scholarly journals Obsahy přirozených radioaktivních prvků (K, U, Th) v půdách na mapovém listu 24-22 Olomouc – vztah mezi radioaktivitou půdy a matečné horniny

2019 ◽  
Vol 26 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Natural Radioactivity ◽  
Gamma Ray ◽  
Parent Material ◽  
Soil Samples ◽  
Fluvial Sediments ◽  
Radioactive Elements ◽  
Quaternary Sediments ◽  
Gamma Ray Spectrometer ◽  
Parent Rocks ◽  
Mass Activity

The paper deals with natural radioactivity of soils on the map sheet 24-22 Olomouc and compares contents of natural radioactive elements in soils and in their parent rocks (soilforming substrates). Three main types of parent rocks can be distinguished in the studied area: i) siliciclastic flysch sediments of the Moravo-Silesian Palaeozoic, ii) Quaternary sediments of the river Morava floodplain, iii) Quaternary loesses. Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in 1 077 soil samples. It is evident from calculated values of mass activity of 226Ra equivalent (am) that natural radioactivity of the studied soils is low. The average am of soils developed on siliciclastic flysch sediments is 142 Bq.kg-1, 133 Bq.kg-1 on fluvial sediments of the river Morava and 148 Bq.kg-1 on loesses. The average am values calculated for soils developed on siliciclastic flysch sediments and for soils on loesses are almost the same as average am values calculated for their parent rocks. The soils of the river Morava floodplain show higher am values compared to their parent material (sands and pebbles dominate) due to higher uranium and thorium contents.

scholarly journals Přirozená radioaktivita krystalinika, paleozoických sedimentárních hornin a vybraných kenozoických sedimentů na mapovém listu 24-22 Olomouc

2017 ◽  
Vol 24 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Natural Radioactivity ◽  
Gamma Ray ◽  
Sedimentary Rocks ◽  
Crystalline Rocks ◽  
Fluvial Sediments ◽  
Gamma Ray Spectrometer ◽  
Clay Shales ◽  
Mass Activity ◽  
Geological Units ◽  
Cenozoic Sediments

The paper deals with natural radioactivity of crystalline rocks, Palaeozoic sedimentary rocks and selected Cenozoic sediments on the map sheet 24-22 Olomouc. Studied rocks belong to the following geological units: the Brunovistulicum (Proterozoic granitoids and dioritoids, often mylonitized), the Moravo-Silesian Palaeozoic (mainly carbonate rocks of the Macocha and Líšeň Fms. and flysch sediments of the Andělská Hora, Protivanov, Horní Benešov, Rozstání, Moravice and Myslejovice Fms.), the Carpathian Foredeep (Miocene marine sands and clays) and the Upper Morava Basin (Pliocene-Pleistocene lacustrine and fluvial sediments, and loesses). Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in 612 rock samples. Data are tabled and discussed. From calculated values of mass activity of 226Ra equivalent (am) it is evident that natural radioactivity of the studied rocks is predominantly low. Slightly increased am values were found in silty shales, clay shales and siltstones of the Rozstání Fm. (189 Bq.kg-1 on average, 308 Bq.kg-1 in the sample with the highest natural radioactivity).

scholarly journals VZTAH MEZI PŘIROZENOU RADIOAKTIVITOU HORNIN A PŮD NA NICH VYTVOŘENÝCH – ZÁKLADNÍ PROBLÉM INTERPRETACE DAT ZÍSKANÝCH LETECKOU A TERÉNNÍ GAMASPEKTROMETRIÍ

2016 ◽  
Vol 22 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Natural Radioactivity ◽  
Gamma Ray ◽  
Natural Radionuclides ◽  
Size Fraction ◽  
Mineralogical Composition ◽  
Gamma Ray Spectrometry ◽  
Spectrometric Analysis ◽  
Radiation Dose Rate ◽  
Parent Rocks ◽  
Mass Activity

