A thesis submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy University of the Witwatersrand School of Geosciences and Dublin Institute for Advanced Studies School of Cosmic Physics Geophysics Section February 2016 / Archean cratons, and the Proterozoic orogenic belts on their flanks, form an integral part of the Southern Africa tectonic landscape. Of these, virtually nothing is known of the position and thickness of the southern boundary of the composite Congo craton and the Neoproterozoic Pan African orogenic belt due to thick sedimentary cover. In this work I present the first lithospheric-scale geophysical study of that cryptic boundary and define its geometry at depth. The results are derived from two-dimensional (2D) and three-dimensional (3D) inversion of magnetotelluric data acquired along four semi-parallel profiles crossing the Kalahari craton across the Damara-Ghanzi-Chobe belts (DGC) and extending into the Congo craton. Two dimensional and three-dimensional electrical resistivity models show significant lateral variation in the crust and upper mantle across strike from the younger DGC orogen to the older adjacent cratons. The Damara belt lithosphere is found to be more conductive and significantly thinner than that of the adjacent Congo craton. The Congo craton is characterized by very thick (to depths of 250 km) and resistive (i.e. cold) lithosphere. Resistive upper crustal features are interpreted as caused by igneous intrusions emplaced during Pan-African magmatism. Graphite-bearing calcite marbles and sulfides are widespread in the Damara belt and account for the high crustal conductivity in the Central Zone. The resistivity models provide new constraints on the southern extent of the greater Congo craton, and suggest that the current boundary drawn on geological maps needs revision and that the craton should be extended further south. The storage possibilities for the Karoo Basins were found to be poor because of the very low porosity and permeability of the sandstones, the presence of extensive dolerite sills and dykes. The obvious limitation of the above study is the large spacings between the MT stations (> 10km). This is particularly more limiting in resolving the horizontal layers in the Karoo basin. However the 1D models provide layered Earth models that are consistent with the known geology. The resistivity values from the 1D models allowed porosity of the Ecca and Beaufort group lithologies to be calculated. It is inferred that the porosities values are in the range 5-15 % in the region below the profile. This value is considered too low for CO2 storage as the average porosity of rock used for CO2 is generally more than 10 to 12 percent of the total rock unit volume.

A dissertation submitted to the Faculty of Science, University of Witwatersrand in the fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2015. / Northwest Botswana holds a key position for the correlation of the Pan-African mobile belts of southern Africa (i.e. the Damara-Zambezi-Lufilian Orogeny). Phanerozoic cover (Kalahari Group) precludes direct correlation between Proterozoic lithologies of the Damara Belt and thick metasedimentary sequences of northwest Botswana. A combination of new geological and geophysical field observations, interpretation of 50 m resolution aeromagnetic data, and 2.2 km resolution gravity data of Namibia and Botswana, have led to the development of a new sub- Kalahari geological map of the Damara Belt and northwest Botswana. The interpretation of potential field and magnetotelluric (MT) data complemented with both new and published geological data, has improved the identification of the northern and southern margins of the Damara Belt and northwest Botswana, and tectonostratigraphic zones within them. In addition, these correlations have established that the northern margin of the Kalahari Craton on geological maps extends further north than previously noted. The northeast trending Damara Belt is confidently traced into northwest Botswana (Ngamiland) to ~19.5°S, 22.0°E. At this location, in map view, aeromagnetically interpreted structures follow a radial distribution from northwest-striking in the west to northeast-striking in the east. The lithostratigraphic units to the north of this location cannot be confidently correlated with lithostratigraphic units of the