Record details

Title
    Syn-convergent high-temperature metamorphism in the Variscides: a discussion of potential heat sources
Statement of responsibility
    A. Henk, F. von Blankenburg, Friedrich Finger, Urs Schaltegger, Gernold Zulauf
Other titles
    Orogenic Processes: Quantification and Modelling in the Variscan Belt (Variant.)
Author
    Blankenburg, F., von
    Finger, Friedrich
    Henk, A.
    Schaltegger, Urs
    Zulauf, Gernold
Language
    anglicky
Source title - serial
    Geological society special publication
Vol./nr.
    Vol. 179
Pages
    p. 387-399
Year
    2000
Notes
    2 obr., 4 s.bibl.
    Zkr. název ser.: Geol. Soc. spec. Publ. (London).
Subject group
    Český masiv
    granitoidy
    litosféra
    metamorfóza vysokostupňová
    paleozoikum
    plášťový chochol
    tavení
    tepelný tok
    vrásnění variské
    zóna subdukční
Geographical name
    Česká republika
    Evropa střední
Keyword
    Discussion
    Heat
    High-temperature
    Metamorphism
    Potential
    Sources
    Syn-convergent
    Variscides
Abstract (in english)
   A period of pervasive high-temperature metamorphism and igneous activity from 340 to 325 Ma is a well-established characteristic of the Variscan Orogen of Central Europe. During this stage, the internal zone of the orogen was virtually soaked by granitic to granodioritic magmas. Petrological data point to temperatures of 600-850 °C at upper- to mid-crustal levels. These elevated temperatures occurred during the final convergence stage and may be comparable with similar processes inferred from geophysical evidence for the present-day Tibetian Plateau, in both regional extent and significance for the orogen's evolution. We review various geodynamic scenarios that may have provided the heat for melting and metamorphism, and compare model predictions with field data from the Variscides. All lines of evidence point to a geodynamic scenario that led to thickening of the continental crust with increased internal radiogenic heating, but without simultaneous thickening of the mantle lithosphere
   .
   Possible mechanisms include convective removal of the thermal boundary layer, delamination of part of the lithospheric mantle, and subduction of the mantle lithosphere of the downgoing plate. However, with the present stage of knowledge it is virtually impossible to single out one of these three mechanisms, as their geological consequences are so similar
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    3. 5. 2007
Import date
    8. 8. 2012