Record details

    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.)
    Jaeckel, P.
    Kröner, Alfred
    Schulmann, Karel
    Štípská, Pavla
Source title - serial
    Geological society special publication
    Vol. 179
    p. 175-197
    9 obr., 3 s.bibl.
    Zkr. název ser.: Geol. Soc. spec. Publ. (London).
Subject group
    datování U/Pb
    orlicko-sněžnické krystalinikum
    staroměstské krystalinikum
    vápenato-alkalický typ
    zóna riftová
Geographical name
    Hanušovice (Šumperk)
    Horní Lipová (Jeseník)
    Kouty nad Desnou (Šumperk)
    Králíky (Ústí nad Orlicí)
    Ludvíkov (Bruntál)
    Skorošice (Jeseník)
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
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    3. 5. 2007
Import date
    8. 8. 2012