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Geology and Petrography of Uraniferous Bitumens in Permo-Carboniferous Sediments (Vrchlabí, Czech Republic)
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SYSNO ASEP 0557659 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Geology and Petrography of Uraniferous Bitumens in Permo-Carboniferous Sediments (Vrchlabí, Czech Republic) Author(s) Havelcová, Martina (USMH-B) RID, ORCID
Sýkorová, Ivana (USMH-B) RID, ORCID
René, Miloš (USMH-B) RID, ORCID, SAI
Mizera, Jiří (USMH-B) ORCID
Coubal, Miroslav (USMH-B)
Machovič, Vladimír (USMH-B)
Strunga, V. (CZ)
Goliáš, V. (CZ)Number of authors 8 Article number 544 Source Title Minerals. - : MDPI
Roč. 12, č. 5 (2022)Number of pages 20 s. Language eng - English Country CH - Switzerland Keywords bireflectance ; bitumen ; halos ; radiolytic alteration ; uraninite Subject RIV DB - Geology ; Mineralogy OECD category Geology R&D Projects GA19-05360S GA ČR - Czech Science Foundation (CSF) Method of publishing Open access Institutional support USMH-B - RVO:67985891 UT WOS 000802389100001 EID SCOPUS 85128760774 DOI 10.3390/min12050544 Annotation Uraniferous bitumens found in black shales from the Permian rocks at Vrchlabí in the Krkonoše Piedmont Basin (Czech Republic) were described and characterized petrologically and mineralogically. The Permian sediments originated from weathering products in metasediments and granitoids of the Krkonoše–Jizera and Orlice–Sněžník crystalline complexes. The organic matter contained up to 4.8 wt.% uranium, as uraninite grains. Elements associated with uraninite, such as Pb, Zr, Cu, and As, may have accumulated from epigenetic fluids in layers rich in organic matter during their late diagenesis. The bitumen structures were extremely heterogeneous, a feature attributed to the radiolytic effects of uranium. Amorphous bitumens, alternating with various forms of nodular and corroded bitumen types from multiple generations, were present. Low and highly altered bitumens with weak anisotropy were recognized, together with halo zones, with reflectance up to 4.37%. The halo zones differed in size, brightness, and reflectance, increasing from the edge to the center. Halos often revealed dark rims between uraninite inclusions and clear zones, originating probably as a result of weaker alterations in organic matter due to the presence of other inorganic components. Uranium concentration was the main factor controlling the degree of radiolytic alteration. The studied uraniferous bitumens are an excellent example of multistage formation and diverse evolution during burial and diagenesis. Workplace Institute of Rock Structure and Mechanics Contact Iva Švihálková, svihalkova@irsm.cas.cz, Tel.: 266 009 216 Year of Publishing 2023 Electronic address https://www.mdpi.com/2075-163X/12/5/544
Number of the records: 1