National Repository of Grey Literature 86 records found  beginprevious38 - 47nextend  jump to record: Search took 0.01 seconds. 
Mineralogy and genesis of gold ores hosted by porphyry dykes at Petrov and Bohuliby
Petrov, Ivan ; Zachariáš, Jiří (advisor) ; Strnad, Ladislav (referee)
This bachelor thesis is focused on mineralogy and genesis of Au-bearing ores in southwestern part of the Jílové ore district, in between Petrov and Bohuliby. Crystallization sequence of hydrothermal minerals was identified by textural relationships of mineral phases. Arsenopyrite and chlorite thermometry suggest formation of sulphides and gold at 400-300 řC. Within the scope of this thesis the paragenesis of rock-forming minerals of granodiorite porphyry dikes hosting Au-bearing ores, as well as of late-magmatic to hydrothermal minerals filling in miarolitic cavities in these porphyries, were also interpreted. A hypothesis of granodiorite dikes' origin is suggested as well, involving mixing of magmas with different geochemical signatures.
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...
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...

National Repository of Grey Literature : 86 records found   beginprevious38 - 47nextend  jump to record:
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2 Zachariáš, Jan
2 Zachariáš, Jindřich
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