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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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Spatial interpolation and soil erosion modeling
Bek, Stanislav ; Ježek, Josef (advisor) ; Segeth, Karel (referee) ; Dostál, Tomáš (referee)
The doctoral thesis deals with selected methods of spatial interpolation and their applications to numerical modeling of the earth's surface, in particular soil erosion. The first part contains the description of the studied methods. Firstly and foremost, the method called regularized spline with tension (RST) is introduced. It has proven to be useful in interpolating elevation data. In the thesis, RST is presented in depth with the derivation of its radial basis function and its links to kriging. Further on the mathematics of digital terrain models and the tools for terrain geometric analysis are covered. The following chapter deals with the description of the soil erosion process and of the selected erosion models. The second part of the thesis summarizes five of the author's research articles which include applications of the described mathematical methods. The first two articles are devoted to the problem of elevation data interpolation and the building of digital elevation models. They deal with the optimization of the RST method for particular input data and target erosion models. The third article analysis the spatial structure of the soil data and the pedogenesis of the Žofínský prales natural forest. The last two articles deal with the spatial properties of heavy rainfalls and the mapping of...
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Numerical simulations of geodynamic processes
Krýza, Ondřej ; Lexa, Ondrej (advisor) ; Ježek, Josef (referee)
ENGLISH ABSTRACT The aim of this work is to provide a basic overview in numerical modeling of geodynamic processes. Therefore, work is divided into two main parts that almost independently describe its main topic. Both parts are designed to allow reader easily locate sources for more detailed and deeper description of the problem. The first part deals with the mathematical and physical apparatus, which is used to describe the geodynamic processes and their formalization due to the application for the construction of mathematical models. This section is mainly based on the description of conservation laws and related equations (continuity equation, Navier-Stokes equations, heat transfer equation) and also gives an overview of relations describing the force interactions in solids and rheology. The second aspect of this work is explanation of the principle of numerical methods (finite differences, finite volumes, finite elements and spectral methods) and their brief overview. In this part, the work is focused on finite differences, a description of which is the main topic of this part. In last chapter of this work, an example of the implementation of finite difference method for modeling of the thermal evolution of fold structures is given. We elaborate simple kinematic and thermal model to simulate time and...
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Current Trends in Quantitative Analysis of Geographical Data: Potentialities and Limitations of Spatial Data Analysis
Netrdová, Pavlína ; Čermák, Zdeněk (advisor) ; Ježek, Josef (referee) ; Horák, Jiří (referee)
of the Ph.D. Thesis Netrdová, P.: Current trends in quantitative analysis of geographical data: potentialities and limitations of spatial analysis The thesis is a contribution to the discussion about the potentialities of the quantitative approach in geography. It follows the current trends in quantitative analysis of geographical data, specifically spatial analysis, particularly from the perspective of changes in the concept and character of applied methods and their possible contribution in geographical research. Due to the research focus of the author, the entire work is focused primarily on the issue of using quantitative methods in terms of social geography. Attention is focused particularly on statistically spatial analyses, which are the most widely used techniques in social geography, with a wide range of possible applications. One of the goals of this work is to bring the current development in quantitative geography closer to the Czech academic community, and thus contribute to the increased awareness of the potentialities of the application of quantitative methods and spatial analyses in geographical research. Methodological problems in the analysis of spatial data, theoretical changes in the concept of quantitative analysis and also newly emerging quantitative methods have not so far...
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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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Spatial interpolation and soil erosion modeling
Bek, Stanislav ; Ježek, Josef (advisor) ; Segeth, Karel (referee) ; Dostál, Tomáš (referee)
The doctoral thesis deals with selected methods of spatial interpolation and their applications to numerical modeling of the earth's surface, in particular soil erosion. The first part contains the description of the studied methods. Firstly and foremost, the method called regularized spline with tension (RST) is introduced. It has proven to be useful in interpolating elevation data. In the thesis, RST is presented in depth with the derivation of its radial basis function and its links to kriging. Further on the mathematics of digital terrain models and the tools for terrain geometric analysis are covered. The following chapter deals with the description of the soil erosion process and of the selected erosion models. The second part of the thesis summarizes five of the author's research articles which include applications of the described mathematical methods. The first two articles are devoted to the problem of elevation data interpolation and the building of digital elevation models. They deal with the optimization of the RST method for particular input data and target erosion models. The third article analysis the spatial structure of the soil data and the pedogenesis of the Žofínský prales natural forest. The last two articles deal with the spatial properties of heavy rainfalls and the mapping of...
