Outcrop analogue studies of fluvial sedimentary systems are often undertaken to identify spatial and temporal characteristics (e.g. stacking patterns, lateral continuity, lithofacies proportions). However, the lateral extent typically exceeds that of the exposure, and/or the true width and thickness are not apparent. Accurate characterisation of fluvial sand bodies is integral for accurate identification and subsequent modelling of aquifer and hydrocarbon reservoir architecture. The studies presented in this thesis utilise techniques that integrate lidar, highresolution photography and differential geospatial measurements, to create accurate three-dimensional (3D) digital outcrop models (DOMs) of continuous 3D and laterally extensive 2D outcrop exposures. The sedimentary architecture of outcrops in the medial portion of a large Distributive Fluvial System (DFS) (Huesca fluvial fan) in the Ebro Basin, north-east Spain, and in the fluvio-deltaic succession of the Breathitt Group in the eastern Appalachian Basin, USA, are evaluated using traditional sedimentological and digital outcrop analytical techniques. The major sand bodies in the study areas are quantitatively analysed to accurately characterise spatial and temporal changes in sand body architecture, from two different outcrop exposure types and scales. Several stochastic reservoir simulations were created to approximate fluvial sand body lithological component and connectivity within the medial portion of the Huesca DFS. Results demonstrate a workflow and current methodology adaptation of digital outcrop techniques required for each study to approximate true geobody widths, thickness and characterise architectural patterns (internal and external) of major fluvial sand bodies interpreted as products of DFSs in the Huesca fluvial fan, and both palaeovalleys and progradational DFSs in the Pikeville and Hyden Formations in the Breathitt Group. The results suggest key geostatistical metrics, which are translatable across any fluvial system that can be used to analyse 3D digital outcrop data, and identify spatial attributes of sand bodies to identify their genetic origin and lithological component within fluvial reservoir systems, and the rock record. 3D quantitative analysis of major sand bodies have allowed more accurate width vs. thickness relationships within the La Serreta area, showing a vertical increase in width and channel-fill facies, and demonstrates a 22% increase of in-channel facies from previous interpretations. Additionally, identification of deposits that are products of a nodal avulsion event have been characterised and are interpreted to be the cause for the increase in width and channel-fill facies. Furthermore, analysis of the Pikeville and Hyden Fms contain sand bodies of stacked distributaries and palaeovalleys, as previously interpreted, and demonstrates that a 3D spatial approach to determine basin-wide architectural trends is integral to identifying the genetic origin, and preservation potential of sand bodies of both palaeovalleys and distributive fluvial systems. The resultant geostatistics assimilated in the thesis demonstrates the efficacy of integrated lidar studies of outcrop analogues, and provide empirical relationships which can be applied to subsurface analogues for reservoir model development and the distribution of both DFS and palaeovalley depositional systems in the rock record.

Syn-rift exposures are a prime source of knowledge on the structure and stratigraphy of rift basins and are vital for the petroleum industry as analogues for subsurface reservoirs. Focusing on superb exposures of the Oligo-Miocene rift initiation Nukhul half-graben in the Suez Rift, Egypt, this study investigates applications of 3D digital survey techniques, particularly terrestrial light detection and ranging (lidar), for (i) the analysis of syn-rift fault and facies architecture, and (ii) the building and testing of outcrop-based reservoir analogue models for early syn-rift settings. Lidar-based digital outcrop mapping of the Nukhul half-graben, combined with conventional fieldwork, facilitated quantification of thickness and facies relationships within syn-rift strata, and variations of throw along normal faults. The results provide new insights into the tectono-sedimentary evolution of the intra-block half-graben. At rift initiation, regional/eustatic sea-level and antecedent drainage are interpreted as the dominant controls on accommodation development and deposition, respectively. However, after just c. 2.5 myr of rifting, the structural template imposed by the propagation and linkage of four initially isolated pre-cursor segments of the Nukhul Fault became the dominant control on accommodation development and basin physiography. Progressive SE-NW back-stepping of facies strike-parallel to the Nukhul Fault suggests hangingwall subsidence was locally sufficient to outpace falls in regional sea-level, resulting in a dynamic transgressive system that progressed from a restricted tidal embayment to shallow marine seaway along fault strike. After c. 4.3 myr of rifting, regional drowning of the tidal system provides evidence for progressive localisation of displacement onto the present-day block-bounding structures and declining activity on the intra-block Nukhul Fault during the transition from rift initiation to rift climax. Development of digital outcrop techniques such as point cloud facies classification, 3D deterministic channel modelling and net-to-gross analysis provided reliable geostatistics on the