|
|
Highly siderophile element and Re-Os isotopic geochemistry of carbonatites and associated alkaline rocks from selected occurrences in India
Polák, Ladislav ; Ackerman, Lukáš (advisor) ; Krmíček, Lukáš (referee)
Carbonatites are intrusive and extrusive rocks with content of carbonate minerals > 50% predominantly derived from upper mantle. They represent a potential economical source for platinum- group elements as can be seen on actively mined sites like Phalaborwa in South Africa or Ipanema in Brazil. The first complete dataset for highly siderophile element (HSE) abundances along with their 187 Os/188 Os compositions for carbonatites, silicocarbonatites and associated alkaline rocks (pyroxenite, syenite, monzogabbro and tonalite) from two Neoproterozoic (~ 800 Ma) suites from Samalpatti and Sevattur, Tamil Nadu region in south India is presented. The data were obtained by a standard methods in involving decomposition of samples in Carius Tubes, Os separation by CHCl3 following microdistillation and Ir, Ru, Pt, Pd isolation by anion exchange chromatography. The data show that carbonatites from Samalpatti and Sevattur are characterized by very low HSE contents, lower than other mantle-derived mafic melts such as basalts or komatiites. Suprachondritic OsN/IrN ratios might suggest that carbonatites are able to concentrate not negligible amount of Os. Due to high, non-uniform 187 Os/188 Os ratios, we suggest that the source of carbonatitic melts was largely heterogeneous with high contribution of crustal...
|
|
|
Physico-mechanical properties of the system syenite-enclave in the Královec quarry
Umlauf, Jiří ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor thesis focuses on mechanical properties of syenitoids and their mafic microgranular enclaves collected in actively mined quarry Královec near Jaroměřice nad Rokytnou. In overview part of the thesis are described selected methods for determining the physical-mechanical properties of the rocks as well as geology of the studied site. The practical part brings the results and principal conclusions from the measurements of the mechanical properties of these rocks.
|
|
| |
|
| |
|
|
Testing of polymeric materials under climatic conditions of Antarctica
Mičkal, Petr ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor's thesis generally deals with polymer materials and evaluates the possibility of testing their resistance to extreme climates of Antarctica. Described herein are various polymer materials, their characteristics, structure, properties and more thorough and detailed descriptions of selected polymers. The next section describes the basic types of degradation these polymers are exposed to, when facing the extreme conditions of the Antarctic climate. The practical part contains evaluations of tests made on the degraded polymer materials that were collected in Antarctica during the southern Antarctic season of 2013-2014 by Ing. Bc. Pavel Kapler, Ph.D, who is a superintendent at the Czech scientific station JG Mendel.
|
|
| |
|
|
Clay minerals in polymeric materials
Zaťko, Petr ; Sluková, Michaela (referee) ; Krmíček, Lukáš (advisor)
The bachelor thesis deals with the clay minerals as fillers in polymer materials and their polymer/clay nanocomposites. The thesis brings an introduction to the structure of polymers and clay minerals and their application in polymer materials. The practical part of the thesis deals with testing the diffusivity of CO2 through the film made of recycled polyvinyl butyral with fillers Nanofil®5, Dellite® 67 and Cloisite® 93A and their comparison with reference samples from recycled PVB without added fillers and commercial films of extruded PVB.
|
|
| |
|
| |
|
|
Geochemistry of Cenozoic volcanic rocks of the Faroe Islands with a focus on their ultra-trace contents of Hg
Šišková, P. ; Krmíček, Lukáš ; Coufalík, Pavel
According to geophysical research performed in the eastern part of the North Atlantic, many authors inferred that the basalt flows on the Faroe Islands overlie a continental metamorphic basement supposedly of Precambrian age. With respect to this, we focused our study on determination of ultratrace mercury contents by means of atomic absorption spectrometry to test this hypothesis. Mercury contents in basalts seem to be a sensitive tool for distinguishing between the basalts not affected by interaction with the continental crust and the basalts enclosing crustal xenoliths. Contents of Hg show great variability between samples even within the same formation. We presume that high concentrations of Hg in some samples are related to stagnation of individual pulses of parent magma in the continental crust below the Faroe Islands.
|
guest ::
