Viktor Goliáš

Charles University

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Jakub Plášil

Czech Academy of Sciences, Institute of Physics

Jiří Sejkora

National Museum

Ladislav Strnad

Charles University

PŠ

Pavel Škácha

National Museum

RŠ

Radek Škoda

Masaryk University

Martin Mihaljevič

Charles University

JČ

Jiří Čejka

Institute of Technology and Business

Vojtěch Ettler

Charles University

Vojtěch Vlček

University of California, Santa Barbara

Milan Zuna

Nuclear Research Institute Rez (Czechia)

Cooperative Institutions

Charles University

Czech Academy of Sciences

Czech Geological Survey

Czech Academy of Sciences, Institute of Physics

Czech Academy of Sciences, Institute of Geology

Czech Technical University in Prague

National Museum

Czech University of Life Sciences Prague

Masaryk University

University of Chemistry and Technology, Prague

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The absence of disturbances promoted Late Holocene expansion of silver fir (Abies alba) in the Bohemian Forest

Palaeogeography Palaeoclimatology Palaeoecology (2023)

Nick Schafstall Hélèna Svobodova Martin Kadlec Mariusz Gałka Petr Kuneš

Abies alba

10.1016/j.palaeo.2023.111950

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Citations (1)

Supergene minerals in the Horní Slavkov uranium ore district, Czech Republic

Journal of Geosciences (2007)

Jakub Plášil J. Sejkora Petr Ondruš František Veselovský Pavel Beran

This paper presents the existing and newly obtained information on supergene minerals of the Horní Slavkov uranium ore district.Mineralogical studies confirmed occurrences of the following minerals: anglesite, annabergite, arsenolite, autunite, carnotite, compreignacite, cuprosklodowskite, kaatialaite, liebigite, meta-autunite, metanováèekite, metatorbernite, mohrite, nováèekite, phosphuranylite, rutherfordine, schultenite, siderite, torbernite, uranophane, zeunerite, and unnamed phase UNK5.The present study did not confirm the presence of previously reported occurrences of bassetite, soddyite, uranophane-ß and uranospinite.Also presented is interpretation of formation of the supergene mineralization in this ore district.

Supergene (geology)

Uranium ore

Copper ore

10.3190/jcgs.991

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Citations (9)

Supergene mineralization of the Medvědín uranium deposit, Krkonoše Mountains, Czech Republic

Journal of Geosciences (2009)

Jakub Plášil J. Sejkora Jiřı́ Čejka Radek Škoda Viktor Goliáš

Supergene mineralization of the hydrothermal vein uranium deposit Medvědín (Krkonoše Mts., northern Bohemia) is rather varied both in number of the mineral phases and their chemical variation.The supergene minerals agardite-(Y), autunite/metaautunite, dewindtite, churchite-(Y), kasolite, new unnamed phase Pb(Ce,REE) 3 (PO 4 ) 3 (OH) 2 .nH 2 O, parsonsite, phosphuranylite, plumbogummite, pseudomalachite, pyromorphite, saléeite, torbernite/metatorbernite and uranophane were studied using powder XRD, EPMA, IR-spectroscopic and thermal analysis, contributing significantly to the clarification of their crystal chemistry.The alteration mineral assemblage consisting mostly of uranyl phosphates and silicates exhibits relatively high contents of REE and Pb.Minerals with a composition corresponding to pure mineral end-members have not been observed; instead most of the studied phases represent members of isomorphic series.Studied mineral assemblage is a stable association in surface conditions resulting apparently from a long-term alteration of the primary uranium mineralization.

Supergene (geology)

Uranium ore

10.3190/jgeosci.029

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Citations (43)

Hydrothermal uranium-base metal mineralization of the Jánská vein, Březové Hory, Příbram, Czech Republic: lead isotopes and chemical dating of uraninite

Journal of Geosciences (2008)

Pavel Škácha Viktor Goliáš Jiří Sejkora Jakub Plášil Ladislav Strnad

The Jánská vein is one of the important veins of Březové Hory mining district (central Bohemia, Czech Republic).Base metals were mined here since 14 th century and uranium ore during late 1950's.Uranium mineralization is younger than most of the base metal mineralization according to macroscopic and microscopic study.Most specimens of uraninite, obtained from archive, contain more or less abundant galena inclusions.Galena of this type is non-radiogenic as indicated by its Pb isotopic composition (ICP-MS).Its origin can be explained by remobilisation of the older base-metal mineralization during the younger, uranium-bearing mineralization event.The amount of radiogenic Pb in uraninite fluctuates from 48 up to 89.8 %.The age of theoretical end member of uraninite, calculated statistically from all measured data (for intersection 208 Pb/ 206 Pb = 0), is 269.8 ± 20.3 Ma (2σ).The only uraninite grain without galena inclusions yielded an age of 263.2 ± 8.9 Ma by chemical dating using electron microprobe.The calculated age of the uranium mineralization is in agreement with published data for other uranium deposits genetically associated with the Central Bohemian Plutonic Complex.