geometry, distribution and heterogeneity of tide-influenced facies of the syn-rift Nukhul Formation. The high volume, reliability and spatial coverage of data reduced uncertainties related to stochastic facies modelling (in this case sequential indicator simulation and object-based techniques), facilitating building and testing of high-resolution analogue models for the complex facies and sequence architecture of early syn-rift tidal reservoirs. Visual analysis of static reservoir connectivity suggests some of the smallest-scale depositional elements, i.e. thin intercalations of mudstone and sandstone lamina in heterolithic facies, have the biggest impact on both reservoir volume and vertical connectivity in this syn-rift tidal system. Heterogeneities at the sequence stratigraphic scale also have significant impact on vertical reservoir compartmentalisation, whereas tidal channel lag deposits and tidal mud drapes have more localised effects. Use of lidar, when combined with conventional fieldwork, offers a powerful tool for quantitative spatial analysis of fault and facies architecture, tightly constraining 3D structural and stratigraphic interpretations and effectively increasing the statistical significance of outcrop analogues for reservoir characterisation. Future developments in survey technologies alongside geoscience-specific software for the integration and analysis of outcrop datasets will provide more diverse and quantitative information on geological heterogeneity, and promote wider-ranging applications in Earth sciences.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the recent years there has been a constant discussion between the others and leading researchers in health and the world's environment, which are the benefits (inhibition of caries and dental enamel remineralization) and harm (dental fluorosis and skeletal fluorosis, mostly) by ingestion of fluoride in drinking water. Thus, the objective of this study was to diagnose fluoride anomalies and sort outcrop zone waters of the Guarani Aquifer System, in cities in the Central Region of Rio Grande do Sul. Therefore, the specific objectives were defined: Firstly, recognize the municipalities located in the Central Depression, with occurrences of anomalies in fluoride concentrations in groundwater. This study was done through research on the Company's website for Research on Mineral Resources (CPRM), selecting some funding for field sampling; Identifying fluoride anomalies from the results of chemical analyzes of samples; Sort the waters sampled in Piper diagram and Stiff diagrams and apply statistical method of correlation to find possible correlations, especially between electrical conductivity and fluoride. There were performed in total, twenty collections in the cities of Dona Francisca, Faxinal do Soturno, Restinga Seca, Santa Maria and São João do Polêsine. Among the twenty samples, twelve of them pointed fluoride index greater than the Maximum Allowed by law. Eighteen samples were identified as moles. In the chemical classification, eight samples proved bicarbonate with sodium, seven had sodic chlorinated and five mixed sodium. The statistical processing pointed out that there is no significant correlation between conductivity and fluoride. It is concluded that there is need for further work on the subject. In addition, the water knowledge with fluoride anomalies in other municipalities is essential for public health problems to be controlled and/or prevented. / Nos últimos anos verifica-se uma constante discussão entre os diversos e principais pesquisadores em saúde e meio ambiente do mundo: os benefícios (inibição da cárie e remineralização do esmalte dentários) e os malefícios (fluorose dentária e fluorose óssea, principalmente) da ingestão do flúor em água de consumo humano. Diante disso, o objetivo deste trabalho foi diagnosticar anomalias de fluoreto em captações por poços tubulares e classificar águas da zona de afloramento do Sistema Aquífero Guarani, em municípios da Depressão Central do Rio Grande do Sul. Para tanto, foram definidos os objetivos específicos: reconhecer, primeiramente, os municípios da Depressão Central, com ocorrências de anomalias nas concentrações de flúor nas águas subterrâneas através de pesquisa no sítio da Companhia de Pesquisas em Recursos Minerais (CPRM), selecionando algumas captações para amostragem em campo; Identificar anomalias de fluoreto a partir dos resultados das análises químicas realizadas nas amostras; Classificar as águas amostradas através de diagrama de Piper e diagramas de Stiff e Aplicar método estatístico de correlação para constatar possíveis correlações, sobretudo, entre a condutividade elétrica e fluoreto. Foram realizadas, ao todo, vinte coletas nos municípios de: Dona Francisca, Faxinal do Soturno, Restinga Seca, Santa Maria e São João do Polêsine. Das vinte amostras, doze apontaram concentração de fluoreto maior do que o Valor Máximo Permitido pela legislação vigente. Dezoito amostras foram identificadas, quanto a dureza, como moles. Na classificação química, oito amostras mostraram-se bicarbonatadas sódicas, sete apresentaram-se sódicas cloretadas e cinco, sódicas mistas. O processamento estatístico apontou que não há correlação significativa entre condutividade elétrica e flúor. Concluí-se que há necessidade de continuidade de trabalhos referentes à temática. Além disso, que o (re) conhecimento de águas com anomalias de fluoreto em outros municípios é imprescindível para que problemas de saúde pública sejam controlados e/ou evitados.

