Podrobnosti záznamu

Název
    Bitumens in the Late Variscan Hydrothermal Vein-Type Uranium Deposit of Příbra,, Czech Republic: Sources, Radiation-Induced Alteration, and Relation to Mineralization
Údaj o odpovědnosti
    Bohdan Kříbek, Karel Žák, Jorge Spangenberg, Jan Jehlička, Stanislav Prokeš, Jiří Komínek
Další názvy
    A special issue on organic matter and ore deposits: interactions, applications, and case studies (Variant.)
Autor
    Jehlička, Jan
    Komínek, Jiří
    Kříbek, Bohdan, 1946-
    Prokeš, Stanislav
    Spangenberg, Jorge
    Žák, Karel, 1957-
Jazyk
    anglicky
Zdrojový dokument - seriál
    Economic geology
Svazek/č.
    Vol. 94, no. 7
Strany
    p. 1093-1114
Rok
    1999
Poznámky
    16 obr., 2 fot., 3 tab., 3 s.bibl.
    Zkr. název ser.: Econ. Geol. (Littleton).
Předmětová skupina
    Barrandien
    bitumen
    ekonomika surovin
    izotopy C
    metamorfóza kontaktní
    organická substance
    pluton
    polymerizace
    proterozoikum
    radioaktivita
    rudy U
    středočeský pluton
    uraninit
    whewellit
    žíla rudní
Geografické jméno
    ČR-Čechy
    Háje (Příbram)
    Kamenná (Příbram)
    Lešetice (Příbram)
    Obořiště (Příbram)
    Příbram-Brod
    Příbram-Bytíz
    Příbram-Jerusalem
    Skalka (Příbram)
    Třebsko (Příbram)
Klíčové slovo
    Alteration
    Bitumens
    Czech
    Deposit
    Hydrothermal
    Late
    Mineralization
    Příbra
    Radiation-Induced
    Relation
    Republic
    Sources
    Uranium
    Variscan
    Vein-Type
Abstrakt (anglicky)
   The late Variscan (275-278 Ma) Příbram uranium deposit is one of the largest known accumulations of uraniferous bitumens in hydrothermal veins. The deposit extends along the northwestern boundary of the Central Bohemian Pluton (345-335 Ma) with low-grade metamorphosed Late Proterozoic and unmetamorphosed Cambrian rocks. From a net uranium production of 41,742 metric tons (t), more than 6,000t were extracted from bitumenuraninite ores during 43 years of exploration and mining. Three morphological varieties of solid bitumen are recognized: globular, asphaltlike, and cokelike. While the globular bitumen is uranium free, the other two types are uraniferous. The amount of bitumen in ore veins gradually toward the contact with the plutonic body and increase with depth. Two types of bitumen microtextures are recognized using high-resolution transmission electron microscopy: amorphous and microporous, the former being less common in uraniferous samples.
   A lower raman pear area ratio (1,360/1,575 cm-1) in mineralized bitumens (0,9) compared with uranium-free samples (2.0) indicates a lower degree of microtextural organization in the latter. The H/C and O/C atomic ratios in uranium-free bitumens (0.9-1.1 and 0.09, respectively) are higher than those in mineralized samples (H/C = 0.3-0.8, O/C = 0.03-0.09). The chloroform extractable matter yield is very low uranium content increase. The extracted soil uraniferous bitumen infrared spectra show depletion in aliphatic CH2 and CH3 groups compared to uranium-free samples. The concentration of oxygen-bearing functional groups relative to aromatic bonds in the IR spectra of uranium-free and mineralized bitumen, however do not differ significantly. 13C NMR confirmed than the aromaticity of a uraniferous sample is higher (far=0.61) than in the uranium-free bitumen (Far=0.51).
   Pyrolysates from uraniferous and nonuraniferous bitumens do not differ significantly, being predominatly cresol, alkylphenols, alkylbenzenes, and alkylnaphthalenes
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    28. 1. 2008
Datum importu
    8. 8. 2012