Damara Belt. Instead, these units are better correlated with lithostratigraphic units in southern Angola and/or Zambia. The southeastern margin of the Damara Belt is in tectonic contact with the northern margin of the Ghanzi-Chobe Belt as identified in the aeromagnetic images. The Ghanzi-Chobe Belt is correlated with the Sinclair Supergroup in the Rehoboth Subprovince in Namibia. The basal Kgwebe volcanics are correlated with the Oorlogsende Porphyry Member and Langberg Formation and the unconformably overlying metasediments of the Ghanzi Group are correlated with the metasediments of the Tsumis Group. The correlations are based on similar aeromagnetic signatures, lithologies, mineralisation and age dates constrained by carbon isotope chemostratigraphy. Physical property measurements were collected on Meso- to Neoproterozoic lithologies of the Damara Belt, northwest Botswana and Zambia. The measurements included hand held magnetic susceptibility measurements on 303 samples and density measurements on 174 samples. The measurements provide one of the largest physical property databases for Namibia, Botswana and Zambia. In general, the sedimentary units have the lowest magnetic susceptibility values of ~0.207 x 10-3 SI units, respectively. The exceptions are the iron formation and diamictite of the Chuos Formation and conglomerate of the Naauwpoort Formation of 15.2 x 10-3 SI units. The iron iii formation ranges in magnetic susceptibility from 3.34 x 10-3 SI units to 92.0 x 10-3 SI units and the diamictite has a magnetic susceptibility of 7.68 x 10-3 SI units. The igneous lithologies have a density and magnetic susceptibility range from 2.58 g.cm-3 to 3.26 g.cm-3 and 0.001 x 10-3 SI units to 11.6 x 10-3 SI units, respectively. The lower values are associated with pegmatites and rhyolites and the higher values are associated with mafic lithologies and magnetite bearing granites (Omangambo, Salem, Sorris-Sorris and Red Granites). The metamorphic lithologies have the widest range of density and magnetic susceptibility values, between 2.61 g.cm-3 and 3.37 g.cm-3, and -0.299 x 10-3 SI units and 49.5 x 10-3 SI units, respectively. The lower values are associated with low grade metamorphic facies of sedimentary origin, and the higher values are associated with high-grade metamorphic facies of an igneous origin. The first upper crustal-scale interpretation of the Southern African MagnetoTelluric EXperiment (SAMTEX) was developed. The results were derived from 1D Occam inversion models, at depth intervals of 1 – 5 km, 1 – 15 km and 1 – 35 km. The MT data were acquired across the semiparallel, north-south striking DMB, NEN and OKA-CAM profiles in the vicinity of the Namibia – Botswana border between 2006 and 2009. Beneath the MT profiles are two zones of enhanced conductivity, a northern and southern zone. The enhanced conductivity of the northern zone (> 100 Ωm) is associated with individual geological bodies. The southern zone forms an elongated belt of enhanced conductivity (> 300 Ωm) at a depth of less than 5 km. This zone of enhanced conductivity is associated with Proterozoic plate boundaries and subduction zones. Three ~350 km long, north-south trending magnetic profiles were 2D forward modelled to investigate the proposed northward subduction of oceanic crust and subsequently a portion of the Kalahari Plate beneath the Congo Craton. Additionally, the folding pattern of the Ghanzi- Chobe Belt was developed. The interpretation of the magnetic models suggests a northward subduction is a possible cause for the evolution of the Damara Orogen with the regionally eastwest striking negative aeromagnetic anomaly, in northern Namibia, being caused by a thick package (~12 km to 20 km) of metasediments with a modelled magnetic susceptibility of 0. 829 x 10-3 SI units. The Damara Orogen has passed through the subduction-collisional transition but did not evolve into a large-hot orogen. Evidence suggests that the Damara Orogen has gone through the transition of subduction of oceanic crust to terrane accretion (speculated to be represented by the Deep-Level Southern Zone and Chihabadum Complex) and continental collision. However, the doubly vergent wedges did not evolve into an orogenic plateau completing the transition from a small-cold orogen to a large-hot orogen. This is similarly observed in the Alps Orogeny.

