Geological Survey of Slovak Republic

Bratislava, Slovakia

Geological Survey of Slovak Republic

Bratislava, Slovakia
Time filter
Source Type

Hurai V.,Slovak Academy of Sciences | Paquette J.-L.,CNRS Magmas and Volcanoes Laboratory | Paquette J.-L.,French National Center for Scientific Research | Lexa O.,Charles University | And 2 more authors.
Mineralogy and Petrology | Year: 2015

Sodic metasomatites (albitites) occur around and within siderite veins in the southern part of the Gemeric tectonic unit of the Western Carpathians. Accessory minerals of the metasomatites represented by monazite, zircon, apatite, rutile, tourmaline and siderite are basically identical with the quartz-tourmaline stage of other siderite and stibnite veins of the tectonic unit. Statistical analysis of chemical Th-U(total)-Pb isochron method (CHIME) of monazite dating yielded Jurassic-Cretaceous ages subdivided into 3–4 modes, spreading over time interval between 78 and 185 Ma. In contrast, LA-ICPMS 206Pb/238U dating carried out on the same monazite grains revealed a narrow crystallization interval, showing ages of Th-poor cores with phengite inclusions identical within the error limit with Th-rich rims with cauliflower-like structure. The determined lower intercept at 139 ± 1 Ma overlapped the Vallanginian-Berriasian boundary, thus corroborating the model of formation of hydrothermal vein structures within an arcuate deformation front built up in the Variscan basement as a response to Early Cretaceous compression, folding and thrusting. In contrast, associated zircons are considerably older than the surrounding Early-Palaeozoic volcano-sedimentary rocks, showing Neoproterozoic ages. The zircon grains in albitite metasomatites are thus interpreted as fragments of Pan-African magmatic detritus incorporated in the vein structures by buoyant hydrothermal fluids. © 2015, Springer-Verlag Wien.

Hogdahl K.,Uppsala University | Majka J.,Uppsala University | Sjostrom H.,Uppsala University | Nilsson K.P.,Geological Survey of Sweden | And 2 more authors.
Contributions to Mineralogy and Petrology | Year: 2012

Monazite in melt-producing, poly-metamorphic terranes can grow, dissolve or reprecipitate at different stages during orogenic evolution particularly in hot, slowly cooling orogens such as the Svecofennian. Owing to the high heat flow in such orogens, small variations in pressure, temperature or deformation intensity may promote a mineral reaction. Monazite in diatexites and leucogranites from two Svecofennian domains yields older, coeval and younger U-Pb SIMS and EMP ages than zircon from the same rock. As zircon precipitated during the melt-bearing stage, its U-Pb ages reflect the timing of peak metamorphism, which is associated with partial melting and leucogranite formation. In one of the domains, the Granite and Diatexite Belt, zircon ages range between 1.87 and 1.86 Ga, whereas monazite yields two distinct double peaks at 1.87-1.86 and 1.82-1.80 Ga. The younger double peak is related to monazite growth or reprecipitation during subsolidus conditions associated with deformation along late-orogenic shear zones. Magmatic monazite in leucogranite records systematic variations in composition and age during growth that can be directly linked to Th/U ratios and preferential growth sites of zircon, reflecting the transition from melt to melt crystallisation of the magma. In the adjacent Ljusdal Domain, peak metamorphism in amphibolite facies occurred at 1.83-1.82 Ga as given by both zircon and monazite chronology. Pre-partial melting, 1.85 Ga contact metamorphic monazite is preserved, in spite of the high-grade overprint. By combining structural analysis, petrography and monazite and zircon geochronology, a metamorphic terrane boundary has been identified. It is concluded that the boundary formed by crustal shortening accommodated by major thrusting. © 2011 Springer-Verlag.

Melikadze G.I.,Ilia State University | Chelidze T.,Nodia Institute of Geophysics | Zhukova N.,Nodia Institute of Geophysics | Malik P.,Geological Survey of Slovak Republic | Vitvar T.,International Atomic Energy Agency
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

Borjomi mineral waters field is a source of famous mineral water, which is exported to dozens of countries and forms a significant part of budget of Georgia. Currently, in connection with construction of Baku-Tbilisi-Ceyhan pipeline by British Petroleum (BP), serious concerns arise with respect to vulnerability of water supply of the city of Borjomi to possible oil spills related to operation of the pipeline. In this paper, we consider mainly the interaction between surface water and groundwater of the Bakuriani-Borjomi lava flow and the possibility of their pollution with hydrocarbons in case of oil spilling. In order to define the possible pollution propagation, we apply stable isotope technology and other modern hydro-geophysical methods that we have created. © Springer Science+Business Media B.V. 2011.

