PŘIROZENÁ RADIOAKTIVITA PALEOZOICKÝCH A PROTEROZOICKÝCH HORNIN SEVEROVÝCHODNÍ ČÁSTI ČESKÉHO MASIVU V PROFILOVÉ LINII MEZI VIDNAVOU A OSTRAVOU-PORUBOU

Concentrations of natural radioactive elements (K, U, Th) were measured using a field gamma-ray spectrometer in Palaeozoic and Proterozoic rocks of the Silesicum and in rocks of Upper Devonian - Lower Carboniferous siliciclastic flysch formations called the Moravian-Silesian Culm, in approximately 200 km long section line Velká Kraš (near Vidnava) Mexiko (SW of Ostrava-Poruba). Relatively high natural radioactivity was found in granitoids (especially biotite granites) of the Žulová Massif, migmatites and biotite gneisses with garnet and sillimanite of the Žulová Massif mantle, and siliciclastic sediments (graywackes, siltstones and clay shales) of the Moravice Fmt. and Hradec-Kyjovice Fmt. in the eastern part of the Moravian-Silesian Culm