Weathering of silicate minerals has long been a known source of natural CO2 sequestration, that could be increased in the presence of microorganisms. Bio-enhanced weathering of silicate minerals could increase the sequestration of CO2 from the atmosphere.   The aim of this project was to evaluate the potential for a new Neutral emission technology (NET), using four different organisms, Aspergillus Niger, Knufia Petricola, Bacillus Subtilis and Cupriavidus Metallidurans and their potential to increase olivine weathering (dunite). Straw, manure and digestate was used as carbon sources. In total 9 biotic - and 9 abioitc reactors were made, containing a mixture of dunite and one of the three carbon sources. In total 250 mL of water was added to each reactor per week, for 6 weeks, and collected at the end of the week for analysis. Geochemical analyses of the leachate were performed, including pH, conductivity, alkalinity, total organic carbon (TOC), total inorganic carbon (TIC), cations, anions and three organic acids: citrate, acetate, and oxalate. Scanning emission microscope (SEM) was used to monitor potential differences pre- and post-treatment.   Straw reactors produced the most growth, both on the carbon source and the dunite grains. Likely due to the increased labile organic carbon concentrations. The total inorganic carbon and alkalinity demonstrated that inoculation of the reactors promoted weathering for all carbon sources, most significantly for the straw reactors. This observation was evidenced by etch pits in the SEM images and higher TIC, alkalinity, and magnesium values. Microbially enhanced silicate weathering has demonstrated it could be used for the development of NETs for the sequestration of atmospheric carbon. / BAM!

The utilisation of 3D digitisation and visualisation has grown considerably since 2008 and is becoming an increasingly useful tool for the digital documentation and metric analysis of archaeological artefacts and skeletal remains. It provides public access to rare and fragile specimens of palaeontological and palaeopathological importance whilst reducing the physical impact on these remains. Research in engineering and computer vision provides some insight into the impact of surface properties such as colour, specularity, reflectance and shape on the quality of the recorded 3D image, but within the archaeological and palaeontological disciplines comparable work has not yet been developed. If archaeology and anthropology are to provide long term reliable data from archaeological and palaeontological specimens in a way that doesn’t require repeated re-digitisation, we need to understand the impacts that the taphonomic histories of such samples have on our ability to 3D record them. Understanding the relationship of these taphonomic histories and the surface and optical properties will promote informed choices about the suitability of recording techniques. This thesis considers the taphonomic processes that affect the preservation of bone over archaeological, forensic and palaeontological timescales and the effect this has on the quality of 3D digital models. The digital refit of fragmentary bone samples is considered in relation to the effect of taphonomic alterations to bone. Conclusions regarding the key taphonomic factors and 3D digital model quality are drawn and areas of further work are identified. / Arts and Humanities Research Council

Missing page 48 / <p> The low ambient air temperatures, together with the low annual rainfall and complete lack of vegetation in the Canadian High Arctic, results in a breakdown of the carbonate rock material by mechanical means. The importance of chemical decomposition, soil formation and transport of ionic material in solution is negligible, when compared with the role played by these same processes in more temperate climates. </p> <p> The purpose of this thesis is to investigate certain aspects of the alkali, alkaline earth and heavy metal geochemistry of selected components of the weathering cycle. The discussion will deal with concentration levels of these parameters in stream waters and, to a lesser extent, soils and stream sediments. </p> <p> Analytical results show that element distributions in the streams resemble those of more temperate carbonate terrains. However, the solute levels are, in general, lower, indicating that a greater proportion of the metals is travelling in colloidal form and/or adsorbed to slit-sized material carried by the streams. </p> <p> These findings confirm the belief that chemical weathering and transport in solution are of little importance in the area studied. </p> / Thesis / Bachelor of Science (BSc)

No description available.