Uraninite

Radiogenic nuclide

Base metal

Uranium ore

10.3190/jgeosci.030

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Citations (21)

Widenmannite, a rare uranyl lead carbonate: occurrence, formation and characterization

Mineralogical Magazine (2010)

Jakub Plášil Jiří Čejka Jiří Sejkora Pavel Škácha Viktor Goliáš

Abstract The rare uranyl lead carbonate widenmannite, Pb 2 (UO 2 )(CO 3 ) 3 , was found at the Jánská vein, Příbram, Czech Republic, where two generations occur in several morphological types and mineral associations in hydrothermal veins. Alpha spectroscopy shows that these two generations have different ages, >220,000 and 118±12 y. ICP-MS analysis indicates that both widenmannites have a dominance of non-radiogenic Pb which originates from weathered galena. The older widenmannite I forms fine-grained, grey to beige aggregates in the highly altered supergene part of the hydrothermal ore vein in association with pyromorphite, cerussite and goethite. The younger widenmannite II occurs as white, yellow or greenish-yellow thin tabular crystals upto 0.5 mm long in association with cerussite, anglesite, limonite, kasolite and an unnamed Pb-U-O phase. Thermal analysis suggests that widenmannite decomposes in several steps, with Pb uranate as the final product. Infrared and Raman spectroscopy confirm the presence of non-equivalent (CO 3 ) 2– groups, bidentately coordinated in uranyl hexagonal polyhedra, forming the well known uranyl tricarbonate complex. Infrared spectroscopy shows conclusively that widenmannite does not contain molecular H 2 O.

Uranyl

Supergene (geology)

Malachite

10.1180/minmag.2010.074.1.97

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Citations (9)

New data for metakirchheimerite from Jáchymov (St. Joachimsthal), Czech Republic

Journal of Geosciences (2010)

Jakub Plášil Jiří Čejka Jiří Sejkora Jan Hloušek Viktor Goliáš

Metakirchheimerite was found only on a few samples from the Jan Evangelista vein at the "Adit level" of the Svornost shaft, Jáchymov (St.Joachimsthal) ore district, Krušné Hory/Erzgebirge Mountains, Czech Republic.It forms rare crystalline aggregates consisting of fine tabular crystals reaching 0.1 mm in size, which are very brittle, having light pink to light orange colour, with a high vitreous lustre.Metakirchheimerite crystalline aggregates occur on carbonate gangue with disseminated primary minerals: arsenopyrite, uraninite and skutterudite.Studied metakirchheimerite is a (sub-)recent alteration product of the primary minerals, connected to the old open mine adit environment.According to electron microprobe analyses, the empirical formula of metakirchheimerite can be expressed, based on As + P = 2 apfu, as: (Co 0.53 Mg 0.25 Ni 0.08 Zn 0.07 Fe 0.05 Ca 0.03 ) Σ1.01 (UO 2 ) 2.07 [(AsO 4 ) 1.99 (PO 4 ) 0.01 )] Σ2.00 .8H 2 O. Metakirchheimerite from Jáchymov exhibits an extensive cationic substitution trend of the metanováčekite component.The X-ray diffraction pattern of metakirchheimerite is consistent with a triclinic symmetry inferred from the single-crystal study of the synthetic metakirchheimerite analogue.Refined unit-cell parameters for the triclinic space group P-1 are a 7.210(4) Å, b 9.771(6) Å, c 13.252(9) Å, α 75.39(4)°, β 83.94(6)°, γ 81.88(6)° with unit-cell volume V 892(1) Å 3 .Both infrared and Raman spectra of metakirchheimerite exhibited stretching and bending vibrations of (UO 2 ) 2+ , (AsO 4 ) 3-, (PO 4 ) 3-and H 2 O groups.The vibration bands of all these units were tentatively assigned.The U-O bond lengths in uranyl and O-H…O hydrogen bond lengths, which were inferred from the spectra, are consistent with published crystal structure data for a synthetic analogue of metakirchheimerite.

