Bibliography: pages 147-161. / This study deals with the physical aspects of sedimentation in Saldanha Bay and Langebaan Lagoon. On the basis of detailed textural investigations the depositional history of the study area has been established. The sediments in the bay and in the lagoon consist of a fine terrigenous quartz population and a coarser skeletal carbonate population, which have been mixed in various proportions. In order to gain size parameters that are more closely related to the hydraulic nature of depositional processes observed in the marine environment, grain size analyses were performed with an automatically recording settling tube system. The instrument was developed in the course of this study. Construction costs were kept extremely low without, however, impairing the scientific requirements of the instrument. Over 500 sediment samples were recovered on a closely-spaced grid; in each case, a size analysis was performed on the total sample and on the insoluble, terrigenous fraction. By subtracting the terrigenous size distribution from that of the total sediment, the relevant size parameters of the bioclastic component were calculated. In this manner 1500 individual size distributions were available for interpretation.

Includes bibliographical references (leaves 213-231). / Fractals and scaling laws abound in nature, and it is said that geometry of river networks and basins is an epitome of this. This study investigates how on the tectonically unique African continent, scaling parameters, and in particular deviations from 'perfect fractal patterns' relate to parameters like underlying geology, climate, and vegetation through which the river flows. Stream and basin patterns are also used to reconstruct the past network geometry of rivers, and to shed some light on the drainage evolution of major African rivers.

Includes bibliographical references (leaves 201-217).

The western margin of southern Africa underwent major palaeoceanographic changes since the initiation of the Benguela Upwelling System during the Neogene. Microfossils in marine sediments provide key proxies in our understanding of how the margin evolved. Fossil shells (tests) of foraminifera (singlecelled protists) from twenty cores from the Namibian shelf (199 to 309 m water depth) and three cores from the western slope (874 to 3631 m water depth) of South Africa were studied to determine the middle Miocene to Quaternary stratigraphy, palaeoenvironment and palaeoceanography of the western margin of southern Africa. Cores from the Namibian shelf recovered middle Miocene calcareous mud in erosional contact with overlying Pliocene to Pleistocene phosphatic sediments. Strontium isotope stratigraphy and planktic foraminifera biostratigraphy provide age control of the Namibian shelf sediments. The planktic indicator species Globoquadrina dehsicens and Globigerinoides bisphericus support strontium isotope stratigraphy results for the olive-green mud unit of the northern Namibian shelf indicating an age of 16 to 14 Ma, and the overlying Plio-Pleistocene age of the phosphorite-rich unit supported by planktic indicator species Globorotalia truncatulinoides and Globorotalia (Globoconella) inflata. Middle Miocene foraminifera reflect a warmer, oligotrophic, subtropical, deeper environmental setting in contrast to the shallower depositional environment, cooler conditions and a eutrophic bottom water setting indicated by Pleistocene foraminifera in the phosphatic units. The palaeoenvironment on the Namibian shelf was progressively shoaling during the Pleistocene as sea level amplitudes increased. An Uvigerina spp.- dominated association occurs in deeper shelf deposits dated to the early Pleistocene and the Ammonia beccarii association occurs in shallower shelf deposits of the late Pleistocene to Holocene. The planktic and benthic foraminiferal stable oxygen isotope records, colour reflectance (L*) and non-carbonate mineral counts provide age control on cores from the western slope of South Africa, whose records extend to just beyond Glacial Termination (GT) II. Sediment and benthic foraminiferal accumulation rates were higher during interglacial periods and lower during glacial periods. The major planktic species in the slope cores include Globorotalia (Globoconella) inflata, Globigerina bulloides and Neogloboquadrina incompta. Principal component analysis (PCA) reveals that the major factors influencing planktic foraminiferal abundances are upwelling intensity, the penetration of colder waters during glacial periods and the inflow of subtropical waters from the South Indian Ocean during interglacial periods. The major benthic species in the slope cores include Uvigerina peregrina, Uvigerina hispidocostata and Cibicidoides wuellerstorfi indicating the delivery of organic matter and oxygen availability to have the largest influence on the benthic foraminiferal faunal composition. Uvigerina spp. on the slope show increased relative abundances during periods of lower oxygen conditions. Bottom water masses identified by Nd (neodymium isotopic compositions) values recorded by foraminifera, along with the stable carbon isotope composition and abundance of the benthic foraminifer C. wuellerstorfi indicate shifts from Southern Component Water to North Atlantic Deep Water during GT II and I. Variation in Nd values in an upper slope core (874 m water depth) indicate Antarctic Intermediate Water (AAIW) influence was stronger during glacial periods compared to interglacial periods.