[pt] Esta tese apresenta um estudo sobre os efeitos do grau de intemperismo de um solo residual de gnaisse facoidal, em suas características física, química, mineralógica, microestrutural e de resistência. O objetivo da presente pesquisa é contribuir, por meio da avaliação de suas características, para o desenvolvimento de um Modelo Conceitual de Comportamento de Solos Residuais, considerando efeitos do grau de intemperismo no comportamento destes. Para tal foram realizados ensaios em três amostras de solos com diferentes graus de alteração, provenientes da mesma rocha de origem. Foram realizados, entre outros, ensaios de caracterização, ensaios de resistividade elétrica, calculados índices de intemperismo químico, analisada a composição mineralógica por meio de lupa binocular e equipamentos de difração de raio-x, realizada avaliação microestrutural por meio de microtomografia computadorizada, ensaios de resistência utilizando-se equipamento triaxial servo-controlado com instrumentação interna de bender elements, e análise da quebra de grãos após os ensaios de resistência. Os ensaios de resistência, realizados na prensa triaxial, com diferentes caminhos de tensões, foram interpretados utilizando-se a Teoria dos Estados Críticos. Observou-se que alguns ensaios de caracterização não se mostraram adequados para a avaliação do grau de intemperismo, para o solo estudado. Este fato pode estar associado à heterogeneidade do material, solo desenvolvido de rochas metamórficas gnáissicas quartzo-feldspáticas, e à dificuldade da coleta dos mesmos. Observou-se que, conforme menor o grau de alteração do solo, maior a resistividade do mesmo De modo geral, os solos estudados apresentaram uma envoltória de resistência única. Observou-se, ainda, que, conforme menor o grau de alteração do solo, maior a curva de plastificação do mesmo. Por meio dos resultados obtidos, verificou-se que a Teoria dos Estados Críticos pode ser aplicada no solo residual estudado. / [en] This thesis presents a study about the effects of the weathering degree of a phacoidal gneiss residual soil, in its physical, chemical, mineralogical, microstructural and resistance characteristics. The objective of the present research is to contribute, through the evaluation of its characteristics, to the development of a Conceptual Model of Residual Soil Behavior, considering the effects of the weathering degree on its behavior. For this, tests were carried out on three samples of soils with different weathering degrees, originating from the same rock. Some executed test were characterization tests, electrical resistivity tests, chemical weathering indexes calculation, mineralogical analysis using binocular magnifying glass and X-ray diffraction, microstructural evaluation by microtomography, resistance tests using triaxial servo-controlled equipment with internal instrumentation of bender elements, and grain break analysis after resistance tests. The resistance tests, realized in the triaxial press, with different stress path, were also interpreted using the Critical States Theory. It was observed that some characterization tests were not adequate for the weathering degree evaluation, for the studied soil. This fact may be associated with the soil heterogeneity, soil developed from metamorphic gneissic quartz feldspathic rocks, and the difficulty of collecting them. It was also observed that, the lower the soil weathering degree, the greater the resistivity of the soil. In general, the studied soils presented a unique resistance envelope. It was also observed that, the lower the soil weathering degree, the greater the soil yield curve. Through the obtained results, it was verified that the Critical States Theory can be applied in the residual soil studied.

Continued increase in CO2 emissions has unquestionably led to rising global temperatures. To aid in themitigation of climate change new Negative Emission Technologies (NETs) have been proposed. CO2-sequestration by bio-enhanced silicate weathering is one such proposed NET that seeks to captureatmospheric CO2 by weathering silicate rocks. The research focuses on investigating whether the naturalprocess of weathering can be enhanced using biology. Previous studies have shown promising resultswhere microbes have increased the weathering rates of silicates.As such, this project aimed to investigate how the presence of citric acid affects the weathering rateof dunite. Furthermore, the study aimed to investigate how the process is affected by biological growth.The setup consisted of 50 g of dunite powder mixed with 1 M citric acid that was incubated for aboutthree months. Due to this extensive time-period, most of the analyses made were performed on anexperiment started in December of 2023. The following analyses consisted of Scanning ElectronMicroscopy (SEM) imaging, geochemical analyses such as pH, anions, organic carbon content, specificsurface area analyses (BET) and X-ray diffraction spectroscopy (XRD). The second part of this studyconsisted of starting up a new more extensive setup similar to the original one. Furthermore, the studyalso investigated the biological growth that could be seen on the original setup and how the weatheringrate was affected.The setup demonstrated a substantial increase in weathering rate in the presence of citric acid. Theanalyses also showed that the alkalinity had significantly increased during incubation, demonstratingthe method’s possible use in mitigating acidification as well as