Esta tese apresenta um estudo com base em zoneamentos de parâmetros geotécnicos provenientes de sondagens rotativas, realizadas no maciço basáltico, localizado na área das obras de Usina Hidrelétrica de Itaipu (Foz do Iguaçu - PR). Estes zoneamentos foram realizados a partir de interpolação dos dados por meio de krigagem ordinária e equações multiquádricas. Os dados provenientes de sondagens rotativas analisados nesta pesquisa são: Rock Quality Designation (RQD), grau de alteração, grau de consistência e grau de fraturamento. Os métodos de interpolação foram avaliados para o parâmetro de RQD, pois tais métodos apresentam características matemáticas similares, assim, foram comparadas interpolações realizadas com krigagem ordinária e equações multiquádricas, sendo comprovada a similaridade destes métodos com dados reais. Sendo assim, os demais parâmetros, por se caracterizarem como variáveis categóricas e, portanto, discretas, e apresentarem complexidade para realização da análise variográfica dos dados (semivariograma experimental e modelagem do semivariograma), foram interpolados apenas pelo método das equações multiquádricas. A validação dos dados interpolados foi realizada a partir de um estudo de caso relativo ao comportamento hidrogeotécnico do maciço rochoso, o qual é monitorado por piezômetros do tipo standpipe. Esta validação mostrou que os métodos utilizados para obter os zoneamentos e os parâmetros de modelagem considerados foram adequados, pois se verificou alta correlação entre as tendências de comportamento obtidas pelas interpolações dos parâmetros geotécnicos do maciço rochoso e o comportamento revelado pelo conjunto de piezômetros instalados no mesmo local. Este trabalho teve como etapa primordial o levantamento de dados históricos relativos às investigações geológico-geotécnicas da área das obras de Itaipu, a partir destes dados foi composto um mapa interativo de localização dos diferentes tipos de investigação realizados no substrato rochoso e terroso. Tal documento permite uma busca rápida e dinâmica das informações geotécnicas, pois apresenta como referência a própria planta da barragem de Itaipu. Cada ponto de investigação está vinculado ao perfil geotécnico. As investigações utilizadas neste mapa são: sondagem rotativa, sondagem à percussão (SPT), ensaio de cone (CPT) e poço manual. Sendo assim, o resgate das informações históricas obtidas nas campanhas de investigação geotécnica na área das obras de Itaipu, resultou na compilação dos dados de forma digital, em que foi elaborado um conjunto de planilhas com formato capaz de ser utilizado em diferentes Sistemas de Informação Geográfica e de interpolação de dados georreferenciados. / This thesis presents a study based on the zoning of geotechnical parameters resulting from core boring, carried out in the basaltic bedrock located in the area of the Itaipu Hydroelectric Power Plant (Foz do Iguaçu - PR). These zonings were carried out based on the interpolation of the data by means of ordinary kriging and multiquadric equations. The data provided by core boring analyzed in this research are: Rock Quality Designation (RDQ), degree of alteration, degree of consistency and degree of fracturing. The interpolation methods were evaluated for the RQD parameter, since such methods present similar mathematical characteristics; therefore, comparisons were made between interpolations resulting from ordinary kriging and multiquadric equations, demonstrating the similarity of these methods with real data. In this manner, the remaining parameters due to being categorized as categorical variables and, therefore, discrete, and presenting complexity for the execution of the variographic analysis of the data (experimental semi-variogram and modeling of the semi-variogram), were interpolated only by the method of the multiquadric equations. The validation of the interpolated data was carried out on the basis of a case study relating to the hydrogeotechnical behavior of the bedrock mass, which is monitored by standpipe piezometers. This validation showed that the methods employed to obtain the zonings and the modeling parameters chosen were adequate, since a high correlation was verified between the behavior trends obtained by the interpolations of the geotechnical parameters of the bedrock mass and the behavior revealed by the set of piezometers installed in the same site. The primordial stage of this job was the acquisition of historical data relating to the geological-geotechnical investigations in the area of Itaipu Dam. This data served as a starting point for the composition of an interactive map showing the location of the different types of investigations carried out in the rock and earthen masses. The resulting document permit a rapid and dynamic search through the geotechnical information, since it presents as its reference the plan view of the Itaipu dam itself. Each point of investigation is linked to the geotechnical profile. The investigations utilized in this map are: core boring, standard penetration test (SPT), cone penetration test (CPT) and manual pit. In this manner, the recovery of the historical information obtained by the geotechnical investigation the Itaipu Dam area resulted in data compilations in digital format, based upon which, a set of tabular forms was obtained of a type capable of being utilized in different Systems of Geographical Information and of interpolation of geo-referenced data.

