Detailed studies, both chemical and physical, have been performed on various dolomites and vug-filling carbonates, to determine the pathways and extent of the mineralizing fluids associated with the Pering Zn-Pb deposit within the Griqualand West sub-basin. Three carbonate phases were identified within the vugs using cathodoluminescence microscopy. The first phase formed a reaction rim on the host dolomites during the deposition of sphalerite and oscillatory zoned carbonate. Finally calcite was deposited, which is associated with post-mineralizing fluids. The vug-filling carbonates have very radiogenic 87Sr/86Sr values (0.72-0.76) compared with the host dolomites (0.70-0.73). The gangue carbonate minerals deposited within the vugs have similar radiogenic 87Sr/86Sr values to the gangue minerals of the main Pering orebody, indicating that the vugs formed part of the aquifer system through which the mineralizing fluids migrated. Radiogenic 87Sr was not acquired from the surrounding host dolomite. The mineralizing fluids may have picked up radiogenic 87Sr when migrating through porous rocks such as the Makwassie Quartz Porphyry of the Ventersdorp Supergroup or felsic rocks forming the Kaapvaal Craton. In addition, radiogenic Sr may have been acquired from dewatering of the Lokammona shales within the area, or expelled from amphibolite and granulite rocks involved in the Kheis or Namaqua Tectonic events. Two models are proposed to explain the genesis of the main Pering deposit and the occurrence of sphalerite in the vug-filling carbonates surrounding the deposit: 1) Mixing Model; and 2) Single Fluid Model. The Single Fluid Model is preferred which involves a single fluid migration and interaction with the carbonate host rock and/or pore fluid. The metals were probably transported as chloride complexes together with reduced sulphur at temperatures greater than 2000 C. Deposition of the ore minerals resulted from either a dilution of the fluid, a pH increase or a temperature decrease. Both dolomites and vug-filling carbonates have a model Pb age between 2.0 and 2.7. Secondary 1Ga model ages indicate a minor Namaqua tectonic influence. Carbon and oxygen isotopes indicate that the fluids originated in a deep burial environment. Future exploration work using cathodoluminescence microscopy and staining techniques will be both useful and cost-effective. Isotopic work should concentrate on the Rb-Sr system as radiogenic 87Sr/86Sr values are the best indicators of the path of the mineralizing fluid, and the proximity to ore concentrations. / Thesis (M.Sc.)-University of Natal, 1992.

The Shu Shu thermal springs are located in central KwaZulu-Natal in South Africa at an altitude of 250m above mean sea level at the bottom of the Tugela Valley. They have been investigated in an attempt to ascertain whether or not they possibly share a common origin with fifteen other springs which are located in a north-northwestern trending, 1000km long zone within the eastern interior of the country. They have also been studied to establish if they potentially represent a viable and sustainable geothermal energy resource that may be developed in the future. Isotope ratios confirm that the thermal springs are meteoric in origin, and are likely recharged within a 130km long band located to the west toward the Great South African Escarpment. These waters then descend vertically to a depth of approximately 1827m – 2153m, at which point the fractures along which they move close due to escarpment-associated confining pressure. It is a reduction in this self-same confining pressure along the coastal plain, which occurs due to the continual removal of overburden, which forces the thermal water to migrate toward the east along ever-more opening fractures. Due to a slightly elevated geothermal gradient of 3.1°C / 100m at depth, this groundwater reaches a temperature of approximately 75°C – 85°C as it traverses toward the Shu Shu thermal springs over a time period of > 61 years (at present). The geochemical signature of the Shu Shu thermal waters is derived through leaching from the basement rocks through which they pass, with elevated concentrations of Na, K, Ca, Mg, Fe, Al, Si, F, Sr and SO₄ detected. Once below the floor of the Tugela Valley, at a depth of approximately 990m, the thermal groundwater commences its ascent, likely along the west-southwest – east-northeast orientated thrusts and associated fractures of the Tugela Terrane of the Natal Metamorphic Province. However, the thermal waters abut against those brittle structures trending north-northwest – south-southeast, which are perpendicular to the axis of least principle compressive stress, and so are ultimately forced to rise within the Shu Shu thermal springs. Prior to surfacing, the temperatures of these waters drop to approximately 67°C as a result of natural, conductive cooling processes. However intermixing with shallow, cold groundwater, which is discernible through geochemical and isotopic variations, and atmospheric impacts, further cool the thermal waters to a surfacing temperature of approximately 50°C. Nevertheless, a binary cycle geothermal energy power plant remains a possibility. Although thermal efficiency and volume flow rate values are favourable, heat transfer values are low and require further investigation through exploratory drilling. Nevertheless, the establishment of a 400kW power plant, should it occur, will typically be sufficient to service 625 rural homes. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.

