A mineralogical, geochemical and metallogenic study of unusual Mn/Na/Ba assemblages at the footwall of conglomeratic iron-ore at farm Langverwacht, Northern Cape Province of South Africa
- Authors: Bursey, James Rodney
- Date: 2018
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Conglomerate -- South Africa -- Northern Cape , Petrology -- South Africa -- Northern Cape , Manganese -- South Africa -- Northern Cape , Sodium -- South Africa -- Northern Cape , Barium -- South Africa -- Northern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62516 , vital:28201
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape province of South Africa, plays host to significant deposits of iron and manganese that have been utilized since their discovery in 1922 by Captain L.T. Shone. Further afield, lies the massive high-grade manganese deposit of the Kalahari Manganese Field (KMF), which drew attention away from the PMF after its discovery. These deposits are not limited to iron and manganese ore, but contain significant assemblages of alkali-rich rocks - which is the focus of this study. The existence of alkali-rich assemblages beneath conglomeratic iron-ore on farm Langwervacht, has come under investigation in this study, and in particular, the enrichment of these rocks in Ba, Na and Mn. Petrographic analysis of the clast-supported conglomerate unit (ore-zone), has uncovered the presence of vugs (up to 8mm across) which contain barite, K-feldspar and fluorapatite. In addition to this, the ore-zone of one of the three boreholes contains late carbonate veins (kutnohorite), which travel along Fe-clast boundaries, and exploit clast-fractures and areas of weakness. Further down, within the ‘enriched-zone’ of alkalis, the mineralogy is more diverse - containing elevated concentrations of Ba, Na and Mn. Seventeen distinct minerals containing these three key elements have been identified - along with one solid-solution series in the form of hollandite-coronadite. The existence of minerals such as natrolite, aegirine, albite, banalsite, barite, serandite, celsian and hollandite-coronadite are indicative of hydrothermal activity having influenced these rocks. Bulk-geochemistry was used to compare the major and trace elements of each borehole and the associated units. Both the trace elements and the REE’s from the ore-zone are enriched by an average of 5-10x relative to the BIF standard used - which immediately suggests an influx of elements. Compared to PAAS (Post Archaean Australian Shales), the ore-zone REE’s are slightly depleted, but more importantly the profiles are very similar to that of the Mapedi shales achieved in previous studies. This result points towards a strong shale influence in the ore-zone protolith. Expectedly, many of the enriched-zone trace elements and REE’s show far greater enrichment than what is observed in the ore-zone. Trace and Rare Earth Element profiles between the ore-zone and the enriched-zone are, however, generally correlative, with profiles reflecting similar enrichments and depletions for a given element - even within different rock units. This suggests that the hydrothermal fluid has moved in a general upward direction, reacting with host-rock units, and relinquishing elements carried in solution - wherever conditions have been favourable for the accommodation of these elements. This study has shed light on the relationship between the ore-zone and the enriched-zone, and results suggest that the process of alkali enrichment is not directly related to the process of upgrading of the iron ores. This is due to the extent of the alkali-enrichment below the ore-zone, as well as enrichment factors in some trace elements being superior to that of Fe2O3 in the ore- zone. Hence, both of these zones have both been affected by a later hydrothermal fluid. The source of the fluid is likely a mature basinal brine, of oxidized, alkaline nature - which leached elements (Ba, K, Na, Pb, Ca) from older rocks, and carried them in solution. On a local-scale, this fluid has exploited areas of weakness in the form of fractures, less consolidated conglomeratic material and crosscutting veins. Manganese and iron has been remobilized on a local scale - producing secondary textures and partitioning into phases such as Mn-rich calcite and serandite. Comparisons to other studies in the PMF and KMF have revealed very similar alkali-rich assemblages, bearing many of the same minerals observed in this study - even within more manganiferous deposits. These findings have led to suggestions of a possible regional-scale hydrothermal overprint, which may have imparted a similar geochemical signal over the entire region - with the assistance of faults and unconformities. Of course, proving this is no mean feat, but current work on the source of barium in barite, using Sr isotopes from samples across the region may shed light on the source of at least one key element of these deposits.
