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Metallogeny of selected gold deposits of the Bohemian Massif
Němec, Matěj
The overall text was processed on the bases of two separate articles published recently by the author and collective, and one more article, which is currently submitted for editorial. All the articles in full are attached at the end of this work. First article is trying to decipher the evolution of formation of the Sb-Au deposits Krásná Hora-Milešov, and Příčovy. The second article is in very detail dedicated to transition of gold to aurostibite and formation of Au-Ag-Sb(S) phases at Krásná Hora-Milešov Sb-Au deposit. The third article is looking into genesis of the Voltýřov Au deposit. The Krásná Hora-Milešov and Příčovy deposits are examples of in the Bohemian Massif unique Sb-Au deposits. The deposits consist of vein type mineralization and ore is represented by massive to disseminated stibnite and disseminated gold postdating stibnite. The quartz gangue vein system is developed in Těchnice granodiorite, within robust E-W trending fault zone, and in close association with same oriented repeatedly tectonically rejuvenated lamprophyre dikes. The fluid inclusions (FI) study suggested formation of stibnite at ~250 to ~130 řC and gold at about ~200 to ~130 řC from low salinity aqueous fluids. The bulk of quartz precipitated from the same type of fluid. Disseminated arsenopyrite along with early quartz...
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Metallogeny of selected gold deposits of the Bohemian Massif
Němec, Matěj ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee) ; Sejkora, Jiří (referee)
The overall text was processed on the bases of two separate articles published recently by the author and collective, and one more article, which is currently submitted for editorial. All the articles in full are attached at the end of this work. First article is trying to decipher the evolution of formation of the Sb-Au deposits Krásná Hora-Milešov, and Příčovy. The second article is in very detail dedicated to transition of gold to aurostibite and formation of Au-Ag-Sb(S) phases at Krásná Hora-Milešov Sb-Au deposit. The third article is looking into genesis of the Voltýřov Au deposit. The Krásná Hora-Milešov and Příčovy deposits are examples of in the Bohemian Massif unique Sb-Au deposits. The deposits consist of vein type mineralization and ore is represented by massive to disseminated stibnite and disseminated gold postdating stibnite. The quartz gangue vein system is developed in Těchnice granodiorite, within robust E-W trending fault zone, and in close association with same oriented repeatedly tectonically rejuvenated lamprophyre dikes. The fluid inclusions (FI) study suggested formation of stibnite at ~250 to ~130 řC and gold at about ~200 to ~130 řC from low salinity aqueous fluids. The bulk of quartz precipitated from the same type of fluid. Disseminated arsenopyrite along with early quartz...
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Variscan fluids of the Barrandian Lower Paleozoic: case study from the Žák's quarry at Velká Chuchle
Stárková, Petra ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee)
Hydrothermal veins in the Paleozoic of the Barrrandian testify for fluid migration during diagenesis and/or epigenesis. A more detailed mineralogical and geochemical research of these veins has started since the end of the 20th century. The subject of a research included in this thesis is determination of conditions of formation of syntectonic calcite and quartz-calcite veins in the lokality called Žák's quarry in Velká Chuchle. This thesis is based on field determination of succession of hydrothermal veins and laboratory study of fluid inclusions in minerals as a basic tool for determination of temperatures during formation of veins. In total, there were distinguished four types/generations of calcite and quartz-calcite veins in Žák's quarry (from oldest to youngest): 1) veins of ,,beef calcite", 2) veins with flat crystals of smoky quartz located in joints perpendicular to bedding, 3) shear veins with calcite located in the big fold, 4) a big calcite vein with tectonic striae spatially bound to significant local fault. Veins have thickness aproximatelly from 1 mm to about 15 cm. By the way, veins of ,,beef calcite" are characteristic by orientation of prolonged grains of calcite in the direction orthogonal towards to the plane of vein. The microscopic study of fluid inclusions revealed presence of...
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Principles of application of fluid inclusions for the study of hydrothermal mineralizations
Štrba, Martin ; Zachariáš, Jiří (advisor) ; Dobeš, Petr (referee)
The bachelor thesis is subdivided into two review parts and one experimental part. The first part focuses on petrography and microthermometric study of fluid inclusions. Petrography chapter lists genetic types of inclusions, and various mechanisms that determine their shape and digree of fill. Emphasis is placed especially on the microthermometric study of fluid inclusions. The phase changes in H2O - NaCl and H2O - CO2 - salts systems at low and high temperatures are described in detail. A separate chapter is dedicated to interpretation of microthermometric data and to their use in determination of pressure-temperature conditions of minerals formation. The second part of the thesis lists several examples of using the fluid inclusions in the study of hydrothermal deposits and in prospecting of ore deposits (Pb - Zn - fluorite deposits of Mississippi valley type, porphy - type, Cu - ores at Bingham). One chapter is dedicated to Bleïda deposit (Morocco), Kanmantoo deposit (Australia) and San Cristobal vein (Peru). This chapter discribes geology, mineralogy and fluid inclusion data of these deposits. Third, experimental, chapter deals with hydrothermal mineralization in the Ševětín quarry. It includes the regional geology of Ševětín massif, geology of the quarry and the mineralogy of hydrothermal...
