Record details

    Early Carboniferous Rb-Sr mica - whole-rock ages of phases of medium- and low-pressure metamorphism in the saxothuringian zone, western Bohemia
Statement of responsibility
    D.R. Bowes, C. M. Farrow, A. M. Hopgood, Emil Jelínek, Jan Košler, Graeme Rogers
    Bowes, D. R.
    Farrow, C. M.
    Hopgood, A. M.
    Jelínek, Emil, 1943-
    Košler, Jan, 1965-
    Rogers, Graeme
Source title - serial
    Neues Jahrbuch für Mineralogie. Abhandlungen
    Vol. 175, no. 1
    p. 83-103
    2 obr., 1 fot., 3 tab., 4 s.bibl.
    Zkr. název ser.: Neu. Jb. Mineral., Abh.
Subject group
    břidlice chloritická
    datování Rb/Sr
    krušnohorské krystalinikum
    metamorfóza nízkostupňová
    vrásnění variské
Geographical name
    Kraslice (Sokolov)
    Rotava (Sokolov)
Abstract (in english)
   A Rb-Sr white mica- whole-rock age of 327 6 Ma for a muscovite-paragonite, chlorite schist in the eastern Fichtelgebirge, near Kraslice, is recorded and interpreted as the time of the D2-S2 event at the peak of Barrovian-type dynamothermal metamorphism. A corresponding age of 327 5 Ma, obtained using the same isotopic system in another mica schist from the same district, is also recorded for a muscovite porphyroblast - whole-rock. The age is interpreted as the time of cooling through the closure temperature of muscovite following the overgrowth of randomly-disposed porphyroblasts and of paragonite-out reactions resulting from a low-pressure metamorphic overprint that had reset the Rb-Sr isotopic systems relatively late in the deformation sequence. With formation of three sets of thrusts that were major contributors to the tectonic stacking of the disparate crystalline units in the western part of the Bohemian Massif and of a number of sets of fold being between the two ca.
   330-325 Ma metamorphic events in the deformational sequence, the timing of the Hercynian orogenic episode in the southern Fichtelgebirge tectonic domain is deduced to have staddled the Viseán-Namurian boundary. The new data together with the ca. 320 Ma age of emplacement of the earliest of the granites in the Fichtelgebirge indicate a relatively short time span for this late Early Carboniferous episode during ehich (1) compressional tectonism, expressed by the development of intrafolial folds and schistosity during medium-pressure dynamothermal metamorphism, and then by sets of thrusts and upright folds, was followed by (2) a low-pressure metamorphic overprint and then by (3) further weak compressional ( transpressional) tectonism with the deformation of upright folds and then a set of thrusts
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    14. 2. 2008
Import date
    8. 8. 2012