Nama is a Khoekhoe-language variety spoken in more than three countries namely Namibia, South Africa, Botswana and Angola. The language was previously called the Nama language, however, for pragmatic reasons, to cater for a Damara/Nama union, it is called Khoekhoegowab in Namibia. As far as I know there has been no comprehensive study on Nama/Damara/Khoekhoegowab. A preliminary study was done by Haacke, Eiseb and Namaseb (1997). However, as can be seen from the title of this study, it was ‘preliminary’ which means the authors are the first to admit that their study was not complete. The aim of this thesis was to undertake an extensive linguistic analysis of Khoekhoegowab as a way to come up with a comprehensive dialectal inventory. The established dialectal inventory will not only help in the linguistic development of Khoekhoegowab, but also in the determination of a standard linguistic code, leading to iv development of materials. This is important in grammatical descriptions needed for literacy material development and language policy implementation. Following Haacke, Eiseb and Namaseb (1997) and Guldenmann (2000, 2003, 2008), the study employed a dialectal difference or comparative approach. Considering the nature of the study, a mixed research design was used to collect the data. The data was drawn from the few available studies on Nama/Damara or Khoekhoegowab dialects such as those by Haacke, Eiseb and Namaseb (1997) and Du Plessis (2009). This was supplemented and complemented by document analysis and the various Khoekhoegowab literature. Interviews of limited key informants and focus groups were undertaken in various regions namely (Hardap, Karas and Kunene). The narratives from these interviews were used to determine the dialects currently in place as well as the differences and similarities. The collected data was then treated to a linguistic and dialectal analysis (cf. Guldenmann 2000, 2003, 2008; Du Plessis, 2009) as a way to discover similarities and differences, which will in turn inform the proposal on a possible standard form and composite orthography. The phonological differences of the three dialects under discussion were identified where the vowel system was discussed. With regard to the plain vowels, an argument was made that the Central Nama and Central Damara are in fact similar in terms of vowel inventory compared to Central Nama and the Bondelswarts dialects. The phonetic aspects of the consonant system of the identified dialects were also discussed. A discussion on clicks and click consonants was also made where a distinction was drawn between plain clicks and complex clicks. The morphosyntax v of Khoehoegowab was also discussed where it was obvious that there were mainly more similarities than differences between the dialects. The phonetic inventories identified in chapters 4 and 5 were assessed using data from different sources such as the Bible, the Social Security booklet, the grade 9 school textbook, Facebook (a social media page), Google maps, Khoekhoegowab orthography (2003), and the Ministry of Health booklet. The aim of this was to account for differences and similarities between various materials in terms of symbols used for writing Khoekhoegowab. There were differences observed which were because of the influence of modern technology (especially the electronic keyboard) on the writing practices of Khoekhoegowab speakers. The proposed orthography takes technological developments into account. As a contribution, this study provides new insight into the issues of voicing, and voiced and voiceless consonants. In terms of theory the handling of tone and length was discussed in detail where it was established that tone is phonemic and not vowel length. The issue of whether or not complex clicks should be treated as units or clicks plus an accompaniment was discussed where I argued that the sounds are co-articulated and should be treated as one. Regarding the orthography, although there is orthography, the existing orthography is clearly not adequate as some of the sounds were not correctly captured. This has an implication on teaching the language in the schools. It will help in the revitalizing of Khoekhoegowab compared to more established Bantu languages. / Philosophiae Doctor - PhD

Zugl.: Göttingen, Universiẗat, Diss., 1995.