Esta tese apresenta um estudo com base em zoneamentos de parâmetros geotécnicos provenientes de sondagens rotativas, realizadas no maciço basáltico, localizado na área das obras de Usina Hidrelétrica de Itaipu (Foz do Iguaçu - PR). Estes zoneamentos foram realizados a partir de interpolação dos dados por meio de krigagem ordinária e equações multiquádricas. Os dados provenientes de sondagens rotativas analisados nesta pesquisa são: Rock Quality Designation (RQD), grau de alteração, grau de consistência e grau de fraturamento. Os métodos de interpolação foram avaliados para o parâmetro de RQD, pois tais métodos apresentam características matemáticas similares, assim, foram comparadas interpolações realizadas com krigagem ordinária e equações multiquádricas, sendo comprovada a similaridade destes métodos com dados reais. Sendo assim, os demais parâmetros, por se caracterizarem como variáveis categóricas e, portanto, discretas, e apresentarem complexidade para realização da análise variográfica dos dados (semivariograma experimental e modelagem do semivariograma), foram interpolados apenas pelo método das equações multiquádricas. A validação dos dados interpolados foi realizada a partir de um estudo de caso relativo ao comportamento hidrogeotécnico do maciço rochoso, o qual é monitorado por piezômetros do tipo standpipe. Esta validação mostrou que os métodos utilizados para obter os zoneamentos e os parâmetros de modelagem considerados foram adequados, pois se verificou alta correlação entre as tendências de comportamento obtidas pelas interpolações dos parâmetros geotécnicos do maciço rochoso e o comportamento revelado pelo conjunto de piezômetros instalados no mesmo local. Este trabalho teve como etapa primordial o levantamento de dados históricos relativos às investigações geológico-geotécnicas da área das obras de Itaipu, a partir destes dados foi composto um mapa interativo de localização dos diferentes tipos de investigação realizados no substrato rochoso e terroso. Tal documento permite uma busca rápida e dinâmica das informações geotécnicas, pois apresenta como referência a própria planta da barragem de Itaipu. Cada ponto de investigação está vinculado ao perfil geotécnico. As investigações utilizadas neste mapa são: sondagem rotativa, sondagem à percussão (SPT), ensaio de cone (CPT) e poço manual. Sendo assim, o resgate das informações históricas obtidas nas campanhas de investigação geotécnica na área das obras de Itaipu, resultou na compilação dos dados de forma digital, em que foi elaborado um conjunto de planilhas com formato capaz de ser utilizado em diferentes Sistemas de Informação Geográfica e de interpolação de dados georreferenciados. / This thesis presents a study based on the zoning of geotechnical parameters resulting from core boring, carried out in the basaltic bedrock located in the area of the Itaipu Hydroelectric Power Plant (Foz do Iguaçu - PR). These zonings were carried out based on the interpolation of the data by means of ordinary kriging and multiquadric equations. The data provided by core boring analyzed in this research are: Rock Quality Designation (RDQ), degree of alteration, degree of consistency and degree of fracturing. The interpolation methods were evaluated for the RQD parameter, since such methods present similar mathematical characteristics; therefore, comparisons were made between interpolations resulting from ordinary kriging and multiquadric equations, demonstrating the similarity of these methods with real data. In this manner, the remaining parameters due to being categorized as categorical variables and, therefore, discrete, and presenting complexity for the execution of the variographic analysis of the data (experimental semi-variogram and modeling of the semi-variogram), were interpolated only by the method of the multiquadric equations. The validation of the interpolated data was carried out on the basis of a case study relating to the hydrogeotechnical behavior of the bedrock mass, which is monitored by standpipe piezometers. This validation showed that the methods employed to obtain the zonings and the modeling parameters chosen were adequate, since a high correlation was verified between the behavior trends obtained by the interpolations of the geotechnical parameters of the bedrock mass and the behavior revealed by the set of piezometers installed in the same site. The primordial stage of this job was the acquisition of historical data relating to the geological-geotechnical investigations in the area of Itaipu Dam. This data served as a starting point for the composition of an interactive map showing the location of the different types of investigations carried out in the rock and earthen masses. The resulting document permit a rapid and dynamic search through the geotechnical information, since it presents as its reference the plan view of the Itaipu dam itself. Each point of investigation is linked to the geotechnical profile. The investigations utilized in this map are: core boring, standard penetration test (SPT), cone penetration test (CPT) and manual pit. In this manner, the recovery of the historical information obtained by the geotechnical investigation the Itaipu Dam area resulted in data compilations in digital format, based upon which, a set of tabular forms was obtained of a type capable of being utilized in different Systems of Geographical Information and of interpolation of geo-referenced data.

