Este trabalho apresenta a quantificação da expansão e suas características, principalmente a influência da sucção, em amostras de materiais sedimentares argilosos provenientes da Formação Corumbataí, aflorantes no interior do estado de São Paulo. Foram testadas amostras indeformadas, e amostras destorroadas e compactadas em diferentes umidades, em ensaios de pressão de expansão a volume constante por inundação, e também, com sucção controlada por meio da técnica da transferência de vapor. Foram ensaiadas, ainda, misturas compactadas desse material com bentonita em diferentes proporções, e misturas de bentonita com material não expansivo arenoso oriundo da Formação Botucatu. O controle de sucção foi realizado pelo uso de soluções salinas de NaCl em concentrações preparadas para impor sucções de 40.000, 25.000, 10.000 e 5.000 kPa. Para a realização dos ensaios, construiu-se um sistema de aplicação de cargas e de aquisição automática dos dados de pressão. Para acelerar o processo de umedecimento por vapor, utilizou-se um reservatório externo ligado em uma bomba de ar adaptada para promover a circulação do vapor de ar para dentro da célula edométrica, especialmente construída para esta pesquisa. Os resultados de expansão nos ensaios com inundação mostraram pressões de expansão crescentes com a diminuição dos teores de umidade, e consequente aumento da sucção inicial das amostras ensaiadas, bem como crescentes com o aumento na proporção de bentonita nas misturas, com valores máximos em torno de 700 kPa para o ensaio com a bentonita pura compactada seca. A análise da microestrutura das amostras por meio da porosimetria por intrusão de mercúrio permitiu constatar que as amostras indeformadas apresentaram variação, apenas, nos macroporos após a expansão; e as compactadas na umidade ótima e, posteriormente secas ao ar, não mostraram evolução significativa após a expansão. Na microscopia eletrônica de varredura (MEV) foi possível verificar a mudança nos vazios das amostras, bem como, visualizar a variação na estrutura e na textura. Além disso, no MEV foram confirmados, também, os argilominerais determinados na caracterização mineralógica. Os resultados dos ensaios de expansão com sucção controlada mostraram ausência de pressão de expansão para as amostras da Formação Corumbataí nas condições indeformada, e na condição compactada na umidade ótima e posteriormente seca ao ar. No entanto, esse material, quando compactado seco na forma de pó, e também, compactado seco misturado com bentonita em diferentes proporções, revelou pressões de expansão com a transferência de vapor, assim como, as misturas de bentonita com material não expansivo da Formação Botucatu. A ausência de expansão foi justificada pela forma lenta de umedecimento proporcionada pela transferência de vapor que, apesar de promover o aumento do teor de umidade das amostras, não mobilizou variação volumétrica suficientemente capaz de transmitir como pressão de expansão. Portanto, os ensaios de expansão, com a utilização da técnica de transferência de vapor, foram efetivos para avaliar a expansão somente nos casos em que argilominerais com potencial expansivo estavam presentes em proporções consideráveis. / This thesis presents the quantification and characterization of expansion, especially the influence of suction on samples of sedimentary materials from Corumbatai Formation that occurs in Sao Paulo. Undisturbed and compacted samples with different moisture contents were tested with swelling pressure tests at constant volume method by flooding, and also with suction control by vapour transfer technique. Compacted mixtures of this material with bentonite in differents proportions, and mixtures of bentonite with sandy non-expansive material from the Botucatu Formation were also tested. The suction control was performed by the use of NaCl salt solutions at concentrations prepared to perform 40,000, 25,000, 10,000 and 5,000 kPa suctions. For the tests, it was developed a system for load application and automatic retrieval of pressure. To accelerate the wetting process by vapour, we used an external reservoir connected to an air pump adapted to promote air circulation inside the edometric cell, specially made for this study. The expansion results in flooding tests showed increasing swelling pressure with decreasing moisture content. Consequently there was an increase in the initial suction of the tested samples, which kept increasing as the rate of bentonite was raised in the mixtures, with a peak of ca. 700 kPa for the test with dry pure bentonite compacted. In the microstructure analysis of the samples by mercury intrusion porosimetry, the samples showed variation only in macropores after swell; and the ones compacted at optimum moisture, and subsequently air dried, showed no significant change after the swell. In scanning electron microscopy (SEM) it was possible to verify the change in the voids of the samples, as well as to visualize the variation in the structure and texture. In addition, the SEM confirmed clay minerals deterninated in mineralogical characterization. The results of controlled suction with swell tests showed absence of swell pressure for Corumbatai samples tested in undisturbed conditions, and compacted condition at optimum moisture content, and then air dried. However, when compacted in the form of dry powder, as well as when compacted dry, mixed with different proportions of bentonite, this material showed swelling pressures with vapor transfer technique, as well as mixtures of bentonite with non-expansive material of Botucatu Formation. The absence of swell was explained by the slow damping provided by the vapor transfer that although promoting increasing dampen, did not sufficiently mobilized volume variation capable of transmitting blowing pressure. Therefore, the swell tests with the vapor transfer technique were effective to evaluate the swelling just in cases where clay minerals with swell potential were present in significant proportions.