The seed bank dynamics of five habitats as well as a grazing gradient in the southwestern Kalahari, South Africa were studied. Soil samples were collected in the following habitats: dune crests, dune slopes, dune streets, a calcrete outcrop and a riverbed on the farm Alpha. Soil samples were also collected along a grazing gradient from a watering point. Three methods of soil seed bank analysis were used to analyse the soil samples and to gain insight into soil seed bank response to habitat type and to grazing pressure, over four seasons in the year 2004. Results from the three methods of analysis were also compared to each other. They included the direct seedling germination method, the seedling germination re-examination and the seed extraction method. These analyses were used to (a) estimate seed bank size and composition in response to habitat type and grazing pressure; (b) the differences between the standing vegetation- and the seed bank-flora in different habitats and along a grazing gradient and (c) the type of seed banks that tend to form in certain habitats and in response to grazing pressure. Analyses of soil seed bank size along a grazing gradient showed that the seedling emergence re-examinations estimated a larger size for the seed bank than the direct seedling emergence method. The seed extraction method estimated a significantly larger seed bank size than the other two methods. Heavy grazing pressure favoured annual/opportunistic species such as Schmidtia kalahariensis, which formed very large seed banks in heavily trampled areas. When Schmidtia kalahariensis data was removed from the seed bank analyses, it was found that, in contrast to previous results, the direct germination method mostly estimated a larger seed bank size than the re-examination. Also, the estimation of seed bank size by the flotation method, in this case, was much smaller. The flotation method produced data mostly for hard-seeded species, while the seedling emergence method produced data for species with small seeds and which were readily germinable. In all seasons, the dune crest habitat always had the smallest seed bank and the riverbed habitat always had the largest seed bank. All the dune habitats were characterised by perennial grasses. Perennial grasses formed transient seed banks which were relatively small. The riverbed habitat’s vegetation was mostly composed of annuals. Annual plants formed persistent seed banks which were relatively large. Species richness of the readily germinable seed bank in all habitats, fluctuated between the four seasons and was usually largest in summer. The difference in species richness between the above- and belowground floras fluctuated over four seasons. The dune habitats showed a large difference between the species richness of the above- and the below-ground flora, while the riverbed habitat showed a much smaller difference. The dune habitats had many species with transient seed banks while the riverbed was characterised by many species with short-term persistent and ‘permanent’ seed banks. / Dissertation (MSc)--University of Pretoria, 2011. / Plant Science / unrestricted

This thesis investigates how architectural element analysis (AE) can be utilized to deconstruct the sedimentary architecture of glacial sedimentary successions, and its significance for paleoenvironmental reconstruction, understanding depositional histories, and providing insight to the hydrostratigraphy of glaciated terrains. The first component of this thesis explores the applicability of AEA to the local-scale analysis of a till succession exposed in outcrop sections in order to understand the significance of the bounding surface hierarchy and architectural elements in sediments deposited in a subglacial depositional environment. Fieldwork was conducted at two outcrop sites in north-central Illinois, U.S.A., which expose Late Wisconsin-age till of the Tiskilwa Formation, in order to test the local-scale applicability of AEA to the architectural analysis of a subglacial succession (Chapter 2). A major finding of this study was that fifth-order bounding surfaces delineate ‘element associations’ which can be mapped across the local study area, and utilized for detailed paleoenvironmental reconstruction