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Microtextures and compositional relations in multiple grown garnet formed during subduction of crustal and mantle rocks
Kulhánek, Jan ; Faryad, Shah Wali (advisor) ; Collett, Stephen (referee) ; Konrad-Schmolke, Matthias (referee)
English abstract Studies of rocks from high- to ultrahigh-pressure metamorphic environments in subduction zones play a crucial role in advancing our understanding of Earth's dynamic processes and geodynamic evolution. Such samples, which have experienced Earth's mantle conditions, provide valuable insights into the subduction and exhumation processes associated with the tectonic collision of lithospheric plates. By analysing the mineral assemblages, textures, and chemical compositions of these rocks, we can unravel the complex history of the subducted rocks and determine the pressure-temperature paths experienced during their formation. Additionally, the investigation of high- to ultrahigh-pressure metamorphic rocks aids in constraining the mechanical behaviour of subduction zones, deciphering the fluid-rock interactions and element cycling processes. Such studies contribute to our broader understanding of plate tectonics, the formation of mountain ranges, and the geodynamic processes that shape our planet. This research focuses on the investigation of metapelitic and metabasic rocks from the Saxothuringian zone of the Bohemian Massif and the Western Gneiss Region of the Norwegian Caledonides. The studied rocks have a shared history of being part of subducted material that experienced high- to...
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CRISM sensor - available data and possible applications for mineral detection on Mars
Pavlová, Martina ; Červená, Lucie (advisor) ; Potůčková, Markéta (referee)
This bachelor's thesis focuses on data accumulated by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) sensor and the possibilities of their subsequent processing. The first part of this paper focuses on the history of remote sensing of Mars since its beginning in the 1960s, with the most detailed description of the Mars Reconnaissance Orbiter (MRO) mission which carries the CRISM spectroradiometer. The nine different data products acquired by this instrument are described in detail together with the possibilities of their download and subsequent processing. Furthermore, the minerals found on the surface of Mars are mentioned and examples of their spectral curves are shown. In the practical part, the processing of CRISM data in JCAT is first presented, from the actual data download to the creation of spectral curves suitable for comparison with spectral libraries. Subsequently, an image containing low calcium pyroxene was selected. This image was preprocessed in CAT in ENVI and using three different methods which were Linear Spectral Unmixing (LSU), Spectral Angle Mapper (SAM) and spectral parameter calculation, the detection of the selected mineral was performed. The LSU and SAM methods gave similar results, but the calculation of spectral parameters differed more from them, which...
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Crystal chemistry of pyroxenes and amphiboles from the České středohoří
Kallistová, Anna ; Skála, Roman (advisor) ; Ulrych, Jaromír (referee)
Contents of major, minor and trace elements in clinopyroxenes and clinoamphiboles of basanites, volcanoclastics, essexites, sodalitic syenites, and monzodiorites of the České středohoří Mts. has been determined using an electrone microprobe and LA-ICP-MS techniques. Composition of clinopyroxenes corresponds to either diopside or augite and clinoamphiboles can be classified as kaersutite or pargasite. Some pyroxenes display pronounced sector zoning showing increased contents of Mg and Si in pyramidal sectors whereas prismatic sectors show Fe, Ti and Al enrichment. Chemical composition of both sectors corresponds to diopside. Growth zoning has been found in the samples from basanites and volcanoclastics. Grain cores display the chemistry of augite and towards the rim the chemical composition changes to diopside. Samples have also been analyzed by powder and single crystal X-ray diffraction techniques. Samples of pyroxenes appear to be either pure or they contain negligible admixtures of phlogopite. Samples of amphiboles are also either without any admixtures or they show contamination by low amounts of diopside or augite, or phlogopite may rarely be encountered. Mutual relationship between the size of the unit cell parameters b and and substitutions in M1,2,3 and A sites has been observed. Longer mean T-O...
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