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Genetic relationships between intrusions of porphyry dykes and formation of Au ores at Petrov and Bohuliby
Petrov, Ivan ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee)
This master's thesis is focused on genetic relationships between Au-bearing ores and associated granodiorite porphyry dykes in Petrov and Bohuliby area in southwestern part of the Jílové ore district. Subvolcanic rocks with hydrothermally induced alteration and Au/bearing mineralization were characterized by petrography, mineralogy and crystallochemistry. Mutual genetic and textural relationships of studied materials were examined as well and were validated by biotite, arsenopyrite and chlorite empirical geothermometry. First identified generation of sulfide mineralization was formed at 360řC and consist of arsenopyrite, galenite and native gold. At circa 274řC porphyry mineral association was chloritized, and chlorite gangue crystallized. Second generation of sulfide mineralization precipitated at 264řC. Anomalous absence of Bi-Te-S phases and scheelite in hydrothermal paragenesis is important indicator of contrasting conditions of mineralization at the studied areas and main zone of the Jílové ore deposit. Based on acquired data, granodiorite porphyry dikes were categorized to two separate genetic types, which have mutual origin in deep magma chamber of Central Bohemian Plutonic Complex but intruded non-contemporaneously.
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Genetic relationships between intrusions of porphyry dykes and formation of Au ores at Petrov and Bohuliby
Petrov, Ivan ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee)
This master's thesis is focused on genetic relationships between Au-bearing ores and associated granodiorite porphyry dykes in Petrov and Bohuliby area in southwestern part of the Jílové ore district. Subvolcanic rocks with hydrothermally induced alteration and Au/bearing mineralization were characterized by petrography, mineralogy and crystallochemistry. Mutual genetic and textural relationships of studied materials were examined as well and were validated by biotite, arsenopyrite and chlorite empirical geothermometry. First identified generation of sulfide mineralization was formed at 360řC and consist of arsenopyrite, galenite and native gold. At circa 274řC porphyry mineral association was chloritized, and chlorite gangue crystallized. Second generation of sulfide mineralization precipitated at 264řC. Based on acquired data, granodiorite porphyry dikes were categorized to two separate genetic types, which have mutual origin in deep magma chamber of Central Bohemian Plutonic Complex but intruded non-contemporaneously.
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Distribution of arsenic in the soil of gold mineralizations in Central Bohemian metallogenetic zone
Řeháček, Jan ; Drahota, Petr (advisor) ; Kindlová, Helena (referee)
Univerzita Karlova v Praze Přírodovědecká fakulta Ústav geochemie, mineralogie a nerostných zdrojů Obsahy arzenu v půdách zlatonosných ložisek středočeské metalogenetické zóny Bakalářská práce Jan Řeháček Vedoucí bakalářské práce: doc. Mgr. Petr Drahota, Ph.D. Praha, 2016 Summary This bachelor thesis reviews scientific publications regarding high concentrations of arsenic in soils of natural geochemical anomalies and former gold mines in the Central Bohemian Metallogenic Zone. High concentrations of arsenic in these areas originates primarily from sulfide minerals which are associated with gold mineralization. Arsenopyrite and pyrite are the most important primary As carriers in the bedrock. Due to natural weathering of sulfide minerals hosting rocks, release of arsenic and other potentially toxic elements into the surrounding environment takes place. This presents danger not only to soil fauna and flora but also to local inhabitants as contamination may also affect water sources in the area. At the beginning of this thesis some general aspects of the presence of arsenic in the environment are described, followed by chapters about the Central Bohemian Metallogenic Zone and its sites with anomalous concentration of arsenic in soil.
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Variation of isotopic composition in selected natural and archeological samples, methodical approach
Venhauerová, Petra ; Trubač, Jakub (advisor) ; Magna, Tomáš (referee)
This thesis is focused on elaboration of the methodical approaches for determination silver isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICP- MS) from Centrum of stable and radiogenic isotopes on Science Faculty on Charles University. Therefore, this thesis describes in detail methodology of chromatographic separation and conditions of further measurement. For analysis of isotopic ratios 107 Ag/109 Ag in individual samples are used natural samples of various silver and gold deposits in Czech Republic and Poland. Also, archeological findings of fractures of silver coins from our country. The aim of this work is to find out if there is a variability among this two types of samples. Measured values are further correlated with already published works specialized on similar types of natural and archeological samples. The obtained values could be used for an interpretation of geological processes (e. g. physicochemical fractionation during ore forming processes) or as an identification source of the origin of coins and other archeological findings (e. g. silver ornaments). Gained knowledge of this work will help improve contemporary methodology in measurement of silver isotopes, such as standard calibration and tuning the stability of a signal. Key words: isotopes of...
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Distribution of arsenic in the soil of gold mineralizations in Central Bohemian metallogenetic zone
Řeháček, Jan ; Drahota, Petr (advisor) ; Kindlová, Helena (referee)
Univerzita Karlova v Praze Přírodovědecká fakulta Ústav geochemie, mineralogie a nerostných zdrojů Obsahy arzenu v půdách zlatonosných ložisek středočeské metalogenetické zóny Bakalářská práce Jan Řeháček Vedoucí bakalářské práce: doc. Mgr. Petr Drahota, Ph.D. Praha, 2016 Summary This bachelor thesis reviews scientific publications regarding high concentrations of arsenic in soils of natural geochemical anomalies and former gold mines in the Central Bohemian Metallogenic Zone. High concentrations of arsenic in these areas originates primarily from sulfide minerals which are associated with gold mineralization. Arsenopyrite and pyrite are the most important primary As carriers in the bedrock. Due to natural weathering of sulfide minerals hosting rocks, release of arsenic and other potentially toxic elements into the surrounding environment takes place. This presents danger not only to soil fauna and flora but also to local inhabitants as contamination may also affect water sources in the area. At the beginning of this thesis some general aspects of the presence of arsenic in the environment are described, followed by chapters about the Central Bohemian Metallogenic Zone and its sites with anomalous concentration of arsenic in soil.
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