Abstract Alexandra Molnárová: The study of U-REE-Au mineralizations of Gemeric Unit: Prakovce - Zimná voda a Hnilec - Peklisko (Diploma thesis). Comenius University in Bratislava. Faculty of Natural Sciences. Department of Mineralogy and Petrology. Supervisor: doc. Martin Ondrejka, PhD. Bratislava, 2019, pages: 80. A certain specificity of the Gemeric tectonic unit of the Western Carpathian is the unique mineralization of critical metals U-REE ± Au, the occurrence of which is bound by e.g. to locations Čučma - Majerská dolina, Prakovce - Zimná voda, or Hnilec - Peklisko. Mineralogically diverse composition of the locality Prakovce - Zimná voda is represented primarily by primary hypogene paragenesis of botryoidal uraninite I., gold, brannerite, REE-Ca phosphates of monazite-(Ce), monazite-(Nd), xenotime-(Y), fluorapatite and accompanying sulfides (arsenopyrite, gersdorffite, antimonite-bismuthinite) and sulfosalts (tintinaite-kobellite) and also Nb-V rich rutile. These minerals are altered in supergene conditions and uranyl phosphates and arsenates of the autunite group, scorodite, limonite, alunite supergroup minerals (phillipsbornite and segnitite with significant enrichment in Bi and Sb) and pharmacosiderite are formed. The locality Hnilec - Peklisko has relatively poor mineralogy and includes mainly remobilized REE-Ca phosphates monazite-(Ce), xenotime-(Y) and fluorapatite together with rutile. The P-T conditions (350 - 500° C a 1,5 - 8,2 kbar) indicate formation of mineralization with hydrostatic pressure, which tends to lithostatic pressure. The specific mineral composition of both primary and secondary phases suggests significant remobilization in particular REE, Y, U, P, As, Fe, Sb, Bi, W, Nb and F, as well as REE + Y fractionation in hypogene hydrothermal conditions as well as in low-thermal to supergene conditions by leaching in the presence of sulfuric acid released by the decomposition of primary sulfides. Age of mineralization approx. 246-241 Ma determined for uraninite I and xenotime- (Y) as well as geochemical specifications (especially the presence of W, F, Nb) suggests genetic relationship of mineralization with post-magmatic activity and enplacement of so-called Gemeric specialized S-type granites in Middle Triassic. The presented thesis deals with the study of U-REE-Au hydrothermal mineralization in Gemeric unit, namely in two localities: Prakovce - Zimná voda and Hnilec - Peklisko. Three main objectives have been set. The first objective was a detailed mineralogical research of these selected U-REE-Au hydrothermal mineralizations in the Gemeric unit. It is mainly about the research of primary and secondary (supergene) minerals U-REE, as well as the exploration of accompanying minerals. In particular, we investigated their occurrence, chemical composition, distribution of individual chemical elements within specific mineral phases and substitution trends. To obtain this information, we used available laboratory methods, namely EPMA electron microanalysis (BSE, WDS, EDS, X-ray mapping). Another aim of this thesis was to determine the PT conditions of mineralization. Optical microtermometry was used for this part of the research, which is the basic method for investigating fluid inclusions. From the measured values from the inclusion measurements, we were able to calculate their salinity, density and isochores using a computer program. To be able to use another TitaniQ thermometer, we had to get the Ti concentration in the quartz. This was obtained by laser ablation. For a more accurate result, we combined both of these thermometers. The last, third objective of my work was to attempt to date the mineralization of suitable hydrothermal minerals in situ by chemical U-Th-Pb isochron dating. The laboratory method used was an EPMA electron microanalysis that allows in-situ chemical U-Th-Pb dating. Dated minerals were uraninite and xenotime- (Y). The obtained information on chemical composition, textures, superposition, PT-conditions and age was taken into account in the succession mineralization scheme. Key words: remobilization, uraninite, uranyl minerals, REE phosphates, thermometry, fluid inclusions, chemical dating