Formation of elongated granite–migmatite domes as isostaticaccommodation structures in collisional orogens

0425801 - GFÚ 2015 RIV GB eng J - Journal Article
Verner, K. - Žák, J. - Šrámek, F. - Paclíková, J. - Zavřelová, A. - Machek, Matěj - Finger, F. - Johnson, K.
Formation of elongated granite–migmatite domes as isostaticaccommodation structures in collisional orogens.
Journal of Geodynamics. Roč. 73, January (2014), s. 100-117. ISSN 0264-3707
Institutional support: RVO:67985530
Keywords : anisotropy of magnetic susceptibility * Bohemian Massif * granite-migmatite dome * metamorphic core complex * exhumation
Subject RIV: DB - Geology ; Mineralogy
Impact factor: 2.217, year: 2014

The mid-Carboniferous Pelhřimov core complex, Bohemian Massif, is a crustal-scale elongated granite–migmatite dome interpreted to have formed by gravity-driven diapiric upwelling of the metapelitic middle crust. The vertical diapiric flow is evidenced by outward-dipping foliation and lineation patterns, deformation coeval with the widespread presence of melt, rapid exhumation of the dome center from depths corresponding to pressure of about 0.6 GPa to shallow levels (pressure less than 0.2 GPa) within 2 M.y., and kinematic indicators of downward return flow of the mantling rocks. As compared to common diapirs, however, the Pelhřimov complex exhibits a more complicated inferred strain pattern with two perpendicular, irregularly alternating directions of horizontal extension in what is interpreted as the diapir head. Comparison of structural data from migmatites with anisotropy of magnetic susceptibility (AMS) data in granites also reveals that only final increments of strain are recorded in the granites.
Permanent Link: http://hdl.handle.net/11104/0231586