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Mineral assemblages, alteration reactions and transport model of the greisen formation in the Horní Blatná granite pluton, Krušné hory Mts.
Heřmanská, Matylda ; Dolejš, David (advisor) ; Štemprok, Miroslav (referee)
English abstract Hydrothermal systems related to highly evolved granitic magmas host diverse mineralization styles and provide an important source of economic metals. This master thesis concentrates on description and interpretation of geological structure, petrographic and textural variability, alteration zoning and calculation of time-integrated fluid fluxes recorded in highly evolved granites and tin-mineralized greisens of the Horní Blatná massif in the Western Krušné hory pluton. The massif is a composite intrusion, which consists of a large number of intrusive units emplaced during two stages. The first stage is represented by sparsely porphyritic fine-grained low-lithian annite granites that can be correlated with marginal granites (G2) of the Fichtelgebirge (Smrčiny) batholith or with intermediate granites (Walfischkopf type) of the Western Krušné hory (Erzgebirge) pluton. Intrusive batches of the second stage progressively evolve from medium- to coarse-grained serial high-lithian annite and zinnwaldite granites with topaz and rare tourmaline towards aphyric fine-grained zinnwaldite (or trilithionite) granites. This suite corresponds to the EIB2 and EIB3 facies of the younger intrusive complex in the Western Krušné hory (Erzgebirge) pluton and it can be compared to the G3 Waldstein and G4 units in...
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Reactive fluid flow and origin of the fracture-controlled greisens in the Horní Blatná granite pluton, Krušné hory Mts.
Heřmanská, Matylda ; Dolejš, David (advisor) ; Štemprok, Miroslav (referee)
Magmatic intrusions emplaced in the shallow continental crust are often associated with hydrothermal alteration and mineralization systems. Alteration zones and their assemblages can be described by means of reaction progress and this variable then used to calculate the time-integrated fluid fluxes, responsible for the mineral formation, if gradients in fluid composition, temperature and pressure are known or estimated. Two limiting cases of this approach have been applied in previous numerical models: (i) infiltration of aqueous fluid that is out of equilibrium with the host rocks, thus producing an alteration sequence as the fluid flux increases, and (ii) fluid flow in local equilibrium with host rocks, where mineral changes are induced by pressure and temperature gradients along the flow path. These two models generally yield results that differ by several orders of magnitude but are both in use for estimating fluid fluxes and transport properties in the lithosphere. We propose a combined model that evaluates the disequilibrium fluid infiltration and the pressure-temperature gradients simultaneously, and apply it to the interpretation of fracture-controled greisen alteration in the Horní Blatná granite pluton in the Krušné hory Mts. (Czech Republic). The Horní Blatná pluton is a composite...
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Mineral assemblages, alteration reactions and transport model of the greisen formation in the Horní Blatná granite pluton, Krušné hory Mts.
Heřmanská, Matylda ; Dolejš, David (advisor) ; Štemprok, Miroslav (referee)
English abstract Hydrothermal systems related to highly evolved granitic magmas host diverse mineralization styles and provide an important source of economic metals. This master thesis concentrates on description and interpretation of geological structure, petrographic and textural variability, alteration zoning and calculation of time-integrated fluid fluxes recorded in highly evolved granites and tin-mineralized greisens of the Horní Blatná massif in the Western Krušné hory pluton. The massif is a composite intrusion, which consists of a large number of intrusive units emplaced during two stages. The first stage is represented by sparsely porphyritic fine-grained low-lithian annite granites that can be correlated with marginal granites (G2) of the Fichtelgebirge (Smrčiny) batholith or with intermediate granites (Walfischkopf type) of the Western Krušné hory (Erzgebirge) pluton. Intrusive batches of the second stage progressively evolve from medium- to coarse-grained serial high-lithian annite and zinnwaldite granites with topaz and rare tourmaline towards aphyric fine-grained zinnwaldite (or trilithionite) granites. This suite corresponds to the EIB2 and EIB3 facies of the younger intrusive complex in the Western Krušné hory (Erzgebirge) pluton and it can be compared to the G3 Waldstein and G4 units in...
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Reactive fluid flow and origin of the fracture-controlled greisens in the Horní Blatná granite pluton, Krušné hory Mts.
Heřmanská, Matylda ; Dolejš, David (advisor) ; Štemprok, Miroslav (referee)
Magmatic intrusions emplaced in the shallow continental crust are often associated with hydrothermal alteration and mineralization systems. Alteration zones and their assemblages can be described by means of reaction progress and this variable then used to calculate the time-integrated fluid fluxes, responsible for the mineral formation, if gradients in fluid composition, temperature and pressure are known or estimated. Two limiting cases of this approach have been applied in previous numerical models: (i) infiltration of aqueous fluid that is out of equilibrium with the host rocks, thus producing an alteration sequence as the fluid flux increases, and (ii) fluid flow in local equilibrium with host rocks, where mineral changes are induced by pressure and temperature gradients along the flow path. These two models generally yield results that differ by several orders of magnitude but are both in use for estimating fluid fluxes and transport properties in the lithosphere. We propose a combined model that evaluates the disequilibrium fluid infiltration and the pressure-temperature gradients simultaneously, and apply it to the interpretation of fracture-controled greisen alteration in the Horní Blatná granite pluton in the Krušné hory Mts. (Czech Republic). The Horní Blatná pluton is a composite...
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