Kral J.,Geological Survey of Slovak republic | Hok J.,University of Tirana | Bachlinski R.,Instytut Nauk Geologicznych PAN | Ivanicka J.,Geological Survey of Slovak republic
Acta Geologica Slovaca | Year: 2013

Minerals separated from diaphtoritic rocks of the Selec block of the Považský Inovec crystalline complex were dated by 40Ar/39Ar method (coarse-grained muscovites), and accessory apatites, coarse-grained muscovites and whole rocks were also analyzed by Rb-Sr method. Obtained 40Ar/39Ar muscovite plateau ages and calculated Rb-Sr ages for two point accessory apatite - coarse-grained muscovite pairs are identical (307-310 Ma) and are considered as age of diaphtoresis in the Považský Inovec Mts. crystalline complex. Both isotopic systems in minerals registered no metamorphic Alpine overprint. But in whole rocks, increasing of Rb/Sr ratio is documented that can be explained by loss of ordinary strontium from acid plagioclases during low temperature alteration under significant Alpine tectonics influence. © Univerzita Komenského v Bratislave (2009-2014).

Ondrejka M.,Comenius University | Uher P.,Comenius University | Putis M.,Comenius University | Broska I.,Slovak Academy of Sciences | And 3 more authors.
Lithos | Year: 2012

The initial to advanced stage of monazite breakdown was identified in a granitic orthogneiss from the pre-Alpine basement in the Veľký Zelený Potok Valley (the Veporic Unit, Western Carpathians, central Slovakia). Monazite-(Ce) formed during Variscan metamorphism of the original Cambrian to Ordovician granitic rock. Two younger, Permian post-magmatic hydrothermal, and Cretaceous metamorphic-hydrothermal events caused a breakdown of the monazite to secondary egg-shaped coronal structures (100 to 500μm in diameter) with concentric newly-formed mineral phases. Two principal breakdown stages and newly formed mineral assemblages are recognizable: (1) partial to complete replacement of primary monazite with an internal apatite+ThSiO 4 (huttonite or thorite) zone and an external allanite-(Ce) to clinozoisite zone; (2) hydroxylbastnäsite-(Ce) partly replacing apatite+ThSiO 4 and allanite to clinozoisite aggregates. The monazite breakdown was initiated by fluid sources differing in composition. Stage (1) originated due to post-magmatic hydrothermal fluids, whereas stage (2) indicates an input of younger, CO 2-bearing metamorphic-hydrothermal fluids. © 2012 Elsevier B.V.

Ondrejka M.,Comenius University | Putis M.,Comenius University | Uher P.,Comenius University | Schmiedt I.,Comenius University | And 2 more authors.
Mineralogy and Petrology | Year: 2016

A variety of rare earth elements-bearing (REE) accessory mineral breakdowns were identified in granitic orthogneisses from the pre-Alpine basement in the Veporic Unit, Central Western Carpathians, Slovakia. The Ordovician granitic rocks were subjected to Variscan metamorphic-anatectic overprint in amphibolite facies. Chemical U-Th-Pb dating of monazite-(Ce) and xenotime-(Y) reveal their primary magmatic Lower to Middle Ordovician age (monazite: 472 ± 4 to 468 ± 6 Ma and xenotime: 471 ± 13 Ma) and/or metamorphic-anatectic Variscan (Carboniferous, Visean) age (monazite: 345 ± 3 Ma). Younger fluid-rock interactions caused breakdown of primary magmatic and/or metamorphic-anatectic monazite-(Ce), xenotime-(Y), fluorapatite and allanite-(Ce). Fluid-induced breakdown of xenotime-(Y) produced numerous tiny uraninite inclusions within the altered xenotime-(Y) domains. The monazite-(Ce) breakdown produced secondary egg-shaped coronal structures of different stages with well-developed concentric mineral zones. Secondary sulphatian monazite-(Ce) (up to 0.15 apfu S) occasionally formed along fluorapatite fissures. Localized fluorapatite and monazite-(Ce) recrystallization resulted in a very fine-grained, non-stoichiometric mixture of REE-Y-Fe-Th-Ca-P-Si phases. Finally, allanite-(Ce) decomposed to secondary REE carbonate minerals (members of the bastnäsite and synchysite groups) and calcite in some places. Although the xenotime alteration and formation of uraninite inclusions is believed to be the result of dissolution-reprecipitation between early magmatic xenotime and late-magmatic granitic fluids, the monazite, apatite and allanite breakdowns were driven by metamorphic hydrothermal fluids. While earlier impact of post-magmatic fluids originated probably from Permian acidic volcanic and microgranitic veins crosscutting the orthogneisses, another fluid-rock interaction event most likely occurred during Late Cretaceous metamorphism in the Veporic basement and covering rocks. This stage indicates carbon-bearing fluids precipitating the carbonate minerals. © 2016 Springer-Verlag Wien

Loading Geological Survey of Slovak Republic collaborators
Loading Geological Survey of Slovak Republic collaborators