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Elastic anisotropy of eclogites and peridotites from the Bohemian Massif
Pohořalá, Anna ; Staněk, Martin (advisor) ; Machek, Matěj (referee)
This bachelor thesis describes the structure of the lithosphere and the factors influencing the velocity of P-wave propagation and their anisotropy in rocks. Fundamental aspects of seismic and laboratory methods for the study of elastic properties of rocks are described with particular emphasis on the method of ultrasonic irradiation of spherical samples under high confining stresses. The results of measurements by this method are presented on 18 samples of eclogites and peridotites from the Bohemian Massif. The rock set is separated according to modal composition, compared and then evaluated using graphs showing P-wave velocity, anisotropy and confining stress relationships. Furthermore, the relationship between anisotropy, P-wave velocity of propagation, density and grain size is shown using a correlation matrix. For the sets of studied rocks, the presence of kelyphites, symplectites, and serpentinites decreases the P-wave velocity, and anisotropy decreases with increasing amounts of serpentinites. Eclogites having high seismic velocities have low anisotropy. Keywords: elastic anisotropy, eclogites, serpentinized peridotites, Bohemian Massif
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Quantitative correlation of textural data obtained with CIP and EBSD method
Slunská, Petra ; Lexa, Ondrej (advisor) ; Machek, Matěj (referee)
Since 2011, the Institute of Petrology and Structural Geology, Charles University in Prague, worked with CIP - Computer Integrated Polarization microscopy as fast, inexpensive measurement of c-axis orientation of uniaxial minerals, mostly quartz in high definition. CIP method is developed from the early nineties in Switzerland (Heilbronner & Pauli 1993) and later in many other workplaces. The aim of this work was testing and calibration of optical and camera equipment to verify the accuracy and reliability of data obtained. Served as an independent measurement of EBSD (Electron Backscatter Diffraction) data obtained from the same part of the studied thinsections. The data obtained were analyzed by quantitative analysis of microstructures (PolyLX - MATLABTM toolbox; Lexa 2003). The samples used for testing the methodology mentioned were taken on the profile of Hvězdná and Zdobnice near Rokytnice in the Eagle Mountains by contact orlica-snieznik complex and its mantle. Field studies showed the existence of west dipping shear zone along the said contact and deformed orthogneiss show a macroscopic superposition of several deformation events. The resulting frequency histograms similarities and differences of angles c-axes and angles misorientace grains have a high consensus in the azimuthal criterion, axes...
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Quantitative correlation of textural data obtained with CIP and EBSD method
Slunská, Petra ; Lexa, Ondrej (advisor) ; Machek, Matěj (referee)
Since 2011, the Institute of Petrology and Structural Geology, Charles University in Prague, worked with CIP - Computer Integrated Polarization microscopy as fast, inexpensive measurement of c-axis orientation of uniaxial minerals, mostly quartz in high definition. CIP method is developed from the early nineties in Switzerland (Heilbronner & Pauli 1993) and later in many other workplaces. The aim of this work was testing and calibration of optical and camera equipment to verify the accuracy and reliability of data obtained. Served as an independent measurement of EBSD (Electron Backscatter Diffraction) data obtained from the same part of the studied thinsections. The data obtained were analyzed by quantitative analysis of microstructures (PolyLX - MATLABTM toolbox; Lexa 2003). The samples used for testing the methodology mentioned were taken on the profile of Hvězdná and Zdobnice near Rokytnice in the Eagle Mountains by contact orlica-snieznik complex and its mantle. Field studies showed the existence of west dipping shear zone along the said contact and deformed orthogneiss show a macroscopic superposition of several deformation events. The resulting frequency histograms similarities and differences of angles c-axes and angles misorientace grains have a high consensus in the azimuthal criterion, axes...
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