Podrobnosti záznamu

Název
    Vzácné zeminy v aleuropelitech Barrandienu
Údaj o odpovědnosti
    Marek Kundrát, František Lepka
Další názvy
    Rare earth elements in aleuropelites of the Barrandian area
    Rare earth elements in aleuropelites of the Barrandien area
Autor
    Kundrát, Marek
    Lepka, František
Jazyk
    česky
Zdrojový dokument - seriál
    Sborník geologických věd. Geologie
Svazek/č.
    Roč. 48
Strany
    s. 5-17
Rok
    1998
Poznámky
    4 obr., 11 tab., 4 pl.
    4 obr., 11 tab., 4 pl., 41 bibl.
    Anglické resumé
    il.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Sbor. geol. Věd, Geol.
Předmětová skupina
    Barrandien
    břidlice jílová
    devon
    fosfáty
    fylit
    kambrium-střední
    krkonošsko-jizerské krystalinikum
    ordovik
    prachovec
    proterozoikum
    silur
    thorium
    vzácné zeminy
Geografické jméno
    Beroun
    Černošice (Praha-západ)
    ČR-Čechy
    Dobříš (Příbram)
    Hlásná Třebaň (Beroun)
    Jince (Příbram)
    Kožlany (Plzeň-sever)
    Plzeň
    Praha
    Příbram
    Rabštejn nad Střelou (Plzeň-sever)
    Suchomasty (Beroun)
    Úvaly (Praha-východ)
    Železný Brod (Jablonec nad Nisou)
Klíčové slovo
    Aleuropelitech
    Barrandienu
    Vzácné
    Zeminy
Abstrakt (anglicky)
   The increase in concentration of light rare elements (LREE) have been found in clay-silty shales of the ordovician age compared with similar sediments of Upper Proterozoic, Cambrian and Silurian age. Rare earths are bound up in particular with the relatively varied association of phosphates. In addition to apatite it comprises the following groups of minerals and mineral matters, respectively: 1. REE-phosphates, empiric formula of those corresponds to monazite-(Ce) or rhabdophane-(Ce). 2. The analogical group of xenotime-(Y) and churchite-(Y), respectively. 3. Phosphates of the crandallite group represented by the transitional member between florencite and goyazite. 4. Insufficiently identified mineral matter with chemical composition close to the theoretical formula of some REE-phosphates and REE-phosphosilicates. The above mentioned fine-grained phosphates and mineral matters are intimately intergrown with clay components or the shales characterized by the predominant role of illite
   .
   In accordance with characteristic features of the observed phosphates as habitus, intimate association with clay minerals and disordered dissemination of crystals variable in size, we may consider most of the phosphates to be authigenic. Significantly different concentration of REE in selected of phosphates as well as varying quantity distribution of them within individual Barrandian formations affects differences in average contents of REE among aleuropelites of authigenic rhabdophanes or monazites with high REE content. On the other hand for example Silurian shales contain considerable amountd of apatite and phosphates of the crandallite group with markedly lower concentration of REE. The statistically tested distribution of REE in studied sediments noteworthy agree with the distribution of Th. The positive correlation has been determined between Th and LREE.
   With the increasing number of information it has confirmed that the results verified for the Barrandian are meet with general acceptance and may be available for applicatio

   The increased in concentration of light rare elements (LREE) have been found in clay-silty shales of the Ordovician age compared with similar sediments of Upper Proterozoic, Cambrian and Silurian age. Rare earths are bound up in particular with the relatively varied association of phosphates. In addition to apatite it comprises the following groups of minerals and mineral matters, respectively: 1. REE-phosphates, empiric formula of those correspond to monazite-(Ce) or rhabdophane-(Ce); 2. The analogical group of xenotime-(Y) and churchite-(Y), respectively; 3. Phosphates of the crandallite group represented by the transitional members between florencite and goyazite; 4. Insufficiently identified mineral matters with chemical composition close to the theoretical formula of some REE-phosphates and REE-phosphosilicates.
   The above mentioned fine-grained phosphates and mineral matters are intimately intergrown with clay components of the shales characterized by the predominant role of illite. In accordance with characteristic features of the observed phosphates as habitus, intimate association with clay minerals and disordered dissemination of crystals variable in size, we may consider most of the phosphates to be authigenic. Significantly different concentration of REE in selected groups of phosphates as well as varying quantity distribution of them within individual Barrandian formations affects differences in average contents of REE among aleuropelites of Ordovician age and of other stratigraphic systems. The Ordovician shales are characterized by the occurrences of authigenic rhabdophanes or monazites with high REE content. On the other hand for example Silurian shales contain considerable amounts of apatite and phiosphates of the crandallite group with markedly lower concentration of REE.
   The statistically tested distribution of REE in studied sediments noteworthy agree with the distribution of Th. The positive correlation has been determined between Th and LREE. With the increasing number of information it has c
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    20. 2. 2008
    6. 3. 2009
Datum importu
    8. 8. 2012