Abstract not available

The development of composite materials by combining two or more constituents with improved mechanical properties, when compared to either of the constituents alone, has existed since biblical times when straw or horse hair was mixed with clay or mud to produce bricks. During the second half of the twentieth century, modern composites known as fiber reinforced polymers (FRP) - consisting of a reinforcing phase (fibers) embedded into a matrix (polymeric resin or binder) - were developed to meet the performance challenges of space exploration and air travel. With time, externally-bonded FRP applications for strengthening of reinforced concrete (RC) structures gained popularity within the construction industry. To date, the confinement of RC columns using FRP systems is a convenient and well established solution to strengthen, repair and retrofit structural concrete members. This technology has become mainstream due to its cost effectiveness, and relative ease and speed of application with respect to alternative rehabilitation techniques such as steel or concrete jackets. However, significant margins exist to advance externally-bonded composite rehabilitation technologies by addressing economic, technological, and environmental issues posed by the use of organic polymer matrices, some of which are addressed in this dissertation. Articulated in three studies, the dissertation investigates the development of a sustainable, reversible, and compatible fiber reinforced cement-based matrix (FRC) composite system for concrete confinement applications in combination with a novel test method aimed at characterizing composites under hydrostatic pressure. Study 1 develops and characterizes a FRC system from different fiber and inorganic matrix combinations, while evaluating the confinement effectiveness in comparison to a conventional FRP system. The feasibility of making the application reversible was investigated by introducing a bond breaker between the concrete substrate and the composite jacket in a series of confined cylinders. The prototype FRC system produced a substantial increase in strength and deformability with respect to unconfined cylinders. A superior deformability was attained without the use of a bond breaker. The predominant failure mode was loss of compatibility due to fiber-matrix separation, which points to the need of improving fiber impregnation to enable a more efficient use of the constituent materials. Additionally semi-empirical linear and nonlinear models for ultimate compressive strength and deformation in FRC-confined concrete are also investigated. Study 2 compares through a life cycle assessment (LCA) method two retrofitting strategies: a conventional organic-based, with the developed inorganic-based composite system presented in Study 1, applied to concrete cylinders by analyzing three life cycle impact indicators: i) Volatile Organic Compound (VOC) emissions, ii) embodied energy, and, iii) carbon foot print. Overall the cement-based composite provides an environmentally-benign alternative over polymer-based composite strengthening system. Results also provide quantitative information regarding the environmental and health impacts to aid with the decision-making process of design when selecting composite strengthening systems. Study 3 is divided into two parts, Part A presents the development of a novel "Investigation of Circumferential-strain Experimental" (ICE) methodology for characterization of circumferential (hoop) strain of composite laminates, while Part B uses the experimental data reported in Part A to explicitly evaluate the effect of FRP jacket curvature and laminate thickness on strain efficiency. Results showed that the proposed ICE methodology is simple, effective and reliable. Additionally, the ultimate circumferential strain values increased with increasing cylinder diameter, while being consistently lower when compared to similar flat coupon specimens under the same conditions. The ultimate FRP tensile strain was found to be a function of the radius of curvature and laminate thickness, for a given fiber ply density and number. The effect of these findings over current design guidelines for FRP confined concrete was also discussed.

Volatiles are a fundamental component of the Magmatic-Hydrothermal model of platinum group element (PGE) ore deposition for PGE deposits in layered mafic intrusions such as Bushveld and Stillwater. Volatiles have the potential to complex with PGEs in silicate melts and hydrothermal fluids, increasing PGE solubility; in order to assess the models of PGE ore deposition reliable estimates on the solubilities in the various magmatic phases must be known. However, experimental studies on the solubility and partitioning behaviour of PGEs in mafic magmatic-hydrothermal systems under relevant conditions are sparse, and the data that do exist produce conflicting results and new or adapted experimental methods must be applied to investigate these systems. Experimental results are presented here, investigating the effect of volatiles (i.e. H2O, Cl and CO2) on Pt and Ir solubility in a haplobasaltic melt and fluid-melt partitioning of Pt between an aqueous fluid and a haplobasaltic melt under magmatic conditions using a sealed-capsule technique. Also included are the details of the development of a novel experimental technique to observe fluid-melt partitioning in mafic systems and application of the method to the fluid-melt partition of Pt. Solubility experiments were conducted to assess the effect of volatiles on Pt and Ir solubility in a haplobasaltic melt of dry diopside-anorthite eutectic composition at 1523K and 0.2GPa. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42-Di58) haplobasalt composition was sealed in a platinum or platinum-iridium alloy capsule and was allowed to equilibrate with the noble metal capsule and a source of volatiles (i.e. H2O, H2O-Cl or H2O-CO2) at experimental conditions. All experiments were run in an internally-heated pressure vessel equipped with a rapid quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). The resultant crystal- and bubble-free run product glasses were analyzed using a combination of laser ablation ICP-MS and bulk solution isotope-dilution ICP-MS to determine equilibrium solubilities of Pt and Ir and investigate the formation and contribution of micronuggets to overall bulk determined concentrations. In water-bearing experiments, it was determined that water content did not have an intrinsic effect on Pt or Ir solubility for water contents between 0.9 wt. % and 4.4 wt. % (saturation). Water content controlled the oxygen fugacity of the experiment and the resulting variations in oxygen fugacity, and the corresponding solubilities of Pt and Ir, indicate that over geologically relevant conditions both Pt and Ir are dissolved primarily in the 2+ valence state. Pt data suggest minor influence of Pt4+ at higher oxygen fugacities; however, there is no evidence of higher valence states for Ir. The ability of the sealed capsule technique to produce micronugget-free run product glasses in water-only experiments, allowed the