- Title
- Sediment characteristics and hydrodynamic conditions of the Swartkops estuary, Eastern Cape Province of South Africa
- Creator
- Best, Lutho https://orcid.org/0000-0001-6400-9061
- Subject
- Geology, Stratigraphic
- Subject
- Estuarine oceanography
- Subject
- Swartkops River Estuary (South Africa)
- Date Issued
- 2021-11
- Date
- 2021-11
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10353/22611
- Identifier
- vital:52596
- Description
- This study is a part of an environmental research project aimed at providing assessment information to the grain-size distribution, mineral compositions, sedimentary structures and coastal erosion and rehabilitation methods along the Swartkops estuary, a recent developing industry area of South Africa. The methodologies used in this study comprise desk study of literature, field geological investigation and sampling, and laboratory analyses including grainsize analysis, thin section microscope study, XRD mineral composition study and SEM-EDX grain surface texture and composition analyses.The basement and surrounding areas of the Swartkops estuary consist of three formations: the Enon Formation of mainly conglomerate, the Kirkwood Formation of sandstone and mudstone, and the Sundays River Formation of dominantly mudstone with sandstone, which integrated as Uitenhage Group of Cretaceous sequence with modern estuarine sand and alluvial sediments filled in the entire basin. Grain size analysis is a useful tool to assess hydrodynamic environments. The grain size parameters showed that most of the Swartkops estuary sediments are moderately sorted with very few well and poorly sorted, coarse to fine skewed in grain size distribution.Whereas the Bluewater Bay beach sediments are mostly fine grained, well sorted, fine to coarse skewed in grain size distribution. The bivariate scatter plots are an indication of shallow marine environment by beach and coastal processes with the influence of water flow and wind influence during transportation and deposition processes. Mineralogy studies revealed that the Swartkops estuary sediments are dominantly composed of minerals such as: quartz, calcite, feldspar (orthoclase and plagioclase), aragonite, clay minerals (smectite and illite), and salts such as NaCl and MgCl2. Skeletal carbonate minerals (shell fragments) are more than chemical precipitated carbonate minerals. Quartz is the most abundant detrital mineral observed in all the sediments and it comes from inland and transported into the estuary and the beach by fluvial streams, whereas skeletal calcite/aragonite is the most abundant biogenic carbonate derived from sea side and transported by marine currents. The study shows that grain surface textures reveal the existence of several features that reflect the depositional environments. Observed grain surface textures by microscope and SEM include V-shape pits, upturned pits caused by mechanical crashing and corrosion during transportation; crystalline precipitation of calcite, quartz, salt and clay by chemical precipitation and crystallization; dissolution pits and pores formed by dissolution, and burrow and boring by biogenetic activities. The grain surface morphologies are closely linked to different formation mechanisms and depositional environments. Well-developed sedimentary structures have been found in the beach and estuary, including sand dune, sand ridge, straight and sinuous ripple, ripple marks, aeolian nail marks, high angle tabular cross bedding, antidune, rill mark, rhomboid mark, swash line, mud crack, gravel pavement, interfering ripples, flat topped ripple mark, linguiod mark, asymmetric sinuous ripples, dendritic pattern on sandy beach, boring and bioturbation, burrows desiccation cracks and water escape hole. Different sedimentary structures are reflective of different hydrodynamic conditions and depositional environments. Coastal erosion is a major problem for damage of road, bridge and properties in the industrial areas in Swartkops, which is also a task for this study. The author had suggested some practical mitigation-methods to local government, such as groins, revetments, shoreline hardening, planting of vegetation, and vertical walls, bulkheads, sills, which could be useful for the protection of coastal erosion.
- Description
- Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (195 leaves)
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
- Rights
- All Rights Reserved
- Rights
- Open Access
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UFH Department of Geology
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Best MSc Geology dissertation.pdf | 8 MB | Adobe Acrobat PDF | View Details Download |