Record details

Title
    Metamorphism and microstructures along a high-temperature metamorphic field gradient: the north-eastern boundary of the Královský hvozd unit (Bohemian Massif, Czech Republic)
Statement of responsibility
    Dirk Scheuvens
Author
    Scheuvens, Dirk
Language
    anglicky
Source title - serial
    Journal of Metamorphic Geology
Vol./nr.
    Vol. 20, no. 4
Pages
    p. 413-428
Year
    2002
Notes
    5 obr., 2 fot., 3 tab., 3 s.bibl.
    il.
    Zkr. název ser.: J. metamorph. Geol.
Subject group
    anatexe
    chemismus minerálů
    cordierit
    deformace
    granáty
    metamorfóza vysokostupňová
    migmatit
    moldanubikum Šumavy
    pararula
    plagioklasy
    slídy
    vrásnění variské
    zonálnost
    zóny metamorfní
Geographical name
    ČR-Čechy
    Nýrsko (Klatovy)
Keyword
    Along
    Bohemian
    Boundary
    Czech
    Field
    Gradient
    High-temperature
    Hvozd
    Královský
    Massif
    Metamorphic
    Metamorphism
    Microstructures
    North-eastern
    Republic
    Unit
Abstract (in english)
   metamorphic field gradient has been inv estigated in the Moldanubian zone of the central European Variscides encompassing, from base to the top, a staurolite-kyanite zone, a muscovite-sillimanite zone, a K-feldspar-sillimanite zone, and a K-feldspar-cordierite zone, respectively. The observed reaction textures in the anatectic metapsammopelites of the higher grade zones are fully compatible with experimental data and petrogenetic grids that are based on fluid-absent melting reactions. From structural and microstructural observations it can be concluded that the boundary between the kyanite-staurolite zone and the muscovite- and K-feldspar-sillimanite zones coincides with an important switch in deformation mechanism(s).
   Besides minor syn-anatectic shearing (melt-enhanced deformation), microstructural criteria point (a) to a switch in deformation mechanism from rotation recrystallization (climb-accommodated dislocation creep) to prism
   At still higher metamorphic grades (K-feldspar-cordierite zone), where the rheological critical melt percentage is reached, rock rheology is mainly governed by the melt and other deformation mechanisms are of minor importance. In the study area, the switch in deformation mechanism(s) is responsible for large-scale strain partitioning and concentration of deformation within the higher-temperature hanging wall during top-to-the-S thrusting, thus preserving a more complete petrostructural record within the rocks of the footwall including indicators for a ?Devonian high-to medium-pressure/medium-temperature metamorphic event. Thrusting is accompanied by diapiric ascent to diatexites of the K-feldspar-cordierite zone and infolding of the footwall, suggetsing local crustal overturn in this part of the Moldanubian zone
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    3. 10. 2007
Import date
    8. 8. 2012