- Full Text:
- Date Issued: 2018
- Authors: Bursey, James Rodney
- Date: 2018
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Conglomerate -- South Africa -- Northern Cape , Petrology -- South Africa -- Northern Cape , Manganese -- South Africa -- Northern Cape , Sodium -- South Africa -- Northern Cape , Barium -- South Africa -- Northern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62516 , vital:28201
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape province of South Africa, plays host to significant deposits of iron and manganese that have been utilized since their discovery in 1922 by Captain L.T. Shone. Further afield, lies the massive high-grade manganese deposit of the Kalahari Manganese Field (KMF), which drew attention away from the PMF after its discovery. These deposits are not limited to iron and manganese ore, but contain significant assemblages of alkali-rich rocks - which is the focus of this study. The existence of alkali-rich assemblages beneath conglomeratic iron-ore on farm Langwervacht, has come under investigation in this study, and in particular, the enrichment of these rocks in Ba, Na and Mn. Petrographic analysis of the clast-supported conglomerate unit (ore-zone), has uncovered the presence of vugs (up to 8mm across) which contain barite, K-feldspar and fluorapatite. In addition to this, the ore-zone of one of the three boreholes contains late carbonate veins (kutnohorite), which travel along Fe-clast boundaries, and exploit clast-fractures and areas of weakness. Further down, within the ‘enriched-zone’ of alkalis, the mineralogy is more diverse - containing elevated concentrations of Ba, Na and Mn. Seventeen distinct minerals containing these three key elements have been identified - along with one solid-solution series in the form of hollandite-coronadite. The existence of minerals such as natrolite, aegirine, albite, banalsite, barite, serandite, celsian and hollandite-coronadite are indicative of hydrothermal activity having influenced these rocks. Bulk-geochemistry was used to compare the major and trace elements of each borehole and the associated units. Both the trace elements and the REE’s from the ore-zone are enriched by an average of 5-10x relative to the BIF standard used - which immediately suggests an influx of elements. Compared to PAAS (Post Archaean Australian Shales), the ore-zone REE’s are slightly depleted, but more importantly the profiles are very similar to that of the Mapedi shales achieved in previous studies. This result points towards a strong shale influence in the ore-zone protolith. Expectedly, many of the enriched-zone trace elements and REE’s show far greater enrichment than what is observed in the ore-zone. Trace and Rare Earth Element profiles between the ore-zone and the enriched-zone are, however, generally correlative, with profiles reflecting similar enrichments and depletions for a given element - even within different rock units. This suggests that the hydrothermal fluid has moved in a general upward direction, reacting with host-rock units, and relinquishing elements carried in solution - wherever conditions have been favourable for the accommodation of these elements. This study has shed light on the relationship between the ore-zone and the enriched-zone, and results suggest that the process of alkali enrichment is not directly related to the process of upgrading of the iron ores. This is due to the extent of the alkali-enrichment below the ore-zone, as well as enrichment factors in some trace elements being superior to that of Fe2O3 in the ore- zone. Hence, both of these zones have both been affected by a later hydrothermal fluid. The source of the fluid is likely a mature basinal brine, of oxidized, alkaline nature - which leached elements (Ba, K, Na, Pb, Ca) from older rocks, and carried them in solution. On a local-scale, this fluid has exploited areas of weakness in the form of fractures, less consolidated conglomeratic material and crosscutting veins. Manganese and iron has been remobilized on a local scale - producing secondary textures and partitioning into phases such as Mn-rich calcite and serandite. Comparisons to other studies in the PMF and KMF have revealed very similar alkali-rich assemblages, bearing many of the same minerals observed in this study - even within more manganiferous deposits. These findings have led to suggestions of a possible regional-scale hydrothermal overprint, which may have imparted a similar geochemical signal over the entire region - with the assistance of faults and unconformities. Of course, proving this is no mean feat, but current work on the source of barium in barite, using Sr isotopes from samples across the region may shed light on the source of at least one key element of these deposits.