solubility of Pt to be determined in hydrous haplobasalt at lower oxygen fugacities (and concentrations) then was previously observed. Pt and Ir solubility can be represented as a function of oxygen fugacity (bars) by the following equations: [Pt](ppb)= 1389(fO-sub-2)+7531(fO-sub-2)^(1/2) [Ir](ppb)=17140(fO-sub-2)^(1/2) In Cl-bearing experiments, experimental products from short run duration (<96hrs) experiments contained numerous micronuggets, preventing accurate determination of platinum and iridium solubility. Longer run duration experiments showed decreasing amounts of micronuggets, allowing accurate determination of solubility; results indicate that under the conditions studied chlorine has no discernable effect on Pt solubility in the silicate melt from 0.6 to 2.75 wt. % Cl (saturation). Over the same conditions, a systematic increase in Ir solubility is found with increasing Cl content; however, the observed increase is within the analytical variation/error and is therefore not conclusive. If there is an effect of Cl on PGE solubility the effect is minor resulting in increased Ir solubilities of 60% at chlorine saturation. However, the abundance of micronuggets in short run duration experiments, which decreases in abundance with time and increases with Cl-content, offers compelling evidence that Cl-bearing fluids have the capacity to transport significant amounts of Pt and Ir under magmatic conditions. It is suggested that platinum and iridium dissolved within the Cl-bearing fluid are left behind as the fluid dissolves into the melt during the heating stages of the experiment, leaving small amounts of Pt and Ir along the former particle boundaries. With increasing run duration, the metal migrates back to the capsule walls decreasing the amount of micronuggets contained within the glass. Estimates based on this model, using mass-balance calculations on the excess amount of Pt and Ir in the run product glasses (i.e. above equilibrium solubility) in short duration experiments, indicate estimated Pt and Ir concentrations in the Cl-bearing fluid ranging from tens to a few hundred ppm, versus ppb levels in the melt. Respective apparent (equilibrium has not been established) partition coefficients (D,fluid-melt) of 1x10^3 to 4x10^3 and 300-1100 were determined for Pt and Ir in Cl-bearing fluids; suggesting that Cl-bearing fluids can be highly efficient at enriching and transporting PGE in mafic magmatic-hydrothermal ore-forming systems. Platinum solubility was also determined as a function of CO2 content in a hydrous haplobasalt at controlled oxygen fugacity. Using the same sealed capsule techniques and melt composition as for H2O and Cl, a hydrous haplobasaltic melt was allowed to equilibrate with the platinum capsule and a CO2-source (CaCO3 or silver oxalate) at 1523 K and 0.2 GPa. Experiments were conducted with a water content of approximately 1 wt. %, fixing the log oxygen fugacity (bars) between -5.3 and -6.1 (log NNO = -6.95 @ 1573 K and 0.2 GPa). Carbon dioxide contents in the run product glasses ranged from 800-2500 ppm; and over these conditions, CO2 was found to have a negligible effect on Pt solubility in the silicate melt. Analogous to the Cl-bearing experiments, bulk concentrations of Pt in CO2-bearing experiments increased with increasing CO2 content due to micronugget formation. Apparent Pt concentrations in the H2O-CO2 fluid phase, prior to fluid dissolution, were calculated to be 1.6 to 42 ppm, resulting in apparent partition coefficients(D,fluid-melt) of 1.5 x 10^2 to 4.2 x 10^3, increasing with increasing mol CO2:H2O up to approximately 0.15, after which increasing CO2 content does not further increase partitioning. As well, a novel technique was developed and applied to assess the partitioning of Pt between an aqueous fluid and a hydrous diopside-anorthite melt under magmatic conditions. Building upon the sealed-capsule technique utilized for solubility studies, a method was developed by adding a seed crystal to the capsule along with a silicate melt and fluid. By generating conditions favourable to crystal growth, and growing the crystal from the fluid, it is possible to entrap fluid inclusions in the growing crystal, allowing direct sampling of the fluid phase at the conditions of the experiment. Using a diopside seed crystal with the diopside-anorthite eutectic melt, it was possible to control diopside crystallization by controlling the temperature, thus allowing control of the crystallization and fluid inclusion entrapment conditions. Subsequent laser ablation ICP-MS analysis of the fluid inclusions allowed fluid–melt partition coefficients of Pt to be determined. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42¬Di58) haplobasalt composition (with ppm levels of Ba, Cs, Sr and Rb added as internal standards), water and a diopside seed crystal were sealed in a platinum capsule and were allowed to equilibrate at experimental conditions. Water was added in amounts to maintain a free fluid phase throughout the experiment, and the diopside crystal was separated from the melt. All experiments were run in an internally heated pressure vessel equipped with a rapid-quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). Experiments were allowed to equilibrate (6-48 hrs) at experimental conditions (i.e. 1498K, 0.2 GPa, fluid+melt+diopside stable) before temperature was dropped (i.e. to 1483K) to induce crystallization. Crystals were allowed to grow for a period of 18-61 hours, prior to rapid isobaric quenching to 293K at the conclusion of the experiment. Experimental run products were a crystal- and bubble-free glass and the diopside seed crystal with a fluid-inclusion-bearing overgrowth. Analysis of fluid inclusions provides initial solubility estimates of Pt in a H2O fluid phase at 1488 K and 0.2 GPa at or near ppm levels and fluid melt partition coefficients ranging from 2 – 48. This indicates substantial metal enrichment in the fluid phase in the absence of major ligands such as carbonate or chlorine. The results of this study indicate that the volatiles studied (i.e. H2O, CO2, and Cl) do not have a significant effect on Pt and Ir solubility in a haplobasaltic melt at magmatic conditions. These results suggest that complexing of Pt and Ir by OH, Cl, and carbonate species in a haplobasaltic melt is insignificant and the presence of these volatiles will not result in significantly increased PGE contents over their dry counterparts, as has been suggested. Preliminary evidence of minor Cl-complexing of Ir is presented; however, resulting in only a slight increase (<100%) in Ir solubility at Cl-saturation. Significant partitioning of Pt and Ir into a fluid phase at magmatic conditions has been demonstrated; with estimates of fluid-haplobasaltic melt partition coefficients increasing from 1x10^1 for pure water to up to an apparent 4x10^3 with the addition of Cl or CO2 to the system. This result indicates complexing of Pt and Ir with OH< HxCOy≤ Cl. Using these estimates, Cl- or CO2-bearing magmatic fluids can be highly efficient at enriching and transporting platinum group elements (PGEs) in mafic magmatic-hydrothermal ore-forming systems.

