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Conditions of formation of selected hydrothermal vein deposits in central part of the Bohemian Massif
Ulmanová, Jana ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee)
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...
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Volumetric and electrostatic properties of water and their application to aqueous thermodynamics and mineral solubility at high temperatures and pressures
Hanková, Barbora ; Dolejš, David (advisor) ; Zachariáš, Jiří (referee)
Hydrothermal fluids are important mass and heat transfer agents in the Earth's crust and mantle. Aside from their transport role, the aqueous fluids act as reactants or products in rock environment during diverse processes ranging from partial melting, magmatic and metamorphic devolatilization. This study evaluates the effect of equations of state and thermodynamic data for aqueous species on prediction of mineral solubility in aqueous fluids at high temperatures and pressures employing the Helgeson-Kirkham-Flowers model (HKF). These calculations require: (i) volumetric properties of water; (ii) dielectric properties of water; (iii) aqueous species thermodynamic properties. A comparison of ten equations of state against the IAPWS scientific standard reveals that volumetric properties of water up to 1200 řC and 50 kbar are predicted within 5 %, except at low pressure (below 2 kbar), temperatures higher than 1000 řC, and the liquid-vapor equilibrium curve, particularly in the proximity of the critical point of water. The deviations of volumetric and electrostatic properties of water propagate into the mineral solubility calculations. For quartz and corundum these deviations lead to discrepancy in mineral solubility of up to half an order of magnitude for molal concentrations. These discrepancies...
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Fluid inclusion study of pegmatites from Vepice and Vlastějovice
Surmová, Petra ; Zachariáš, Jiří (advisor) ; Dolníček, Zdeněk (referee)
Fluid inclusions of pegmatites from two localities in the Moldanubina Zone were studied in order to constrain PT conditions of their crystallization and establish composition and properties of fluids associated with pegmatite formation. The first locality is Vepice near Tábor, second locality is Vlastějovice near Zruč nad Sázavou. Pegmatit of Vepice consists of irregular pockets in amphibole- biotic granite dark type to a porphyric syenodioritot Čertova břemene. Fluid inclusions have been studied in several cm large quartz crystals of miarolic cavities from the central zone pegmatites pockets within the central zone of the pegmatite pockets. The collected fluids are aqueous- type with a low salt content (usually in the range of 4-6 hm% NaClekv. Pegmatites in Vepice among the complex Y-REE-Nb-Ta-Ti pegmatites. In terms of PT conditions pegmatites belong to the classification of rare element pegmatite or miarolitic's pegmatites. The studied sample of Vlastějovice (skarn's body) represented a transition from quartz-feldspar pegmatite lithium zone to zone with predominance of quartz (quartz core). Only one sample was studied, which originated from the historical collections F. Čech (Čech, 1985). The sample is an exceptional presence of large quantities of the solid phase (up to 4-5 stages). Using Raman...
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