D. Phil. / The Kalahari Manganese Deposit (KMD) is the largest of five erosional relics of the Hotazel Formation that are located near Kuruman in the Northern Cape Province of South Africa. Manganese ores are exploited from the lowermost of three manganiferous beds that are interbedded with banded iron-formation (BIF) and hematite lutite, that together constitute the Hotazel Formation. Two major ore types have been delineated previously, viz. low grade braunite lutite of the Mamatwan-type, and high grade oxidic ores of the Wessels-type, with the latter spatially restricted to the northern KMD. Genesis of the ores was temporally distinct, with the Mamatwan-type ore considered as a sedimentary-diagenetic precursor to the hydrothermally altered Wessels-type ore. Drill core samples from the Nchwaning-Gloria area of the northern KMD were analysed, with the aim to better characterise ore genesis, with emphasis on ore alteration. A second part of the study aimed at the application of mineralogical and geochemical information to aspects of ore smelting for the production of Mn alloy for use in the steel industry. Methods employed were drill core logging, X-ray diffraction (XRD), petrography, electron probe microanalysis (EPMA), major and trace element (including REE) analysis (employing artificial neural networks for evaluation of elemental trends), and stable isotope (C and O) analysis. Significant effort was invested in method development for quantitative mineralogical modal analysis using Rietveld refinement of XRD data. The study shows that a number of ore types can be differentiated in the northern KMD on the basis of mineral assemblage, grade, texture and geochemical characteristics. The ores are broadly classified into least altered (LA), partially altered (PA) and advanced altered (AA) types. The LA ores are low grade (<40 wt%Mn) Mn lutites, with dolomite-group carbonate a significant component in addition to braunite. Serpentine is a ubiquitous trace mineral, and boron is a characteristic trace element hosted predominantly by braunite in these ores. Ores of the PA type comprise either braunite-hausmannite-calcite or hausmannite-calcite assemblages, are fine to coarse grained, and display intermediate Mn grades (40-45 wt%Mn). They exhibit a transitional trace element signature. Advanced altered ores may be classified into five different types, based on mineral assemblages that contain hausmannite and/or braunite as significant minerals. Carbonates occur predominantly in the form of calcite, present in minor to trace proportions. Textures vary from fine to very coarse grained, and high Mn grades (typically >45 wt%Mn), are recorded. Trace elements of significance include Zn, associated with hausmannite, B, associated with massive braunite and a number of trace minerals, and P, typically present in trace quantities of apatite. In terms of ore genesis, mineralogical, geochemical and geological considerations suggest that Mn (and Fe) originated from submarine hydrothermal vents, from which it travelled in hydrothermal plumes, prior to rapid deposition ~2.2 Ga ago. Diagenesis followed soon after deposition, through redox reactions involving organic matter and higher oxides of Mn to produce the braunite-carbonate assemblage primarily observed in LA ores. The carbonate:oxide ratio and nature of the carbonates varied slightly depending on fluctuations in organic matter flux to the sediment, as well as marine bicarbonate concentrations. Metamorphism, in relation to diagenesis and metasomatism, is poorly understood, but is perceived to have resulted in serpentine formation, as observed in LA and PA ores.

A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, 2016 / Since the latter part of the 20th century to the present, we have seen growing concerns about the potential collapse of socio-ecological systems due to climate change. On the other hand, palaeoenvironmentalists, archaeologists and anthropologists consistently point to evidence of how Homo-sapiens have survived within climate variability underpinned by an embodied/embedded relationship to their environments. Archaeological data shows how indigenous groups such as the Bushman have inhabited landscape features such as caves for longer than 10 000 years and thus survived through periods of climate variability. Another well researched element of Bushman life is their ritual practices. Given the low supply of livelihood resources within the contexts where such communities have survived, this study hypothesised a possible relationship between Bushman ritual practices and their long-term resilience when faced with variability. Using the Holocene habitation of the Wonderwerk Cave as the main case study, this study explored the relationship between people, place and ritual. Furthermore, the study applied phenomenology as the primary data collection method. The resultant first-person experience guided the researcher in engaging with secondary data from archaeology and ethnography. The study found that Bushman ritual practices such as trance constituted a critical adaptation tool in response to perpetually variable environments. Through such practices and their related tools such as art, space and myth, such communities managed to sustain a synchronised dialogue with place thus facilitating for ongoing dissolution of maladaptive behaviour. Another key finding is that our inability to change constitutes a key characteristic of our species today as we have been seduced into the trap of our deep psychic longing for existential continuity. The study argues for an architecture for resilience whose primary role would be to facilitate higher fluidity in our embeddedness to place and allowing for faster and trauma-free transitioning in synchronicity to our changing environments. In conclusion, the study finds that our own contemporary climate change has implications far beyond the techno-scientific understanding which has prevailed so far and is instead calling to be understood as an existential phenomenon to be primarily resolved through relevant/responsive ritual practices to facilitate our own transitioning and continued resilience. / MT2017