scholarly journals Uraninite, Coffinite and Ningyoite from Vein-Type Uranium Deposits of the Bohemian Massif (Central European Variscan Belt)

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 123 ◽  
Author(s):  
Miloš René ◽  
Zdeněk Dolníček ◽  
Jiří Sejkora ◽  
Pavel Škácha ◽  
Vladimír Šrein
Keyword(s):  
Chemical Composition ◽  
Electron Microprobe ◽  
Bohemian Massif ◽  
Uranium Deposit ◽  
Ore Deposits ◽  
Metamorphic Rocks ◽  
Uranium Deposits ◽  
Massif Central ◽  
Vein Type ◽  
Ore District

Uraninite-coffinite vein-type mineralisation with significant predominance of uraninite over coffinite occurs in the Příbram, Jáchymov and Horní Slavkov ore districts and the Potůčky, Zálesí and Předbořice uranium deposits. These uranium deposits are hosted by faults that are mostly developed in low- to high-grade metamorphic rocks of the basement of the Bohemian Massif. Textural features and the chemical composition of uraninite, coffinite and ningyoite were studied using an electron microprobe. Collomorphic uraninite was the only primary uranium mineral in all deposits studied. The uraninites contained variable and elevated concentrations of PbO (1.5 wt %–5.4 wt %), CaO (0.7 wt %–8.3 wt %), and SiO2 (up to 10.0 wt %), whereas the contents of Th, Zr, REE and Y were usually below the detection limits of the electron microprobe. Coffinite usually forms by gradual coffinitization of uraninite in ore deposits and the concentration of CaO was lower than that in uraninites, varying from 0.6 wt % to 6.5 wt %. Coffinite from the Jáchymov ore district was partly enriched in Zr (up to 3.3 wt % ZrO2) and Y (up to 5.5 wt % Y2O3), and from the Potůčky uranium deposit, was distinctly enriched in P (up to 8.8 wt % P2O5), occurring in association with ningyoite. The chemical composition of ningyoite was similar to that from type locality; however, ningyoite from Potůčky was distinctly enriched in REE, containing up to 22.3 wt % REE2O3.

Precisions nouvelles sur les terrains metamorphiques du mont Pilat (Massif central) et leur histoire cristallogenetique

1964 ◽  
Vol S7-VI (1) ◽  
pp. 55-63 ◽  
Author(s):  
Maurice Chenevoy
Keyword(s):  
Chemical Composition ◽  
Contact Metamorphism ◽  
Metamorphic Rocks ◽  
Shearing Stress ◽  
The South ◽  
Mountain Area ◽  
Massif Central

Abstract Metamorphic rocks of the Pilat mountain area of the Central Massif near St. Etienne exhibit three periods of metamorphic effects involving anomalies. Period I, the oldest, is represented by mesozonal gneiss and schist (amphibolite-almandine facies) cropping out along the NW side of the area. They are part of the pre-Hercynian metamorphics of the south flank of the Lyonnais mountains. Period II involved epizonal retromorphism and recrystallization. These rocks crop out in a belt along the SE margin of the Period II series. Period III involved thermal, and probably contact metamorphism, resulting in zonation of a belt with chlorite, biotite, cordierite, andalusite, and sillimanite zones in succession SE to the Pilat mountain granite. Period III probably is younger than II. The chemical composition of the granite is anomalous. This may be the metamorphism under deficient shearing stress described by Harker, or Buchan type metamorphism, as described by Read and used by Forestier to explain the schists of the upper Allier river area of the massif.

The earliest ostracods from the Ordovician of the Prague Basin, Czech Republic

2014 ◽  
Vol 64 (4) ◽  
pp. 367-392 ◽  
Author(s):  
Karolína Lajblová ◽  
Petr Kraft
Keyword(s):  
Czech Republic ◽  
Bohemian Massif ◽  
Massif Central ◽  
Central European ◽  
Middle Ordovician ◽  
Prague Basin ◽  
Barrandian Area ◽  
Fossil Assemblages ◽  
European Variscides

Abstract The earliest ostracods from the Bohemian Massif (Central European Variscides) have been recorded from the Middle Ordovician of the Prague Basin (Barrandian area), in the upper Klabava Formation, and became an abundant component of fossil assemblages in the overlying Šarka Formation. Both early ostracod associations consist of eight species in total, representing mainly eridostracans, palaeocopids, and binodicopids. The revision, description, or redescription of all species and their distribution in the basin is provided. Their diversification patterns and palaeogeographical relationships to ostracod assemblages from other regions are discussed.

Natural radionuclides 238U, 226RA, AND 222RN in the surface water of the ELKONSKY uranium-ore district (South Yakutiya)

2019 ◽  
Vol 46 (6) ◽  
pp. 613-620
Author(s):  
A. P. Chevychelov ◽  
P. I. Sobakin ◽  
L. I. Kuznetsova
Keyword(s):  
Chemical Composition ◽  
Surface Water ◽  
20Th Century ◽  
Radioactive Contamination ◽  
Raw Materials ◽  
Natural Radionuclides ◽  
Water Migration ◽  
Uranium Ore ◽  
Wide Scale ◽  
Ore District

Chemical composition of the surface water and the contents of the radionuclides 238U, 226Ra, and 222Rn in water was examined within the natural and man-made landscapes of South Yakutiya. It was demonstrated that intense water migration of these radionuclides from radioactive dump pits of the man-made landscapes of the Elkonsky uranium-ore district, which were created during the process of wide-scale exploration surveys for radioactive raw materials conducted during the last third of the 20th century, had occurred. Currently, the areas of water dissipation of 238U and 226Ra are detected at a distances of 2 km and greater from the source of the radioactive contamination along the outflow vector.

scholarly journals Research Regarding the Quality of Lambs Carcass Resulted from Tsigaia Purebred Compared with Hybrids of Tsigaia Ewes Crossed with Blanc du Massif Central Rams

2017 ◽  
Vol 74 (1) ◽  
pp. 7
Author(s):  
Mihai Marian BORZAN ◽  
Dana PUSTA ◽  
Liviu BOGDAN ◽  
Alexandra TABARAN ◽  
Attila MATE ◽  
...  
Keyword(s):  
Body Weight ◽  
Chemical Composition ◽  
Massif Central ◽  
Live Body Weight ◽  
Almost All ◽  
Qualitative Characteristics

Abstract: The research aims to compare some qualitative characteristics of purebred Tsigaia lambs and Tsigaia crossed with Blanc du Massif Central lambs. The criteria assessed were: chemical composition of purebred and Tsigaia crossed meat, the live body weight, the slaughtering performance, the weight of different carcass cut. For almost all criteria chosen the crossed individuals registered better results.

scholarly journals Electron microprobe monazite geochronology of magmatic events: Examples from Variscan migmatites and granitoids, Massif Central, France

Lithos ◽  
2006 ◽  
Vol 87 (3-4) ◽  
pp. 276-288 ◽  
Author(s):  
E. Be Mezeme ◽  
A. Cocherie ◽  
M. Faure ◽  
O. Legendre ◽  
Ph. Rossi
Keyword(s):  
Electron Microprobe ◽  
Massif Central
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