of the ‘subglacial bed mosaic’ and local-scale reconstruction of the depositional history of the till sheet, including periods of separation and reattachment of the ice and its bed. The second part of this research explores AEA at Sólheimajökull (Iceland), specifically to test the validity of AEA for the analysis of glacial successions, and to better understand the environmental significance of unit contacts (bounding surfaces) and sedimentary geometries in a modern glacial landscape. Fieldwork was conducted at Sólheimajökull and basic principles of AEA and landsystems analysis were integrated in order to facilitate delineation of the sedimentary architecture and allostratigraphy of the Sólheimajökull landsystem (Chapter 3). Fifth-order surfaces delineate landsystem tract components, which can be utilized to characterize the heterogeneity and sedimentary architecture, delineate allostratigraphic units, and reconstruct the depositional hist¬ory of the Sólheimajökull landsystem. Data from Sólheimajökull (Chapter 3) and Illinois (Chapter 2) were utilized as a modern and outcrop analogue, respectively, to provide insight to the sedimentary architecture of subsurface Quaternary glacial deposits in Georgetown, southern Ontario (Canada; Chapter 4). Basic concepts of AEA were applied to the analysis of sediments recovered from fully-cored boreholes. A major finding of this study is that AEA can be effectively utilized for delineation of subsurface architectures from the analysis of core, and the hierarchies of bounding surfaces and units of AEA can be utilized to organize the sedimentary heterogeneity into a ‘nested’ architectural framework. The geometry and spatial relationship of architectural units (sixth-order surfaces) and architectural components (fifth-order surfaces) provides insight to the hydrostratigraphy of Georgetown. AEA, as utilized in this thesis, provides a systematic methodology with which to deconstruct glacial successions into their basic architectural building blocks at various scales of resolution. AEA enhances traditional facies models by facilitating site-specific delineation, visualization, and characterisation of the sedimentary geometry of facies associations, which in turn, allows direct comparison of sedimentary architectures at different study sites; this has significant implications for analogue selection for the purpose of reservoir analysis. The architectural framework of glacial deposits and its potential significance to hydrostratigraphic models (as discussed in this thesis) may help to facilitate communication and translation of data between the disciplines of ‘geology’ and ‘hydrogeology’. The results of this project can be utilized as a framework to better understand the sedimentary geometry and hydrostratigraphy of modern and Quaternary glacial deposits in southern Ontario, previously glaciated terrains elsewhere, and other modern glacial landsystems, and provide insight into other applications such as civial engineering projects, aggregate resources, placer mining exploration, and land use planning. / Thesis / Doctor of Philosophy (PhD)

Sub-seismic meter-scale interwell depositional facies heterogeneity and microporosity are critical components behind properties and fluid flow heterogeneities of many Middle eastern giants and supergiants carbonate reservoirs. The Hanifa reservoir is one of the most petroliferous Arabian carbonate strata that hosts the notoriously heterogenous stromatoporoid/coral facies. Paradoxically, the 3D geometry, architecture, and subsurface implication of these facies are poorly understood or completely ignored in most studies. The lower part of the Arab-D reservoir is dominated by microporosity. However, studies that investigate the influence of microcrystals that host microporosity to petrophysical properties and upscale it to reservoir simulation grid-block scale are modicum. This dissertation aims to bridge this paucity by performing an advanced three-dimensional outcrop analog investigation and multiscale microporosity studies of these formations. We document the 3D morphology and spatial distribution of the stromatoporoid/coral facies part of the Hanifa reservoir outcrop analog in Wadi Birk, Saudi Arabia, using 3D drone-based