Late Pleistocene sediments recovered from ODP Leg 175, Site 1085 are used to generate a high-resolution (500 yr) record of continental climate change in Southern Africa. The location of Site 1085, the SW African continental slope, provides a continuous hemipelagic section with a significant terrigenous component. Terrigenous sediments are transported via fluvial and/or eolian transport mechanisms with MIS 1 being dominated by eolian transport. Analyses, including grain-size, color reflectance, biogenic sediment geochemistry (%CaCO3, %TOC, and C/N), bulk sediment geochemistry, and clay mineralogy, are used to identify continental climate conditions in southern Africa. Analyses indicate glacial/interglacial variation. Median grain-size peaks are associated with changes in transport. Clay mineralogy indicates the presence of kaolinite, smectite, and illite in varying percentages. Smectite and illite dominate the clay mineral assemblages except during MIS 2. Maximum kaolinite was found during MIS 2 and is associated with poleward transport by the Angola Counter Current.

The purpose of this study is to understand mineral diagenesis authigenic mineral and the effect of climate on mineral of Pleistocene-Holocene sediment deposits in the Southern Kenya Rift. Lake Magadi unique geologic settings are characterized by extreme alkalinity and high silica activities. The mineralogical analysis was achieved by X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM) applications. The bulk mineralogy (quartz, halite, calcite) is the same on all localities due to similar volcaniclastics compositions throughout the Kenya Rift Valley. The clay mineralogy significantly differ among the groups of sample localities. The differences reflect different tectonic settings and ambient climate regime. In humid climate at higher elevation detrital clay minerals are abundant (feldspars, phillipsite). At lower elevation like Lake Magadi, the clay fractions dominated by authigenic minerals (zeolites and silicate minerals found with zeolites). These results show the potential of clay minerals as terrestrial climate proxies.

