Thesis (Ph.D.)--University of Tulsa, 1993. / Includes bibliographical references (p. 190-195).

Thesis (Ph. D.)--Carleton University, 1992. / Also available in electronic format on the Internet.

This thesis deals with fluid inclusion study of quartz samples from Ratibořské Hory and Stará Vožice and baryte samples from Stříbrná Skalice and Černé Voděrady. Samples were studied by methods of microthermometry of fluid inclusions, Raman spectrometry, UV-fluorescence spectrometry and EDX analysis. In quartz sample from Stará Vožice there were detected low-salinity H2O-CO2-N2 fluids that were trapped at min. 240 MPa and 260 řC. This mineralization is probably connected with initial stages of structural evolution of the Blanice Graben. Late-metamorphic fluids were probable source of these solutions. In sample of quartz containing grains of galena there were trapped mesothermal (Th = 110-195 řC) low- to medium-salinity H2O-NaCl fluids, hydrocarbon fluids and low- salinity (H2O)-CO2-N2-CH4 fluids (containing max. 13 mol. % N2+CH4 in carbonic phase) trapped at low pressure (max. 10 MPa) and relatively low temperature (105-120 řC). In Ratibořské Hory there were detected heterogeneously trapped low- to medium-salinity H2O±CO2±N2±CH4- NaCl±KCl±MgCl2±FeCl2 (with max. 26 mol. % N2+CH4 in carbonic phase) fluids trapped at 1-25 MPa and 160-315 řC. In barite sample from Černé Voděrady were detected low- to high-salinity aqueous fluids with Na and Ca ± K, Fe, Mg chlorides. These solutions are probably derived...

No description available.

Low temperature phase relations in the ice-stable field of the system NaCl-CaCl₂-H₂O were determined under 1 atm. total pressure along the NaCl-H₂O and CaCl₂-H₂O binaries and along five pseudobinaries with constant NaCl/(NaCl+CaCl₂) weight ratios. The results are in excellent agreement with published data along the NaCl-H₂O binary but show large discrepancies when compared to previous determinations of the ice liquidus along the CaCl₂-H₂O binary and in the NaCl-CaCl₂-H₂O ternary. At moderate to high salinities, isotherms cross the ice sub-field at lower total salt concentrations than previously reported. In addition, NaCl/(NaCl+CaCl₂) weight ratios estimated from hydrohalite- and ice-melting temperatures may be low by as much as 15%. Relative densities were measured for NaCl(aq) and CaCl₂(aq) solutions to 250°C and 400 bars and over the range of ionic strengths 0.2 - 5.5 and 0.2 - 19.2 mol·kg⁻¹, respectively. The results span the pressure and temperature of earlier volumetric studies and extend to higher molalities than reported previously. The relative densities have been fitted as apparent molar volumes (V_Φ) using the Pitzer ion-interaction treatment, with appropriate expressions chosen for the temperature- and pressure-dependence of the virial coefficients of the model. The results presented for NaCl(aq) are in good agreement with published results to 250°C. The results presented for CaCl₂(aq) are in good agreement with published values to approximately 125°C. Above 125°C the inter- and intralaboratory precision of the published data deteriorate and are often in very poor agreement with the data from this Study. The representation for V_Φ for CaCl₂(aq) was integrated with respect to pressure to establish the pressure dependence of excess free energies over the temperature range studied. CaCl₂ activity coefficients (γ±) have been derived to 250°C, 400 bars and 4 mol·kg⁻¹ using published fits of CaCl₂ activity coefficient data along the vapor saturation surface and the pressure dependence determined in this work. The volumetric data indicate that the mean ionic activity coefficient, γ±(CaCl₂), increases by a maximum of 32% at 400 bars, 250°C, and 4 mol·kg⁻¹ as compared with its value at saturation pressure. Relative densities were also measured for several ternary { NaCl+CaCl₂}(aq) solutions at 25 and 35°C and 1 atm. These results substantially expand the volumetric data base for ternary solutions. Based on the results of this study most of the previously reported 308.15 K density data in the ternary appear to contain large errors. / Ph. D.