digital outcrop model, cores, near-surface geophysical measurements, and deep-learning methodology. We construct a high-fidelity outcrop analog reservoir model from these observations and utilize it for dynamic simulation during waterflood. Further, based on the Upper Jubaila Formation outcrop analog in Wadi Laban, Saudi Arabia, we investigate the influence of microcrystals that host microporosity on petrophysical properties. We upscale the relationships and utilize seismic-derived acoustic-impedance data to arrive at reservoir grid block-scale microporosity distribution. Our results provide a novel and valuable insight into the growth morphology of the stromatoporoid/coral buildups and their relationship with subsurface fluid flow previously unknown for the Hanifa reservoir. The results demonstrate that sweep efficiency is greatly influenced by the interaction between the buildup clusters with the background strata. Our results also provide a practical method to integrate key sub-grid scale micro and macro heterogeneities into reservoir grid block-scale property models.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: This study presents an outcrop characterisation and modelling of the excellently exposed Permian Kookfontein Formation of the Ecca Group in the Tanqua-Karoo sub-Basin. The sedimentary modelling (i.e. facies architecture and geometry) and petrophysical characterisation followed a hierarchical and deterministic approach. Quantitative outcrop data were based on the thirteen sedimentary cycles that characterise this stratigraphic succession at the Pienaarsfontein se Berg locality; and these data were analysed using a combination of detailed sedimentary log, gamma ray log and photopanel analysis, as well as petrographic thin-section and grain size-based petrophysical analysis. Based on texture and sedimentary structures, twelve depofacies are recognised which are broadly grouped into four lithofacies associations i.e. sandstone facies, heterolithic facies, mudstone facies and soft-sediment deformation facies; these depofacies and lithofacies form the basic building blocks for the flooding surface-bounded facies succession (i.e. cycle). Also, based on sediment stacking and cycle thickness patterns as well as relative position to the shelf break, the succession is sub-divided into: (1) the lower Kookfontein member (i.e. cycles 1 to 5) exhibiting overall upward thickening and coarsening succession with progradational stacking pattern; representing deposition of mid-slope to top-slope/shelf-margin succession, and (2) the upper Kookfontein member (i.e. cycles 6 to 13) exhibiting overall upward thickening and coarsening succession with aggradational stacking pattern; representing deposition of top-slope/shelf-margin to outer shelf succession. Lateral juxtaposition of observed vertical facies variations across each cycle in an inferably basinwards direction exhibits upward change in features, i.e. decrease in gravity effects, increase in waves and decrease in slope gradient of subsequent cycles. This systematic upward transition in features, grading vertically from distal to proximal, with an overall upward thickening and coarsening progradational to aggradational stacking pattern indicates a normal regressive prograding delta. However, in detail, cycles 1-3 show some anomalies from a purely thickening and coarsening upward succession. Deposition of each cycle is believed to result from: (1) primary deposition by periodic and probably sporadic mouthbar events governed by stream flow dynamics, and (2) secondary remobilisation of sediments under gravity. The facies distribution, architecture and geometry which governs the sedimentary heterogeneity within the deltaic succession is therefore mainly a consequence of the series of mouthbar flooding events governed by sediment supply and base-level changes. These series of flooding events resulted in the delineation of the studied stratigraphic interval into two main parasequence sets, i.e. transgressive sequence set and the overlying regressive sequence set. This delineation was aided through the identification of a maximum flooding surface (i.e. maximum landwards shift in facies) above Cycle 3 in the field. The architecture and geometry of the