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Study of bioapatite geochemistry using Laser Ablation ICP-MS
Kroupa, Vojtěch ; Doležalová Weissmannová, Helena (referee) ; Vašinová Galiová, Michaela (advisor)
This diploma thesis deals with topic of investigating bioapatite from conodont samples using laser ablation ICP-MS. The aim is to evaluate effect of diagenesis on the chemical composition and content of rare earth elements (REE) in the structure of conodonts. During diagenesis, bioapatite was transformed into mineral francolite and as part of this process, adsorbed REE into its crystalline structure. The degree of adsorption of REE was influenced by presence of seawater, presence of siliciclastics in surrounding REE-enriched rocks, redox conditions and also the effects of elements such as Mn and Fe present in the pore water. It was found that a group of conodont samples from the Col des Tribes (France) underwent a major diagenetic transformation, late recrystallization with REE desorption, and also due to the increased presence of Mn ions and influence of the original suboxic conditions contains rarer positive Ce anomalies. While groups of conodont samples from the Mramorový lom near Křtiny (Czech Republic) have undergone a minor diagenetic change, they contain a larger amount of REE elements.
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Study of bioapatite geochemistry using Laser Ablation ICP-MS
Kroupa, Vojtěch ; Doležalová Weissmannová, Helena (referee) ; Vašinová Galiová, Michaela (advisor)
This diploma thesis deals with topic of investigating bioapatite from conodont samples using laser ablation ICP-MS. The aim is to evaluate effect of diagenesis on the chemical composition and content of rare earth elements (REE) in the structure of conodonts. During diagenesis, bioapatite was transformed into mineral francolite and as part of this process, adsorbed REE into its crystalline structure. The degree of adsorption of REE was influenced by presence of seawater, presence of siliciclastics in surrounding REE-enriched rocks, redox conditions and also the effects of elements such as Mn and Fe present in the pore water. It was found that a group of conodont samples from the Col des Tribes (France) underwent a major diagenetic transformation, late recrystallization with REE desorption, and also due to the increased presence of Mn ions and influence of the original suboxic conditions contains rarer positive Ce anomalies. While groups of conodont samples from the Mramorový lom near Křtiny (Czech Republic) have undergone a minor diagenetic change, they contain a larger amount of REE elements.
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Steppe or woodland? Ecological Conditions of Formation and Evolution of Chernozems in Central Europe
Vysloužilová, Barbora ; Šefrna, Luděk (advisor) ; Kalvoda, Jan (referee) ; Havlicek, Elena (referee)
Chernozem became the crucial soil for the beginnings of soil science through the work of Dokuchaev from 1883. Since then the genesis of chernozems in Central Europe has raised many questions among soil scientists, botanists and paleo-environmentalists. While in Eastern Europe chernozems have been described as zonal soils, that are typical for continental steppe and forest-steppe areas, there are areas in Central Europe which are predisposed by their climatic characteristics to the presence of woodlands. The goal of this dissertation is to enrich the discussion about the genesis of chernozems by restoring the environmental conditions that were prevalent during the formation of chernozem soils in Central Europe. Chernozems are usually developed on loess with a very thick and dark organic surface which passes directly to a calcareous horizon. The organic matter underwent a polymerization in dependence on climate contrasts. However, in Central Europe, the climatic characteristics of the areas of chernozems are a bit different. These chernozems are supposed to have been formed under the climatic conditions that dominated Central Europe during the Late Glacial and the Early Holocene. The climatic nuances may contribute to the explanation of the differences in distribution of chernozems ("drier") and...
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Steppe or woodland? Ecological Conditions of Formation and Evolution of Chernozems in Central Europe
Vysloužilová, Barbora ; Šefrna, Luděk (advisor) ; Kalvoda, Jan (referee) ; Havlicek, Elena (referee)
Chernozem became the crucial soil for the beginnings of soil science through the work of Dokuchaev from 1883. Since then the genesis of chernozems in Central Europe has raised many questions among soil scientists, botanists and paleo-environmentalists. While in Eastern Europe chernozems have been described as zonal soils, that are typical for continental steppe and forest-steppe areas, there are areas in Central Europe which are predisposed by their climatic characteristics to the presence of woodlands. The goal of this dissertation is to enrich the discussion about the genesis of chernozems by restoring the environmental conditions that were prevalent during the formation of chernozem soils in Central Europe. Chernozems are usually developed on loess with a very thick and dark organic surface which passes directly to a calcareous horizon. The organic matter underwent a polymerization in dependence on climate contrasts. However, in Central Europe, the climatic characteristics of the areas of chernozems are a bit different. These chernozems are supposed to have been formed under the climatic conditions that dominated Central Europe during the Late Glacial and the Early Holocene. The climatic nuances may contribute to the explanation of the differences in distribution of chernozems ("drier") and...
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The Holocene Climatic Optimum in Northern Africa: Geoarchaeological research of the environmental and cultural interaction
PARVONIČOVÁ, Lenka
This research work summarises results of geological and archaeological investigation in the Sahara Desert. The analyses of paleoclimatic and paleoenvironmental deposits are combined with archaeological records of the human occupational development during the Early and Middle Holocene. The period characterised by higher humidity is called The Holocene Climatic Optimum. The region of the Eastern Sahara consisted of Libyan, Egyptian, Sudanian and Chadian area provides unique opportunities to study the relationship between climate changes and human occupation.
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