Volatiles are a fundamental component of the Magmatic-Hydrothermal model of platinum group element (PGE) ore deposition for PGE deposits in layered mafic intrusions such as Bushveld and Stillwater. Volatiles have the potential to complex with PGEs in silicate melts and hydrothermal fluids, increasing PGE solubility; in order to assess the models of PGE ore deposition reliable estimates on the solubilities in the various magmatic phases must be known. However, experimental studies on the solubility and partitioning behaviour of PGEs in mafic magmatic-hydrothermal systems under relevant conditions are sparse, and the data that do exist produce conflicting results and new or adapted experimental methods must be applied to investigate these systems. Experimental results are presented here, investigating the effect of volatiles (i.e. H2O, Cl and CO2) on Pt and Ir solubility in a haplobasaltic melt and fluid-melt partitioning of Pt between an aqueous fluid and a haplobasaltic melt under magmatic conditions using a sealed-capsule technique. Also included are the details of the development of a novel experimental technique to observe fluid-melt partitioning in mafic systems and application of the method to the fluid-melt partition of Pt. Solubility experiments were conducted to assess the effect of volatiles on Pt and Ir solubility in a haplobasaltic melt of dry diopside-anorthite eutectic composition at 1523K and 0.2GPa. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42-Di58) haplobasalt composition was sealed in a platinum or platinum-iridium alloy capsule and was allowed to equilibrate with the noble metal capsule and a source of volatiles (i.e. H2O, H2O-Cl or H2O-CO2) at experimental conditions. All experiments were run in an internally-heated pressure vessel equipped with a rapid quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). The resultant crystal- and bubble-free run product glasses were analyzed using a combination of laser ablation ICP-MS and bulk solution isotope-dilution ICP-MS to determine equilibrium solubilities of Pt and Ir and investigate the formation and contribution of micronuggets to overall bulk determined concentrations. In water-bearing experiments, it was determined that water content did not have an intrinsic effect on Pt or Ir solubility for water contents between 0.9 wt. % and 4.4 wt. % (saturation). Water content controlled the oxygen fugacity of the experiment and the resulting variations in oxygen fugacity, and the corresponding solubilities of Pt and Ir, indicate that over geologically relevant conditions both Pt and Ir are dissolved primarily in the 2+ valence state. Pt data suggest minor influence of Pt4+ at higher oxygen fugacities; however, there is no evidence of higher valence states for Ir. The ability of the sealed capsule technique to produce micronugget-free run product glasses in water-only experiments, allowed the solubility of Pt to be determined in hydrous haplobasalt at lower oxygen fugacities (and concentrations) then was previously observed. Pt and Ir solubility can be represented as a function of oxygen fugacity (bars) by the following equations: [Pt](ppb)= 1389(fO-sub-2)+7531(fO-sub-2)^(1/2) [Ir](ppb)=17140(fO-sub-2)^(1/2) In Cl-bearing experiments, experimental products from short run duration (<96hrs) experiments contained numerous micronuggets, preventing accurate determination of platinum and iridium solubility. Longer run duration experiments showed decreasing amounts of micronuggets, allowing accurate determination of solubility; results indicate that under the conditions studied chlorine has no discernable effect on Pt solubility in the silicate melt from 0.6 to 2.75 wt. % Cl (saturation). Over the same conditions, a systematic increase in Ir solubility is found with increasing Cl content; however, the observed increase is within the analytical variation/error and is therefore not conclusive. If there is an effect of Cl on PGE solubility the effect is minor resulting in increased Ir solubilities of 60% at chlorine saturation. However, the abundance of micronuggets in short run duration experiments, which decreases in abundance with time and increases with Cl-content, offers compelling evidence that Cl-bearing fluids have the capacity to transport significant amounts of Pt and Ir under magmatic conditions. It is suggested that platinum and iridium dissolved within the Cl-bearing fluid are left behind as the fluid dissolves into the melt during the heating stages of the experiment, leaving small amounts of Pt and Ir along the former particle boundaries. With increasing run duration, the metal migrates back to the capsule walls decreasing the amount of micronuggets contained within the glass. Estimates based on this model, using mass-balance calculations on the excess amount of Pt and Ir in the run product glasses (i.e. above equilibrium solubility) in short duration experiments, indicate estimated Pt and Ir concentrations in the Cl-bearing fluid ranging from tens to a few hundred ppm, versus ppb levels