Holocene shoreline sequences and associated shelf stratigraphy are described from a high gradient, high wave energy shelf offshore the central KwaZulu-Natal and northern KwaZulu-Natal coastlines. These are examined using high resolution single-channel seismic and multibeam bathymetric means in order to describe the shallow stratigraphy and seafloor geomorphology of each area. The development and preservation of two distinct planform shorelines at -100 m (northern KwaZulu-Natal) and -60 m (northern KwaZulu-Natal and central KwaZulu-Natal) is described. The shallow seismic stratigraphy of northern KwaZulu-Natal comprises three seismic units (Units 1-3) corresponding to calcarenite barriers (Unit 1), back barrier lagoonal sediments (Unit 2) and the contemporary highstand sediment wedge (Unit 3). At intervening depths between each shoreline the shelf is characterised by erosional surfaces that reflect ravinement processes during periods of slowly rising sea level. Where shorelines are not preserved, areas of scarping in the ravinement surface at depths coincident to adjoining shorelines are apparent. These areas represent rocky headlands that separated the sandy coastal compartments where the shorelines formed and are a function of the high gradient. In central KwaZulu-Natal where the shelf is notably wider and gentler, shoreline building was more intense. Five major seismic units are identified (Units 1-5) with several subsidiary facies. The formation of the -60 m barrier complex (Unit 2) in central KwaZulu-Natal was accompanied by the simultaneous formation of a back-barrier system comprising lake-lagoon depressions (Unit 3) and parabolic dune fields aligned to the local aeolian transport direction, formed on a widened coastal plain. On the seaward margins of the barrier, gully and shore platform features developed coevally with the barrier system. Several relict weathering features (Unit 4) are associated with the barrier and reflect similar processes observed in contemporary aeolianite/beachrock outcrops on the adjacent coastline. The two submerged shoreline sequences observed are attributed to century to millennial scale periods of stasis during which shoreline equilibrium forms developed and early diagenesis of beachrock and aeolianite occurred. These extensive phases of shoreline development are thought to have occurred during periods of stillstand or slowstand associated with the Bølling-Allerod Interstadial (~14.5 ka BP) and the Younger Dryas Cold Period (~12.7-11.6 Ka BP). Shoreline preservation in such an environment is considered unlikely as a result of intense ravinement during shoreline translation, coupled with the high energy setting of the KwaZulu-Natal shelf. Preservation of both the 100 m and 60 m shorelines occurred via overstepping where preservation was promoted by particularly rapid bouts of relative sea-level rise associated with meltwater pulses 1A and 1B (MWP-1A and -1B). This was aided by early cementation of the shoreline forms during stillstand. Differences in shelf setting have led to variations in the style of barrier preservation and associated transgressive stratigraphies between the central KwaZulu-Natal and northern KwaZulu-Natal shelves. The main differences include a much thicker post-transgressive sediment drape, higher degrees of transgressive ravinement and an overall simplified transgressive system’s tract (TST) architecture on the steeper and narrower continental shelf of northern KwaZulu-Natal. In comparison, the central KwaZulu-Natal shelf’s 60 m shoreline complex reflects more complicated equilibrium shoreline facets, large compound dune fields formed in the hinterland of the shoreline complex, higher degrees of preservation and a more complicated transgressive stratigraphy. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.

Thesis (DSc) -- Stellenbosch University, 1967. / INTRODUCTION: This dissertation aims to illuminate some surprises which the deceptively uncomplicated Table Mountain sandstone had long been harbouring in its kloofs and cliffs . The major contributions of this first systematic investigation of an extensive portion of the Table Mountain sandstone are the discovery of diagnostic marine fossils by means of which the first direct dating of the deposit is effected and important sedimentological conclusions drawn...

