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Picritic rocks of the České Střredohoří Mts.
Šnellerová, Zuzana ; Jelínek, Emil (advisor) ; Ulrych, Jaromír (referee)
The first part of the thesis represents a summary of background knowledge about the geology of the České středohoří Mnt. In the second part, picritic rocks were investigated in detail. General aspects of the chemical and mineralogical compositions of this rock type and classification of picrites are discussed. In addition, macro and microscopic characteristics of rocks are included. The results of macroscopic and microscopic investigations indicate that the studied subvulcanic rocks from the České středohoří Mnt. can be characterised as picritic. However, chemical analyses of the rocks did not confirm this conclusion. Only the samples S-39 and S-40 can be disignated as picrites. Although the other samples show similar mineralogical composition, they need to be classified as basic subvulcanites of picritic type due to higher alkali content.
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Geochemistry of subvolcanites of Roztoky volcanite complex
Jahoda, Jan ; Jelínek, Emil (advisor) ; Matějka, Dobroslav (referee)
Subvulcanics rocks of the Roztoky volcanic centre consists of trachytic and phonolitic intrusions, accompanied by hypabyssal intrusions of trachybasaltic (essexite, monzodiorite) and syenitic (sodalite syenite) charakter and dyke swarm of lamprophyres > semilamprophyres. Intrusions of the hypabyssal faintly alcalic series (essexite, monzodiorite, sodalite syenite) are 33-28 Ma old, the lamprophyres of greatly alcalic series (monchiquite, camptonite) are 31-26 Ma old and the semilamprophyres of faintly alcalic series (gauteite, bostonite) are 28-24 Ma old (sensu Ulrych, 1998). The datas corresponds to the trachybasalt - basaltit - trachyandesite suite of the Děčín Formation and the interval of České středohoří Mts. volcanic activity to (42-16 Ma, Eocene -Miocene). 14 samples plutonic rocks of the essexite-monzodiorite-sodaliticsyenite suite and 10 samples of theirs venous equivalents from (semi)lamprophyres and tinguaites groups were withdrawaled in the Roztoky nad Labem area. I analyzed in detail 5 essexite samples and 6 (semi)lamprophyres samples in those study. I studied the sampels using polarization microscope and subsequently elektron micro-analyzer in the analitic metods laboratory of the Geologic institute of Academy of Science, Czech Republic. All analyzed samples belong to II., hypabysal,...
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Thalium in soils
Fisher, Meir ; Mihaljevič, Martin (advisor) ; Vaněk, Aleš (referee)
SUMMARY: Thallium is a nonessential element, more toxic than mercury, lead, cadmium, zinc or copper. It exists in the two oxidation states Tl+ and Tl3+ . Thallium is toxic to all organisms in both monovalent and trivalent form. In biological processes it can substitute K+ due to their similar ionic radii. In the past it was extensively used for medicinal purposes and as a rodenticide. In the present there are over 150 uses and potential applications for thallium and its compounds. Thallium is generally present in very low concentrations (less than 1 mg.kg-1 ), however, in artificially polluted areas (in the vicinity of power plants, cement factories, smelting works, sulphide ore wastes from mining activity and others) it may exceed much higher levels. The amount of thallium of natural origin strongly depends on the lithology of the parent rock on which soil was derived. Detection of thallium in soils is usually performed by ICP-MS. The total intake of thallium should be less than 5µg per day, but no recommended maximum values are available in the present time in most countries. Different soil properties can influence the behavior of thallium. Through uptake by plants thallium is entering the food chain. Plant varieties and plant parts differ in the degree of uptake and accumulation of thallium, thus, in...