in the melt. Respective apparent (equilibrium has not been established) partition coefficients (D,fluid-melt) of 1x10^3 to 4x10^3 and 300-1100 were determined for Pt and Ir in Cl-bearing fluids; suggesting that Cl-bearing fluids can be highly efficient at enriching and transporting PGE in mafic magmatic-hydrothermal ore-forming systems. Platinum solubility was also determined as a function of CO2 content in a hydrous haplobasalt at controlled oxygen fugacity. Using the same sealed capsule techniques and melt composition as for H2O and Cl, a hydrous haplobasaltic melt was allowed to equilibrate with the platinum capsule and a CO2-source (CaCO3 or silver oxalate) at 1523 K and 0.2 GPa. Experiments were conducted with a water content of approximately 1 wt. %, fixing the log oxygen fugacity (bars) between -5.3 and -6.1 (log NNO = -6.95 @ 1573 K and 0.2 GPa). Carbon dioxide contents in the run product glasses ranged from 800-2500 ppm; and over these conditions, CO2 was found to have a negligible effect on Pt solubility in the silicate melt. Analogous to the Cl-bearing experiments, bulk concentrations of Pt in CO2-bearing experiments increased with increasing CO2 content due to micronugget formation. Apparent Pt concentrations in the H2O-CO2 fluid phase, prior to fluid dissolution, were calculated to be 1.6 to 42 ppm, resulting in apparent partition coefficients(D,fluid-melt) of 1.5 x 10^2 to 4.2 x 10^3, increasing with increasing mol CO2:H2O up to approximately 0.15, after which increasing CO2 content does not further increase partitioning. As well, a novel technique was developed and applied to assess the partitioning of Pt between an aqueous fluid and a hydrous diopside-anorthite melt under magmatic conditions. Building upon the sealed-capsule technique utilized for solubility studies, a method was developed by adding a seed crystal to the capsule along with a silicate melt and fluid. By generating conditions favourable to crystal growth, and growing the crystal from the fluid, it is possible to entrap fluid inclusions in the growing crystal, allowing direct sampling of the fluid phase at the conditions of the experiment. Using a diopside seed crystal with the diopside-anorthite eutectic melt, it was possible to control diopside crystallization by controlling the temperature, thus allowing control of the crystallization and fluid inclusion entrapment conditions. Subsequent laser ablation ICP-MS analysis of the fluid inclusions allowed fluid–melt partition coefficients of Pt to be determined. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42¬Di58) haplobasalt composition (with ppm levels of Ba, Cs, Sr and Rb added as internal standards), water and a diopside seed crystal were sealed in a platinum capsule and were allowed to equilibrate at experimental conditions. Water was added in amounts to maintain a free fluid phase throughout the experiment, and the diopside crystal was separated from the melt. All experiments were run in an internally heated pressure vessel equipped with a rapid-quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). Experiments were allowed to equilibrate (6-48 hrs) at experimental conditions (i.e. 1498K, 0.2 GPa, fluid+melt+diopside stable) before temperature was dropped (i.e. to 1483K) to induce crystallization. Crystals were allowed to grow for a period of 18-61 hours, prior to rapid isobaric quenching to 293K at the conclusion of the experiment. Experimental run products were a crystal- and bubble-free glass and the diopside seed crystal with a fluid-inclusion-bearing overgrowth. Analysis of fluid inclusions provides initial solubility estimates of Pt in a H2O fluid phase at 1488 K and 0.2 GPa at or near ppm levels and fluid melt partition coefficients ranging from 2 – 48. This indicates substantial metal enrichment in the fluid phase in the absence of major ligands such as carbonate or chlorine. The results of this study indicate that the volatiles studied (i.e. H2O, CO2, and Cl) do not have a significant effect on Pt and Ir solubility in a haplobasaltic melt at magmatic conditions. These results suggest that complexing of Pt and Ir by OH, Cl, and carbonate species in a haplobasaltic melt is insignificant and the presence of these volatiles will not result in significantly increased PGE contents over their dry counterparts, as has been suggested. Preliminary evidence of minor Cl-complexing of Ir is presented; however, resulting in only a slight increase (<100%) in Ir solubility at Cl-saturation. Significant partitioning of Pt and Ir into a fluid phase at magmatic conditions has been demonstrated; with estimates of fluid-haplobasaltic melt partition coefficients increasing from 1x10^1 for pure water to up to an apparent 4x10^3 with the addition of Cl or CO2 to the system. This result indicates complexing of Pt and Ir with OH< HxCOy≤ Cl. Using these estimates, Cl- or CO2-bearing magmatic fluids can be highly efficient at enriching and transporting platinum group elements (PGEs) in mafic magmatic-hydrothermal ore-forming systems.