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The southern portions of the Early- to Mid-Archaean Barberton granitoid-greenstone terrain of South Africa consists of a high-grade metamorphic granitoid-gneiss terrain that is juxtaposed against the low-grade metamorphic supracrustal sequence of the Barberton Greenstone Belt. The boundary of the two different crustal domains corresponds to the Theespruit Formation, an amphibolite-facies, highly tectonized mélange of metabasites, felsic volcanics and rare, aluminous clastic sediments that occurs along the granitoidgreenstone margins. Amphibolite-facies lithologies in the Theespruit Formation are characterized by strongly prolate mylonitic fabrics that formed in a constrictional tectonic regime. Away from the granitoid-greenstone margin and towards the central parts of the greenstone belt, these rocks grade to, and are overprinted by, greenschist-facies S-L mylonites that formed during non-coaxial deformation. Both peak and retrograde minerals define, and are aligned parallel to, the fabrics in these rocks, indicating that shearing was initiated under peak metamorphic conditions and continued during retrogression. S-C’ fabric relationships indicate that shearing occurred in an extensional tectonic regime and that, during deformation, the gneiss terrain was uplifted relative to the greenstone belt. Peak metamorphic assemblages of grt-st-bt-chl-pl-qtz and ky-st-btms- pl-qtz in metasediments and grt-ep-hbl-pl-qtz in amphibolite constrain peak metamorphic conditions of 7.4 ± 1.0 kbar and 560 ± 20 ºC that were attained during the main accretionary episode in the Barberton terrain at 3229 ± 25 Ma. Peak assemblages in all rocks are pre-tectonic and were deformed and re-equilibrated during retrogression, resulting in these being minimum estimates of peak metamorphic conditions. Petrographic evidence and retrograde pressure-temperature estimates indicate that retrogression involved near-isothermal decompression of ca. 4 kbar prior to cooling into the greenschist-facies. The style and timing of metamorphism in the Theespruit Formation is similar to that of the granitoid-gneiss terrain, suggesting that the Theespruit Formation shares a geological history with the gneiss terrain and that it is allochtonous to the greenstone belt. The main deformational and fabric-forming event exhibited in the Theespruit Formation occurred during the exhumation of the granitoid-gneiss terrain subsequent to peak metamorphism. Consequently, the juxtaposition of this terrain againstthe greenstone belt was achieved by tectonic underplating and core complex formation at ca. 3.23 Ga. The occurrence of high-grade constrictional mylonites that are overprinted by low-grade non-coaxial mylonites as well as extension in an overall compressional tectonic regime is consistent with exhumation by extensional orogenic collapse. Burial of the high-grade terrain to depths of 25 – 30 km is only possible in a relatively cold and rigid crustal environment, while the extremely low apparent geothermal gradients of ca. 20 ºC/km preserved in this terrain suggest that burial and exhumation occurred rapidly, within a time-span of ca. 15 – 20 Ma. These parameters strongly suggest that metamorphism occurred in response to a lateral plate tectonic process that was operational in the Barberton terrain at 3230 Ma. / AFRIKAANSE OPSOMMING: Die suidelike dele van die Vroeg- tot Middel-Argaïese Barberton graniet-groensteen terrein van Suid-Afrika bestaan uit ‘n hoë-graad metamorfe graniet-gneiss terrein wat die lae-graad metamorfe groenstene van die Barberton Groensteen Gordel begrens. Die grens tussen die twee verskillende kors-domeine hang saam met die Theespruit Formasie, ‘n amfiboliet-fasies, getektoniseerde melange van metabasiete, felsiese vulkaniese gesteentes en skaars, alumineuse klastiese