIFs) are chemically precipitated sedimentary rocks in which Fe-rich bands or laminae alternate with Fe-poor ones. They formed within a specific time-span of the geological record. Their occurrence is restricted between 2.3 and 1.9 Ga, and characterises virtually all the major Precambrian-aged sedimentary basins of the world. The Precambrian Transvaal Basin in Griqualand West, South Africa, is noted for its well-developed BIF units. The Kuruman and Griquatown BIFs comprising the Asbesheuwels Subgroup (up to 1000m thick) are the best known and thickest of these. As far as metallogenesis is concerned, the Kuruman BIF is of major importance, for it carries the world's largest crocidolite (blue asbestos) deposits. The uppermost, youngest member of iron-formation deposition in the Griqualand West Sequence is represented by the Voëlwater BIF. The direct association between the latter and the giant Mn-deposits of the Kalahari Field, renders the Voëlwater association unusual, if not unique, in the geological record. The Voëlwater BIF represents a typical example of the so-called "Superior-type", and in the area of study it has undergone late-diagennetic to low-grade metamorphic processes. This is evident from the mineralogical composition and textural signature of the various BIF lithologies. Specifically, the minerals that make up the Voëlwater BIF are mainly chert(quartz), Fe-oxides (magnetite and hematite), Fe-silicates (greenalite, stilpnomelane, minnesotaite, riebeckite, Fe-mica), Fe-carbonates (members of the dolomite-ankerite series and siderite), calcite and pyrite. Soft-sediment deformation structures and shear-stress indicators are abundant in carbonate-rich and granular, silicate-rich BIF lithologies respectively. The bulk chemical composition of the study rocks is relatively simple and is characterised by the abundance of essentially three elements, namely Si, Fe, and Ca, which make up more than 90% of the total chemical composition of the Voëlwater BIFs. The detrital component of the study rocks is negligible. Mn-enrichments characterise all the transitional lithologies towards the interbedded Mn-orebodies, as well as the well-developed, hematitic BIF-unit between the Ongeluk lavas and the lower Mn-horizon. In terms of trace element composition, no significant enrichments or depletions, were encountered, except for some unusually high values of Sr and Ba and Co in carbonate-rich and Mn-rich lithologies respectively. Geochemical comparisons on the basis of major, trace and light rare-earth element composition verified the similarity between the Voëlwater BIF and other major Superior-type BIFs of the world (e.g. Kuruman, Griquatown, Sokoman, Biwabik, Gunflint, Mara-Mamba, Brockman, etc.). The processes that led to the formation of the Voëlwater BIFs may have been very similar to the ones described in various genetic models proposed in recent years. They would have involved a combination of: i. hydrothermal processes related to mid-ocean ridge (MOR) or hot-spot activity that acted as major iron suppliers; ii. storm-mixing in stratified oceans (bottom, anoxic, Fe⁺² reservoir-thermo- pycnocline zone-upper, mixed, SiO₂-saturated layer), largely dictated by seasonal changes and contemporaneous volcanism; iii. periodic, convection-driven upwelling mechanisms acting as major Fe-precipitators; and, iv. organic carbon productivity that was responsible for the anoxic diagenesis of the initial sediment. However, the origin of Fe and Mn for the genesis of the Voëlwater sediments was difficult to explain with typical convection-cell models in active mid-ocean ridges, in contrast to previous hypotheses. Instead, large-scale endogenous processes in the form of magma convection, underplating, differentiation and associated degassing, may have played a critical role in the supply of metals for the formation of large amounts of BIFs in the Precambrian. The present study of the Voëlwater BIF also bears strong implications regarding the metallogenesis of Mn in the Precambrian. The common association of Mn with carbonate-bearing sediments, the transitional character of the Voëlwater BIF towards carbonate lithologies (Mooidraai dolomites) and the critical timing of the deposition of the former in terms of the Precambrian atmospheric-lithospheric- hydrospheric evolution, may be important indicators for the exploration of large Mn-deposits in Precambrian sedimentary basins of the world.
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  • Date Issued: 1995