Vapor-saturated solubility relationships in the system NaCl-KCl-H₂0 have been determined by experimentally synthesizing fluid inclusions in quartz in the presence of known brine compositions and then measuring the dissolution temperatures of halite and/or sylvite daughter crystals within the inclusions using a microscope equipped with a heating stage. These data, along with other literature values have been used in a regression routine to generate a series of equations describing vapor-saturated solubility relations within the halite, sylvite and hydrohalite stability fields. These equations, together with a recently published equation for the ice stability field (Hall et al., 1987), have been used to construct the complete vapor-saturated solubility surface in the NaCl-KCl-H₂O ternary system. The diagram may be used in the interpretation of microthermometric data to determine the compositions of fluid inclusions approximated by the NaCl-KCl-H₂O system. P-T conditions inferred from fluid inclusions in metamorphic rocks often disagree with values predicted from mineral equilibria calculations suggesting that inclusions formed during early stages of regional metamorphism continue to re-equilibrate during burial and subsequent uplift in response to differential pressure. P-T conditions accompanying burial and uplift were experimentally simulated by forming pure-H₂0 inclusions in quartz, and then re-equilibrating the inclusions such that final confining pressures ranged from 5 kbar above to 4 kbar below the original formation pressure. Homogenization temperatures of re-equilibrated inclusions indicated densities intermediate between the initial and final P-T conditions. In short-term experiments (7 days) where the initial internal overpressure exceeded 1 kbar most H₂O inclusions re-equilibrated until their internal pressures were between ~75O and 1500 bars above the confining pressure, regardless of the initial pressure differential. In a long-term experiment (52 days) some inclusions were found to have completely re-equilibrated. In experiments where the confining pressure during re-equilibration exceeded the original formation pressure, the densities of pure-water inclusions increased to values intermediate between the initial and final P-T conditions. Additionally, these inclusions were generally surrounded by a halo of smaller inclusions also of intermediate density and resulting in a texture similar to that previously ascribed to decrepitation resulting from internal overpressure. Pressure-volume-temperature-composition (PVTX) relations in the CO₂-H₂O system have been experimentally determined from 2 to 6 kbar and 400° to 700°C for fluid compositions between 12.5 and 87.5 mole % CO₂ using the synthetic fluid inclusion technique. The method involves trapping CO₂-H₂O fluids of known composition as inclusions in quartz at elevated pressures and temperatures (P_F and T_F) and then calculating the desired fluid properties using microthermometric data combined with available PVTX data for this system at low pressures and temperatures. PTX properties of CO₂-H₂O mixtures were determined from the total homogenization temperatures (Th (total)) of fluid inclusions trapped in the one-fluid phase field. Internal pressures on the solvus (at Th (total)) were calculated using the equation of state of Connolly and Bodnar (1983) and the inclusion densities as determined above. The pressure and temperature of total homogenization of each inclusion defines a point on the solvus unique to that particular bulk fluid composition and density. Thus, the array of many such points determined in this manner delineates the boundary between the one-phase and two-phase fields over a portion of PTX-space. / Ph. D.

When these fluids interact with the surrounding rocks, small aliquots of these fluids are trapped as imperfections in the crystal lattice and fractures of minerals. These microscopic features are called fluid and melt inclusions, and are one of the best tools available to probe, measure and determine the chemical and physical properties of crustal fluids. In the present study we examine new developments into our understanding of fluid-rock interactions using fluid and melt inclusion as tools to provide insights into the evolution of the Earth's crust from the deep continental crust to the surface. Chapter II "Raman spectroscopic characterization of H2O in CO2-rich fluid inclusions in granulite facies metamorphic rocks", is a brief review of the current understanding of granulite rocks and their formation, and a new development into our ability to characterize the composition of the fluids trapped as fluid inclusions in minerals in granulite facies rocks. Chapter III "Reassessment of the Raman CO2 densimeter", details new developments in the use of the Raman spectroscopy to characterize the density of CO2. In this chapter we describe briefly the Raman effect of CO2 and the density dependence of the Fermi diad using different Raman instruments, laser sources and gratings to understand the differences in the published data. Chapter IV "Serpentinization reaction rates measured in olivine micro-batch reactors" describes new insights into the serpentinization process by using olivine micro-reactors. The micro-reactor technique is a new experimental development that allows researchers to monitor the fluid chemistry as well as the mineral composition changes inside synthetic fluid inclusion. / Ph. D.

M.Sc. / A fluid inclusion study was performed on the following rock types: ● Metapelitic granulites that occur as xenoliths in the Bulai Pluton. ● Metapelitic granulites that occur around the Bulai Pluton. ● Granite from the Bulai Pluton. These rocks outcrop on the farm Boston near Messina in the so called Three Sisters area. The main aims of this study are the following: ● Which fluids are associated with granulite metamorphism? ● Do the fluid inclusions record more than one metamorphic event, if so, what are the P-T conditions of this/these event(s)? ● How do the fluids compare to fluids in the Southern Marginal Zone in terms of composition and density? The metapelites are typically characterised by a peak metamorphic mineral assemblages of (1) quartz, K-feldspar, plagioclase, garnet, biotite, cordierite and sillimanite and (2) quartz, K-feldspar, plagioclase, garnet, orthopyroxene and biotite. The first assemblage have been used by other workers (Van Reenen et al., in prep.) to derive a P-T path for the metapelitic xenoliths and host rock, which is characterised by decompression-cooling. This assemblage also shows typical high temperature metasomatic formation of feldspar around quartz that is in contact with quartz. The peak metamorphic conditions were estimated to be ~850°C and ~7.5 kbar. Fluid inclusions were studied in garnet, quartz inclusions in garnet, and matrix quartz. The following principle fluid types were identified: ● High salinity aqueous fluids. ● CO2-rich (±CH4) carbonic fluids. ii Petrographic evidence indicates that both fluids were present at peak metamorphic conditions under conditions of fluid-fluid immiscibility. The high-salinity aqueous fluid is most likely responsible for the high temperature metasomatic textures. The density of the fluids trapped at peak metamorphic conditions have been reset to lower values at pressures below that of the peak metamorphic conditions. This is probably the result of the emplacement of the Bulai Pluton at shallow crustal levels (2- 3 kbar). Later fluids are dominated by low-density carbonic fluids with significant amounts of CH4. The CH4 is the result of retrograde hydration reactions at relatively low oxygen fugacities.