sedimente wat langs die graniet-groensteen kontakte voorkom. Amfiboliet-fasies gesteentes in die Theespruit Formasie word gekenmerk deur sterk prolaat milonitiese maaksels wat in ‘n vernouende tektoniese omgewing gevorm het. Hierdie rotse word weg van die graniet-groensteen kontak en na die sentrale dele van die groensteen gordel oordruk en vervang deur groenskis-fasies S-L miloniete wat tydens nie-koaksiale vervorming gevorm het. Beide piek en retrograad minerale definieer, en is georienteer parallel aan, die maaksel in die rotse, wat daarop dui dat skuifskeur onder piek metamorfe toestande begin het en volgehou het tydens retrogressie. S-C’ maaksels dui daarop dat skuifskeur in ‘n verlengende tektoniese omgewing plaasgevind het en dat die gneiss terrein opgehef is relatief tot die groensteengordel tydens vervorming. Piek metamorfe versamelings van grt-st-bt-chl-plqtz en ky-st-bt-ms-pl-qtz in metasedimente en grt-ep-hbl-pl-qtz in amfiboliet bepaal piek metamorfe toestande van 7.4 ± 1.0 kbar en 560 ± 20 ºC wat bereik is gedurende die hooffase van akkresie in die Barberton terrein teen 3229 ± 25 Ma. Die piek metamorfe versamelings in alle rotse is pre-tektonies en is vervorm en geherekwilibreer tydens retrogressie, wat maak dat die beramings minimum skattings van piek metamorfe toestande is. Petrografiese getuienis asook druk-temperatuur beramings dui daarop dat retrogressie gepaard gegaan het met byna-isotermiese drukverligting van naastenby 4 kbar voor afkoeling tot in die groenskis-fasies. Die styl en tydsberekening van metamorfose in die Theespruit Formasie is vergelykbaar met metamorfose in die granietgneiss terrein, wat daarop dui dat die Theespruit Formasie ‘n geologiese geskiedenis met die gneiss terrein deel en allochtoon is tot die groensteen gordel. Die hooffase van vervorming en maakselvorming in die Theespruit Formasie het plaasgevind gedurende die herontbloting van die graniet-gneiss terrein na piek metamorfose. Gevolglik is dieteenplasing van dié terrein teen die groensteen gordel vermag deur tektoniese onderplasing en kernkompleksvorming teen ongeveer 3.23 Ga. Die verskynsel van hoëgraadse vernoude miloniete wat oordruk word deur lae-graadse nie-koaksiale miloniete asook verlenging in ‘n algeheel saamdrukkende tektoniese omgewing dui daarop dat herontbloting plaasgevind het deur middel van verlengende orogenetiese ineenstorting. Die begrawing van die hoë-graadse terrein tot dieptes van 25 – 30 km is net moontlik in ‘n relatief koel en star kors-omgewing, terwyl die uitermate lae geotermiese gradiente van ongeveer 20 ºC/km wat in die terrein behoue gebly het daarop dui dat begrawing en herontbloting vinnig geskeid het, binne ‘n tydsverloop van ongeveer 15 – 20 Ma. Hierdie beperkings is ‘n sterk aanduiding dat metamorfose plaasgevind het as gevolg van ‘n laterale plaattektoniese proses wat werksaam was in die Barberton terrein teen 3230 Ma.

Thesis (MSc (Earth Sciences))—University of Stellenbosch, 2005. / The integration of whole-rock chemistry, heavy mineral chemistry, detrital zircon morphology and age dating has enabled high-resolution characterization of the Permian Laingsburg and Tanqua submarine fan provenance in the Karoo Basin, upper Ecca Group, South Africa. Geochemically, the Laingsburg and Tanqua sandstones are classified as greywacke and litharenite. The chemical index of alteration values for these sandstones suggest low to moderately weathered sources and a relatively cold climate. Abundant angular clastic grains and lithic fragments as well as the predominance of pristine zircons indicate a near provenance and a first cycle derivation. The investigated sandstones originated from a continental island arc and an active continental margin. The source is dominantly intermediate to felsic and includes tonalites, granodiorites, and adamellites or their volcanic equivalents.