The origin of compositional gaps in volcanic deposits remains controversial. In Akaroa Volcano (9.6 to 8.6 Ma), New Zealand, a dramatic compositional gap exists between basaltic and trachytic magmas. Previously, the formation of more evolved magmas has been ascribed to crustal melting. However, the interpretation of new major and trace element analysis from minerals and bulk-rocks coupled with the mechanics of crystal-liquid separation offers an alternative explanation that alleviates the thermal restrictions required for crustal melting models. In a two-stage model, major and trace element trends can be reproduced by polybaric crystal fractionation from dry melts (less than 0.5 wt.% H2O) at the QFM buffer. In the first stage, picritic basalts are separated from an olivine-pyroxene dominant mush near the crust-mantle boundary (9 to 10 kbar). Ascending magmas stagnated at mid-crustal levels (5 to 6 kbar) and fractionated an olivine-plagioclase assemblage to produce the alkali basalt-hawaiite trend. In the second stage, trachyte melt is extracted from a crystal mush of hawaiite to mugearite composition at mid-to-upper crustal levels (3 to 5 kbar) after the melt has crystallised 50 vol.%. The fractionated assemblage of plagioclase, olivine, clinopyroxene, magnetite, and apatite is left in a cumulate residue which corresponds to the mineral assemblage of sampled ultramafic enclaves. The results of trace element modelling of Rayleigh fractionation using this extraction window is in close agreement with the concentrations measured in trachyte (= liquid) and enclaves (= cumulate residue). The compositional gap observed in the bulk-rock data of eruptive products is not recorded in the feldspar data, which show a complete solid solution from basalt and co-magmatic enclaves to trachyte. Complexly zoned plagioclases further suggest episodical magma recharge events of hotter, more mafic magmas, which lead to vigorous convection and magma mixing. In summary, these models indicate that the Daly Gap of Akaroa Volcano formed by punctuated melt extraction from a crystal mush at the brittle-ductile transition.

The Comet Gold Mine is in the Murchison mineral field which lies within the Yilgarn Craton of Western Australia. Several different geophysical methods were used in this study to define the geophysical signatures of sedimentary iron formations (SIF) and altered basalt associated with gold mineralisation. The geophysical surveys carried out at the Comet Gold Mine were gravity, sub-audio magnetics (SAM), transient electromagnetics (TEM) and downhole geophysical logging. Data from previous geophysical surveying were also used, and these included highresolution aeromagnetics and TEMPEST airborne electromagnetics. Other exploration information, such as geology and drillhole data, were integrated with geophysical results to study the geophysical responses and generate a geophysical interpretation map. / The main aim of this study was to generate an understanding of the various geophysical responses of geology and gold mineralisation in the Comet Mine area for future gold exploration in this region. Particularly, the study focused on the ability of the SAM method to map out geology and geophysical response for gold mineralisation. The response from SAM surveying has been investigated over an area of 13 sq kms. The SAM surveying was completed using a transmitter current of 5-8 Amp with a 50% duty cycle at 4 Hz frequency, which was considered the best setting for the Comet area. The SAM anomalies were compared to results from other geophysical methods. The results of all geophysical surveying suggested that the TEM method was also effective for identifying altered sulphide and magnetic altered rock associated with gold mineralisation. / Experiments were carried out using SAM surveying with electrodes in standard surface pits and pits placed directly into the gold mineralised structure. Both surveys showed very similar results, so in this area, surface electrode pits work well for current injection during SAM surveys. The similarities are probably due to the lack of conductive regolith cover in the Comet Mine area. / The SAM response was studied for survey grids using different electrode positions and directions. Experiments in changing SAM electrode position over the same area were carried out along and across geological strike to detect the different geological structure directions. The EQMMR response was different for electrodes oriented at 90º when surveys were repeated over the same area. SAM mainly measures conductive features running sub-parallel to the electrode direction, but the EQMMIP response was mostly the same, despite the difference in electrode direction. In addition, the EQMMIP result was very similar for rotated grids, with some distortion occurring around the main EQMMR anomaly near the Venus open cut pit. Therefore, SAM chargeability was not strongly polarised along the electrode direction like the EQMMR response. This is consistent with the theory of MIP that the method detects the effect of induced polarisation in the earth by virtue of the magnetic fields associated with current flow in polarisable bodies within the earth. / Gravity data were collected along in 4 transects 500 m apart and at 50 m station spacing. 3D gravity modelling using polygonal shapes was completed to a good fit with felsic and mafic rocks by having rock units dip to the SE. Euler depth solution calculations were applied to locate contacts and deep gravity sources. Gravity surveying has also proved to be a useful survey method for geological mapping and locating regional structures. / Ground TEM survey data were used at the Venus prospect to map out conductive zones at depths ranging from 30 to 90 m. All anomaly bodies were interpreted to have a SE dip. The modelled ground TEM results were compared to TEMPEST airborne electromagnetic conductivity depth slices. Both EM survey results showed reasonably similar patterns, but the ground TEM method provided more reliable conductor locations and depth estimations that correlated well with the drilling information and downhole conductivity logging. / Geophysical logs of natural gamma and inductive conductivity were surveyed in 5 drillholes that intersected gold alteration zones. The alteration zones associated with gold mineralised sediments, sulphide and magnetic minerals were identified in the downhole logs as increased conductivity, with a sight increase in the natural gamma response. Natural gamma was usually high above a background of host rock in the gold mineralised shear zones. This was likely due to K associated with the clay rich SIF units, and sericite and biotite from gold related alteration. During this study, drillhole CTRC028 was drilled into a modelled TEM anomaly, and gold mineralised SIF was intersected at the predicted location from the model. / Geophysical survey information (magnetics, gravity, SAM and TEM) and anomalies in the Comet area were found to be primarily controlled by the local structures and mineralisation along these structures. Modelled ground TEM results were compared to TEMPEST airborne, EM data and showed reasonably similar patterns. The geophysical survey data also highlights black shale units, which can produce a false target commonly running parallel to the sulphide altered fault zones and SIF units, because of graphite and sulphide in the black shale. / The TEMPEST data were a valuable guide to bedrock conductivity over the outline project area at Comet, and the follow–up ground TEM and SAM survey data was very useful for accurately pin-pointing anomalies for drill testing. / Geophysical and geological data analysed in this study was used to generate a geophysical interpretation map at 1:5,000 scale. The new interpretation of geological units and structures at Comet will provide geologists with a better understand about the geological and structural setting for mineralisation in the Comet area. For example, the Comet Fault represents a faulted limb of the Comet fold structure that has both limbs dipping to the SE, and plunges to the NE. Magnetic anomalies associated with SIF are considered to correlate with some gold bearing horizons and the location of the Comet Fault, that has become more siliceous and altered by sulphide minerals and magnetite minerals. / It is recommended that other prospect areas in the region should be surveyed using the SAM method in order to identify shallow gold bearing structures and improve geological interpretations ahead of drilling.

