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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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Substitution trends in apatites of Cenozoic igneous rocks of the Czech Republic
Mészárosová, Noemi ; Skála, Roman (advisor) ; Ulrych, Jaromír (referee)
This bachelor thesis is focused on studying crystal chemistry of apatites of the Cenozoic igneous rocks of the Czech Republic. The main goal of this thesis is to determine the substitution trends in 23 samples of apatites from selected volcanic rocks of České středohoří Mts., Doupovské hory Mts. and the Labe Tectono-volcanic Zone. It was found that contents of REE (Ce, La, Bd, Sm, as well as Y) and Si correlate mutually. In addition to that this group of elements displays the inverse correlation with Ca and P. These observations confirm the coupled substitution of REE, Y and Si. The second part deals with refinement of crystal structures of studied apatites. The crystal structure of selected samples was refined by Rietveld method. All samples displayed different peak shapes for 00l reflections compared to other reflections. It can be assumed that the change of the shape parameters was caused by different size of crystallites in this direction. During the refinement it was found that the samples A7 and A10 contain two different apatites displaying very similar crystal lattice parameters. In the sample A7 this fact is caused by chemical zoning, in particular, by different concentrations of Ce and La.
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Crystal chemistry of pyralspite garnets
Soumar, Jan ; Skála, Roman (advisor) ; Ulrych, Jaromír (referee)
Bohemian garnets have been known as a jewellery stone for many centuries. There is still a lot of interest in them, however, the reserves in traditional locations are getting smaller. That is why search for alternative source of similar garnets in gem quality started. Shavaryn Tsaram deposit in Mongolia is considered as one of the potential sources. Pyrope samples from eight Bohemian localities of two areas (České středohoří [The Central Bohemian Uplands] and Podkrkonoší [The Giant Mountains]) and from Shavaryn Tsaram deposit in Mongolia were analysed using electron microprobe, LA-ICP-MS, ICP-OES, Mössbauer spectroscopy and x-ray powder diffraction. The data were compared with the conclusion that the Mongolian garnets from Shavaryn Tsaram deposit are so different from the Bohemian ones that it will not be possible to use them as a gem material of similar qualities. Bohemian garnet can be characterised as a red garnet with refraction index 1.747 (+/- 0.001) with dominant pyrope component of the average composition Py78Alm17Gr5 and Cr2O3 content above 1 wt.%. The data were also evaluated from two classification schemes point of view. The schemes by Schulze (2003) and Grütter (2004) are used in determining source materials and in diamond prospection. According to them source rocks of Bohemian garnets...
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Chemical and Spectroscopic Characterization of Celtic Metal Artifacts
Išková, Petra ; Skála, Roman (advisor) ; Šrein, Vladimír (referee)
The thesis comprehensively investigates 2 pcs of ferrous and 14 pcs of bronze Celtic artefacts from a region of Zdejciny by Beroun. The study by means of ore microscopy, x-ray fluorescent microspectrometry, chemical microanalysis, Raman microspectrometry and x-ray powder diffractive analysis has showed that the bronze artefacts are made mainly of bronze. The phases present in the studied items correspond to fields and + of the Cu-Sn phase diagram. Content of Sn in bronze ranges between 4 and 33 wt.%. For the bronze selected items there was also Vickers microhardness measured. There were two artefacts where areas with a significant lead enrichment were found. Corrosive products were also deeply analysed and identified.
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Crystal chemistry of micas from České středohoří
Goll, Jan ; Skála, Roman (advisor) ; Ulrych, Jaromír (referee)
Six methods have been used to study micas from České středohoří mts.: X-ray difractometry (transmission and reflection), ICP MS, electron microprobe, Mössbauer spectroscopy and termogravimetry. The measurements of trace elements and REE's revealed very low tendency by normalization on chondrite reservoir and primitive mantle. Micas show high contents of TiO2 (9,47 wt.%) and BaO (up to 2,1 wt.%) in separated grains from rock. The micas classifications were determined by Tischendorf (2007) and Rieder (1998) as Fe-phlogopites. X-ray powder diffraction revealed cell dimensions and a common polytype 1M with space group C2/m. By Mössbauer spectroscopy have been studied the rates of Fe2+ /Fe3+ and they were 1,08 - 1,86 (except rock sample, which were 9:1). Termogravimetrical measurement until 1450řC revealed weight jump from 1120řC to 1270řC.
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Crystal chemistry of micas from České středohoří
Goll, Jan ; Skála, Roman (advisor) ; Rieder, Milan (referee)
Micas from České středohoří mts. have been studied by X-ray difractometry, ICP-MS and electron microprobe. The measurements of trace elements and REEs revealed very low tendency by normalization of chondrite reservoir and primitive mantle. The micas classifications were determined by Tischendorf (2007) and Rieder (1998) as Fe- or Fe-Ti phlogopites. The abundances of Ti are very high up to 0,46 (a.p.f.u.). X-ray powder diffraction revealed double layered polytype 2M1 with space group C/2c.
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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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Ověření obsahu azbestu v horninách lomu Sýkořice : závěrečná zpráva
Skála, Roman
Zpráva je volně šiřitelná. Anotace: U pěti vzorků hornin z lomu v Sýkořici byl vyhodnocován možný obsah azbestu. Horniny byly podrobeny makroskopickému a mikroskopickému pozorování a studiu elektronovým mikroanalyzátorem a práškovou rentgenovou difrakcí. V žádném ze studovaných vzorků nebyly nalezeny významné akumulace azbestových minerálů, jak jsou definovány právními normami ČR.
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