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Determination of geological provenance by cathodoluminescence spectroscopy of apatites and carbonates
Pánik, Róbert ; Matějka, Dobroslav (advisor) ; Ježek, Josef (referee) ; Skála, Roman (referee)
This work presents new method for determination of geological provenance based on the statistical analysis of cathodoluminescence spectra of marbles and carbonate rocks from various localities in the Bohemian Massif. Analysis is based on the combination of data from seven different measures of spectral similarity and provides results that are more robust than those obtained by approach based only on a single measure of similarity. These results may be further improved by employing meta-analysis that evaluates behaviour of spectra during the individual steps of analysis. Analysis was performed on the original cathodoluminescence spectra, as well as on the residual spectra in which relative variability was amplified by the subtraction of Gaussian trend present in all spectra of carbonates. By combining results from analysis and meta-analysis of both original and residual spectra it was possible to almost unambiguously determine provenance of samples from all studied localities. Agglomerative hierarchical clustering was employed as a supplementary method for classification of spectra. Out of 72 different methods for clustering, one was selected for both original and residual data based on the number of correctly classified spectra. Second part of this work presents analysis of cathodoluminescence...
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Application of multivariate statistical methods for analysis of 2D thermo-mechanical numerical models of diapirism
Krýza, Ondřej ; Lexa, Ondrej (advisor) ; Ježek, Josef (referee)
Application of multivariate statistical methods for analysis of thermomechanical numerical models of diapirism Most of the thermo-mechanical processes, that are associated with the geodynamic evolution of the lithosphere, can be derived from the laws of conservation of mass, momentum and energy in a continuous conception of space. The study of such dynamical systems reveals their strong sensitivity to variation of the initial conditions. For testing the applicability of multivariate statistics in analyzing the influence of the initial conditions, two independent 2D thermo-mechanical multilayer numerical models of crustal diapirism of the Moldanubiam zone were created. The diapirism in central part of Moldanubian zone is characterized by exhumation of HP-HT granulites during the Variscan orogeny (Lexa et al., 2011) which is influenced by density contrast of the middle mafic and lower felsic crust, the ratio of the amount mafic and felsic material, radiogenic heat productivity of the felsic lower crust and shape of the interface of this two layers. The initial setup of this models reflects the situation in future central part of the Bohemian Massif after subduction of the Saxothuringian continental crust and after redistribution of felsic material beneath a base of a lower-crustal area of the...
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Numerical simulations of geodynamic processes
Krýza, Ondřej ; Lexa, Ondrej (advisor) ; Ježek, Josef (referee)
ENGLISH ABSTRACT The aim of this work is to provide a basic overview in numerical modeling of geodynamic processes. Therefore, work is divided into two main parts that almost independently describe its main topic. Both parts are designed to allow reader easily locate sources for more detailed and deeper description of the problem. The first part deals with the mathematical and physical apparatus, which is used to describe the geodynamic processes and their formalization due to the application for the construction of mathematical models. This section is mainly based on the description of conservation laws and related equations (continuity equation, Navier-Stokes equations, heat transfer equation) and also gives an overview of relations describing the force interactions in solids and rheology. The second aspect of this work is explanation of the principle of numerical methods (finite differences, finite volumes, finite elements and spectral methods) and their brief overview. In this part, the work is focused on finite differences, a description of which is the main topic of this part. In last chapter of this work, an example of the implementation of finite difference method for modeling of the thermal evolution of fold structures is given. We elaborate simple kinematic and thermal model to simulate time and...
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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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