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Mechanisms of differentiation and emplacement of peraluminic granite magma: Říčany pluton, Bohemian Massif
Trubač, Jakub ; Žák, Jiří (advisor) ; Závada, Prokop (referee)
English abstrakt This thesis is focused on emplacement mechanisms of granitic magma into upper continental crust. The studied area is the Říčany pluton due to its unusual and asymmetric shape. Therefore, it represents a suitable intrusion for interpretation different models referring to emplacement of granitic magma. Common model for ascent of magma is incremental diking in present. The Říčany pluton of the Central Bohemian Plutonic Complex is a post-tectonic elliptical shallow-level intrusion emplaced into low-grade Neoproterozoic and Lowe Carboniferous times (~337 Ma). It comprises of outer, more fractionated, strongly porphyritic granite and inner, less evolved, weakly porphyritic granite. Mesoscopic foliation represents an onion-skin pattern and corresponds well to the magnetic (AMS) foliations. Magnetic lineation has a gentle dip (0-20ř) and closely parallels with the pluton contact in its outer part whereas the lineation dips steeply (60-70ř) with a variable trend in the pluton interior. Author interprets these fabrics as a result of a helical flow, which is a faster subvertical flow in the low-viscosity pluton centre being accompanied by a subhorizontal flow in the outer, higher-viscosity (phenocryst-rich) margin. The proposed scenario of the helical magma flow can provide a viable mechanism for the...
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Subduction-driven shortening and differential exhumation in a Cadomian accretionary wedge: The Teplá?Barrandian unit, Bohemian Massif
Hajná, Jaroslava ; Žák, Jiří (advisor) ; Franěk, Jan (referee)
2. English abstract This doctoral thesis is focused on analysis of tectonic deformations a geodynamic evolution of Neoproterozoic and Lower Paleozoic rocks of the Teplá−Barrandian Unit along the northwestern margin of the Prague basin (central Bohemian Massif). Using a wide range of modern methods, correlation of finite deformation patterns in different units allowed separation of structures formed during Cadomian and Variscan orogeny and interpretation of tectonic processes and tectonic history of the Cadomian orogenic belt during late Neoproterozoic. The research found direct evidence for and enabled new interpretations of Cadomian tectonic processes in the Bohemian Massif, including a succesion of deformation phases, quantification of finite deformation gradients and mechanisms. The different data sets were finally combined into an overall geotectonic model of Cadomian orogeny and its Variscan tectonothermal overprint in the Bohemian Massif, as well as the data were used for correlation with other Avalonian−Cadomian terranes. 5
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Numerical model for the origin of magmatic textures and its application to the Fichtelgebirge/Smrčiny granite batholith
Špillar, Václav ; Dolejš, David (advisor) ; Ježek, Josef (referee) ; Žák, Jiří (referee)
Magmatic processes are major agents responsible for the formation and differentiation of the Earth's crust. In contrast to extensive efforts to improve understanding and utility of igneous geochemistry, physical processes of magma differentiation and solidification remain largely unclear. Large variability of igneous textures provides record of these processes and intensive parameters governing the crystallization. In this thesis, we develop quantitative methods, which allow us to better interpret igneous textures in the framework of physics of solidification. We have developed a new three-dimensional model of crystallization from one- component melt driven by homogeneous and heterogeneous nucleation and crystal growth. The predicted textures are quantitatively characterized by crystal size distributions, spatial distribution functions and parameters representing grain contact relationships. The model employs high resolution in a large volume simulation domain in order to produce statistically stable results. Our simulations, performed for various functional forms of nucleation and growth rates with respect to time, imply that (i) crystals are ordered (anti-clustered) on short length scales. This reflects that other crystals already have a finite size at the time of nucleation of younger crystal,...
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Usage of basic elements of Greco-Roman wrestling for teaching physical culture on basic school
Žák, Jiří ; Štěpánek, Jan (advisor) ; Vejsada, Jindřich (referee)
Title work: Usage of hasíc elements of Greco-Roman wrestlíng for teaching physícal culture on hasíc school Purposes work: The maín goal of the presented díploma work ís to compile the elements of the Greco-Roman wrestling style to a form of a methodícal guíde for the ínstructors, hased on the research propaganda, and create the propsal ofa thematic plan ofthe tuitíons suitahle for the primary schools. Method: methodologícal studies evaluation postures questioning questionnaíre analysis Results: Setting up the resistance exercises to the schools education schedules. Improvement of the gym classes and hringíng out of the stereotypes, especially ofhall games. Possitive evaluatíon ofthe students and ímprovement oftheir physical form. Increasing interest of the students in the comhat sports as in consequences ofthe contemporary fears. Key words: wrestle Greco-Roman, rules, hasíc elements, metodology ofthe education, comhat sports, material comparison, decision makíng
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Forearc deformation and strain partitioning during growth of a continental magmatic arc: the northwestern margin of the Central Bohemian Plutonic Complex, Bohemian Massif
Dragoun, František ; Žák, Jiří (advisor) ; Ulrich, Stanislav (referee)
This doctoral thesis is focused on analysis of tectonic deformations associated with the Late Devonian subduction followed by the Early Carboniferous continental collision of the Saxothuringian and overriding upper-crustal Teplá-Barrandian units, which led to the growth of a large magmatic arc (the ~354-337 Ma Central Bohemian Plutonic Complex) in the central part of the Bohemian Massif. Far-field tectonic forces resulting from the collision produced ~WNW-ESE to ~NW-SE regional shortening across the forearc upper crust above the subduction zone; the shortening was accommodated by predominantly top-to-the-ESE tectonic transport along the southeastern flank of the Teplá-Barrandian unit. Approaching the magmatic arc margin, the regional structural pattern changes and exhibits significant acrossand along-strike variations interpreted as a result of strain partitioning, where the Saxothuringian/Teplá-Barrandian convergence interacted in different ways with the intruding magma pulses. Around the voluminous, northeasterly ~354 Ma Sázava pluton the principal shortening was at high angle to the forearc-facing intrusive contact and the host rocks were significantly thermally softened. The regional top-to-the-ESE tectonic transport converted here into arc-parallel ductile flow within the structural aureole...
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