the CO2 emissions. Although the initialpH of the citric acid solution was low (pH 2), fungal growth became evident after a few weeks. Thisobservation holds promise for an efficient bio-enhanced silicate weathering experimental setup, as lowerpH levels are associated with an increased weathering rate. This report concludes that citric acid cansignificantly enhance silicate weathering, thus proving to be a promising NET to mitigate climatechange. However, earlier research has shown that weathering of olivine risks accumulation of heavymetals. As such, further studies are needed to fully understand how the combination of organic acid andmicrobes affect the weathering rate of dunite and other silicate minerals and the net accumulation ofheavy metals in leachate and cells. / Med de ökande koldioxidutsläppen ökar även de globala temperaturerna såväl som andraklimatförändringar. För att på ett snabbt men även rimligt sätt sänka CO2-utsläppen har så kalladeNegative Emission Technologies (NETs) lagts fram som en möjlig lösning. En sådan teknik ärkoldioxidinfångst med hjälp av accelererad silikatvittring, som bygger på att använda biologi för attpåskynda vittringsprocessen som naturligt tar upp CO2 från atmosfären. Tidigare studier har visat på attmikrober kan förbättra vittringen av silikater.Detta arbete hade som syfte att undersöka hur vittringen av dunitpulver påverkas av citronsyra.Utöver detta undersöktes även hur vittringen påverkas av mikrobiologisk tillväxt inom reaktorerna.Reaktorerna bestod av 50 g dunitpulver och 1 M citronsyra som fick inkuberas under ungefär tremånaders tid. På grund av denna tidsperiod utfördes majoriteten av analyserna på experiment somstartades i december 2023. Analyser som utfördes var bland annat svepelektronmikroskopering (SEM),geokemiska analyser såsom pH, anjoner, organiska syror, organiskt kol samt analys av specifik ytarea(BET) och röntgendiffraktion (XRD). Förutom analyser av det originella experimentet, startades ävenett nytt, utökat experiment liknande det första. En tredje del av denna studie bestod av att undersöka denbiologiska tillväxten inom reaktorerna och hur den har påverkat vittringen.Experimentet visade på en betydande ökning i vittringshastighet med citronsyra närvarande.Analyser visade också på en markant ökning i alkalinitet, vilket pekar på en möjlig användning avaccelererad silikatvittring för att motverka försurning så väl som CO2-utsläppen. Trots de låga pHnivåerna i början av experimentet (pH 2), fanns ingen antydan om att citronsyran påverkademöjligheterna för tillväxt av liv, vilket öppnar för möjligheten att påskynda vittringen ännu mer iexperiment för bio-accelererad silikatvittring. Slutsatsen för projektet blir att citronsyra kan användasför att accelerera silikatvittring, och därmed användas för att motverka de stigande koldioxidutsläppen.Dock har tidigare forskning visat att vittring av olivin kan leda till en ackumulation av tungmetaller,vilket har gjort att andra silikater såsom basalt har blivit populära. Därför behövs mer undersökning föratt fullt förstå hur kombinationen av organisk syra och mikrober påverkar vittring av dunit och andrasilikatmineral samt ackumulation av tungmetaller i lakvatten och celler.

Water quality and space constraints have become major concerns regarding the No. 7 waste water dam at Petra Diamonds’ Cullinan mine. The unique location of the dam constrains further development, while unsustainable accumulation of waste water inside the dam increases the risk of potential environmental contamination from seepages and spillages. The dam retains a significant amount of very poor quality water. Its excessively high pH, dissolved salt content, density and extreme turbidity result from the concentration of natural weathering products of the diamond bearing kimberlite ore. The turbidity results from the dispersion of colloidal chlorite, saponite and nontronite clay. Along with the chemistry of the solution, their colloidal shape contributes equally significantly to the non-settlement of these suspended clays. Flocculation of the dispersed clay particles will provide (a) for easy and effective separation of the clay material from the waste water and (b) more convenient options for water treatment (and subsequent redistribution) This study was aimed at contributing to a better understanding of the dynamic interactions in the No 7 Dam system to contribute towards identifying a suitable means/method for chemical flocculation of the clay particles. The individual components of the system (clays, water quality) and influx contributors (kimberlite and its leachate) were systematically characterized by means of X-Ray Diffraction, X-Ray Fluorescence, petrographic microscopy, electron microscopy, electrophoretic mobility and standard water- and soil quality analyses. The baseline quality of the Cullinan kimberlite leachate was obtained based on ASTM D5744 principles. It was found that adjusting the pH-level and ionic strength of the waste water to the critical coagulation point (cK) (as determined by electrophoretic mobility and batch jar experiments) automatically induced coagulation. Higher valence cations were displaced from pH dependent surface charge sites by proton adsorption. The resultant increased ionic strength, in combination with decreased thickness of the ionic double layer, was sufficient for the automatic initiation of high strength disordered face-face and edge-face bonds. During batch Jar tests, flocculation initiated within 4 minutes after the addition of HCl (0.5 M) and total sedimentation completed within 3 hours. The use of commercial flocculants might decrease the sedimentation time. As expected a significant increase in dissolved salt content of the clear supernatant was observed. No re-dispersion of the dried clay occurred. Throughout the study geochemical modeling was performed with PHREEQC software to identify/determine possible effective experimental conditions, minimizing experimental time and expenses. The program was also used to model outcomes of the possible water treatment options, indicated in literature as viable options for similar situations. These options can be tested to extend upon the current research. