Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

Lukáš Vondrovic, Kryštof Verner, David Buriánek, Patricie Halodová, Václav Kachlík, Jitka Míková

Emplacement, structural and P-T evolution of the ˜346 Ma Miřetín Pluton (eastern Teplá-Barrandian Zone, Bohemian Massif): implications for regional transpressional tectonics

Journal of Geosciences, volume 56 (2011), issue 4, 343 - 357

DOI: http://doi.org/10.3190/jgeosci.109

The calc-alkaline Miřetín Pluton (newly dated at 346 Ma ± 5 Ma; an U-Pb age obtained by laser-ablation ICP MS method on zircons) is a NNE-SSW elongated intrusive body emplaced into the upper- to mid- crustal rocks of the Polička Unit (eastern Teplá-Barrandian Zone; Bohemian Massif). Its composition reveals similarities to other calc-alkaline granitoids, which are mostly interpreted as products of magma mixing between the basic magmas derived from mantle wedge above a subduction zone with crustally-derived acid melts. The conditions of magma crystallization estimated at 653-681 °C and 0.29-0.43 GPa roughly correspond to peak metamorphic evolution of the host volcano-sedimentary rocks of the northwestern part of the Polička and Hlinsko units. The Miřetín Pluton was emplaced into a NNE-SSW oriented transpressional domain, well recognized on a regional scale along the eastern margin of the Teplá-Barrandian Zone. During, or shortly after, the magma emplacement, the Miřetín Pluton was affected by pervasive submagmatic to high-T solid-state deformation, reflecting an additional strain increment of regional transpression in a narrow zone of thermal softening. Sharply superimposed low-T solid-state fabric preserved along the western part of the Pluton was connected with normal shearing between the Polička Unit at the bottom and the overlying Hlinsko Unit after 335 Ma.