The objective of this study was to assess the amount of natural radionuclides in fresh parent rocks and their effect on natural radioactivity of soils developed from them. Forty-five fresh rocks consisting mainly of granitoids, syenitoids, acid to basic metavolcanites, mica schists, gneisses, quartzites, serpentinites, sandstones, graywackes, and limestones and their corresponding overlying soils were sampled for laboratory gamma-ray spectrometric analysis. Contents of potassium, uranium and thorium were converted to mass activity of 226Ra equivalent (am) and terrestrial gamma radiation dose rate (D). Data are tabled and discussed. The highest am values occured in syenitoids (386–441 Bq·kg-1) followed by granitoids, mica schists, greywackes and gneisses, whereas the lowest am values were found in quartzose sandstones (15–36 Bq·kg-1) followed by limestones (less than 15 Bq·kg-1) and serpentinites (less than 6 Bq·kg-1). The natural radioactivity of soils is usually slightly lower than that of parent rocks due to the lower content of potassium, uranium and thorium in soils. This is typical for granitoids, syenitoids and rocks of similar mineralogical composition. In soils developed on granitoids and syenitoids were found increased concentrations of all three elements in the grain size fraction below 0.063 mm. Soils developed on rocks with low natural radioactivity (such as limestones and serpentinites) tend to have significantly higher natural radioactivity than their parent rocks. This may complicate the interpretation of data obtained by airborne gamma-ray spectrometry.

scholarly journals Uran, thorium a draslík v krystaliniku a paleozoických sedimentech na mapovém listu 14-33 Polička – laboratorní gamaspektrometrie a parciální chemické složení variských plutonitů

2017 ◽  
Vol 24 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Natural Radioactivity ◽  
Gamma Ray ◽  
Igneous Rocks ◽  
Crystalline Complex ◽  
Rock Samples ◽  
Gamma Ray Spectrometer ◽  
Variscan Granitoids ◽  
Mass Activity ◽  
Geological Units

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.

scholarly journals Geochemie a radioaktivita paleozoických hornin na listech 15-31 Bruntál a 15-33 Moravský Beroun a jejich souvislost se složením variské hydrotermální mineralizace

2019 ◽  
Vol 26 (1-2) ◽  
Author(s):  
Jiří Zimák ◽  
Marek Slobodník ◽  
Přemysl Pořádek
Keyword(s):  
Natural Radioactivity ◽  
Gamma Ray ◽  
Sedimentary Rocks ◽  
Low Grade ◽  
Rock Samples ◽  
Quartz Veins ◽  
Gamma Ray Spectrometer ◽  
Clay Shales ◽  
Mass Activity ◽  
Flysch Rocks

This paper deals with the natural radioactivity of Palaeozoic rocks on the map sheets 15- 31 Bruntál and 15-33 Moravský Beroun in the NE part of the Bohemian Massif. Studied rocks belong to the Vrbno Group (greenschists and phyllites) and mainly to the MoravoSilesian Palaeozoic, particulary to the Andělská Hora, Horní Benešov and Moravice Fms. Potassium, uranium and thorium contents were measured in 1 596 rock samples using a laboratory gamma–ray spectrometer, values of mass activity of 226Ra equivalent (am) were calculated. The average am of analysed rock samples is 138 Bq.kg-1. This value is very close to the am value calculated for the average continental crust. Natural radioactivity of flysch sedimentary rocks of the Andělská Hora, Horní Benešov and Moravice Fms. (1 350 analysed samples, avg. am = 150 Bq.kg-1) grows from psefi tes (conglomerates) to psammites (dominating greywackes) up to the group of aleurites and pelites (siltstones, silty shales, clay shales). The highest uranium and thorium contents, along with other metals (Cs, Ga, Rb, Sn, Zr, La, Ce, Pb, Zn, As) were found in flysch rocks of the Horní Benešov Fm. in the area near Valšov: greywacke shows content up to 13 ppm U and 25 ppm Th (am = 364 Bq.kg-1) and siltstone up to 21 ppm U and 43 ppm Th (am = 624 Bq.kg-1). Low-grade metamorphic mobilization of elements is documented by hydrothermal minerals in syntectonic quartz veins which are e.g. fluorite, sulphides, REE-bearing phases, U-bearing phases.

