Record details

Title
    Microfossils in carbonaceous cherts from Barrandian Neoproterozoic (Blovice Formation, Czech Republic)
Statement of responsibility
    Milada Vavrdová
Author
    Vavrdová, Milada
Language
    anglicky
Source title - serial
    Věstník Českého geologického ústavu (Bulletin of the Czech Geological Survey)
Vol./nr.
    Vol. 75, no. 3
Year
    2000
Notes
    1 obr., 9 fot.
    České resumé
    il.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Věst. Čes. geol. Úst. (Bull. Czech geol. Surv.)
Subject group
    Barrandien
    benthos
    biostratigrafie
    plankton
    prostředí mělkovodní
    proterozoikum
    rohovec křemitý
    schránky
    silicity
Geographical name
    ČR-Čechy
Keyword
    Barrandian
    Blovice
    Carbonaceous
    Cherts
    Czech
    Formation
    Microfossils
    Neoproterozoic
    Republic
Abstract (in english)
   Silicified organic-walled microfossils occur abundantly in dark carbonaceous cherts of Neoproterozoic age (Kralupy-Zbraslav Group, Teplá Barrandian Unit). Investigated localities of siliceous lenses, which outcrop mostly in the lower part of the Bohemian Neoproterozoic succession, yielded rare planktonic acritarchs, large agglomerations of coccoidal cyanobacteria, filamentous microbial mats, degraded trichomes of algal and/or cyanobacterial origin, colonial forms and vase-shaped bodies. Three successive "generations" have been distinguished among recovered associations, based on dominating mat-forming (Gunflitia - Eomicrocoleus - Siphophycus) and planktic (Huroniospora - Leiosphaeridia - Buedingiisphaeridium) microfossils. Stromatolitic biosedimentary textures and structures have been ascertained in algal laminites from the Stříbro - Plasy metamorphic belt. Main volcanic belt and Nepomuky - Příbram, Kralupy and Slaný.
   Recovered organic remains indicate primary chemogenous, most probably carbonate nature of silicites and silicified sediments. Together with additional geochemical, mineralogical, and sedimentological evidence, recovered microfossils enabled to recognize the following sedimentary biofacies in the Bohemian Late Proterozoic coastal sequences: subtidal limestones with oolitic and algal intraclasts, restricted basins with organic sludge, tidally influenced facies of stromatolitic build-ups, volcanoclastic sequences and supratidal evaporitic algal marshes
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    31. 3. 2008
Import date
    8. 8. 2012