A dissertation submitted to the Faculty of Science, University or the Witwatersrand, for the degree of Master of Science. / The study of an area north of the Johannesburg Dome has revealed that the rocks of the Transvaal Supergroup have been affected by widespread deformation, as well as metamorphism to the greenschist facies. Thermal modelling suggests that the metamorphism, and hence porphyroblast growth, can probably be attrIbuted to the thermal effect of the Bushveld Complex. Thus, textural relationships between porphyroblasts and cleavage microstructure in slates could be utilized to establish the relative timing of ductile deformation events in the area. (Abbreviation abstract) / AC 2018

A Dissertation Submitted to the Faculty of Science University of the Witwatersrand, Johannesburg for the degree of Master of Science / AC 2018

Various methods and techniques developed by researchers worldwide for enhancement and processing ATM, MSS· and TM remotely sensed data are tested. on LANDSAT 5 Thematic Mapper data from a part of the Barberton Greenstone Belt straddling the border between the Republic of South Africa and the Kingdom of Swaziland. Various enhancement techniques employed to facilitate the extraction of structural features and lineaments, and the findings Of the ensuing photogeologlcal interpretation are compared with existing geological maps~ Methods for the detection of zones of hydrothermal alteration. are also considered. The reflectance from vegetation, both natural and cultivated, and the possible reduction of the interference caused by this reflectance, are considered in detail. Partial unmixing of reflectances through the use of various methods and techniques, some of which are readily available from the literature, are performed and its effectiveness tested. Since large areas within the study area are covered by plantations, the interfereiice from the two types of vegetation present (i.e. natural and cultivated), were initially considered separately. In an attempt to isolate the forested areas from the natural vegetation, masks derived through image classification were used to differentially enhance the various features. Results indicate that the use of any particular method to the exclusion of all others will seriously limit the scope of conclusions possible through interpretation of the information present. Enhancement of information in one domain will inadvertently lead to the suppression of information from one or more of the coexisting domains. A series of results from a sequence of procedures interpreted in parallel will in every case produce information of a higher decision making quality. / AC2017

M.Sc. (Geology) / Please refer to full text to view abstract

Tectonics plays an important role in the genesis and subsequent mlnlng development of the Kwaggashoek East ore body. Lithological key units control the effectiveness of the ore forming processes, affecting the in situ ore reserve, The Kwaggashoek East deposit is the product of primary and secondary processes. A genetic model focussed on the source, migration and deposition of iron suggests a possible original source of iron as the product of very dilute hydrothermal input into deep ocean waters, with subsequent migration through structural conduits. Supergene processes account for the upgrading of the ore and the phosphorus redistribution. A good correlation between samples in a preliminary geostatistical study reflects the effectiveness of this process in the high grade ore zone. A broad overview of the economic issues which affect the commercialization of iron, indicates a balanced supply-demand situation for the five next years. The reserve estimation procedure requires accurate scientific terminology and appropriate methodology. Documentation is essential and should be detailed enough to allow for future reassessment. The results of three estimation methods in Kwaggashoek East differ by less than 5%. The accuracy of the final results depends more on geological interpretation and assumptions than on the method applied. Although optimization of grade and tonnage in the Kwaggashoek East deposit seems to be met with the actual cut-off grade used in the Thabazimbi mine district, the grade-quality concept introduced in this thesis indicates a decrease in the estimated reserves for the deposit

M.Sc. (Geology) / Please refer to full text to view abstract

Thesis (Ph.D.)-University of Durban-Westville, 1999.

[Introduction] During 1965 the author, in looking for a project for a thesis to be submitted for the degree of Master of Science in Geology, decided to map a suitable region in order to gain experience in geological field work. The exact nature of the region itself was of no great importance, but since this study was to be conducted through Rhodes University, it was decided that an area, as near to Grahamstown as possible, would be the most suitable. With this in view, the geologist in charge of the Grahamstown Office of the Geological Survey was invited to suggest an area suitable for study, and if possible, to obtain financial assistance. He indicated the region which has been mapped and which will eventually form part of the proposed sheet 143. It is immediately adjacent to, and to the west of the 1:125,000 sheet 136 of Grahamstown completed by Mountain in 1940.

M.Sc. (Geology) / Please refer to full text to view abstract

M.Sc. (Geology) / Rocks of the Witwatersrand Super group in the northern portion of the East Rand Goldfield have been examined on surface and in underground exposures in an attempt to establish the chronology, movement vectors, amount of strain and displacement associated with bedding parallel faults. It was found that more than one age of movement occurred along most of the non-bedding parallel fault planes with normal, reverse and strike-slip senses of motion. The ductile bedding plane faults are manifested in all lithologies, but the shale units have, in particular, acted as a locus for shearing and it is suggested that they should be regarded as phyllonites. Bedding parallel faults are generally characterised by the presence of quartz veins and the development of phyllosilicates. They are categorised as mylonitic quartz schists. Syntectonic fault restricted quartz veins generally parallel the foliation, developed in the plane of flattening, and aided the movement of overlying strata during fault formation. Kinematic indicators imply a broad northerly up dip movement on the bedding parallel faults; implying they are thrust faults. Directionally specific kinematic indicators display at least two directions of thrust movement in the Central Rand Group, one to the NE and a second to the N to NW. The second group may represent two overlapping directions of movement. Only NE thrust movement are indicated in the West Rand Group. The NE thrust event occurred after emplacement of Ventersdorp dykes and before deposition of the rocks of the Black Reef Quartzite Formation. The N thrust fault event occurred after deposition of the Black Reef Quartzite Formation and before deposition of Karoo age rocks. A possible third event of Bushveld Igneous Intrusion age may be manifested as thrust faults towards the NW. The contact between the Central and West Rand Groups has acted as a major decollement during the N thrust event. The folds in this region may initially have been the result of thrust faulting towards the NE. Tilting of the fold axes during the postulated NW event is possible.