Record details

Title
    Structural and anisotropy of magnetic susceptibility records of granitoid sheets emplacement during growth of a continental gneiss dome (Central Sudetes, European Variscan Belt)
Author
    Chopin, Francis
    Edel, Jean-Bernard
    Hrouda, František
    Ježek, J.
    Lehmann, Jeremie
    Lexa, Ondrej
    Schulmann, Karel
Language
    anglicky
Publication type
    článek v periodiku
Source title - serial
    Tectonics
Vol./nr.
    Roč. 32, č. 3
Pages
    13
Year
    2013
Thesaurus term
    syntectonic granitoid emplacement, anisotropy of magnetic susceptibility, transpression
Keyword
    Anisotropy
    Belt
    Central
    Continental
    Dome
    During
    Emplacement
    European
    Gneiss
    Granitoid
    Growth
    Magnetic
    Records
    Sheets
    Structural
    Sudetes
    Susceptibility
    Variscan
Abstract (in english)
   Granitoid magmatic sheets emplaced syntectonically during growth of the Orlica-nienik mantled gneiss dome (Central Sudetes, European Variscan belt) were examined by means of structural geology, quartz, and anisotropy of magnetic susceptibility (AMS) fabric studies. Magmatic emplacement was localized along the eastern transpressive margin of the high metamorphic core and below the low-grade detached mantle rimming the southern margin of the dome. In the first area, the magmatic sheets were emplaced parallel to the dilated subhorizontal foliation of an anisotropic pre-orogenic block. The resulting melt-host rock multilayer localized the transpressive zone along which the bulk of magma was emplaced. The AMS study shows an across-strike fabric zonation underlying a strongly transpressive solid-state deformation in the hanging-wall, magmatic subhorizontal fabric in the foot-wall and a transitional fabric in the center of the intrusion. In contrast, along the southern dome margin, magmatic s
   heets intruded along steep foliations of weakly metamorphic mantle rocks, and are affected by recumbent folding and subhorizontal shearing. The bulk of the sheets present a shallow-dipping magmatic foliation and an along-strike magmatic lineation. The variations of the quartz and magnetic fabrics are attributed to superimposition of pure shear-dominated ductile thinning followed by simple shear-dominated detachment onto the original steep fabric. AMS modeling confirms the role of variation of orientation of pre-intrusive anisotropy during progressive deformation on the resulting fabric pattern and helps explaining observed variations in fabric orientations and symmetries. This study highlights contrasting mechanical behavior of syntectonically emplaced magmas in different parts of a growing crustal-scale mantled gneiss dome.
Contributor
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
    R
Import date
    15. 10. 2014