This master’s thesis studies the problems of high temperatures on cement concretes, their following diagnostics from pre-treatment to rehabilitation, the emphasis was on the use of high-speed water jet. In the experimental part of the design of a concrete composition with basalt aggregate. Were reviewed the physico-mechanical properties after thermal loading. The influence of pressure water jet on the thermal load on concrete, pull-off test, the volume of the removed concrete with a strength evaluation and comparison.

A Província Basáltica Continental do Paraná-Etendeka registra o intenso vulcanismo do Cretáceo inferior que precedeu a fragmentação do supercontinente Gondwana. Tradicionalmente investigações sobre estas rochas priorizaram a aquisição de dados geoquímicos e isotópicos, considerando a pilha vulcânica como uma monótona sucessão de derrames tabulares e espessos. O presente trabalho propõe a análise das características físicas deste vulcanismo aplicando conceitos de arquitetura de fácies vulcânicas, integrados a estudos petrográficos e geoquímicos. A Sinclinal de Torres é uma estrutura tectônica localizada na porção sul do Brasil onde ocorrem preservadas as sequencias vulcânicas do magmatismo Paraná-Etendeka. Na área de estudo As rochas vulcânicas básicas podem ser divididas em duas unidades: derrames e campos de derrames pahoehoe (Unidade I) e derrames rubbly simples (Unidade II). Geoquimicamente as duas unidades pertencem a serie de baixo- TiO2 e ao magma tipo Gramado. As primeiras lavas pahoehoe são olivina basaltos, mais primitivos. A unidade I é composta por inúmeros derrames pahoehoe que ocorrem sobre os arenitos eólicos da Formação Botucatu. Essa lavas ocorrem como sheet pahoehoe, compound lavas, e lavas do tipo ponded nos vales interduna. O emplacement dessas lavas esta relacionado a baixas taxas de erupção sustentadas por longos intervalos de tempo. A unidade II é formada por espessas lavas simples do tipo rubbly, estas são caracterizadas por núcleos maciços e topos fragmentados (rubbly tops). Essas lavas são formadas por altas taxas de erupção e durante a fase principal do vulcanismo na área. O vale principal da Sinclinal de Torres tem uma evolução formada por derames compostos na porção basal e derrames simples nas porções superiores, siilar a de outras Províncias Basálticas Continentais. / The Parana-Etendeka Volcanic Province records the volcanism of the Earlier Cretaceous that precedes the fragmentation of the Gondwana supercontinent. Traditionally, investigations of these rocks prioritized the acquisition of geochemical and isotopic data, considering the volcanic stack as a monotonous succession of tabular flows. This work provides a detailed analysis of the physical conditions of the emplacement of these volcanic rocks, applying the facies architecture integrated to petrographic and geochemical data. Torres Syncline is a tectonic structure located in southern Brazil and where the Parana- Etendeka basalts are well preserved. The basaltic lava flows in the area can be divided in pahoehoe flow fields (Unit I) and simple rubbly flows (Unit II). Geochemically both units are low TiO2 and Gramado magma type. The first pahoehoe lavas are more primitive and are olivine basalts with higher contents of MgO. The fist unit is build up by innumerous pahoehoe lava flows and flow fields that cover the sandstones of Botucatu Fm. These flows occur like sheet pahoehoe, compound pahoehoe, and ponded lavas in the interdune settings. The emplacement of pahoehoe flow fields is related to sustain low eruptive rates. The unit two is formed by thick simple rubbly lavas, characterized by a massive core and a rubbly top. These flows are associated to high effusion rates and were formed during the main phase of volcanism in the area. The Torres Syncline main valley has a similar evolution when compared with other lips with compound flows at the base and simple flows in the upper portions.