Este trabalho apresenta a quantificação da expansão e suas características, principalmente a influência da sucção, em amostras de materiais sedimentares argilosos provenientes da Formação Corumbataí, aflorantes no interior do estado de São Paulo. Foram testadas amostras indeformadas, e amostras destorroadas e compactadas em diferentes umidades, em ensaios de pressão de expansão a volume constante por inundação, e também, com sucção controlada por meio da técnica da transferência de vapor. Foram ensaiadas, ainda, misturas compactadas desse material com bentonita em diferentes proporções, e misturas de bentonita com material não expansivo arenoso oriundo da Formação Botucatu. O controle de sucção foi realizado pelo uso de soluções salinas de NaCl em concentrações preparadas para impor sucções de 40.000, 25.000, 10.000 e 5.000 kPa. Para a realização dos ensaios, construiu-se um sistema de aplicação de cargas e de aquisição automática dos dados de pressão. Para acelerar o processo de umedecimento por vapor, utilizou-se um reservatório externo ligado em uma bomba de ar adaptada para promover a circulação do vapor de ar para dentro da célula edométrica, especialmente construída para esta pesquisa. Os resultados de expansão nos ensaios com inundação mostraram pressões de expansão crescentes com a diminuição dos teores de umidade, e consequente aumento da sucção inicial das amostras ensaiadas, bem como crescentes com o aumento na proporção de bentonita nas misturas, com valores máximos em torno de 700 kPa para o ensaio com a bentonita pura compactada seca. A análise da microestrutura das amostras por meio da porosimetria por intrusão de mercúrio permitiu constatar que as amostras indeformadas apresentaram variação, apenas, nos macroporos após a expansão; e as compactadas na umidade ótima e, posteriormente secas ao ar, não mostraram evolução significativa após a expansão. Na microscopia eletrônica de varredura (MEV) foi possível verificar a mudança nos vazios das amostras, bem como, visualizar a variação na estrutura e na textura. Além disso, no MEV foram confirmados, também, os argilominerais determinados na caracterização mineralógica. Os resultados dos ensaios de expansão com sucção controlada mostraram ausência de pressão de expansão para as amostras da Formação Corumbataí nas condições indeformada, e na condição compactada na umidade ótima e posteriormente seca ao ar. No entanto, esse material, quando compactado seco na forma de pó, e também, compactado seco misturado com bentonita em diferentes proporções, revelou pressões de expansão com a transferência de vapor, assim como, as misturas de bentonita com material não expansivo da Formação Botucatu. A ausência de expansão foi justificada pela forma lenta de umedecimento proporcionada pela transferência de vapor que, apesar de promover o aumento do teor de umidade das amostras, não mobilizou variação volumétrica suficientemente capaz de transmitir como pressão de expansão. Portanto, os ensaios de expansão, com a utilização da técnica de transferência de vapor, foram efetivos para avaliar a expansão somente nos casos em que argilominerais com potencial expansivo estavam presentes em proporções consideráveis. / This thesis presents the quantification and characterization of expansion, especially the influence of suction on samples of sedimentary materials from Corumbatai Formation that occurs in Sao Paulo. Undisturbed and compacted samples with different moisture contents were tested with swelling pressure tests at constant volume method by flooding, and also with suction control by vapour transfer technique. Compacted mixtures of this material with bentonite in differents proportions, and mixtures of bentonite with sandy non-expansive material from the Botucatu Formation were also tested. The suction control was performed by the use of NaCl salt solutions at concentrations prepared to perform 40,000, 25,000, 10,000 and 5,000 kPa suctions. For the tests, it was developed a system for load application and automatic retrieval of pressure. To accelerate the wetting process by vapour, we used an external reservoir connected to an air pump adapted to promote air circulation inside the edometric cell, specially made for this study. The expansion results in flooding tests showed increasing swelling pressure with decreasing moisture content. Consequently there was an increase in the initial suction of the tested samples, which kept increasing as the rate of bentonite was raised in the mixtures, with a peak of ca. 700 kPa for the test with dry pure bentonite compacted. In the microstructure analysis of the samples by mercury intrusion porosimetry, the samples showed variation only in macropores after swell; and the ones compacted at optimum moisture, and subsequently air dried, showed no significant change after the swell. In scanning electron microscopy (SEM) it was possible to verify the change in the voids of the samples, as well as to visualize the variation in the structure and texture. In addition, the SEM confirmed clay minerals deterninated in mineralogical characterization. The results of controlled suction with swell tests showed absence of swell pressure for Corumbatai samples tested in undisturbed conditions, and compacted condition at optimum moisture content, and then air dried. However, when compacted in the form of dry powder, as well as when compacted dry, mixed with different proportions of bentonite, this material showed swelling pressures with vapor transfer technique, as well as mixtures of bentonite with non-expansive material of Botucatu Formation. The absence of swell was explained by the slow damping provided by the vapor transfer that although promoting increasing dampen, did not sufficiently mobilized volume variation capable of transmitting blowing pressure. Therefore, the swell tests with the vapor transfer technique were effective to evaluate the swelling just in cases where clay minerals with swell potential were present in significant proportions.

The Yazoo Clay is a calcareous fossiliferous mudrock that outcrops in a northwest-southeast belt across much of Mississippi and in adjacent states. Based on over 240 X-ray diffraction analyses, the average composition of the Yazoo Clay is 28% smectite, 24% kaolinite, 22% quartz, 15% calcite, 8% illite, 2% feldspar, and 1% gypsum. Exposed Yazoo clay is weathered to a depth of 30-40 ft. and has a distinctive yellow/brown color; unweathered Yazoo is blue/gray. In most wells, smectite is more abundant in weathered clay than in unweathered clay. Mineralogic changes correlate well with engineering properties of the samples, which in general show a decrease in plasticity indices with depth. Weathered Yazoo clay exhibits greater mineralogic variability than unweathered clay. Mineralogical content also varies laterally. Lateral variation, along with correlative smectite content and engineering properties, is the reason for ?roller coaster? roadways and structural damage caused by the swelling Yazoo Clay.

No description available.