ENGLISH ABSTRACT: The farm Geelwal Karoo is situated some 16km north of the Olifants River mouth on the West Coast of South Africa and hosts fluvial, marine and aeolian deposits of post-Gondwana age. The oldest basal fluvial succession, unconformably overlies Proterozoic and Palaeozoic basement rocks and is in turn capped by aeolianite and littoral packages representing two transgressive cycles. The fluvial channel clay succession is deposited in shallow bedrock-incised channels, has a wedge-shape and is deposited parallel to the present coastline. The flow direction is along the coast and the northwardtapering, angular, poorly sorted basal vein-quartz lag indicates a northward palaeo-flow direction. Less than 1% total heavy minerals (THM) is found in the matrix of these gravel units and the heavy mineral suite is distinguished by zircon, pseudorutile and kyanite. The channel clay unit is dominated by an upper, mediumgrained quartzose sand and kaolin clay facies, which shows advanced post-depositional weathering. The fluvial unit is correlated with the channel clay unit of Hondeklip Bay and a Cretaceous age is proposed for the initial channel incision. The two shallow marine successions have been correlated with the Late Miocene, Early Pleistocene, +30m and +50m packages respectively. These marine sediments were first described by John Pether (1994) in the Hondeklip Bay area and were named according to their transgressive maxima. They are transgressive successions arranged en echelon down the coastal bedrock gradient, from oldest and highest to youngest. The offshore environment of the +50m package consists of fine silty sand, which is moderately sorted. The mineral assemblage is dominated by quartz and the average THM is 18%. The inshore environment is distinguished by a single poorly sorted basal cobble lag which shows an overall fining upward succession. The beachface environment is composed of medium to fine-grained sand, which is moderate to well-sorted. Mineral diversity is greatest in the inshore and beachface environments and the average THM for these two units is greater than 35%. The +30m package has been extensively eroded due to its lower erosion and outcrops were sporadic along the coast. The +30m offshore sediments are recognised by fine sediments with high concentrations of glauconite and organic matter. The inshore environment is distinguished by numerous poorly sorted pebble lags with fining upward successions. Both the inshore and beachface units have higher feldspar concentrations than the corresponding +50m units. The average THM for these two units is less than 3%. The aeolianite unit, which comprises several distinct units, extends over the entire length of the study area and is characterized by calcrete and red bed horizons. Colour variations in the otherwise homogeneous unit are due to heavy mineral enrichment and/or different degrees of in situ weathering and cementation. The unit is composed exclusively of fine- to medium-grained sand and the THM concentration averages 9%. This unit is composed of more than one generation of aeolian sand and forms part of an aeolian transport corridor which transported sand from the beach to the interior. The oldest unit has been equated with the Upper Miocene Prospect Hill Formation, whereas the more recent yellow dune sand is equated with the Pleistocene Springfontyn Formation. At Geelwal Karoo, only the heavy sand placer in the +50m package was deemed to be of any economic significance. The average THM of this placer was calculated to be 40% and some 150 thousand tons of Tibearing material can be expected from this succession. This relatively small volume of heavy minerals and extensive cementation however, make this placer a less attractive prospect than the neighbouring Namakwa Sands operation. / AFRIKAANSE OPSOMMING: Die plaas Geelwal Karoo is ongeveer 16km noord van die Olifantsriviermond aan die Weskus van Suid- Afrika geleë en het voorkomste van fluviale, marine en eoliese afsettings van post-Gondwana ouderdom. Die oudste eenheid, ‘n basale fluviale eenheid, oorlê Proterosoiëse en Paleosoiëse plaaslike vloer gesteentes wat op hulle beurt weer bedek word deur eoliese en littorale eenhede verteenwoordigene ven twee transgressiewe siklusse. Die fluviale kanaalklei-opeenvolging, afgeset in vlak ingesnyde rotsbedding-kanale, is wigvormig en is afgeset parallel aan die huidige kuslyn in ‘n alluviale waaier-afsetting. Die vloeirigting was langs die kus en die noorwaards toespitsende, hoekige, swak gesorteerde basale aar-kwarts bodemgruis dui op ‘n noordwaards palaeo-vloeirigting. Minder as 1% totale swaarminerale (TSM) is gevind in die tussenmassa van hierdie gruis-eenhede en die swaarmineraal reeks word onderskei deur sirkoon, pseudo-rutiel en kianiet. Die kanaalklei eenheid word oorheers deur ‘n boonste, medium-korrelrige kwarts-bevattende sand en kaolien kleifasies was dui op gevorderde verwering na afsetting. Die fluviale eenheid word gekorreleer met die kleikanaal en ‘n Kryt-ouderdom word voorgestel vir die aanvanklike insnyding van die