- Full Text:
- Date Issued: 2018
Primary controls on iron and manganese distribution in sphalerite of the Gams Formation, Gamsberg zinc deposit, Namaqualand, South Africa
- Authors: Poignant-Molina, Léo
- Date: 2018
- Subjects: Sphalerite , Sphalerite South Africa Gamsberg , Manganese South Africa Gamsberg , Zinc mines and mining South Africa Gamsberg , Geochemistry South Africa Gamsberg , Metamorphism (Geology) , Electron probe microanalysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63775 , vital:28488
- Description: The Gamsberg deposit is a 200 Mt zinc reserve belonging to the world class base metalrich Aggeneys-Gamsberg mining district. A rifting environment permitted the development of four proximal SEDEX-type deposits whereby Gamsberg is localized in the eastern side of the district and characterised by a peculiar enrichment in manganese. This study investigates the geochemistry of sphalerite in the Gams Formation holding the economic units of the deposit. Microscopic petrography revealed that most of primary textures have been overprinted by recrystallization, alteration, replacement and deformational textures produced during the polyphase metamorphism of the Namaquan Orogeny. Therefore, EPMA analysis provided the bulk of information to define the geochemical distribution of sphalerite. A lateral variation was noticed throughout the Gams Formation, whereby the North orebody presents Zn-rich and Fe+Mn-poor sphalerite while the West and East orebodies contain Zn-poor and Fe-Mn-rich sphalerite. This feature has been interpreted as the association of a chemocline and a variation in the basin topography defining deep Mn+Fe-rich zones and shallow Mn+Fe-poor zones in the primitive basin. It is suggested that mineralized hot brines mixed with seawater developed the chemocline. The uneven topography shaped the geochemical variation between the actual orebodies.
- Full Text:
- Date Issued: 2018
- Authors: Poignant-Molina, Léo
- Date: 2018
- Subjects: Sphalerite , Sphalerite South Africa Gamsberg , Manganese South Africa Gamsberg , Zinc mines and mining South Africa Gamsberg , Geochemistry South Africa Gamsberg , Metamorphism (Geology) , Electron probe microanalysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63775 , vital:28488
- Description: The Gamsberg deposit is a 200 Mt zinc reserve belonging to the world class base metalrich Aggeneys-Gamsberg mining district. A rifting environment permitted the development of four proximal SEDEX-type deposits whereby Gamsberg is localized in the eastern side of the district and characterised by a peculiar enrichment in manganese. This study investigates the geochemistry of sphalerite in the Gams Formation holding the economic units of the deposit. Microscopic petrography revealed that most of primary textures have been overprinted by recrystallization, alteration, replacement and deformational textures produced during the polyphase metamorphism of the Namaquan Orogeny. Therefore, EPMA analysis provided the bulk of information to define the geochemical distribution of sphalerite. A lateral variation was noticed throughout the Gams Formation, whereby the North orebody presents Zn-rich and Fe+Mn-poor sphalerite while the West and East orebodies contain Zn-poor and Fe-Mn-rich sphalerite. This feature has been interpreted as the association of a chemocline and a variation in the basin topography defining deep Mn+Fe-rich zones and shallow Mn+Fe-poor zones in the primitive basin. It is suggested that mineralized hot brines mixed with seawater developed the chemocline. The uneven topography shaped the geochemical variation between the actual orebodies.
- Full Text:
- Date Issued: 2018
Regional value chains and development integration in the SADC Region: the case of the pharmaceutical industry
- Authors: Faydherbe, Sean
- Date: 2018
- Subjects: Pharmaceutical industry -- Africa, Southern , Southern African Development Community , Africa, Southern -- Economic integration , Regional value chains (RVCs) , Global value chains (GVCs)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/62906 , vital:28309
- Description: This thesis investigates how regional value chains (RVCs) can be used to further development integration in the Southern African Development Community (SADC) region with a focus on the pharmaceutical manufacturing industry. The study is motivated by the apparent lack of attention given to the development of the pharmaceutical manufacturing industry in Southern Africa, the region’s high disease burden and the identification of the industry as economically and socially important by the SADC (2015) Industrialisation Strategy and Roadmap and the Department of Trade and Industry (DTI) (2017a) Industrial Policy Action Plan (IPAP). At the same time, South Africa and other countries in the region are exploring alternative approaches to regional integration, given the failure or stagnation of numerous formal integration arrangements throughout Africa, which have often lead to polarised rather than balanced development. This thesis argues that the development of RVCs within SADC may be an effective tool for development integration in the region, particularly in sectors such as pharmaceuticals. The study employs a value chain framework for the analysis and discusses development integration options, drawing on the East Asian experience with RVCs and on case studies involving India in the case of the pharmaceutical industry. It provides a sector profile of the industry in South Africa, due to its dominant status in the region, and also of Zimbabwe, due to that country’s potential to become a pharmaceutical industry leader in the region once again. The thesis first explores the important theoretical aspects underlying value chain analysis, namely governance and upgrading, while also outlining the rise of global value chains (GVCs). It analyses the complex relationships between RVCs and GVCs, and RVCs and regional integration. From this it concludes that RVCs are a stepping stone to participation in GVCs and that RVCs should be promoted within a development integration framework through strong regional cooperation. Value chain analysis is applied to the entire pharmaceutical manufacturing industry with a focus on SADC. The thesis examines how the sector is evolving with manufacturing multinational corporations (MNCs) outsourcing production and setting up centres of excellence in regional production hubs. The study argues that with the application of recommended policies, RVCs in sectors such as pharmaceutical manufacturing may provide a tool for achieving balanced development in the region. However, the study also finds that the pharmaceutical industry in SADC lags a long way behind the rest of the world and that many countries and firms will need to begin at the bottom of the value chain, with formulation, in order to contribute to the development of RVCs. The thesis concludes with recommendations on what policies are needed to foster the growth and development of pharmaceutical RVCs in the SADC region. These include strengthening public procurement, providing incentives for investment into the industry, incremental production and incremental export volumes, as well as certainty and predictability around the regulatory and business environment. Further, policy should aim to construct synergies and linkages on the ground between health systems and industrial developments; regulate service links important to pharmaceutical manufacturing; develop a coherent regional policy agenda; remove unnecessary non-tariff barriers to trade in the region and, in line with development integration, implement trade policy along with trade infrastructure that is efficient and includes airports, rail, roads and ports, as well as effective access to the internet.