10.3190/jgeosci.057

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Citations (9)

Exploration and Investigation of High-Level Radon Medicinal Springs in the Crystalline Units: Lugicum

Water (2022)

Viktor Goliáš Lenka Hájková Tomáš Lipanský Tomáš Černík Pavel Kohn

Radioactive (radon) groundwaters are highly valued among mineral waters for their healing effects. Between 2005 and 2015, a large exploratory event for prospecting and documenting radon water springs took place in the crystalline area of Lugicum (Bohemian Massif) under Czech–Polish cooperation. For these purposes, an exploration method was developed as a combination of GIS (ArcMap 9.1–10.2) area preparation followed by field radiohydrogeochemical mapping at a scale of 1:10,000. The gamma indication method was optimized and used for the selection of water samples. A total of 2354 water sources were examined. Radon activity concentrations were measured at 660 sources found throughout the territory. Of those, 111 sources exhibited 222Rn activity above 1500 Bq/L and, thus, were categorized as sources of mineral radioactive waters according to Czech legislation. The highest 222Rn activity was found in the Michael spring near Nové Město pod Smrkem (up to 6237 Bq/L 222Rn). Many discovered sources with high balneological potential are significant and, therefore, are quickly becoming popular among the public.

Massif

Mineral water

Hot spring

10.3390/w14020200

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Citations (4)

Supergene mineralization of the Medvedin uranium deposit,Krkonose Mountains, Czech Republic

Arabian Journal of Geosciences (2009)

Jakub Plášil Jiří Sejkora Jiří Čejka Radek Škoda Viktor Goliáš

Supergene (geology)

Alunite

Source

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Citations (0)

Methods of grout quality measurement in borehole exchangers for heat pumps and their rehabilitation

Geothermal Energy (2024)

Petr Nakládal Martin Procházka Viktor Goliáš Jaromíra Hrdá

Abstract Methods and instrumentation for measuring grout quality in heat pump boreholes, including the measurement of groundwater flow through boreholes outside partly grouted borehole exchanger pipes, have been developed in the Czech Republic. A Semtex charge has also been developed to repair rock massifs, which reliably disconnects borehole exchanger pipes without severely harming the surrounding rock environment or buildings. The resulting hole can then be used for regrouting, thus preventing undesirable vertical water flow through the borehole.

Grout

10.1186/s40517-024-00313-6

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Uranotungstite, the only natural uranyl tungstate: crystal structure revealed from 3D electron diffraction

American Mineralogist (2021)

Gwladys Steciuk Uwe Kolitsch Viktor Goliáš Radek Škoda Jakub Plášil

Abstract Uranotungstite is an uranyl-tungstate mineral that was until recently only partially characterized with a formula originally given as (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4·12H2O and an unknown crystal structure. This mineral has been reinvestigated by electron microprobe analysis coupled with three-dimensional electron diffraction. According to the electron microprobe data, the holotype material from the Menzenschwand uranium deposit (Black Forest, Germany) has the empirical formula (Ba0.35Pb0.27)Σ0.62[(U6+O2)2(W0.986+☐0.75)O4.7(OH)2.5(H2O)1.75](H2O)1.67 (average of 8 points calculated on the basis of 2U apfu; H2O content derived from the structure). According to the precession-assisted 3D ED data, holotype uranotungstite from Menzenschwand is monoclinic, P21/m, with a = 6.318(5) Å, b = 7.388(9) Å, c = 13.71(4) Å, β = 99.04(13)°, and V = 632(2) Å3 (Z = 2). The structure refinement of the 3D ED data using the dynamical approach (Robs = 0.0846 for 3287 independent observed reflections) provided a structure model composed of heteropolyhedral sheets. A β-U3O8-type sheet of idealized composition [(UO2)2W6+Fe0.253+☐0.75O4.75(OH)1.5(H2O)1.75]0.25– is composed of UO7 polyhedra linked by (W,Fe)O5 polyhedra in which the W:Fe ratio is variable as well as the bulk occupancy of this site; the W site may also host a minor proportion of Cu, Mg, or V. In uranotungstite, the interlayer spaces between adjacent U-W-O sheets host water on one side and, on the other side, a partially occupied cation site mostly occupied by Ba and, to a lesser extent, Pb, as well as a partially occupied H2O site. This work is the first structural description of a natural uranyl-tungstate mineral and confirms the great structural and chemical flexibility of β-U3O8 type of sheets.

Uranyl

Tungstate

Crystal (programming language)

10.2138/am-2022-8112

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Citations (1)