kanaal. Die twee vlak marine opeenvolgings word gekorreleer met die Laat Mioseen, vroeg Pleistoseen, naamlik die +30m en +50m eenhede onderskeidelik. Die aflandige omgewing van die +50m eenhied bestaan uit matiggesorteerde, fyn slikkerige sand. Die mineraalversameling word oorheers deur kwarts en die gemiddelde TSM is 18%. Die subgetysone word onderskei deur ‘n enkele swak-gesorteerde gruislaag en is oorwegende opwaarts fynerwordend. Die strandomgewing is goed verteenwordige en bestaan uit matig tot goedgesorteerde medium- tot fynkorrelrige sand. Die grootste mineraal-diversiteit kom voor in die subgety- en strandomgewings en die gemiddelde TSM vir hierdie eenhede is hoër as 35%. As gevolg van algemene erosie kom die +30m eenheid sporadies voor. Die aflandige omgeving is herken deur fyn kleierige of slikkerige sedimente met hoe konsentrasies gloukoniet en organiese materiaal. Die subgetysone omgewing is gekenmerk deur verskeie gruislae wat almal opwaarts fynwordend is. Altwee die subgety- en strandomgewings het hoer feldspar konsentrasies as die +50m eenhede. Die gemiddelde THM vir hierdie enhede is minder as 3%. Die eolitiese eenheid, bestaan uit verskeie duidelik-onderskeibare eenhede, beslaan die totale lengte van die studiegebied en word kenmerk deur uitgebreide kalkreet en rooi-laag horisonne. Kleurverskille in die andersins homogene eenheid kan verklaar word in terme van lae swaarmineraal konsentrasies en/of as gevolg wan verskillende grade van in situ verwering en sementering. Die eenheid bestaan uitsluitlik uit fyntot medium-korrelrige sand en het ‘n gemiddelde TSM konsentrasie van 9%. Die eenheid bestaan uit meer as een generasie eoliese sand en maak deel uit van ‘n eoliese vervoersisteem wat sand vanaf die strand na die binneland vervoer het. Die oudste sande in hierdie eenheid is gekorreleer met die Laat Mioseen Prospect Hill Formasie terwyl die meer onlangse geelduin sand vergelyk word met die Pleistoseen Springbokfontein Formasie. By Geelwal Karoo is slegs die +50m eenhede beskou as economies van belang. Die gemiddelde TSM van hierdie swaarmineraal-ertsligaam is bereken op 40% met ‘n verwagte 150 duisend ton Ti-draende material van die opeenvolging. Die relatiewe klein volume swaarminerale en uitgebreide sementering het tot gevolg dat dit ‘n minder aanloklike proposisie is as die aanliggende Namakwa Sands aanleg.

Thesis (MSc (Earth Sciences))--University of Stellenbosch, 2009. / Fan 3 is one of four basin-floor fans that form part of the Tanqua Karoo Fan Complex in South Africa. It can be subdivided into several sandstone lobes, based on the presence of thin-bedded siltstone intervals above and below major sandstone packages. Six lobes are identified in the mid fan section, as well as two older groups of thin, low-volume turbidite deposits at the base. Some of the lobes are further divided into an upper and lower lobe-element based on depositional behaviour. The volumetrically and spatially larger lobes have a finger-like appearance in plan view, which is attributed to multiple lobe-scale axial zones. This is especially visible towards the eastern margins of Lobes 2, 4 and 5. The stratigraphy and facies distribution are presented on several 2D panels. Computer generated isopach maps are presented for each lobe, lobe-element and interlobe unit. Autogenic control on the depositional pattern of the Fan 3 lobe complex was inferred from the palaeoflow patterns of the composing lobes and lobe-elements. The majority of the lobes show a north-eastern palaeoflow direction in the south, with a gradual westward shift in the north. Inferred controls are basin-floor topography, the presence of pre-existing lobes, and characteristics of the depositional flow, such strength, density, sediment load, palaeoflow direction.

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2013.

This study represents the first detailed geological, geophysical and geochronological investigation of the continental shelf surrounding the Aliwal Shoal, ~5 km offshore of Scottburgh, in southern KwaZulu-Natal. Mapping of the seafloor geology using geophysics and direct observations from SCUBA diving transects were integrated with the seismic stratigraphy and constrained by new geochronological data. Four seismic stratigraphic units (A to D) were identified and interpreted with the subsequent sequence stratigraphic model consisting of four incompletely preserved stratigraphic sequences separated by three sequence boundaries (SB1 - SB3) comprising complex reworked subaerial unconformity surfaces. Sequence 1 is the deepest, subdivided by a basin-wide marine flooding surface (MFS1) into a lower Campanian (and possible Santonian) TST and an upper Maastrichtian combined regressive systems tract comprising HST/FRST deposits. SB1 follows Sequence 1 and spans most of the Tertiary representing multiple erosional events. Shelf sedimentation resumed during the Late Pliocene to early Pleistocene with deposition of Sequence 2, the shelf-edge wedge, which again was followed by erosion and non-deposition during the high frequency and amplitude