As condições de pressão e temperatura existentes no evento tectônico que atuou na zona de fold-and-thrust da margem oeste do Cráton do São Francisco foram estimadas com base em estudos estruturais, microestruturais, petrográficos e de inclusões fluidas de veios sintectônicos. A presença de veios de diferentes gerações na zona de fold-and-thrust é evidenciada por fluidos atuando em diferentes cenários de paleoestresse ao longo da história deformacional da área. A área é composta por rochas do Grupo Bambuí fracamente deformadas que registram condições de metamorfismo que variam de diagênese a fácies subxisto verde. Dois eventos tectônicos foram identificados através da disposição geométrica dos veios e da superfície dobrada: (i) uma compressão principal NE-SW (D1) com \'sigma\'1 subhorizontal de orientação SW e \'sigma\'3 sub-vertical, relacionado à formação de veios sintectônicos sub-horizontais de orientação NW formados em condições que atingiram pelo menos 140- 160°C e pressões em torno de 200-363 MPa; (ii) uma compressão posterior NW-SE (D2) com \'sigma\'1 sub-horizontal de orientação NW e \'sigma\'3 também sub-horizontal de orientação NE. Estão relacionados à D2 a formação de veios sintectônicos sub-verticais paralelos à clivagem, formados nas mesmas condições mínimas de temperatura de 140-160°C e pressões entre 181- 295 MPa. A indicação de flutuações na pressão durante esses eventos desempenhou um papel crucial, pois os fluidos influenciam significativamente os processos mecânicos, os mecanismos de deformação e as reações químicas que operam em cinturões de fold-andthrust. Os fluidos apresentam composição formada por H2O-NaCl-CaCl2, onde o processo de mistura de diferentes fontes de fluidos (metamórficas e meteóricas) é evidenciado pela tendência evolutiva de temperaturas de homogeneização e salinidades, resultando em alguma variação na salinidade (12 contra 4% em peso equivalente de NaCl para os veios subhorizontais e para os paralelos à clivagem, respectivamente). Este trabalho confirma que a combinação entre a reconstrução do paleoestresse e o estudo de inclusões fluidas podem fornecer informações fundamentais sobre a relação entre o fluxo de fluidos e a tectônica de terrenos orogênicos, contribuindo para o conhecimento científico sobre a evolução deformacional/metamórfica do Grupo Bambuí e, consequentemente, da zona de fold-andthrust da margem ocidental do Cráton do São Francisco. / P-T conditions existing at the tectonic event that acted at the fold-and-thrust zone of the western margin of the São Francisco Craton were estimated on the basis of structural, microstructural, petrographic and fluid inclusion study of syntectonic veins. The presence of veins of different generations in the fold-and-thrust zone is evidenced by fluids operating at different scenarios of paleostress throughout the deformation history. The area are composed of weakly deformed rocks of the Bambuí Group recording a metamorphism with conditions ranging from diagenetic to sub-greenschist facies. Two tectonic events were identified by vein geometric arrangement and folded surface, a major early NE-SW compression (D1 - \'sigma\'1 subhorizontal SW-trending and \'sigma\'3 subvertical), related with subhorizontal NW-trending syntectonic veins formed at conditions that have reached at least 140°C and pressures around 200-363 MPa; and later NW-SE compression (D2 - \'sigma\'1 subhorizontal NW-trending and \'sigma\'3 subhorizontal NE-trending), related with subvertical syntectonic cleavage-parallel veins formed at the same range of temperature and pressures between 181-295 MPa. Indication of fluctuations in pressure during these events played a crucial role as fluids significantly influence the mechanical processes, deformation mechanisms and chemical reactions that operate in fold-thrust belts. Fluids show H2O-NaCl-CaCl2 composition where mixing process of different fluids sources (metamorphic and meteoric) are evidenced by evolutive trending of homogenization temperatures and salinities resulting in some variation in salinity (12 against 4 wt.% NaCl eq. for subhorizontal and cleavage-parallel veins respectively). This research confirms that combine the reconstruction of the paleostress states and fluid inclusion studies can provide fundamental information of relationship between fluid flow and tectonic of orogenic terrains contributing to the scientific knowledge about the deformational/metamorphic evolution of the Bambuí Group and the fold-and-thrust zone of the western margin of the São Francisco Craton.

