Electronic Theses and Dissertations (ETDs) - Items to be moved to 3. Electronic Theses and Dissertations (ETDs).
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Item The Karoo hydraulic fracturing debate : accounting for future generations.(2012-07-12) Yale-Kearney, Robinn Y.The temporal complexities of anthropogenic Global Climate Change (GCC) force us to extend our moral deliberations beyond what appear to be straightforward, contemporary issues to include the interests of future generations. The Karoo hydraulic fracturing debate is a case in point. The ethical debate thus far has focused on the present-day environmental aspects of Shell’s limited exploratory drilling proposal using hydraulic fracturing technology; but the shale-gas reserves that are believed to underlie the Karoo could assist in mitigating South Africa’s significant carbon emissions, the main contributor to anthropogenic GCC. Thus, I argue that the actual ethical debate is whether to allow gas exploration over the Karoo or to disallow the entire possibility of exploiting any gas reserves that may have been found. A consequentialist weighing up of the respective potential harms to all of the morally-considerable interests involved, including future generations, makes clear that not only is allowing exploration of the Karoo the morally correct decision, but it is ethically obligatory to do so.Item Palynology of a coal seam in Karoo deposits of Botswana and correlation with southern African coal-bearing strata(2010-12-02) Barbolini, NatashaA significant amount of palynological work has been done on southern African coal seams in the Ecca Group, but as yet there is little consensus on how these areas relate to each other. This study investigated the palynology of a coal seam from Mmamantswe (Mmamabula area), Botswana, approximately 70 km north-east of Gaborone. A total of 124 samples were taken from two borehole cores and subjected to acid preparation, oxidation and acetolysis. Coal samples were found to be barren of palynomorphs. Fifty carbonaceous mudstones and siltstone samples yielded twenty-two productive samples. A thermal alteration index of 3.0-3.5 was assigned for the sediments. Palynomorph diversity was high, with 64 genera and 90 species present, dominated by trilete and alete spores. This indicates a parent flora of mostly lower order lycopods, sphenophytes and ferns. Non-taeniate bisaccate and monosaccate pollens were scarce, and striates extremely rare (only two species), suggesting an autochthonous origin for the coal swamp. The Mmamantswe core was sub-divided into five microfloral assemblage zones. A transition from monosaccate dominance in the lower part of the core, to equal numbers of monosaccates and non-taeniate bisaccates in the upper part of the core, was seen. As the Mmamantswe palynoflora possesses elements of both the Late Carboniferous glacial floras and the mid-Permian coal floras, it is thought to represent a cross-over assemblage dating to soon after the Permo-Carboniferous boundary (Sakmarian and Early Artinskian). The Mmamantswe assemblage can be correlated with Assemblage Zones II and III of Falcon (1975a); Biozones B and C of MacRae (1988); and Zones 1, 2 and 3 of Anderson (1977) but does not fit well into any existing biozonation. The Mmamantswe palynoflora was most similar to that of Milorgfjella, Dronning Maud Land, Antarctica (Larrson et al. 1990) and the No. 2 Seam, Witbank, South Africa (Falcon 1989). Taphonomic controls on palynomorph preservation suggest that future studies should also attempt to focus on Permian sediments not containing coal, as microfloral assemblages from coal seams tend to be autochthonous, and subject to local climatic influences. Accordingly they are not as useful for inter-basinal correlation across Gondwana.Item A bio- and litho- stratigraphic study of the Ecca-Beaufort contact in the southeastern Karoo basin (Albany District, Eastern Cape Province)(2008-10-27T10:44:30Z) Mason, RichardThe rocks of the Carboniferous to Jurassic aged main Karoo Supergroup of South Africa preserve an internationally significant and stratigraphically continuous retro-arc foreland depositional sequence. This succession documents environmental change from glacial-marine, through fluvio-deltaic to continental fluvial and aeolian, culminating in rift associated continental flood basalt extrusions. The fluvio-deltaic transition from marine to continental deposition has been the subject of much recent research and corresponds with the position of the Ecca-Beaufort contact. Over the entire basin this transition comprises three separate lithofacies associations deposited in the prodelta, deltafront and delta plain environments. Anomolously the southeastern contact is currently mapped as reflecting fluvial deposits of the Koonap Formation lying unconformably on prodelta deposits of the Fort Brown Formation. Detailed study across the Ecca-Beaufort contact in this part of the basin now reveals the same lithological transition as is present in the rest of the basin. Contrary to previuos work, this has shown that the Waterford Formation is indeed present in this part of the basin. This in effect means that the Grahamstown map sheet (1:250 000, Map 3326) requires modification to include this Formation and the new contact placement of the Ecca-Beaufort contact occurs some 70 to 120m above the presently mapped contact. Fossils collected during this and previous studies show that biostratigraphically Tapinocephalus Assemblage Zone fauna occurs in the rocks of the Koonap Formation in this part of the basin, indicating that the Ecca-Beaufort contact in the southern part of the basin youngs towards the east. This supports the prograding shoreline deposition model that has been previously proposed for the Ecca-Beaufort contact.