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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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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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Variscan fluids of the Barrandian Lower Paleozoic: case study from the Žák's quarry at Velká Chuchle
Stárková, Petra ; Zachariáš, Jiří (advisor) ; Slobodník, Marek (referee)
Hydrothermal veins in the Paleozoic of the Barrrandian testify for fluid migration during diagenesis and/or epigenesis. A more detailed mineralogical and geochemical research of these veins has started since the end of the 20th century. The subject of a research included in this thesis is determination of conditions of formation of syntectonic calcite and quartz-calcite veins in the lokality called Žák's quarry in Velká Chuchle. This thesis is based on field determination of succession of hydrothermal veins and laboratory study of fluid inclusions in minerals as a basic tool for determination of temperatures during formation of veins. In total, there were distinguished four types/generations of calcite and quartz-calcite veins in Žák's quarry (from oldest to youngest): 1) veins of ,,beef calcite", 2) veins with flat crystals of smoky quartz located in joints perpendicular to bedding, 3) shear veins with calcite located in the big fold, 4) a big calcite vein with tectonic striae spatially bound to significant local fault. Veins have thickness aproximatelly from 1 mm to about 15 cm. By the way, veins of ,,beef calcite" are characteristic by orientation of prolonged grains of calcite in the direction orthogonal towards to the plane of vein. The microscopic study of fluid inclusions revealed presence of...
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Genesis of Au-Sb ores at the Krásná Hora deposit
Němec, Matěj ; Zachariáš, Jiří (advisor) ; Dobeš, Petr (referee)
Ore deposits of the Krásná Hora ore district are the main representative of the Sb-Au mineralization in the Czech Republic. It can be classified genetically as epizonal subtype of orogenic gold deposits. Spatially and partly temporally are associated with the intrusion of the Central Bohemian Pluton. The ore bodies are related to quartz veins that follow the course of E-W striking lamprophyre dykes, which are usually heavily crushed and altered. Ore shoots with massive stibnite are located mainly at the intersections of these E-W trending veins with the NW-SE striking tectonic fault zones. Au-Sb ores at Krásná Hora ore district formed in an area of repeatedly activated fault zones. Three generations of hydrothermal quartz were identified on microscopic scale. Earliest quartz (Qtz1), which was considered in the literature auriferous originated from low-salinity H2O - CO2 fluids at ~350 řC and at a depth of about 5 km. The younger quartz (Qtz2) originated at lower temperatures of about 260 řC and lower depth of about 3-4 km from low/saline aqueous fluids. Both older (Qtz1) and younger quartz (Qtz2) are not auriferous. The gold is associated with younger paragenetic formation (Anti + Au + Cc + Qtz3) that fills in intergranular spaces and fractures in Qtz1 and Qtz2 . Due to the partial exhumation of the...
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Principles of application of fluid inclusions for the study of hydrothermal mineralizations
Štrba, Martin ; Zachariáš, Jiří (advisor) ; Dobeš, Petr (referee)
The bachelor thesis is subdivided into two review parts and one experimental part. The first part focuses on petrography and microthermometric study of fluid inclusions. Petrography chapter lists genetic types of inclusions, and various mechanisms that determine their shape and digree of fill. Emphasis is placed especially on the microthermometric study of fluid inclusions. The phase changes in H2O - NaCl and H2O - CO2 - salts systems at low and high temperatures are described in detail. A separate chapter is dedicated to interpretation of microthermometric data and to their use in determination of pressure-temperature conditions of minerals formation. The second part of the thesis lists several examples of using the fluid inclusions in the study of hydrothermal deposits and in prospecting of ore deposits (Pb - Zn - fluorite deposits of Mississippi valley type, porphy - type, Cu - ores at Bingham). One chapter is dedicated to Bleïda deposit (Morocco), Kanmantoo deposit (Australia) and San Cristobal vein (Peru). This chapter discribes geology, mineralogy and fluid inclusion data of these deposits. Third, experimental, chapter deals with hydrothermal mineralization in the Ševětín quarry. It includes the regional geology of Ševětín massif, geology of the quarry and the mineralogy of hydrothermal...
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