- Full Text:
- Date Issued: 2018
- Authors: Faydherbe, Sean
- Date: 2018
- Subjects: Pharmaceutical industry -- Africa, Southern , Southern African Development Community , Africa, Southern -- Economic integration , Regional value chains (RVCs) , Global value chains (GVCs)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/62906 , vital:28309
- Description: This thesis investigates how regional value chains (RVCs) can be used to further development integration in the Southern African Development Community (SADC) region with a focus on the pharmaceutical manufacturing industry. The study is motivated by the apparent lack of attention given to the development of the pharmaceutical manufacturing industry in Southern Africa, the region’s high disease burden and the identification of the industry as economically and socially important by the SADC (2015) Industrialisation Strategy and Roadmap and the Department of Trade and Industry (DTI) (2017a) Industrial Policy Action Plan (IPAP). At the same time, South Africa and other countries in the region are exploring alternative approaches to regional integration, given the failure or stagnation of numerous formal integration arrangements throughout Africa, which have often lead to polarised rather than balanced development. This thesis argues that the development of RVCs within SADC may be an effective tool for development integration in the region, particularly in sectors such as pharmaceuticals. The study employs a value chain framework for the analysis and discusses development integration options, drawing on the East Asian experience with RVCs and on case studies involving India in the case of the pharmaceutical industry. It provides a sector profile of the industry in South Africa, due to its dominant status in the region, and also of Zimbabwe, due to that country’s potential to become a pharmaceutical industry leader in the region once again. The thesis first explores the important theoretical aspects underlying value chain analysis, namely governance and upgrading, while also outlining the rise of global value chains (GVCs). It analyses the complex relationships between RVCs and GVCs, and RVCs and regional integration. From this it concludes that RVCs are a stepping stone to participation in GVCs and that RVCs should be promoted within a development integration framework through strong regional cooperation. Value chain analysis is applied to the entire pharmaceutical manufacturing industry with a focus on SADC. The thesis examines how the sector is evolving with manufacturing multinational corporations (MNCs) outsourcing production and setting up centres of excellence in regional production hubs. The study argues that with the application of recommended policies, RVCs in sectors such as pharmaceutical manufacturing may provide a tool for achieving balanced development in the region. However, the study also finds that the pharmaceutical industry in SADC lags a long way behind the rest of the world and that many countries and firms will need to begin at the bottom of the value chain, with formulation, in order to contribute to the development of RVCs. The thesis concludes with recommendations on what policies are needed to foster the growth and development of pharmaceutical RVCs in the SADC region. These include strengthening public procurement, providing incentives for investment into the industry, incremental production and incremental export volumes, as well as certainty and predictability around the regulatory and business environment. Further, policy should aim to construct synergies and linkages on the ground between health systems and industrial developments; regulate service links important to pharmaceutical manufacturing; develop a coherent regional policy agenda; remove unnecessary non-tariff barriers to trade in the region and, in line with development integration, implement trade policy along with trade infrastructure that is efficient and includes airports, rail, roads and ports, as well as effective access to the internet.
- Full Text:
- Date Issued: 2018
- «
- ‹
- 1
- ›
- »