scholarly journals ANALÝZA LABORATORNÍCH HODNOT RADIOAKTIVITY HORNIN NA MAPOVÉM LISTU 15-11 ZLATÉ HORY

2016 ◽  
Vol 23 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Gamma Ray ◽  
Sedimentary Rocks ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Radioactive Elements ◽  
Small Areas ◽  
Gamma Ray Spectrometer ◽  
Group A ◽  
Mass Activity ◽  
Geological Units

Natural radioactive elements (potassium, uranium and thorium) abundances were measured in 769 samples of metamorphic and igneous rocks and pre-Cenozoic sedimentary rocks from all geological units on the map sheet 15-11 Zlaté Hory, using a laboratory gamma-ray spectrometer. Metamorphic rocks belong to two geological units of the Silesicum: to the Vrbno Group (a volcanosedimentary complex composed mainly of phyllites, quartzites, amphibolites, greenschists, acid to intermediate metavolcanites and their metatuff s) and the Desná Group (metagranites and blastomylonites). Unmetamorphosed pre-Cenozoic sedimentary rocks are represented by three Variscan flysch formations – the Andělská Hora, Horní Benešov, and Moravice Fms. (rocks of the first formation are unmetamorphosed to anchimetamorphosed), only in small areas by Cretaceous sandstones of the Peruc-Korycany Formation and Devonian limestones of the Líšeň Formation. Unmetamorphosed magmatites are represented by granitoids, lamprophyres andmicrogabbro. From calculated values of mass activity of 226Ra equivalent it is evident that natural radioactivity of most of the studied rocks is low. Slightly increased mass activity values were found in feldspar-rich quartzites (186 Bq.kg-1 on average), metakeratophyres (200 Bq.kg-1) and felsic metatuff s (229 Bq.kg-1) of the Vrbno Group.

scholarly journals PŘIROZENÁ RADIOAKTIVITA PALEOZOICKÝCH SEDIMENTŮ A CHEMISMUS KARBONÁTOVÝCH HORNIN NA MAPOVÝCH LISTECH 25-11 HLUBOČKY A 25-12 HRANICE

2018 ◽  
Vol 25 (1-2) ◽  
Author(s):  
Jiří Zimák
Keyword(s):  
Continental Crust ◽  
Natural Radioactivity ◽  
Carbonate Rocks ◽  
Gamma Ray ◽  
Sedimentary Rocks ◽  
Rock Samples ◽  
Gamma Ray Spectrometer ◽  
Clay Shales ◽  
Mass Activity ◽  
Carbonate Formations

This paper deals with natural radioactivity of Palaeozoic sedimentary rocks in the map sheets 25-11 Hlubočky and 25-12 Hranice. All studied rocks belong to the Moravo-Silesian Palaeozoic, namely to three flysch formations (Horní Benešov, Moravice and Hradec-Kyjovice fms.) and two carbonate formations (Macocha and Líšeň fms.). Contents of potassium, uranium and thorium were measured using a laboratory gamma–ray spectrometer in 1 337 rock samples, values of mass activity of 226Ra equivalent (am) were calculated. The data are tabled and discussed. The average am of analysed flysch sediments is 160 Bq.kg-1. This value is very close to the value of am calculated for the average continental crust. Natural radioactivity of flysch sedimentary rocks grows from psefites (conglomerates) through psammites (graywackes dominate) to the group of aleurites and pelites (siltstones, silty shales, clay shales). Natural radioactivity of the studied carbonate rocks is very low. In dark biodetritic limestones of the Líšeň Fm. there were found slightly increased uranium contents (typically up to 6 ppm). Uranium in the rock is probably bound to graphitic matter.

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