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Neovolcanic Rocks of the SW part of the Most Basin in the area of Tušimice power plant open pit
Sobotka, Martin ; Kachlík, Václav (advisor) ; Novotný, Tomáš (referee)
Diploma thesis deals with geological, petrological and geochemical studies of neovolcanic rocks of the SW part of the Most Basin in the area of Tušimice power plant open pit. There are two lava flows affected by coal mining in northern part of the mine. Petrological and geochemical studies with K-Ar dating relatively recent rocks in mostly weatherworn volcanic rocks showed, that they can be classified as Ti-rich basaltic rocks without olivine (tephrites), which belong to the main volcanic phase in the evolution of the Eger graben. It was evidenced geologicaly and with K-Ar dating, that studied rocks were seperated from underlying beda by hiatus which caused erosion of volcanic rocks as well as crystalline bedrock. Mmajor and trace elements composition of co-magmactic volcanics showed that rock were derived from two slightly different sources of upper mantle. Composition of two samples indicates the formation from low degree of partial melting strongly metasomatic asthenospheric mantle. Chemical features of volcanic rocks show that mantle source was comparamble to recent OIB basalts. Last sample arose from less metasomatized and depth distincted mantle which was affected by higher level of partial melting. Melts from which crystallized both rocks were minimaly affected by asimilation or...
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Petrogenesis and evolution of the Davle Volcanic Complex
Santolík, Václav ; Ackerman, Lukáš (advisor) ; Krmíček, Lukáš (referee)
The Davle Volcanic Complex (DVC) situated in the Teplá-Barrandian unit (TBU) of the Bohemian Massif, is considered as a Neoproterozoic-Cambrian magmatic arc that developed on the northern active margin of Gondwana supercontinent during Cadomian accretionary orogeny. This study combines data obtained from fieldwork, petrography, rock-forming mineral microanalysis, major and trace element analysis, Sr-Nd-Pb isotopic systematics and U-Pb zircon geochronology in order to reveal the petrogenesis and evolution of the DVC. At least three-stage metamorphism including Cadomian seafloor alteration, Variscan regional metamorphism as well as contact metamorphism related to the emplacement of the Central Bohemian Plutonic Complex affected the DVC. The studied rocks follow calc-alkaline trend whereas tholeiitic trend previously reported is rather related to younger magmatic events. The northern part of the DVC is dominated by felsic subvolcanic (plagiogranite), volcanic (dacite- rhyolite) and pyroclastic (dacitic-rhyolitic tuffs and breccias) rocks with a few outcrops of basaltic andesite-andesite pillow lavas documenting the subaqueous activity of the DVC. These rocks are Na-rich, but K-poor, the plagiogranite contains albite most likely primary in origin, and exhibit highly radiogenic εNd values (~ +6 to +11),...
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Silurian and Devonian volcanism of the Prague Basin
Tasáryová, Zuzana
The principal goal of the thesis is to constrain nature of magmatic and alteration processes, character of mantle source(s), geotectonic setting and palaeogeographic implications of the Silurian and Devonian volcanism in Prague Basin (Teplá-Barrandian Unit, Bohemian Massif). The thesis is based on extensive geochemical study covering major- and trace-element geochemistry, neodymium isotope geochemistry and mineral chemistry supported by petrographic and field observations. The most important conclusions of the thesis are as follows: 1. The Silurian volcanic rocks of the Prague Basin represent within-plate, transitional alkali to tholeiitic basalts, which erupted in continental rift setting through thick Cadomian crust. The basalts originated by low degrees of partial melting of garnet peridotite mantle source. Older Wenlock basalts are similar to alkaline ocean island basalts (OIB) derived from subcontinental lithospheric mantle (SCLM), enriched most probably by frozen pods of Ordovician magmas. Younger Ludlow basalts resemble tholeiitic enriched mid-oceanic ridge basalts (EMORB) derived from subduction-modified SCLM depleted by Late Cambrian melting. The Wenlock-Ludlow melting is characterized by contemporaneous mixing of melts derived from both enriched and depleted SCLM mantle domains. 2....
