Record details

Title
    Chronological constraints on the pre-Variscan evolution of the northeastern margin of the Bohemian Massif, Czech Republic
Statement of responsibility
    Alfred Kröner, Pavla Štípská, P. Jaeckel
Other titles
    Orogenic Processes: Quantification and Modelling in the Variscan Belt (Variant.)
Author
    Jaeckel, P.
    Kröner, Alfred
    Schulmann, Karel
    Štípská, Pavla
Language
    anglicky
Source title - serial
    Geological society special publication
Vol./nr.
    Vol. 179
Pages
    p. 175-197
Year
    2000
Notes
    9 obr., 3 s.bibl.
    Zkr. název ser.: Geol. Soc. spec. Publ. (London).
Subject group
    datování U/Pb
    kambrium
    magmatismus
    metamorfika
    ordovik
    orlicko-sněžnické krystalinikum
    silesikum
    staroměstské krystalinikum
    vápenato-alkalický typ
    zirkon
    zóna riftová
Geographical name
    ČR-Morava
    Hanušovice (Šumperk)
    Horní Lipová (Jeseník)
    Kouty nad Desnou (Šumperk)
    Králíky (Ústí nad Orlicí)
    Ludvíkov (Bruntál)
    Skorošice (Jeseník)
Keyword
    Bohemian
    Chronological
    Constraints
    Czech
    Evolution
    Margin
    Massif
    Northeastern
    Pre-Variscan
    Republic
Abstract (in english)
   New single zircon ages enable us to provide an evolutionary scenarion for the Neoproterozoic to Cambro-Ordovician tectonic history of part of the easternmost Sudetes along the northeastern margin of the Bohemian Massif. The easternmost crustal segment (Brunia) yields Neoproterozoic ages from both autochthonous and allochthonous Variscan units; these ages document a Cadomian (Pan-African) history that may be linked with the northern margin of Gondwana. A Cambro-Ordovician magmatic-thermal event in Brunia is represented by granitic to pegmatitic dykes intruding Neoproterozoic crust and by localized partial anatexis. Farther west a narrow zone of Cambro-Ordovician rifting is identified (Staré Město belt), marked by gabbroic magmatism, bimodal volcanism and medium-pressure granulite facies metamorphism.
   The westernmost crustal domain (Orlica-Snieznik dome) is represented by Neoproterozoic crust intruded by Cambro-Ordovician plutons consisting of calk-alkaline granitoid rocks and affected by widespread Cambro-Ordovician anatexis. The geodynamic setting of the Neoproterozoic and Cambro-Ordovician domains is similar to that of the Western Sudetes, where both Cambro-Ordovician rifting and calc-alkaline magmatism were identified. We discuss the rifting mechanics in terms of sequential crustal thinning along the northern margin of Gondwana. The calc-alkaline magmatism, in conjuction with crustal rifting, is related to a back-arc geometry in front of retreating south-dipping subduction zone during progressive closure of the Tornquist Ocean southeast of Avalonia
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    3. 5. 2007
Import date
    8. 8. 2012