Early to Middle Pleistocene sea-level fluctuations resulting in the formation of SB2. Sequence 3 consists of coast-parallel, carbonate cemented aeolianite palaeo-shoreline ridges of various ages overlying Sequence 1 and 2. Sequence 4 unconformably overlies all the earlier sequences and comprises a lower TST component displaying characteristic retrogradational stacking patterns and an upper local HST clinoform component showing progradation and downlapping. Inner and middle shelf TST units constrained between Sequence 3 ridges form thick sediment deposits showing a progression from lagoonal and lower fluvial-estuarine deposits, overlain by foreshore and shoreface sands, documenting the changing depositional environments in response to a sea-level transgression. Laterally, in the absence if Sequence 3 ridges, TST sediments comprise only a thin transgressive sand sheet. The upper HST component comprises a prograding shore-attached subaqueous-delta clinoform sediment deposit, the Mkomazi Subaqueous-Delta Clinoform (MSDC) which evolved in four stages. An initialization and progradation stage (Stage 1) (9.5 to 8.4 ka cal. B.P.) was interrupted by retrogradation (Stage 2) and backstepping of the system due to rapid sea-level rise between 8.4 to 8.2 ka cal B.P. Stage 2 backstepping of the clinoform controlled the subsequent overlying topset morphologies resulting in later stages inheriting a stepped appearance upon which shoreface-connected ridges (SCR’s) are developed. Stages 3 (8.2 to 7.5 ka cal. B.P.) and 4 (7.5 to 0 ka cal. B.P) show a change from ‘proximal’ topset aggradation to ‘distal’ foreset progradational downlap, linked to a change in the dominant sedimentary transport mechanism from aggradational alongshore to progradational cross-shore related to variations in accommodation space and the rate of sediment supply. Morphologically the MSDC is characteristic of sediment input onto a high energy storm-dominated continental shelf where oceanographic processes are responsible for its northward directed asymmetry in plan-view, for the lack of a well defined bottomset and for the re-organisation of its topset into very large SCR’s. The SCR’s are 1 - 6 m in height, spaced 500 to >1350 m apart and vary from 3 km to >8 km in length, attached on their shoreward portions to the shoreface between depths of -10 m to -15 m (average at -13 m) and traceable to depths exceeding -50 m, although the majority occur on the inner shelf between -20 m to -30 m. Several individual crests can be identified forming a giant shoreface-connected sand ridge field with a sigmoidal pattern in plan-view postulated to be a surficial expression of the subjacent retrogradational phase (MSDC Stage 2). SCR’s development occurred in two stages. Stage 1 involved deposition of sediment on the shoreface and ridge initiation during the MSDC Stage 2 retrogradational event. Sediment was reworked during sea-level rise generating clinoforms with proximal along-shore aggradation and distal across-shore progradation. This occurred during the last post-glacial sea-level rise from ca. 8.4 ka cal. B.P. SCR Stage 2 represents modern maintenance of the SCR system which is continually modified and maintained by shelf processes and consists of two physical states. State 1 considers SCR maintenance during fair-weather conditions when transverse ridge migration is dominant and driven by the north-easterly flowing counter current shelf circulation. State 2 considers SCR development during storm conditions when longitudinal ridge growth is suggested to occur as a result of storm return flows. Following the storm, the regional coast-parallel current system is restored and the fair-weather state then moulds the SCRs into a transverse bedform. Deposition on the MSDC is ongoing on a continental shelf that is still in a transgressive regime. The exposed seafloor geology comprises late Pleistocene to Holocene aeolianite and beachrock lithologies, deposited as coastal barrier and transgressive shoreface depositional systems. Extensive seafloor sampling was combined with a multi-method geochronological programme, involving the U-series, C14 and optically stimulated luminescence (OSL) to constrain the evolution of the aeolianite and beachrock complex. The Aliwal Shoal Sequence 3 ridge comprises three distinct aeolianite units (A1 to A3) which represent different types of dune morphologies deposited during the climatic and associated sea-level fluctuations of MIS 5. Units A1 and A2 deposited during the MIS 6/5e (~134 to ~127 ka cal. B.P.) transgression represent contemporaneous evolution of a coastal barrier system which consisted of two different dune forms associated with a back-barrier estuarine or lagoonal system. Unit A1 most likely originated as a longitudinal coastal dune whilst Unit A2 comprised a compound parabolic dune system that migrated into the back-barrier area across an estuary mouth/tidal inlet of the back-barrier system. The coastal barrier-dune configuration established by Unit A1 and A2 was most likely re-established during similar subsequent MIS 5 