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Fabrics of the Weinsberg granitoids on example of the Prášily pluton (Moldanubický plutonický komplex)
Pour, Ondřej ; Verner, Kryštof (advisor) ; Racek, Martin (referee)
This bachelor thesis is concerned with the brief introduction to the structures and fabrics in granitoid plutons. In the next part of this work are sumarized results of structural analyses of Weinsberg-type granite intrusion (Prášily pluton) located in the SW part of high-grade rocks of the Moldanubian Zone. This research proceeded based on a combination of field structural data and results of AMS (Anisotropy of magnetic susceptibility) method. The internal fabrics and structures of the Prášily pluton reflect emplacement mechanisms, kinematic history and evolution of the regional strain field during Variscan orogeny at around 330 Ma. The examined area provides crucial constraints for the geodynamic models of geological evolution of deeper parts of the Variscan orogen in the SW part of the Bohemian Massif.
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Classical iconographical schemes in Iranian art
Šütöová, Silvia ; Bouzek, Jan (referee) ; Stančo, Ladislav (advisor)
The thesis is written in form of a comparative study. It studies the Persian art and evolution of the used iconographic schemes and it tries to recognize the Greek and Roman influences on the iconography of the most widespread motifs in Persian art, but also the acceptance of new motifs and their further evolution. Marginally it brings up some interesting points abou the possible broader relations of Persia and Greece outside of armed conflicts and official propaganda. The thesis proceeds chronologically from the Achaemenid empire through Parthian and Sasanian empire, it observes the motifs of the sculptural decoration of palaces and very popular rock reliefs, metalwork, gems, coins and other artifacts, which changed under the influence of classical models. It considers the iconography of investiure and the deity represented in it, the influence of the iconography of goddess Nike, dionysiac iconograophy, the metamorphosis of the royal iconograph, the appearance of female figures and children, the evolution of nudity and dance in Persian Art and the spreading of floral ornaments from smaller surfaces to whole vessels, in architecture from friezes to covering whole buildings in the Islamic era.
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Phosphates and accessory oxides in selected granitoids and paragneisses of the Moldanubian area in southeastern and southern Bohemia
Procházka, Václav ; Matějka, Dobroslav (advisor) ; Štemprok, Miroslav (referee) ; Petrík, Igor (referee)
The thesis deals with granites and paragneisses prevalently in the area of northern Moldanubian Batholith (especially the Melechov massif). The main object are accessory minerals, also some information replenishing the knowledge about geochemistry and petrography of studied rocks has been obtained. The research has been focused mainly on phosphates and Fe-Ti oxides. Fluorapatite (only "apatite" in the following text) is common in all granitoids as well as paragneisses. In metamorphic rocks and in little fractionated granites (the Lipnice and Pavlov types), apatite is very homogeneous and only exceptionally corroded. In more fractionated granites, complicated evolution of apatite has been documented with the usage of cathodoluminescence. The cathodoluminescence is influenced mainly with admixtures of Fe, Mn, Y and REE, as documented in literature. In addition, irradiation (mainly from monazite inclusions) darkens the luminescence, and the influence of uneven surface is also significant. The contents of Na, Fe, Mn, Y and REE are higher in the interior of unaltered crystals. Trace-elemnt determination (LA-ICP-MS) in apatite in granites of Melechov massif also shows that the unaltered primary apatite has also higher U and lower Sr content, deeper negative Eu-anomaly, and more pronounced M-type tetrad...
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The Changes in Structure of Steel P91 after Short Annealings
Král, Lubomír ; Čermák, Jiří ; Král, Petr
Phase composition of the steel P91 during annealing was studied with the aim to reveal the evolution of new phases. In this paper, the precipitation was characterized using energy-dispersive X-ray spectroscopy (EDS) and electron diffraction in transmission microscopy (TEM). Only Nb-rich particles were found in the studied samples austenitized at 1423 °C for 20h and water cooled. After tempering at 673 °C for 2 h, the formation mainly M3C type carbides and after tempering at 873 °C for 2 h, the formation of M7C3 and M23C6 was observed. These structure changes play an important role for stability and also carbon diffusion.
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Comprehensive study of the sandstone rock forms deterioration (Case study: Pravčická brána Arch, Bohemian Switzerland National Park)
Vařilová, Zuzana
This PhD thesis contains the results of comprehensive research into the Pravčická brána Arch and surrounding sandstone massifs with focus on gaining more knowledge about natural dynamics and evolution of this rock formation, its current level of stability and the weathering processes it displays. Non-destructive methods were used for this comprehensive study; these ranged from detailed field documentation to monitoring temperature regime of the rock and included application of a geophysical survey and control monitoring of the course of arch body deformation. Laboratory testing was carried out for strength parameters and salt efflorescences together with weathered sandstones were analysed for chemical compounds. Main operating factors were monitored simultaneously, which particularly involved changes in external temperature, degree of sunlight and chemical composition of rainfall. Conventional as well as entirely new assessment procedures were used in synthesis and interpretation of the data collected, including knowledge of nonlinear dynamics of complex systems. The survey was designed to fully respect the protective conditions of the site, to make follow-up activities possible in future and to monitor any possible negative changes in the rock massif. The main results incorporate description of...
