Natural radioactivity of metamorphic and igneous rocks and pre-Cenozoic sedimentary rocks on the map sheet 24-21 JevíčkoArticle PDF
Natural radioactivity of metamorphic and igneous rocks and pre-Cenozoic sedimentary rocks on the map sheet 24-21 Jevíčko
The aim of the paper is to inform about natural radioactivity of metamorphic, igneous and pre-Cenozoic sedimentary rocks on the map sheet 24-21 Jevíčko. Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in 1197 rock samples. The studied rocks belong to several geological units: i) four different crystalline complexes, e. g., Nectava Crystalline Complex (composed mainly of orthogneisses, phyllites and marbles) and Kladky Crystalline Complex (phyllonites, phyllites, metabasites), ii) the Konice-Mladeč Belt of the Devonian to Tournaisian age (carbonate rocks and basic volcanites prevail), iii) Givetian flysch sediments (Mohelnice Fm.) and Visean flysch formations (Protivanov Fm., Rozstání Fm., Myslejovice Fm.), iv) Permian siliciclastic sediments of the Boskovice Furrow and the Orlica Basin, and v) siliciclastic sediments of the Bohemian Cretaceous Basin. Data are tabled and discussed. From calculated values of mass activity of 226Ra equivalent it is evident that natural radioactivity of the studied rocks is low. Slightly increased mass activity values (296 Bq.kg-1 in average) were found in alkali-feldspar paleorhyolite outcropping at Ludmírov.
Jiří Zimák, Department of Geology, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic, e-mail: email@example.com