ensuing deposystem is interpreted to have been a river-dominated, gravitationally reworked and waveinfluenced shelf edge Gilbert-type delta. Widespread distribution of soft-sediment deformation structures, their growth-style and morphology within the studied succession are empirically related to progradation of Gilbert-type mouthbars over the shelf break as well as the slope gradients of the Kookfontein deltaic clinoformal geometry. Analysis of hypothetical facies stacking and geometrical models suggests that the Kookfontein sedimentary cyclicity might not be accommodation-driven but rather sediment supply-driven. The workflow employed for petrophysical evaluation reveals that the distribution of reservoir properties within the Kookfontein deltaic sandbody geometries is strongly influenced both by depositional processes and by diagenetic factors, the latter being more important with increased burial depth. The reservoir quality of the studied sandstones decreases from proximal mouthbar sands, intermediate delta front to distal delta front facies. The major diagenetic factors influencing the reservoir quality of the studied sandstones are mechanical compaction, chemical compaction (pressure solution) and authigenic pore-filling cements (quartz cement, feldspar alteration and replacement, calcite cement, chlorite and illite). Mechanical compaction was a significant porosity reducing agent while cementation by authigenic quartz and clay minerals (i.e. illite and chlorite) might play a major role in permeability distribution. The porosity-permeability relationship trends obtained for the studied sandstones show that there is a linear relationship between porosity and permeability. The relative timing of diagenetic events as well as the percentages of porosity reduction by compaction and cementation indicates that compaction is much more responsible for porosity reduction than cementation. The described internal heterogeneity in this work is below the resolution (i.e. mm-scale) of most conventional well-logs, and therefore could supplement well-log data especially where there is no borehole image and core data. The combination of ‗descriptive‘ facies model and schematic geological model for this specific delta, and petrophysical characterisation make the results of this study applicable to any other similar ancient deposystem and particularly subsurface reservoir analogue. / AFRIKAANSE OPSOMMING: Hierdie studie bied ‘n dagsoomkarakterisering en -modellering van die duidelik blootgelegde Permiese Kookfontein-formasie van die Ecca-groep in die Tankwa-Karoo-subkom. Wat die sedimentêre modellering (d.w.s. fasiesargitektuur en -geometrie) en petrofisiese karakterisering betref is ‘n hiërargiese en deterministiese benadering gevolg. Kwantitatiewe dagsoomdata is gebaseer op dertien sedimentêre siklusse wat hierdie stratigrafiese opeenvolging in die Pienaarsfontein se Berg-lokaliteit kenmerk; en die data is geanaliseer met behulp van ‘n kombinasie van gedetailleerde sedimentêre seksie, gammastraal-profiel en fotopaneelanalises, asook petrografiese slypplaatjie- en korrelgrootte-gebaseerde petrofisiese analises. Op grond van tekstuur en sedimentêre strukture is twaalf afsettingsfasies onderskei wat rofweg in vier assosiasies van litofasies gegroepeer kan word: sandsteenfasies, heterolitiese fasies, moddersteenfasies en sagtesediment-deformasiefasies. Hierdie afsettingsfasies en litofasies vorm die basiese boustene vir die fasiesopeenvolging (d.w.s. siklus) wat oorstromingsoppervlakgebonde is. Verder word die opeenvolging aan die hand van sedimentstapeling en skilusdiktepatrone, asook relatiewe posisie tot die rakbreuk, in die volgende onderverdeel: (1) die benede-Kookfontein-deel (d.w.s. siklus 1 tot 5), wat in die geheel ‘n opwaartse verdikkings- en vergrowwingsopeenvolging met ‘n progradasiestapelpatroon vertoon en die afsetting van middelhelling-tot-boonstehelling- of rakrand-opeenvolging verteenwoordig, en (2) die benede-Kookfontein-deel (d.w.s. siklus 6 tot 13) wat in die geheel ‘n opwaartse verdikkings- en vergrowwingsopeenvolging met ‘n aggradasiestapelpatroon vertoon en die afsetting van boonste helling- of rakrand-tot-buiterakopeenvolging verteenwoordig. Die laterale jukstaposisie van waargenome