Master of Science / Department of Agronomy / Michel D. Ransom / Many soils in southeastern Kansas are characterized by high clay contents and high shrink-swell potentials. Their vertic properties and claypan characteristics cause soil management to be difficult and pose problems for agricultural, environmental, and engineering uses. Thus, collecting more information and improving our understanding of these soils is an important step towards bettering our soil management techniques. The objectives of this study were to examine the morphology, processes of soil genesis, clay mineralogy, micromorphology, and potassium fixation potential of the soils of interest and how these characteristics varied between and within individual pedons. Ten pedons expected to represent varying degrees of vertic expression were selected. Methods included the use of field descriptions, routine soil laboratory characterization, micromorphological investigations, the determination of clay mineralogy by X-ray diffraction, and the measurement of potassium fixation potential. Field morphology reflected the geologic parent materials available in the region. The fine sediments that compose these clayey soils are primarily provided by the Pennsylvanian and Permian shales and limestones underlying this region and the Flint Hills to the west. Dominant pedogenic processes currently at work are clay illuviation and shrink-swell processes. Silty, non-expansive surface soils at all but sites 6 and 7 are thought to buffer the rapid wetting and drying cycles needed for maximum vertic expression. Four of the soils were dominated by smectitic minerals in the clay fraction while the rest exhibited a more mixed mineralogy. Disruption of illuvial clay features by shrink-swell movement was evident in thin section. Striated b-fabrics dominated the micromorphology except in non-expansive surface soils. K fixation of the soil surface was found to be negative in all soils, thus K fixation potential is considered very low. In subsurface horizons, K fixation generally increased with increasing vermiculite content. In addition to limited quantities of K-fixing clay minerals, naturally high K levels limited the amount of K fixation in this study. The information presented can be used to improve our understanding and management of high clay, vertic and claypan soils in southeastern Kansas.

Master of Science / Department of Agronomy / Michel D. Ransom / Factors governing potassium fixation and release are poorly understood. This study was conducted to investigate the effects of clay mineralogy and structural iron oxidation state on potassium fixation. Five reference clays and two soil clays were used to capture a range in mineralogical compositions and potassium behaviors. Reference clays used were illite (IMt-1), kaolinite (KGa-1b), montmorillonite (STx-1b), nontronite (NAu-2), and vermiculite (VTx-1). Soil clays used were from the upper 15 cm of a Belvue loam (BEL) and a Cherokee silt (CHE). Potassium fixation capacities were measured on unaltered as well as sodium dithionite reduced forms of each clay. Ferrous and total iron contents were determined photometrically using 1, 10-phenanthroline. Potassium fixation was measured by potassium saturating the clays and washing off exchangeable and solution potassium with solutions of magnesium chloride; samples were then acid digested and the amount fixed was calculated as the amount of potassium in the acid digestion minus the amount originally in the sample. BEL released potassium rather than fixed it while CHE tended to release potassium in the unaltered form and fix potassium in the reduced form. Structural iron reduction significantly impacted the amounts of potassium fixed by VTx-1 and NAu-2, which had the highest total iron contents of all the clays evaluated. NAu-2 and VTx-1 both on average fixed less than 1 mg K g clay[superscript]-1 in the unaltered form and an average of 6 and 11 mg K g clay[superscript]-1, respectively, in the reduced form. Regardless of being in the unaltered or reduced form, KGa-1b fixed essentially no potassium and IMt-1 and STx-1b fixed intermediate amounts of potassium—2 to 4 mg K g clay[superscript]-1 on average. The effects of clay mineralogy and structural iron oxidation state on potassium fixation can largely be explained through an understanding of layer type, layer charge, and charge distribution. In order for potassium fixation to occur, interlayer sites need to be accessible and available. Generally, the greater the negative layer charge the greater the amounts of fixation, with tetrahedral layer charge favoring fixation more than octahedral layer charge, and layer charge being a function of structural iron oxidation state.

An integrated micropaleontological, mineralogical and sequence stratigraphical investigation was carried out across the Cretaceous/Paleogene (K/P) boundary in the Haymana basin, Turkey. A 29.41 m thick boundary section consisting of limestones and marls was measured and 90 samples were analyzed. Biostratigraphic and chronostratigraphic works are based on the planktonic foraminifera. 64 planktonic species were identified and 5 biozones were established. The biozones are, in ascending order, Planoglobulina acervulinoides zone, Racemiguembelina fructicosa zone, Pseudoguembelina hariaensis zone for the Late Maastrichtian / Guembelitria cretacea (P0) zone and Parvulorugoglobigerina eugubina (P1a) zone for the Early Danian. In order to detect the mineralogical changes across the boundary bulk and clay minerals were analyzed using X-ray diffractometry (XRD). Calcite, quartz,feldspar and the clay minerals composed of smectite (montmorillonite) and chlorite are the main components of the rocks. A decrease in calcite and an increase in the detrital minerals (quartz, feldspar) and the clay minerals were detected in the boundary beds. In order to find out the depositional history of the area a detailed microfacies study was performed and 10 microfacies type were determined. The microfacies types defined correspond to slope to basin environment. Based on microfacies analyses, the sequence stratigraphic framework of the boundary beds was constructed. K/P boundary beds were recorded in the transition of transgressive systems tract to highstand systems tract, coinciding with a maximum flooding surface. These beds show a similar pattern with many other K/P boundary beds in different locations of the world indicating eustatic sealevel variations overprint the tectonic control in the basin.

Kirka Boron Plant in Eski