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Mafic and intermediate intrusions accompanying peraluminious granites of the Krušné hory Mts.batholit
Holečková, Pavla ; Jelínek, Emil (advisor) ; Ackerman, Lukáš (referee) ; Leichmann, Jaromír (referee)
Mafic and intermediate intrusions commonly accompany Variscan granitoid plutons in Europe. They are documented from different localities of Iberian Peninsula, from the French Massif Central, Schwarzwald, from different parts of the Bohemian Massif, in Romania, Greece, Corsica and Sardinia. They comprise wide petrographic varieties from quartz gabbros, diorites, granodiorites to monzonites. They usually constitute small bodies or veins, they often occur as mafic microgranular enclaves (MME) in granodiorites and in some granites. Dioritic intrusions are characterized by a relatively high amounts of lithophile elements (Rb, Sr, Ba, Cs, LREE), and they are simultaneously high in compatible elements (Ni, Cr, V a Co). Their isotopic ratios 87 Sr/86 Sr are in all compared locations similar and are close to the Bulk Earth (0.704 - 0.708). εNd values show larger scatter, some intrusions have more crustal composition (to -8), on the other hand, another intrusions have εNd positive, that points to a contribution of basic magma. The age of dioritic intrusions differs according to individual locality suggesting more than one magmatic episode. The oldest occur in the French Massif Central (361 - 365 Ma), whereas the youngest are documented in Iberia (312 - 310 Ma). The oldest mafic intrusions in the Bohemian...
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Radioactive accessory minerals in granitoids and its changes during metamorphosis and alteration.
Tuhý, Marek ; Goliáš, Viktor (advisor) ; Matějka, Dobroslav (referee)
This paper is focused on gathering information about alterations of radioactive accessory minerals in granitic rocks. These minerals become unstable during the influence of fluids and increased temperature and pressure conditions. Allanite is usually metamict therefore it is more easily altered than others. Alteration of monazite is described as decomposing original grains which leads to the formation of secondary minerals such as allanite, apatite, minerals of thorium and epidote. Zircon is the most durable mineral mentioned in this paper. Zircon is altered mainly if it is metamict. Majority of authors agree that during alteration uranium is mobilized into fluids and thorium with REE is incorporate into the secondary minerals.
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Methods of study of porosity of granitic rocks in relation to rock fabric
Votavová, Klára ; Přikryl, Richard (advisor) ; Krutilová, Kateřina (referee)
This bachelor thesis focuses on granitic rocks, which are often used as a building material. Granite are generally rocks with very low porosity, which can be modified (augmented) due to e.g. weathering processes. Increase of porosity is accompanied with deterioration of other physical parameters and decrease of durability. The thesis focuses, after introducing basic petrographical and petrogenetic characteristics of granitic rocks, on the definition of porosity as a physical property, and on various methods used for its determination. Next part of the thesis discusses some case studies which underpin the significance of porosity of granitic rocks by either using combination of several methods, or by using unconventional ones. According to available data, study of porosity and its relationship to rock fabric should be performed by combining several methods of study, encompassing simple petrophysical determination of open and bulk porosities, and microscopic methods allowing for visualisation of pore space - mineral grains relationships. These can be accompanied with less common method of multidirectional ultrasonic sounding allowing for determination of spatial distribution of microcracks present in granitic rocks.
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Methods of study of porosity of granitic rocks in relation to rock fabric
Votavová, Klára ; Přikryl, Richard (advisor) ; Krutilová, Kateřina (referee)
This bachelor thesis focuses on the problem of porosity of granites. The introductory part of the thesis describes granites, their origin, and classification. Specific concern is given to granites as building materials; therefore factors influencing the quality and durability of building stone are mentioned. Porosity of granites can be observed by several different methods. However, none of the methods provides accurate information on present pores from all points of view. From the methods used, mercury porosimentry performed under laboratory conditions seems to be one of the most effective methods. Other effective approaches are microscopic techniques, such as a scanning electron microscopy with energy dispersive spectrometry and/or optical microscopy. Generally, it is suggested to combine several methods to combine information on the volume and distribution of pores with their shape and size.
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Radioactive accessory minerals in granitoids and its changes during metamorphosis and alteration.
Tuhý, Marek ; Goliáš, Viktor (advisor) ; Matějka, Dobroslav (referee)
This paper is focused on gathering information about alterations of radioactive accessory minerals in granitic rocks. These minerals become unstable during the influence of fluids and increased temperature and pressure conditions. Allanite is usually metamict therefore it is more easily altered than others. Alteration of monazite is described as decomposing original grains which leads to the formation of secondary minerals such as allanite, apatite, minerals of thorium and epidote. Zircon is the most durable mineral mentioned in this paper. Zircon is altered mainly if it is metamict. Majority of authors agree that during alteration uranium is mobilized into fluids and thorium with REE is incorporate into the secondary minerals.
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Mafic and intermediate intrusions accompanying peraluminious granites of the Krušné hory Mts.batholit
Holečková, Pavla ; Jelínek, Emil (advisor) ; Ackerman, Lukáš (referee) ; Leichmann, Jaromír (referee)
Mafic and intermediate intrusions commonly accompany Variscan granitoid plutons in Europe. They are documented from different localities of Iberian Peninsula, from the French Massif Central, Schwarzwald, from different parts of the Bohemian Massif, in Romania, Greece, Corsica and Sardinia. They comprise wide petrographic varieties from quartz gabbros, diorites, granodiorites to monzonites. They usually constitute small bodies or veins, they often occur as mafic microgranular enclaves (MME) in granodiorites and in some granites. Dioritic intrusions are characterized by a relatively high amounts of lithophile elements (Rb, Sr, Ba, Cs, LREE), and they are simultaneously high in compatible elements (Ni, Cr, V a Co). Their isotopic ratios 87 Sr/86 Sr are in all compared locations similar and are close to the Bulk Earth (0.704 - 0.708). εNd values show larger scatter, some intrusions have more crustal composition (to -8), on the other hand, another intrusions have εNd positive, that points to a contribution of basic magma. The age of dioritic intrusions differs according to individual locality suggesting more than one magmatic episode. The oldest occur in the French Massif Central (361 - 365 Ma), whereas the youngest are documented in Iberia (312 - 310 Ma). The oldest mafic intrusions in the Bohemian...
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