Podrobnosti záznamu

Název
    Neoproterozoic sedimentary carbonates and their silicified equivalents: Barrandian, Czech Republic
Údaj o odpovědnosti
    Vladimír Skoček, Zdeněk Pouba
Autor
    Pouba, Zdeněk, 1922-
    Skoček, Vladimír, 1934-
Jazyk
    anglicky
Zdrojový dokument - seriál
    Věstník Českého geologického ústavu (Bulletin of the Czech Geological Survey)
Svazek/č.
    Vol. 75, no. 3
Strany
    p. 241-260
Rok
    2000
Poznámky
    4 obr., 19 fot., 1 tab.
    České resumé
    il.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Věst. Čes. geol. Úst. (Bull. Czech geol. Surv.)
Předmětová skupina
    Barrandien
    dolomit
    horniny karbonátové
    prostředí hypersalinní
    proterozoikum
    sedimentace detritická
    sedimenty karbonátové
    silicity
    struktura oolitická
    vápenec
Geografické jméno
    ČR-Čechy
Klíčové slovo
    Barrandian
    Carbonates
    Czech
    Equivalents
    Neoproterozoic
    Republic
    Sedimentary
    Silicified
Abstrakt (anglicky)
   The Neoproterozoic sequence incorporates sedimentary limestones and dolomites in thin layers and lenses. Oolitic, pisolitic, stromatolitic and micritic limestones with an admixture of various allochemical particles were distinguished in addition to breccias. Coated grains occur as two distinctly different types. Microoids (diam. below 0.3 mm) and pisoids (diam. 3-6 mm) are considered a product of repeated growth in agitated water. Volcanic accretionary lapilli are mostly small (diam. below 2 mm) carbonized bodies with poorly developed concentric texture. Limestones with unusual, characteristic crystalline texture are the result of the replacement of chemically unstable layers of evaporites (sulpfates). Arenites and greywackes with carbonate cement and shales with carbonate lenses are the products of diagenetic carbonate redistribution. The sedimentary carbonates differ from carbonized volcanogenic rocks by relict textures, elevated amounts of Sr and typical negative 18O/16O ratios.
   The similarity of structurea and textures,, between sedimentary carbonates and some siliceous rocks evokes the suspicion that some cherts in the sequence are of replacement origin. This is evidenced by quartzose pseudomorphs of dolomite rhombs and by the presence of silicified sulfate aggregates in them. The small size of stromatolitic buil-up indicates a limited extent of favourable circumstances for the growth of algal mats. The areal aasociation of carbonates with shales, siliciclastics, volcanic and volcaniclastic rocks shows that the majority of detrial carbonate were deposited from gravity current initiated at the edges of volcanic islands
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    31. 3. 2008
Datum importu
    8. 8. 2012