As condições de pressão e temperatura existentes no evento tectônico que atuou na zona de fold-and-thrust da margem oeste do Cráton do São Francisco foram estimadas com base em estudos estruturais, microestruturais, petrográficos e de inclusões fluidas de veios sintectônicos. A presença de veios de diferentes gerações na zona de fold-and-thrust é evidenciada por fluidos atuando em diferentes cenários de paleoestresse ao longo da história deformacional da área. A área é composta por rochas do Grupo Bambuí fracamente deformadas que registram condições de metamorfismo que variam de diagênese a fácies subxisto verde. Dois eventos tectônicos foram identificados através da disposição geométrica dos veios e da superfície dobrada: (i) uma compressão principal NE-SW (D1) com \'sigma\'1 subhorizontal de orientação SW e \'sigma\'3 sub-vertical, relacionado à formação de veios sintectônicos sub-horizontais de orientação NW formados em condições que atingiram pelo menos 140- 160°C e pressões em torno de 200-363 MPa; (ii) uma compressão posterior NW-SE (D2) com \'sigma\'1 sub-horizontal de orientação NW e \'sigma\'3 também sub-horizontal de orientação NE. Estão relacionados à D2 a formação de veios sintectônicos sub-verticais paralelos à clivagem, formados nas mesmas condições mínimas de temperatura de 140-160°C e pressões entre 181- 295 MPa. A indicação de flutuações na pressão durante esses eventos desempenhou um papel crucial, pois os fluidos influenciam significativamente os processos mecânicos, os mecanismos de deformação e as reações químicas que operam em cinturões de fold-andthrust. Os fluidos apresentam composição formada por H2O-NaCl-CaCl2, onde o processo de mistura de diferentes fontes de fluidos (metamórficas e meteóricas) é evidenciado pela tendência evolutiva de temperaturas de homogeneização e salinidades, resultando em alguma variação na salinidade (12 contra 4% em peso equivalente de NaCl para os veios subhorizontais e para os paralelos à clivagem, respectivamente). Este trabalho confirma que a combinação entre a reconstrução do paleoestresse e o estudo de inclusões fluidas podem fornecer informações fundamentais sobre a relação entre o fluxo de fluidos e a tectônica de terrenos orogênicos, contribuindo para o conhecimento científico sobre a evolução deformacional/metamórfica do Grupo Bambuí e, consequentemente, da zona de fold-andthrust da margem ocidental do Cráton do São Francisco. / P-T conditions existing at the tectonic event that acted at the fold-and-thrust zone of the western margin of the São Francisco Craton were estimated on the basis of structural, microstructural, petrographic and fluid inclusion study of syntectonic veins. The presence of veins of different generations in the fold-and-thrust zone is evidenced by fluids operating at different scenarios of paleostress throughout the deformation history. The area are composed of weakly deformed rocks of the Bambuí Group recording a metamorphism with conditions ranging from diagenetic to sub-greenschist facies. Two tectonic events were identified by vein geometric arrangement and folded surface, a major early NE-SW compression (D1 - \'sigma\'1 subhorizontal SW-trending and \'sigma\'3 subvertical), related with subhorizontal NW-trending syntectonic veins formed at conditions that have reached at least 140°C and pressures around 200-363 MPa; and later NW-SE compression (D2 - \'sigma\'1 subhorizontal NW-trending and \'sigma\'3 subhorizontal NE-trending), related with subvertical syntectonic cleavage-parallel veins formed at the same range of temperature and pressures between 181-295 MPa. Indication of fluctuations in pressure during these events played a crucial role as fluids significantly influence the mechanical processes, deformation mechanisms and chemical reactions that operate in fold-thrust belts. Fluids show H2O-NaCl-CaCl2 composition where mixing process of different fluids sources (metamorphic and meteoric) are evidenced by evolutive trending of homogenization temperatures and salinities resulting in some variation in salinity (12 against 4 wt.% NaCl eq. for subhorizontal and cleavage-parallel veins respectively). This research confirms that combine the reconstruction of the paleostress states and fluid inclusion studies can provide fundamental information of relationship between fluid flow and tectonic of orogenic terrains contributing to the scientific knowledge about the deformational/metamorphic evolution of the Bambuí Group and the fold-and-thrust zone of the western margin of the São Francisco Craton.