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Study of microstructure evolution during final stage of sintering of advanced ceramic materials
Hrubý, Jan ; Salamon, David (referee) ; Maca, Karel (advisor)
This diploma thesis deals with the study of microstructure development during the final stage of sintering of two zirconia based ceramic materials (tetragonal ZrO2 doped with 3 mol% of Y2O3 and cubic ZrO2 doped with 8 mol% of Y2O3). Conventional, microwave and SPS sintering methods were used. Achieved relative densities and mean grain sizes were evaluated for sintered materials. It was found that the non-conventional sintering methods are capable of rapid processing of ceramics with improved microstructure compared to conventional sintering.
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Geophysical and remote sensing methodologies applied to the analysis of regolith and geology in Burkina Faso, West Africa
Metelka, Václav ; Ježek, Josef (advisor) ; Miller, John (referee) ; Martelet, Guillaume (referee) ; de Kemp, Eric (referee)
The oldest parts of continents, so-called cratons, are the focus of worldwide research not only because they represent primary constraints for our understanding of the early evolution of the Earth, but also because of their significant mineral potential. This work contributes to the understanding of the geological and geomorphological evolution of the West African Craton, by an integrated analysis of airborne geophysical and satellite remote sensing data constrained by field structural, lithological, geophysical, and geomorphological observations acquired around Houndé, Boromo and Banfora greenstone belts and associated granitoid domains in western Burkina Faso. The results of this integration suggest that the granitoid domains of western Burkina Faso are formed by numerous small- to medium-sized plutons, and the magnetic data provided a better definition of the actual pluton shapes. Airborne gamma ray spectrometry data aided in the mapping process in areas with less regolith cover. Three deformation events (D1-D3) can be distinguished in western Burkina Faso. A megacrystic tholeiitic basalt unit allowed us to establish stratigraphic correlations between the two belts and propose a crustal scale anticline (D1). The D1 penetrative structures, resulting from an E-W to WNW-oriented compression are...
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Low-temperature evolution of granulites in the Moldanubian Zone of the southern Bohemian Massif
Kořínková, Dagmar ; Svojtka, Martin (advisor) ; Matějka, Dobroslav (referee)
The Variscan orogeny occured during Devonian to Carboniferous convergence between peri- Gondwanan crustal segments and the northern European plate (Baltica). Due to the convergence, Bohemian Massif represents the easternmost and largest exposure in the European Variscan belt. In the southern part of the Bohemian Massif, the Moldanubian Zone consists of several crustal segments with different polyphase tectonometamorphic histories. Moldanubian Zone is considered to represent the Variscan orogenic root, being surrounded by rigid and less metamorphosed blocks to the NW and SE. Structurally highest unit of the Moldanubian Zone is the Gföhl Unit, which is built by heterogeneous assemblage of high-pressure crustal and upper-mantle rocks comprising granulites, peridotites, pyroxenites and eclogites exhumed during Variscan orogeny. The apatite samples studied in my diploma thesis come from different types of granulites from the Blanský les granulite massif (BLGM) located SW of the town of České Budějovice. BLGM is the largest granulite body of the southern Bohemian Massif, is an integral part of the Gföhl Unit. BLGM consists mainly of calc-alkaline high-pressure felsic garnet ± kyanite granulites, which enclose up to several kilometers long lenses of ultrabasic rocks, numerous boudins of mafic...
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Exhumation of mid-crustal rocks by a brittle-ductile unroofing mechanism, an example from the Veporic crystalline complex in the West Carpathians
Bukovská, Zita ; Jeřábek, Petr (advisor) ; Milovský, Rastislav (referee)
Study of the structural and metamorphic record of the eastern part of contact zone within Vepor and Gemer units in Central West Carpathians has interpreted the burial and exhumation in the evolution of alpine orogeny. The studied area is built by granitoid rocks of Vepor basement and metapelites of cover sequences both Vepor and Gemer units. Three structural fabrics have been identified in the area, which are correlated with so far described deformation stages. Higher metamorphosed rocks with presence of two generation garnets were found out within lower metamorphosed metapelites of cover sequences. From the garnet - biotite thermometry the metamorphic conditions for the rims were established to 550-580řC. Whereas muscovite and in some case chlorite, are the only metamorphic phases in neighbouring cover rocks. Three generations of white micas are documented within structural fabrics. The oldest muscovites, magmatic in origin (Ms1), younger phengites (Phg) present in fabrics S1 and youngest muscovites (Ms2) present in fabric S2. The study of quartz microstructures distinguished aggregates and from aggregates coming band microstructures. These are mostly found in deformed granitoids, sometimes also in cover quartzites and can have sigma-shape geometry. The aggregate microstructure, representing S1...
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