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Chemical character and structure of uraniferous bitumens (Vrchlabí, Czech Republic)
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SYSNO ASEP 0566957 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Chemical character and structure of uraniferous bitumens (Vrchlabí, Czech Republic) Author(s) Machovič, Vladimír (USMH-B)
Havelcová, Martina (USMH-B) RID, ORCID
Lapčák, L. (CZ)
Mizera, Jiří (USMH-B) ORCID
Sýkorová, Ivana (USMH-B) RID, ORCIDNumber of authors 5 Article number 104137 Source Title International Journal of Coal Geology. - : Elsevier - ISSN 0166-5162
Roč. 264, DEC 1 (2022)Number of pages 13 s. Language eng - English Country NL - Netherlands Keywords Bitumen ; Halos ; Micro-ATR-FTIR mapping ; Radiolytic alteration ; Uranium Subject RIV DD - Geochemistry OECD category Geology R&D Projects GA19-05360S GA ČR - Czech Science Foundation (CSF) Method of publishing Limited access Institutional support USMH-B - RVO:67985891 UT WOS 000883101200001 EID SCOPUS 85141226100 DOI 10.1016/j.coal.2022.104137 Annotation Black shales from the Permian rocks at Vrchlabí in the Krkonoše Piedmont Basin (Czech Republic) contain bitumens with uraninite grain inclusions and bulk uranium concentrations up to 4.8 wt%, determined by instrumental neutron activation analysis. The carbonaceous matter in the bitumens has been characterised by gas chromatography/mass spectrometry, attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscopy, and stable carbon isotopic composition. Progressive radiolytic alteration was documented by changes in the chemical composition and structure of both bulk samples and on the microscale. Condensation of aromatic structures, increase in content of oxygenated compounds, and enrichment in 13C were documented in the uranium-rich bulk samples. Micro-ATR-FTIR area mapping throughout the bright halos around uraninite inclusions revealed detailed structural changes, particularly a decrease in aliphatic bond intensities and an increase in the aromaticity of the structures close to the inclusions. A radiolytic alteration pathway has been suggested assuming a complex of reactions between organic matter and uranyl containing hydrothermal solutions, and oxidation by OH radicals produced in radiolysis of water. The organic matter transformations observed in the uraniferous bitumen correspond to the coalification processes, changing the bitumen composition from type I to type III and IV kerogens. Detailed characterisation of the radiation-induced chemical and structural changes in the naturally occurring uraniferous bitumens will contribute to the general understanding of the nature and behaviour of organic matter in other uraniferous environments or in the radioactive waste repositories. 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.sciencedirect.com/science/article/pii/S0166516222002130?via%3Dihub
Number of the records: 1