Natural radioactivity of Upper Devonian – Lower Carboniferous siliciclastic flysch formations on the eastern margin of the Bohemian Massif

Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in more then two thousand samples of Upper Devonian to Lower Carboniferous siliciclastic flysch sediments outcropping on the easternmost margin of the Bohemian Massif (mainly in the Drahany Mts. and Nízký Jeseník Mts.). Studied rocks belong to eight formations: Protivanov Fm., Rozstání Fm., Myslejovice Fm., Mohelnice Fm., Andělská Hora Fm., Horní Benešov Fm., Moravice Fm. and Hradec–Kyjovice Fm. Conglomerates (incl. gravelites), various types of psammites (mainly graywackes), siltstones, silty shales and clay shales occur in all mentioned formations. Quartzites and phyllites dominated in the source zone of clastic sediments of Mohelnice Fm. and Andělská Hora Fm., therefore K, U and Th contents in siliciclastic sediments of the both formations are correspondingly low. Relatively high radioactivity of sediments belonging to remaining six formations suggests a significant contribution of acid or intermediate magmatic rocks in the source zone of clastic material.Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in more then two thousand samples of Upper Devonian to Lower Carboniferous siliciclastic flysch sediments outcropping on the easternmost margin of the Bohemian Massif (mainly in the Drahany Mts. and Nízký Jeseník Mts.). Studied rocks belong to eight formations: Protivanov Fm., Rozstání Fm., Myslejovice Fm., Mohelnice Fm., Andělská Hora Fm., Horní Benešov Fm., Moravice Fm. and Hradec–Kyjovice Fm. Conglomerates (incl. gravelites), various types of psammites (mainly graywackes), siltstones, silty shales and clay shales occur in all mentioned formations. Quartzites and phyllites dominated in the source zone of clastic sediments of Mohelnice Fm. and Andělská Hora Fm., therefore K, U and Th contents in siliciclastic sediments of the both formations are correspondingly low. Relatively high radioactivity of sediments belonging to remaining six formations suggests a significant contribution of acid or intermediate magmatic rocks in the source zone of clastic material