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Geochemistry and petrology of plagiogranites from the Jílové belt
Santolík, Václav ; Ackerman, Lukáš (advisor) ; Jelínek, Emil (referee)
This thesis is focused on the study of the subvolcanic rocks from the northern part of the Jílové belt. The Jílové belt is a strip of magmatic rocks belonging to the Davle Volcanic Complex situated in the center of the Bohemian Massif, south of Prague, close to the border between the Teplá-Barandian and Moldanubian units. The sub-volcanic facies of its northern part has been previously ascribed to trondhjemite, alaskite or plagiogranite. In this study, we provide new geochemical data such as major and trace element analyses paralleled by Sr-Nd isotopic data, which indicate the origin of these rocks in the mantle wedge. They probably represent a final product of a magmatic differentiation of an island arc series. Here, we consider two possible models for their origin, according to which we could also choose the correct classification of these peculiar rocks: adakite, or plagiogranite. Adakites are rocks formed by melting of a subducted slab which are predominantly related to the volcanic arc settings. In comparison, plagiogranites are rocks formed by an extreme differentiation of a mantle- derived basaltic melt in the oceanic crust environment. Our new geochemical data, especially the low degree of light rare earth enrichment (LaN/YbN = 0.8-1.3), is clearly inconsistent with the genetic association...
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Silurian and Devonian volcanism of the Prague Basin
Tasáryová, Zuzana ; Frýda, Jiří (advisor) ; Renno, Axel D. (referee) ; Awdankiewicz, Marek (referee)
The principal goal of the thesis is to constrain nature of magmatic and alteration processes, character of mantle source(s), geotectonic setting and palaeogeographic implications of the Silurian and Devonian volcanism in Prague Basin (Teplá-Barrandian Unit, Bohemian Massif). The thesis is based on extensive geochemical study covering major- and trace-element geochemistry, neodymium isotope geochemistry and mineral chemistry supported by petrographic and field observations. The most important conclusions of the thesis are as follows: 1. The Silurian volcanic rocks of the Prague Basin represent within-plate, transitional alkali to tholeiitic basalts, which erupted in continental rift setting through thick Cadomian crust. The basalts originated by low degrees of partial melting of garnet peridotite mantle source. Older Wenlock basalts are similar to alkaline ocean island basalts (OIB) derived from subcontinental lithospheric mantle (SCLM), enriched most probably by frozen pods of Ordovician magmas. Younger Ludlow basalts resemble tholeiitic enriched mid-oceanic ridge basalts (EMORB) derived from subduction-modified SCLM depleted by Late Cambrian melting. The Wenlock-Ludlow melting is characterized by contemporaneous mixing of melts derived from both enriched and depleted SCLM mantle domains. 2....
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The Origin of Compositional and Textural Zoning of Shallow-Level Granitoid Plutons
Trubač, Jakub ; Janoušek, Vojtěch (advisor) ; Broska, Igor (referee) ; Siebel, Wolfgang (referee)
The principal goal of this Ph.D. Thesis is to contribute to the research on formation of compo- sitional and textural zoning in shallow-level plutons. Processes responsible for emplacement of individual plutons/pulses and the origin of compositional zoning in are addressed in a great detail, from the pluton-scale down to the micro-scale. The main emphasis in the more focused part of this text is on a combination of various quanti- tative data sets from two well-selected plutons (the Říčany Pluton in the Central Bohemian Plu- tonic Complex and the Melechov Pluton in the Moldanubian Batholith). These detailed studies are supported by further research on the Štěnovice, Čistá and Ševětín plutons. In this way we cover the evolution of Variscan magmatism in the heart of Bohemian Massif in its entirety, from Late Devonian till Permian. The thesis is based on combining field and structural studies (including the anisotropy of mag- netic susceptibility, AMS), textural analysis, petrological, geochronological and geochemical methods with geophysical investigations. Mathematical approaches have been designed and applied to the interpretation of geochemical data, with potential applications to other igneous systems. I strongly believe that only such comprehensive studies on well-selected case examples have a...
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