vertikale fasiesvariasies oor elke siklus heen, in ‘n afleibare komwaartse rigting, vertoon opwaartse verandering wat kenmerke betref, naamlik afname in gravitasiegevolge, toename in golwe en afname in die hellinggradiënt van daaropvolgende siklusse. Hierdie stelselmatige opwaartse oorgang van kenmerke, wat vertikaal van distaal tot proksimaal gradiënteer en in die geheel opwaartse verdikking en vergrowwing in ‘n progradasie-tot-aggradasie-stapelpatroon vertoon, dui op ‘n normale regressiewe progradasiedelta. Van naby beskou, vertoon siklus 1-3 egter bepaalde afwykings van ‘n suiwer opwaartse verdikkings- en vergrowwingsopeenvolging. Die afsettings van elke siklus is vermoedelik die gevolg van: (1) primêre afsetting deur periodieke en waarskynlik sporadiese mondversperringsgebeure wat deur stroomvloeidinamika beheer word, en (2) sekondêre hermobilisering van sedimente deur gravitasie. Die fasiesverspreiding, -argitektuur en -geometrie wat die sedimentêre heterogeniteit in die deltaïese opeenvolging beheer, is dus hoofsaaklik ‘n gevolg van die reeks oorstromingsgebeure by die mondversperring, wat deur sedimentvoorsiening en basisvlakveranderings beheer word. Hierdie reeks oorstromingsgebeure het gelei tot die delineasie van die bestudeerde stratigrafiese interval volgens twee hoofparasekwensie stelle, naamlik die transgressiewe opeenvolgings- en die oordekkende, regressiewe opeenvolgingsgroep. Dié delineasie word ondersteun deur die feit dat ‘n maksimum oorstromingsoppervlak (d.w.s. maksimum landwaartse verskuiwing in fasies) bo siklus 3 in die veld uitgeken is. Die argitektuur en geometrie van die daaropvolgende afsettingstelsel word geïnterpreteer as behorende tot ‘n Gilbert-rakranddelta wat deur ‘n rivier gedomineer, deur gravitasie herbewerk en deur golfwerking beïnvloed is. Die wye verspreiding van sagtesediment-deformasiestrukture, en die groeiwyse en morfologie daarvan binne die bestudeerde opeenvolging, is empiries verwant aan die progradasie van Gilbertmondversperrings oor die rakbreuk heen, asook aan die hellinggradiënte van die Kookfontein-deltaïese, klinoformele geometrie. Die analise van hipotetiese fasiesstapeling en geometriese modelle dui daarop dat die Kookfontein-sedimentêre siklisiteit dalk nie deur akkommodasieruimte gedryf word nie, maar deur sedimentvoorsiening. Die werkvloei wat vir petrofisiese evaluering gebruik is dui daarop dat die verspreiding van reservoir-eienskappe in die Kookfontein- deltaïese sandliggaam geometries sterk beïnvloed word deur afsettingsprosesse en diagenetiese faktore. Die diagenetiese faktore word belangriker op groter begrawing diepte. Die reservoir-aard van die bestudeerde sandgesteentes neem algaande af van proksimale mondversperring-sandsoorte tot intermediêre deltafront tot distale deltafrontfasies. Die hoof-diagenetiese faktore wat die reservoir-kenmerke van die bestudeerde sandsteensoorte beïnvloed is meganiese verdigting, chemiese verdigting (oplossingsdruk) en outigeniese porievullingsement (kwartssement, veldspaatomsetting en -vervanging, kalsietsement, chloriet en illiet). Meganiese verdigting is ‘n beduidende poreusheidreduseermiddel, terwyl sementering deur outigeniese kwarts- en kleiminerale (d.w.s. illiet en chloriet) moontlik ‘n belangrike rol by permeabiliteitsverspreiding kan speel. Die poreusheid-permeabiliteit-verhoudingstendense wat bekom is vir die bestudeerde sandsteensoorte dui daarop dat daar ‘n lineêre verhouding tussen poreusheid en permeabiliteit bestaan. Die relatiewe tydberekening van diagenetiese gebeure, asook die persentasie poreusheidvermindering deur verdigting en sementering, dui daarop dat verdigting baie meer as sementering tot poreusheidvermindering bydra. Die interne heterogeniteit wat in hierdie werk beskryf word, is onder die resolusie (d.w.s. mm-skaal) van die meeste konvensionele boorgatopnames, en kan dus boorgatopnamedata aanvul, veral waar daar geen boorgatafbeelding en kerndata bestaan nie. Die kombinasie van die 'deskriptiewe‘ fasiesmodel en skematiese geologiese model vir hierdie spesifieke delta, asook petrofisiese karakterisering, beteken dat die resultate van hierdie studie op enige ander soortgelyke antieke afsettingstelsels toegepas kan word, maar veral op suboppervlakreservoir-analoogstelsels.