The morphology and sedimentology of two unconsolidated quaternary debris slope deposits in the Alexandria district, Cape Province

  • Authors: Illgner, Peter Mark
  • Date: 1995
  • Subjects: Slopes (Physical geography) -- South Africa , Weathering -- South Africa , Geomorphology -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4843 , http://hdl.handle.net/10962/d1005519
  • Description: Research on hillslope surface processes and hillslope stratigraphy has been neglected in southern Africa. The amount of published literature on hillslope stratigraphy in southern Africa is very limited. Hillslope sediments provide a record of past environmental conditions and may be especially useful in calculating the recurrence interval of extreme environmental conditions such as earthquakes and intense rainfall events. The characteristics of hillslope sediments provide information as to their origin, transport and mechanisms of deposition. No published work could be found that had been undertaken on hillslope surface processes or stratigraphy in the eastern Cape coastal region. This study attempted to fill this gap in the geomorphic literature for southern Africa. The surface processes acting on hillslopes at Burchleigh and Spring Grove in the Alexandria district of the eastern Cape were examined in terms of slope morphology, surface sediment characteristics and the internal geometry of the hillslope sedimentary deposits. The late Quaternary hillslope sedimentary deposits at the two study sites are composed of fine grained colluvial sediments intercalated with highly lenticular diamicts. The fine grained colluvial sediments were emplaced by overland flow processes while the diamicts were deposited by debris flows. The sedimentary sequences at both study sites have a basal conglomerate interpreted as a channel lag deposit. Most slope failures preceding debris flow events were probably triggered by intense or extended periods of rainfall associated with cold fronts or cut-of flows. Seismic events may also have triggered slope failure, with or without the hillslope sediments being saturated. The results of this study indicate that a continuum exists between the slopewash dominated processes of the presently summer rainfall regions of Natal to the present winter rainfall regions of the western Cape where mass movement processes are significant. Hillslope deposits, therefore, provide a record of environmental conditions which may greatly facilitate proper management of the landscape.
  • Full Text:
  • Date Issued: 1995

The new labour relations act - A summary of important features

  • Authors: COSATU
  • Date: 1995
  • Subjects: COSATU
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/174426 , vital:42476
  • Description: This summary is intended primarily for unionists who want to get an overview of key substantive features of the new Labour Relations Act (LRA) that will most probably take effect in April or May next year.
  • Full Text:
  • Date Issued: 1995

The politics and poetics of choreography the dancing body in South African dance

  • Authors: Finestone, Juanita
  • Date: 1995
  • Subjects: Dance -- South Africa , Gordon, Gary -- Unspeakable Story , Orlin, Robyn -- In A Corner The Sky Surrenders
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2138 , http://hdl.handle.net/10962/d1002370 , Dance -- South Africa , Gordon, Gary -- Unspeakable Story , Orlin, Robyn -- In A Corner The Sky Surrenders
  • Description: This mini-thesis is situated in the discourse on patriarchy, nationhood and its artistic forms. It is argued that an uncritical pursuit of commonality as a political aesthetic strategy for dance in South Africa repeats the metaphysical foundationalism of this discourse. It is further suggested that a postmodern ethos subverts this heritage, while at the same time offering a viable alternative for accommodating and representing the cultural diversity and plurality characteristic of current theatre dance in South Africa. Chapter One examines the way dance has historically structured its patriarchal form the postmodern discourses Chapter Two as a site and practice through explores the potential of deconstruction and destabilisation of this dance heritage. This chapter also assesses the relevance of a postmodern alternative in a South African dance context. Chapter Three analyses the postmodern choreographic strategies of two South African choreographers, Gary Gordon and Robyn Orlin, in order to reveal how their dance vision to patriarchal aesthetic form and offers an uncritical alternative notions of commonality. In conclusion, it is argued postmodern ethos embodied in the work that the of these choreographers provides viable directions for formulating and articulating new dance directions for theatre dance in South Africa while, at the same time, bearing witness to the diversity that will always structure expressions of commonality in South African dance.
  • Full Text:
  • Date Issued: 1995
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