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Water quality and space constraints have become major concerns regarding the No. 7 waste water dam at Petra Diamonds’ Cullinan mine. The unique location of the dam constrains further development, while unsustainable accumulation of waste water inside the dam increases the risk of potential environmental contamination from seepages and spillages. The dam retains a significant amount of very poor quality water. Its excessively high pH, dissolved salt content, density and extreme turbidity result from the concentration of natural weathering products of the diamond bearing kimberlite ore. The turbidity results from the dispersion of colloidal chlorite, saponite and nontronite clay. Along with the chemistry of the solution, their colloidal shape contributes equally significantly to the non-settlement of these suspended clays. Flocculation of the dispersed clay particles will provide (a) for easy and effective separation of the clay material from the waste water and (b) more convenient options for water treatment (and subsequent redistribution) This study was aimed at contributing to a better understanding of the dynamic interactions in the No 7 Dam system to contribute towards identifying a suitable means/method for chemical flocculation of the clay particles. The individual components of the system (clays, water quality) and influx contributors (kimberlite and its leachate) were systematically characterized by means of X-Ray Diffraction, X-Ray Fluorescence, petrographic microscopy, electron microscopy, electrophoretic mobility and standard water- and soil quality analyses. The baseline quality of the Cullinan kimberlite leachate was obtained based on ASTM D5744 principles. It was found that adjusting the pH-level and ionic strength of the waste water to the critical coagulation point (cK) (as determined by electrophoretic mobility and batch jar experiments) automatically induced coagulation. Higher valence cations were displaced from pH dependent surface charge sites by proton adsorption. The resultant increased ionic strength, in combination with decreased thickness of the ionic double layer, was sufficient for the automatic initiation of high strength disordered face-face and edge-face bonds. During batch Jar tests, flocculation initiated within 4 minutes after the addition of HCl (0.5 M) and total sedimentation completed within 3 hours. The use of commercial flocculants might decrease the sedimentation time. As expected a significant increase in dissolved salt content of the clear supernatant was observed. No re-dispersion of the dried clay occurred. Throughout the study geochemical modeling was performed with PHREEQC software to identify/determine possible effective experimental conditions, minimizing experimental time and expenses. The program was also used to model outcomes of the possible water treatment options, indicated in literature as viable options for similar situations. These options can be tested to extend upon the current research. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Dans la région de Dimbokro-Bongouanou (Centre Est de la Côte d'Ivoire), l'alimentation en eau des populations se fait essentiellement au moyen de puits et forages. Ceux-ci ont été implantés dans les aquifères du socle au cours des différentes campagnes d'hydraulique villageoise mises en place dans ce secteur. L'analyse du taux de réussite et de la productivité de ces forages montre que leur implantation n'a pas toujours été optimale. Afin d'optimiser l'implantation de nouveaux forages, il semble donc nécessaire et primordial de caractériser l'hydrodynamique du socle fracturé. A cette fin, la présente étude procède d'abord à une caractérisation géologique puis hydrogéologique de la région de Dimbokro-Bongouanou. Ensuite, sont élaborés des modèles conceptuels géologiques et hydrogéologiques, qui décrivent la structure de l'aquifère et précisent les propriétés hydrodynamiques de ses différentes couches composites. Ces modèles géologiques et hydrogéologiques permettent de simuler numériquement l'écoulement régional. La caractérisation géologique de la région de Dimbokro-Bongouanou est basée sur une description des différentes formations géologiques de la région ; des hypothèses sur leur mise en place et les cycles d'érosion et d'altération qu'elles ont subis ; et une cartographie des discontinuités régionales par photo-interprétation d'image Radar rehaussée par la technique de filtrages adaptatifs. Les discontinuités identifiées sur l'image rehaussée sont validées à partir d'informations géologiques (données de fracturation mesurées à l'affleurement et données de fracturation relevées sur carte géologique).La caractérisation hydrogéologique de la région de Dimbokro-Bongouanou