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
- 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 development and distribution of heavy mineral concentrations in alluvial systems
- Authors: Lynn, Michael David
- Date: 1992
- Subjects: Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4937 , http://hdl.handle.net/10962/d1005549 , Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Description: The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.
- Full Text:
- Date Issued: 1992
- Authors: Lynn, Michael David
- Date: 1992
- Subjects: Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4937 , http://hdl.handle.net/10962/d1005549 , Heavy minerals -- Research , Alluvial plains -- Research , Geomorphology -- South Africa
- Description: The objective of this review is to summarise the characteristics, significance and evolution of heavy minerals and their accumulations, and to identify the key controls on the development and distribution of heavy mineral concentrations in alluvial systems. These controls can be broadly classified as tectonic setting, geomorphic setting and grain-scale concentrating processes, each of which is discussed. Based on this review, exploration models are developed which are designed to indicate favourable localities for the accumulation of heavy minerals, and trends likely to be exhibited within these accumulations. The models are structured from the broadest scale of target selection, down to the local scale of sample site selection. The major conclusion of this work is that an understanding of process geomorphology is required to develop genetic models of placer development, including a detailed evaluation of climatic fluctuations throughout the Caenozoic. Palaeoplacers such as the Witwatersrand goldfield, are inferred to have formed under similar circumstances of tectonic setting as genetically comparable Caenozoic placers such as those of Otago, New Zealand. The means of preservation of such major basins is however poorly understood.
- Full Text:
- Date Issued: 1992
A geographical study of the Cape Midlands and Eastern Karoo area with reference to the physiography and elements of land use
- Authors: Badenhorst, J J
- Date: 1969 , 2013-11-14
- Subjects: Land use -- South Africa , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4867 , http://hdl.handle.net/10962/d1007581 , Land use -- South Africa , Geomorphology -- South Africa
- Description: The subject has been approached in the conventional geographic manner in successive chapters, Relief, Geology, Soil, Climate, etc. In practice, the relationship between geographic factors and land use is so close that it is usually very difficult to separate the one from the other. When there is any reference to a specific relationship in any chapter, it must be borne in mind that one must always take the other geographic factors into account. In this study the stress falls on an evaluation of the present land use. Even if there is no recommendation regarding the way in which the land should be used, this survey can still be used as the basis for future planning. Intro. p.viii , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1969
- Authors: Badenhorst, J J
- Date: 1969 , 2013-11-14
- Subjects: Land use -- South Africa , Geomorphology -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4867 , http://hdl.handle.net/10962/d1007581 , Land use -- South Africa , Geomorphology -- South Africa
- Description: The subject has been approached in the conventional geographic manner in successive chapters, Relief, Geology, Soil, Climate, etc. In practice, the relationship between geographic factors and land use is so close that it is usually very difficult to separate the one from the other. When there is any reference to a specific relationship in any chapter, it must be borne in mind that one must always take the other geographic factors into account. In this study the stress falls on an evaluation of the present land use. Even if there is no recommendation regarding the way in which the land should be used, this survey can still be used as the basis for future planning. Intro. p.viii , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 1969
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