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Variation of isotopic composition in selected natural and archeological samples, methodical approach
Venhauerová, Petra ; Trubač, Jakub (advisor) ; Magna, Tomáš (referee)
This thesis is focused on elaboration of the methodical approaches for determination silver isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICP- MS) from Centrum of stable and radiogenic isotopes on Science Faculty on Charles University. Therefore, this thesis describes in detail methodology of chromatographic separation and conditions of further measurement. For analysis of isotopic ratios 107 Ag/109 Ag in individual samples are used natural samples of various silver and gold deposits in Czech Republic and Poland. Also, archeological findings of fractures of silver coins from our country. The aim of this work is to find out if there is a variability among this two types of samples. Measured values are further correlated with already published works specialized on similar types of natural and archeological samples. The obtained values could be used for an interpretation of geological processes (e. g. physicochemical fractionation during ore forming processes) or as an identification source of the origin of coins and other archeological findings (e. g. silver ornaments). Gained knowledge of this work will help improve contemporary methodology in measurement of silver isotopes, such as standard calibration and tuning the stability of a signal. Key words: isotopes of...
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Distribution of trace elements in carbonatites using in-situ techniques, with focus on REE
Krátký, Ondřej ; Magna, Tomáš (advisor) ; Kynický, Jindřich (referee)
Carbonatites are unique and enigmatic magmatic rocks of unclear origin, with very specific mineralogy and geochemical properties. They are predominantly composed of magmatic calcite or other carbonate minerals (Le Bas 1987) and have low content of SiO2 (Le Maitre 2002). Origin of these peculiar magmas is still not clear but they appear to represent an important "window" into processes in Earth's mantle. They are considered either as residual melts from a fractionated carbonated nephelinite or melilitite (Gittins 1989; Gittins and Jago 1998), as immiscible fractions of CO2-saturated silicate melts (Freestone and Hamilton 1980; Amundsen 1987; Kjarsgaard and Hamilton 1988, 1989; Brooker and Hamilton 1990; Kjarsgaard and Peterson 1991; Church and Jones 1995; Lee and Wyllie 1997; Dawson 1998; Halama et al. 2005; Brooker and Kjarsgaard 2011), or as primary melts which are were generated from CO2-bearing peridotite through partial melting (Wallace and Green 1988; Sweeney 1994; Harmer and Gittins 1998; Harmer et al. 1998; Ying et al. 2004). Abundances of rare earth elements (REE) are often high in carbonatites because carbonatitic magmas can dissolve these elements much easily than silicate magmas (Nelson et al. 1988). Carbonatitic magma can also dissolve large quantities of Sr, Ba, P and mainly Zr and Nb,...
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