National Repository of Grey Literature 74 records found  beginprevious38 - 47nextend  jump to record: Search took 0.00 seconds. 
The springs of the radioactive medicinal groundwaters in the Chrastava - Bogatynia area
Černík, Tomáš ; Goliáš, Viktor (advisor) ; Vylita, Tomáš (referee)
A radiogeochemical exploration in the area of Chrastava - Bogatynia belonging into lugic region was conducted in the years 2012 - 2013. This exploration's objective was to search for and investigate radioactive water manifestations with radioactivity concentration reaching minimal value of 1500 Bq/l 222Rn. This boundary is set in the spa law no. 164/2001 Sb. as a minimal radioactivity concentration for radioactive mineral water. In this area, 30 water manifestations were discovered meeting the boudary of >1500 Bq/l 222Rn. The most significant cluster is located in Albrechtice by Frýdlant. Close to Kančí vrch (Boar Hill) 12 radioactive water springs were discovered. In the town of Albrechtice, a discovery of dissolved salts- rich radioactive mineral water was made, concerning springs Soumar and Matka. The most mineralized spring Soumar contains more than 1 g/l of dissolved salts (hydrochemical type Na-Ca-Cl water with total mineralization up to 1,5 g/l) combined with it's 222Rn activity surpassing 1500 Bq/l. Another significant cluster is located near the town of Nová Ves by Chrastava, where the most active source of the whole area, Mikulášský pramen (Mikulash Spring), with activity up to 2821 Bq/l 222Rn, was found. Another three radioactive water springs were found in this area. Also, probable dry...
Determination of the age of secondary uranium minerals using 230Th/234U in selected localities of the Bohemian massif
Roll, Michal ; Goliáš, Viktor (advisor) ; Mizera, Jiří (referee)
This thesis is focused on prominent uranium deposits in Czech Republic and their secondary uranium mineralization. Main goal of this thesis is to analyze collected minerals and to determine their ages. Next step is to prove or disprove hypothesis that this secondary uranium minerals are products of Quaternary glacier weathering. As a suitable analytical method, an alpha spectrometry was used and the age was calculated by 230 Th/234 U ratio. Firstly, chosen methodology was verified with admixture of reference material PU1 (Přibram uraninite) in secular equilibrium and internal standard, both with known activity. Analyzed spectra confirmed that some of the samples lay on the very edge of datability, especially in case of PL1 and GF1, both samples are very young, so they easily could be products of anthropogenic activity (changed environment due to mining works). On the other hand, in case of sample GF3, the age was successfully determined, although it is also quite young phase. In case of samples ME3, ME4 and ME6 was used threshold dating method, because they were considered to be too old for age calculation. The rest of the samples chosen for age determination was analyzed without further complications. Based on the age and geological setting, samples GF3 (3 725 ± 845 years), JE1 (10 655 ± 1 795...
Role of the selenium in the late hydrothermal phase of the Příbram uranium region
Škácha, Pavel ; Goliáš, Viktor (advisor) ; Drábek, Milan (referee) ; Makovický, Emil (referee)
Příbram uranium and base-metal district is the most important vein uranium district in the Czech Republic. The main ore was represented by uraninite there and the occurrences of selenium mineralization are directly connected to it. The presence of selenides was not confirmed during the mining activities. Major development of the uranium-carbonate mineralization was found in the Bytíz deposit in the central part of the uranium district. All known occurrences of selenides have been found from this area only so far. Antimonselite, athabascaite, bellidoite (?), berzelianite, brodtkorbite, bukovite, clausthalite, dzharkenite, eskebornite, eucairite, giraudite, hakite, cadmoselite, klockmannite, naumannite, permingeatite, sabatierite, tiemannite and umangite, as well as the new unnamed selenium analogue of chalcostibite were newly identified from the dump material from the shafts No. 16 and 11A. The extremely Hg-rich hakite, which contains up to 30 wt.% of Hg, is the most remarkable mineral from the tetrahedrite group of minerals. The pertinence of the Hg-hakite was verified by means of the transmission electron microscopy. Uncommon recently formed supergene selenium association is represented by molybdomenite, munakataite and piretite. A large scale of associated minerals was found in association with...
Dating of radioactive mineral springs of the Krkonoše-Jizera crystalline by 230Th/234U method
Fanta, Martin ; Goliáš, Viktor (advisor) ; Mizera, Jiří (referee)
The isotopes 238 U, 234 U and 230 Th, as members of the uranium-radium decay chain, are fractionated in the environment by changes of geochemical conditions, and they can be used for dating of recent or past geochemical processes in the Quaternary. Samples of water with uranium and of water-activated solids were taken of radioactive mineral water springs at two study sites in the area of Krkonoše-Jizera crystalline complex: Svatý Vojtěch (St. Adalbert) in Horní Malá Úpa, and Bukový Pramen in the Těsný důl valley in Janské Lázně. Uranium was co-precipitated in field conditions with hydroxides of FeIII+ in 50-liter water samples of the radioactive springs. In the lab, uranium and thorium were separated from water precipitates, as well as from solid samples after their chemical decomposition, using chromatographic extraction agent UTEVA. All the three isotopes of interest emit alpha particles, and so their activities were measured by alpha spectrometry and expressed as 234 U/238 U and 230 Th/234 U ratios. As an internal standard, 232 U/228 Th was used. The resulting 234 U/238 U activity ratios of four water samples measured ranged from 1.0747 to 1.423. In twelve samples of solid phases activity ratios 234 U/238 U from 0.861 to 1.129 were determined. The 230 Th/234 U activity ratios form two distinct...

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