sea-level stands which during MIS 5c/b resulting in the formation of the back-barrier dune system of Unit A3. Palaeoclimatic inferences from Units A1 and A2 aeolianite wind vectors indicate a change from cooler post-glacial climates (lower Unit A1) to warmer interglacial-like conditions more similar to the present (upper Unit A1 and Unit A2). Unit A3 palaeowind vector data show variability interpreted to be related to global MIS 5c climatic instability and fluctuations. For Units A1, A2 and A3 pervasive early meteoric low-magnesium calcite (LMC) cementation followed shortly after deposition protecting the dune cores from erosion during subsequent sea-level fluctuations. Sea-spray induced vadose cementation in Units A1 and A2 may have been a key factor in stabilising dune sediment before later phreatic meteoric cementation. The final preserved Late Pleistocene depositional event in the study area was that of the storm deposit of beachrock Unit B5. Induration followed shortly after deposition by marine vadose high-magnesium calcite (HMC) cementation. Following deposition and lithification, Units A1, A2, A3 and B5 underwent a period of cement erosion associated with decementation and increased porosity due to either 1) groundwater table fluctuations related to the high frequency MIS 5 sea-level fluctuations and/or 2) carbonate solution due to complete subaerial exposure related to the overall MIS 4 - 2 sea-level depression towards the LGM lowstand. In addition to the decementation and porosity development Unit B5 also experienced inversion of the original unstable HMC cement to LMC. During MIS 4 to 2 the Aliwal shelf comprised an interfluve area which was characterised by subaerial exposure, fluvial incision of coast-parallel tributary river systems and general sediment starvation. Beachrock Units B1 to B4 were deposited in the intertidal to back-beach environments and subsequently rapidly cemented by marine phreatic carbonate cements comprising either aragonite or HMC. Unit B1 was most likely deposited at 10.8 ka cal. B.P., B2 at 10.2 ka cal. B.P, B3 at 9.8 ka cal. B.P and B4 <9.8 ka cal. B.P. thereby indicating sequential formation during the meltwater pulse 1b (MWP-1b) interval of the last deglacial sea-level rise. Unit B3 marks the change from a log-spiral bay coastal configuration established by Units B1 and B2 to a linear coastline orientation controlled by the trend of the pre-existing aeolianite units. This change in the morphology of the coastline is also documented by the shape of the underlying transgressive ravinement surface (reflector TRS, Sequence 4) which again was controlled by the subjacent sedimentary basin fill architecture and subsequent transgressive shoreline trajectory (Sequence 4). Sea-level rose at an average rate of 67 cm/100 years from B1 to B2 and 86 cm/100 years from B2 to B2 indicating an acceleration in the rate of sea-level rise supporting enhanced rates of sea-level rise during the MWP-1b interval which also seemed to have altered the coastal configuration and resulted in the closure of the southern outlet of the back-barrier estuarine system. Two cycles of initial aragonite followed by later HMC cement are tentatively linked to two marine flooding events related to different pulses of enhanced rates of sea-level rise during MWP-1b which are considered responsible for significant changes in the marine carbon reservoir ages. Comparisons of the U-series, C14 and optically stimulated luminescence (OSL) methods have shown OSL to be the most reliable method applied to dating submerged aeolianites and beachrocks. OSL not only provides the depositional age of the sediment but also does not suffer from open system behaviour, such as marine reservoir changes and contamination. Acoustic classification of the unconsolidated sediment samples resulted in the demarcation of 3 major acoustic facies, C to E, interpreted with sample analyses as quartzose shelf sand (C), reef-associated bioclastic-rich sand (D) and an unconsolidated lag and debris deposit (E). Grain size distribution patterns of the unconsolidated seafloor sediments indicate that the SCR system delivers fine and medium sand to the inner and middle shelf and imparts a general N-S trending pattern to the gravel and sand fractions. In addition grain size distributions support selective erosion of the seaward flank of the Sandridge with the remobilised sediment deposited in the Basin as low amplitude bedforms over the Facies E lag and debris pavement. The mud fraction is interpreted to be deposited by gravity settling from buoyant mud-rich plumes generated by river discharge. Integration of acoustic mapping, field observations and sample analyses indicate that the present distribution of the unconsolidated sediment is the result of a highly variable distribution of modern and palimpsest sediments which are continually redistributed and reworked by a complex pattern of bottom currents generated by the interaction of opposing oceanographic and swell driven circulation patterns. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.