Open AccessUran, thorium a draslík v krystaliniku a paleozoických sedimentech na mapovém listu 14-33 Polička – laboratorní gamaspektrometrie a parciální chemické složení variských plutonitů
Author(s) -
Jiří Zimák
Publication year - 2017
Publication title -
geologické výzkumy na moravě a ve slezsku v roce .../geologické výzkumy na moravě a ve slezsku v roce ...
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.128
H-Index - 1
eISSN - 2336-4378
pISSN - 1212-6209
DOI - 10.5817/gvms2017-1-2-69
Subject(s) - geochemistry , schist , geology , migmatite , thorium , pegmatite , quartz monzonite , gneiss , pluton , igneous rock , skarn , zircon , metamorphic rock , titanite , uranium , mineralogy , quartz , fluid inclusions , paleontology , materials science , tectonics , metallurgy
The paper deals with natural radioactivity of metamorphic and igneous rocks and Palaeozoic sediments within the map sheet 14-33 Polička. Studied rocks belong to three geological units: the Hlinsko Zone (phyllites and quartzites of the Mrákotín Fm., flysch sediments of the Hlinsko-Rychmburk Fm.), the Svratka Crystalline Complex (mainly mica schists, paragneisses, orthogneisses and migmatites, also amphibolites, skarns, erlans and quartzites) and the Polička Crystalline Complex (mica schists, paragneisses to migmatites and the Variscan granitoids are dominant). Concentrations of potassium, uranium and thorium were measured using a laboratory gamma-ray spectrometer in 805 rock samples. Data are tabled and discussed. Natural radioactivity of rocks is evaluated on the basis of the calculated values of mass activity of 226Ra equivalent (am). Slightly increased am values were found in migmatites and orthogneisses of the Svratka Crystalline Complex (187 Bq.kg-1 on average), granites and granodiorites of the Budislav Pluton (216 Bq.kg-1), granodiorites and rocks of a tonalite suite of the Miřetín Pluton (199 and 194 Bq.kg-1). Increased concentrations of uranium and thorium were found in some samples of pegmatite and aplite. Radioactivity of rocks of the Hlinsko-Rychmburk and Mrákotín Fms. can be assessed as relatively low.