Enormous areas of South West Africa, particularly in its central portion, are occupied by very ancient gneissoid and granitic rooks, a great variety of schists and other more or less highly metamorphosed sediment. These ancient rooks, forming as they do the backbone or nucleus of our continent, on which all younger rocks repose as a veneer of varying thickness and continuity are everywhere generally grouped together under the term Basement or Fundamental Complex. For obvious reasons, chief of which are their invariably highly folded and metamorphosed nature and the entire absence of fossils, these ancient sediments and their intrusives have nearly always after the first initiation of geological surveys in most countries of Africa been somewhat neglected and also visiting geologists have generally preferred to devote their attention and limited time to less complex problems, for the solution of which detailed mapping extended over many years was not an essential or indeed a sine qua non. A notable exception, however, to this rule is the detailed early work of Rogers and Du Toit in the northern Cape and of Hall in the eastern and northeastern Transvaal.

The Hebron fault scarp in southern Namibia is 45 km in length with an average height of 5.5 m and a maximum height of 8.9 m. Namibia is a Stable Continental Region (SCR) — a slowly deforming area within a continental plate. The country also has little recorded seismicity with the largest earthquake on the International Seismological Center (ISC) catalogue being MW 5.4. If the Hebron fault scarp was formed in a single event, this would represent a MW 7.3 earthquake. SCRs do occasionally experience large earthquakes, however, the recurrence intervals between these events is much larger than in rapidly deforming areas. Consequently, studying palaeo-earthquakes allows the record of seismicity to be extended and the characteristics of SCR events to be better understood. These studies may help refine the Mmax estimates required for seismic hazard assessment. Previous work on Hebron has been limited to field descriptions and theodolite survey scarp heights. Furthermore, there have been several interpretations of the fault mechanism and number of rupture events. This study produces a high-resolution Digital Elevation Model (DEM) via stereophotogrammetry using pan-sharpened Worldview-3 satellite imagery (0.31 m resolution). The DEM was used for several geomorphological analyses. These included measuring the scarp height at 160 locations along its length, measuring river channel displacements and identifying knickpoints along river profiles. Results indicate that the scarp formed from a normal, dip-slip fault that ruptured in a single event. This scenario would imply a high slip-to-length ratio. A comparison of other SCR fault scarps in the literature was made which shows that Hebrons’ slip-to-length ratio falls within the values found on other SCR faults. This study also discusses the implications of results for seismic hazard assessment in the region. Due a poor seismic record, probabilistic seismic hazard analysis (PSHA) will calculate a low seismic risk for Namibia. As large earthquakes can occur in SCRs, deterministic seismic hazard analysis (DSHA) can be used to inform policy makers of the worst case scenarios.

Includes bibliographical references (leaves 146-162). / Low-grade metabasites and hydrothermally altered ultramafic rocks comprise most of the ca. 3.5-3.2 Ga, Paleoarchean Barberton Greenstone Belt (BGB) of South Africa. However, PT-constraints and detailed petrological information on the variably altered mafic-ultramafic rocks are sparse and the nature of greenschist facies metamorphism is poorly characterized. In addition, alteration and silicification associated with distinct emerald green, fuchsite-(Crmica)- carbonate-quartz alteration zones is commonly found beneath chert horizons in the mafic-ultramafic rocks of the Onverwacht Group of the BGB. The origin of this silicification is highly debated and has important bearing on the nature of Paleoarchean geodynamic models, crustal geothermal gradients, hydrothermal oceanic regimes, as well as potential early life-sustaining environments. Over the past four decades, widely varying interpretations have been reported for the origin of these silica-rich fuchsitic alteration zones in the BGB, ranging from very low temperature (less than 60oC) atmospheric weathering of komatiites (Lowe and Byerly, 1986; 1999); low-temperature (less than 125oC) seafloor alteration (Hofmann and Harris, 2008); to bedding-parallel ‘flaser-banded gneissesschists’ in oceanic ‘extensionaloverthrust glide planes’ (de Wit, 1982a; 1986a,b; de Wit et al., 1982b; 1987b; 2011). Consequently, these fuchsitic-alteration zones have been at the centre of much debate surrounding stratigraphy models and the possible operation of early Paleoarchean platetectonic processes in the BGB.