est basée sur la description des aquifères de la région et l'identification du rôle des discontinuités régionales dans les écoulements souterrains. La technique proposée à cet effet consiste à analyser les corrélations entre le débit des forages et leur distance au linéament le plus proche.Il est ainsi constaté que le débit des forages est inversement proportionnel à la distance à la discontinuité la plus proche. En d'autres termes, plus le forage est proche d'une discontinuité régionale, plus son débit est important. L'interprétation des lithologs, des données géologiques à l'affleurement et des données de résistivités électriques permet de proposer un modèle conceptuel géologique représentatif du profil d'altération type pour chaque domaine géologique de la région. En particulier, le modèle proposé décrit la structuration verticale du profil d'altération pour les trois principales formations géologiques de la région: les granites, les métasédiments et les métavolcanites. La caractérisation de la structure de l'aquifère permet ensuite de proposer un modèle conceptuel hydrogéologique pour chacun des profils d'altération basé sur l'analyse statistique des arrivées d'eau et de l'interprétation des données d'essais par pompage de différents forages. Cela permet d'identifier pour chaque formation les profondeurs de fréquence, de densité et de débit des arrivées d'eau ainsi que les couches du profil associées aux zones de conductivité et de productivité (débit spécifique) élevées.L'ensemble de ces informations géologiques et hydrogéologiques permet de proposer une modélisation conceptuelle de l'hydrosystème étudié (une partie du Bassin du NZI,environ 6300km2) ainsi qu'une modélisation numériques de l'écoulement, celle-ci servant de base à une réflexion sur la pertinence de l'information disponible et d'une modélisation discrète dans ce type d'environnement au vu des objectifs affichés (modèle de gestion et d'aide à la décision pour l'implantation de nouveaux forages). / The hydraulic characterization of fractured basement in Dimbokro-Bongouanou region, Côte d'Ivoire, is an essential step to achieve an optimization of new well locations, in terms of success rates and productivity.To this end, this study first proposes conceptual models of weathering profile for the three main geological formations of the region: granites, metasediments and metavolcanic rocks. Based on in-situ observations, interpretations of lithology and cycles of erosion and alteration, the typical weathering profiles are proposed for each type geological. These are formed from top to bottom of layers alloterite, isalterite, fissured and fractured fresh basement. The fissured layer shows the maximum density of fractures in the metavolcanic rocks and métasédiments, while the fractured fresh basement concentrates the highest density of fractures in granites. Moreover, interpretation of data from pumping tests conducted in various hydraulic programs indicate that the productivity of wells is not proportional to the depth due to variation, at region scale of the thickness of the fissured layer and fractured fresh basement which totalize the maximum of water arrivals. The spatial variation of hydraulic conductivity and productivity (specific rate) is influenced by the thickness of the fissured layer, alloterite layer of the weathering profile and topography. The regional fractures of the fractured fresh basement are also areas of high productivity, as evidenced by the negative correlation between rate of productive wells and distance to these fractures. A methodology of regional fractures mapping from the use of a Radar image and hydrogeological data is suggested.All of these geological and hydrogeological informations are finally integrated into a flow model and the simulated groundwater levels are compared with measured piezometric. It thus appears that the values of hydraulic conductivities deduced from pumping tests are 103 times lower than those that reproduce the regional flow. In addition, a dual approach (equivalent continuum for alterite layer and fissured layer vs. discrete fracture of the base) confirms the role of accidents in the regional flows.

Use of greisen - a rock mined primarily for (Sn-W) ore components - in sculpture and construction industry is typical for the Slavkovský les area and its surroundings. Material mined in the greisenized granite stock near Prameny for construction purposes was the source of stone used for a valuable Baroque sight - the Holy Trinity column in a nearby town of Teplá. Samples collected in the abandoned construction stone quarry were analysed for the study of properties of the original material mined in the locality Prameny. These samples were compared with the material collected from the monument in the pre-restoration research to prove the source locality of the original material. Provenance of the original material was determined on the basis of qualitative and quantitative petrographic and micro-structural characteristics. Micro-structural petrographic parameters of the studied samples were determined by the microscopic study using the Petrographic Image Analysis (PIA). Distribution of accessories and micro-structural characteristics were observed using the cathode-luminescence. Conventional index and mechanical parameters with respect to the use of the material in construction industry and sculpture were determined for the material collected in the abandoned quarry. Studied material collected in the...