Este projeto teve por objetivo a construção de um modelo hidrogeológico baseado em Elementos Finitos para estudar a variação de nível do aquífero livre em área de afloramento do Sistema Aquífero Guarani. A área é a bacia do Ribeirão da Onça, localizada na região central do Estado de São Paulo. Dados topográficos, hidrológicos e hidrogeológicos da região de interesse foram obtidos principalmente através de mapas, de poços e estações metereológicas próximas e na área de estudo, com o apoio do Centro de Recursos Hídricos e Ecologia Aplicada (CRHEA) da Universidade de São Paulo (USP). Os dados já existentes no Laboratório de Hidráulica Computacional (LHC) da Escola de Engenharia de São Carlos (EESC), bem como os dados coletados no decorrer do trabalho, foram utilizados para definição de suas condições de contorno e calibração do modelo. Estes foram processados e analisados em ferramenta SIG. Assim foram definidos os parâmetros para a construção da malha de elementos finitos dentro do pacote de Simulação de Processos em Aquíferos (SPA), software utilizado para a modelagem numérica desenvolvido no LHC. Foi simulado o fluxo estacionário como condição inicial para a modelagem transiente. Visto as condições de contorno adotadas, o modelo transiente resultou em cálculos satisfatórios de carga hidráulica, considerados os poços de monitoramento existentes na área de estudo e a particular localização de cada um. A ferramenta mostrou bom desempenho e, como sugestão, a continuidade do monitoramento da região se faz necessária para manutenção e melhora das informações a respeito do comportamento da água subterrânea e do SAG como reserva deste importante recurso. / This works presents a hydrogeological model based on finite element to study the variation in level of free aquifer in the outcrop area of the Guarani Aquifer System. The area was the basin of Ribeirão da Onça, located in the central region of São Paulo. Topographic, hydrological and hydrogeological data of the region of interest were obtained mainly through maps, weather stations and wells near and within the study area, with support from the Center for Water Resources and Applied Ecology (CRHEA), University of São Paulo (USP). The data already existing in the Laboratory of Computational Hydraulics (LHC) at the School of Engineering of Sao Carlos (EESC) and the data collected during the study were used to define its boundary conditions and model calibration. These data were processed and analyzed in a GIS tool. Thus were defined the parameters for the construction of the finite element mesh within the package of Process Simulation in Aquifers (SPA), software used for numerical modeling developed at the LHC. Steady flow was simulated as an initial condition for transient modeling. Since the boundary conditions adopted, the transient model resulted in satisfactory hydraulic head calculations, considering the existing monitoring wells in the study area, taking into account the particular location of each. The tool has shown good performance and, as a suggestion, the continued monitoring of the region is necessary for maintenance and improvement of information about the behavior of groundwater and SAG as a store of this important resource.

Thesis (MSc. (Zoology)) --University of Limpopo, 2008 / Refer to document / National Research Foundation - Thuthuka programme

Accessibility to consistent subsurface hydrostratigraphic information is crucial for the development of robust groundwater flow and contaminant transport models. However, full three-dimensional understanding of the subsurface geology is often the missing link. Construction of watershed-scale hydrostratigraphic models continues to be limited by the quality and density of borehole data which often lack detailed geologic information. This can become a serious problem where rapid sediment facies changes and intricate sediment architecture occur. This research is motivated by the idea that if we can understand more about the distribution of sediments and structures of complex deposits, we learn more about depositional processes and how they affect the internal geometry of a deposit and the distribution of hydraulic properties. One approach is to study surficial excavations (e.g. sand and gravel pits) that often punctuate shallow aquifers. The purpose of this study is to develop and test a method of integrating high-resolution georeferenced stratigraphic and sedimentologic information from sand and gravel pits as a means to better document sedimentologic data and improve understanding of the depositional environments. The study area is located within the Waterloo Moraine, in southwestern Ontario, and is an unconsolidated shallow aquifer system with a complex internal architecture and sediment heterogeneity. The method involves the integration of high-resolution field data with borehole and geophysical information in a computer-based 3D environment. A total of fourteen virtual sedimentary sections were constructed by georegistering digital photographs within a framework of georeferenced positions collected using a reflectorless total station and GPS. Fourteen sediment facies have been described in the field. These include crudely stratified gravel beds, planar and cross-laminated sandy strata (ripple and dune scales), along with laminated and massive silty and clayey beds. Calculated hydraulic conductivities span over seven orders of magnitude. The analysis of a single excavation has shown contrasting sediment assemblages from one end of the pit to the other, highlighting the complexity of the Waterloo Moraine. The heterogeneous and deformed layers of gravel, sand, and mud may be the product of an ice-contact to ice-proximal environment, whereas the extensive sandy assemblages may reflect an intermediate subaqueous fan region. The results also suggest that the borehole database overestimates the amount of fine-grained material in the study area. Finally, this research demonstrates that it is possible to build in a timely manner a 3D virtual sedimentologic database. New emerging technologies will lead to increased resolution and accuracy, and will help streamline the process even further. The possibility of expanding the 3D geodatabase to other excavations across the region in a timely manner is likely to lead to improved hydrostratigraphic models and, by extension, to more efficient strategies in water resources planning, management and protection.