Philosophiae Doctor - PhD / Nama is a Khoekhoe-language variety spoken in more than three countries namely Namibia, South Africa, Botswana and Angola. The language was previously called the Nama language, however, for pragmatic reasons, to cater for a Damara/Nama union, it is called Khoekhoegowab in Namibia. As far as I know there has been no comprehensive study on Nama/Damara/Khoekhoegowab. A preliminary study was done by Haacke, Eiseb and Namaseb (1997). However, as can be seen from the title of this study, it was ‘preliminary’ which means the authors are the first to admit that their study was not complete. The aim of this thesis was to undertake an extensive linguistic analysis of Khoekhoegowab as a way to come up with a comprehensive dialectal inventory. The established dialectal inventory will not only help in the linguistic development of Khoekhoegowab, but also in the determination of a standard linguistic code, leading to development of materials. This is important in grammatical descriptions needed for literacy material development and language policy implementation. Following Haacke, Eiseb and Namaseb (1997) and Guldenmann (2000, 2003, 2008), the study employed a dialectal difference or comparative approach. Considering the nature of the study, a mixed research design was used to collect the data. The data was drawn from the few available studies on Nama/Damara or Khoekhoegowab dialects such as those by Haacke, Eiseb and Namaseb (1997) and Du Plessis (2009). This was supplemented and complemented by document analysis and the various Khoekhoegowab literature. Interviews of limited key informants and focus groups were undertaken in various regions namely (Hardap, Karas and Kunene). The narratives from these interviews were used to determine the dialects currently in place as well as the differences and similarities. The collected data was then treated to a linguistic and dialectal analysis (cf. Guldenmann 2000, 2003, 2008; Du Plessis, 2009) as a way to discover similarities and differences, which will in turn inform the proposal on a possible standard form and composite orthography. The phonological differences of the three dialects under discussion were identified where the vowel system was discussed. With regard to the plain vowels, an argument was made that the Central Nama and Central Damara are in fact similar in terms of vowel inventory compared to Central Nama and the Bondelswarts dialects. The phonetic aspects of the consonant system of the identified dialects were also discussed. A discussion on clicks and click consonants was also made where a distinction was drawn between plain clicks and complex clicks. The morphosyntax of Khoehoegowab was also discussed where it was obvious that there were mainly more similarities than differences between the dialects. The phonetic inventories identified in chapters 4 and 5 were assessed using data from different sources such as the Bible, the Social Security booklet, the grade 9 school textbook, Facebook (a social media page), Google maps, Khoekhoegowab orthography (2003), and the Ministry of Health booklet. The aim of this was to account for differences and similarities between various materials in terms of symbols used for writing Khoekhoegowab. There were differences observed which were because of the influence of modern technology (especially the electronic keyboard) on the writing practices of Khoekhoegowab speakers. The proposed orthography takes technological developments into account. As a contribution, this study provides new insight into the issues of voicing, and voiced and voiceless consonants. In terms of theory the handling of tone and length was discussed in detail where it was established that tone is phonemic and not vowel length. The issue of whether or not complex clicks should be treated as units or clicks plus an accompaniment was discussed where I argued that the sounds are co-articulated and should be treated as one. Regarding the orthography, although there is orthography, the existing orthography is clearly not adequate as some of the sounds were not correctly captured. This has an implication on teaching the language in the schools. It will help in the revitalizing of Khoekhoegowab compared to more established Bantu languages.

Thesis (PhD (Earth Sciences))--University of Stellenbosch, 2009. / Fluid-present partial melting has generally been regarded a poor candidate for effecting crustal differentiation. In this study I report on anatectic metasediments from the Pan-African Damara Belt in Namibia that have undergone fluid-present biotite melting at a relatively low temperature, yet appear to have lost a significant volume of melt. In situ anatectic features have been identified on the basis of the existence of new generations of cordierite and/or garnet produced as the solid products of incongruent anatexis within or adjacent to leucosomes, that most commonly occur as lens shaped pods at a high angle to the lineation and formed during extension in a direction parallel to the long axis of the orogeny. Within these sites biotite underwent incongruent melting via the reaction Bt + Qtz + Pl + H2O = Melt + Grt + Crd. Cordierite nucleated on preexisting crystals within the bounding gneiss; garnet nucleated within the fracture sites (leucosomes) and typically occurs as individual, large (50 to 120 mm in diameter) poikiloblastic crystals. Thermobarometry applied to the anatectic assemblage yields low-temperature, granulitefacies peak conditions of 750 °C, 0.5 GPa. This temperature is approximately 100 °C lower than the accepted conditions for the onset of fluid-absent biotite melting. This, coupled to the focussing of anatexis on extensional fractures, suggests that anatexis occurred through waterpresent biotite incongruent melting. In order to better understand this process, both fluid-absent and water present partial melting experiments were conducted within the temperature interval 700 to 900 °C at 0.7 GPa. In the fluid-absent experiments, biotite incongruent melting started between 800 and 850 °C to produce melt coexisting with peritectic garnet and cordierite. In contrast, in water-saturated experiments, biotite melted via the reaction Bt + Pl + Q + H2O = Grt + Crd + Melt, between 700 and 750 °C, to produce melt, cordierite and garnet in the proportions 73:24:3.