Bibliography: v. 1, pages 157-171. / The Sloan diamonds were investigated for their physical characteristics, inclusion mineralogy and composition, and carbon isotope composition. The relationships between these features are described and interpreted with respect to diamond genesis. The physical characteristics investigated include crystal state, crystal regularity, primary morphology, resorption morphology, primary and secondary sizejmass, colour, surface features and inclusion content. Significant relationships between these characteristics were found. The proportion of an individual crystal, lost during resorption, decreases with increasing diamond size. Larger crystals and diamonds displaying brown colours appear to have been more susceptible to breakage relative to smaller crystals and diamonds of other colours, respectively. Brown colours were more common on smaller diamonds relative to larger stones and, further, were more common on single crystal forms relative to twinned/aggregate crystals. Variation in diamond physical characteristics between the various kimberlite phases in the Sloan 1 & 2 complex has been documented. The Sloan 2 phase is characterized by larger and less resorbed diamonds relative to those in other kimberlite phases in the diatreme. In addition, corrosion sculpture is much more common on Sloan 2 diamonds.

Transfrontier conservation areas (TFCAs) have emerged as one of the 21st century’s contemporary approaches to management of natural resources which span the borders of two or more countries. Robust arguments exist that boundaries hamper the conservation objectives of migratory species. On the basis of the claimed potential of TFCAs to reconcile the conservation and economic development objectives of nations through tourism, TFCAs have been widely embraced in Southern Africa as a model for governing shared resources. TFCAs in Southern Africa have been motivated by both ecological and socio-economic factors, TFCAs are also politically motivated. This study uses the lens of political ecology to understand the motivation of Zambia’s participation in the Kavango–Zambezi TFCA (KAZA TFCA). KAZA TFCA is one of the largest TFCAs in the world and is said to be home to the largest number of the remaining African elephants (approximately 120,000). This five-country TFCA spans large rural landscapes that are a potential site for extensive tourism and currently provide livelihood opportunities for many poor rural households. This study assesses the investments of Zambia’s government in the KAZA TFCA. It uses the case study of Simalaha Community Conservancy in the Western Province of Zambia to examine the implications of the KAZA TFCAs on the local population in the conservancy. The research uses semi-structured interviews, field observations and secondary data to advance an argument that TFCAs do not always yield positive gains for both governments and local communities. Gains depend on several factors, such as level of development of a country, level of tourism development and the preparedness of a participating nation to invest in and benefit from a TFCA. The study establishes that KAZA is an unequal investment landscape, with Zambia being one of the lesser investors in the KAZA TFCA. In addition, the notion that the TFCA model embodies the poverty reduction objectives meant to benefit local populations is contestable as the KAZA on the Zambian side (Simalaha community) has not improved the welfare of the local people.

Includes bibliographical references (leaves 99-117). / East Antarctica is dominated by the East Antarctic Craton, which consists of fragments of Archaean continental crust surrounded by polydeformed orogenic belts (e.g. Maud Belt). The Maud Belt in Dronning Maud Land preserves a high-grade polyphase tectono-thermal history. This belt has traditionally been interpreted as a Mesoproterozoic-age (1.3-0.9 Ga) mobile belt that was later affected by thermal overprint associated with little or no deformation during the Neoproterozoic (0.6-0.5 Ga). Therefore the Maud Belt has been used as a piercing point in Mesoproterozoic supercontinent reconstruction. However, with the growing number of geochronological data pointing to major structural reworking and not just a thermal overprint of the Mesoproterozoic crust during the Pan-African orogeny thereby challenging early models of Mesoproterozoic supercontinent reconstruction. Areas east and west of Gjelsvikfjella record major Pan-African reworking. Thus the outcrops of Gjelsvikfjella provide the linkage between the two areas. Yet, so far little data has been available for this crucial sector. Therefore, detailed fieldwork in the Gjelsvikfjella coupled with petrographic, geochemical and geochronogical data obtained from carefully selected samples reveal a complex tectono-thermal history for this part of the Maud Belt. The SHRIMP U-Pb zircon data obtained make it possible to differentiate between a series of magmatic and metamorphic events. The oldest event recorded is the formation of an extensive, 1140-1130 Ma, volcanic arc. This was followed by 1104 ± 8 Ma granitoids that might represent, together with so far undated mafic dykes part of a decompression melting-related bimodal suite. Only very few relics of late Mesoproterozoic granulite-facies metamorphism is constrained in 1070 Ma strain-protected domains.