A plate-kinematic model for the assembly of the Bohemian Massif constrained by structural relationships around granitoid plutons

Abstract

This paper summarizes the current knowledge on the nature, kinematics and timing of movement along major tectonic boundaries in the Bohemian Massif and demonstrates how the Variscan plutonism and deformation evolved in space and time. Four main episodes are recognized: (1) Late Devonian–early Carboniferous subduction and continental underthrusting of the Saxothuringian Unit beneath the Teplá–Barrandian Unit resulted in the orogen-perpendicular shortening and growth of an inboard magmatic arc during c. 354–346 Ma; (2) the subduction-driven shortening was replaced by collapse of the Teplá–Barrandian upper crust, exhumation of the high-grade (Moldanubian) core of the orogen at c. 346–337 Ma and by dextral strike-slip along orogen-perpendicular NW–SE shear zones; (3) following closure of a Rhenohercynian Ocean basin, the Brunia microplate was underthrust beneath the eastern flank of the Saxothuringian/Teplá–Barrandian/Moldanubian ‘assemblage’; this process commenced at c. 346 Ma in the NE and ceased at c. 335 Ma in the SW; and (4) late readjustments within the amalgamated Bohemian Massif included crustal exhumation and mainly S-type granite plutonism along the edge of the Brunia indentor at c. 330–327 Ma, and peripheral tectonothermal activity driven by strike-slip faulting and possibly mantle delamination around the consolidated Bohemian Massif's interior until late Carboniferous–earliest Permian times.

Magnetic fabric and emplacement of dykes of lamprophyres and related rocks of the Central Bohemian Dyke Swarm (Central European Variscides)

“…The Teplá-Barrandian Unit consists of low-to mediumgrade Neoproterozoic metasediments, originally forming a part of the Cadomian accretionary wedge, later intruded by Cambro-Ordovician granitoids and containing unmetamorphosed mid-Cambrian to mid-Devonian volcanosedimentary sequences (for review see Chlupáč et al 1998;Schulmann et al 2009;Žák et al 2014;Hajná et al 2017). …”

“…resulted from stacking of several lithotectonic units at ~360 to 345 Ma followed by HT/LP metamorphism, anatexis and late-Variscan wrench tectonics (for review see Schulmann et al 2009;Žák et al 2014). The Moldanubian Zone consists of metasedimentary sequences of Neoproterozoic to Lower Palaeozoic protolith age (Košler et al 2014) dominated by sillimanite-biotite (± cordierite) paragneisses to migmatites with variable presence of small bodies of metaquartzites, marbles, calc-silicate rocks, graphite-bearing schists and amphibolites (e.g.…”

Geochemical variability of granite dykes and small intrusions at the margin of the Granulite Complex in southern Bohemia

“…Finger et al 1997;Holub 1997;Gerdes et al 2000;Janoušek et al 2000Janoušek et al , 2004bJanoušek et al and Žák et al 2014). …”

“…Numerous granite studies published during the last two decades on the Variscan plutons in southern Bohemia, Austria and Bavaria (see Klomínský et al 2008;Žák et al 2014 for review) cause an impression…”

Petrology and geochemical characteristics of phlogopite pyroxenite related to durbachites, Moldanubian Zone, Bohemian Massif

“…Amphibole-biotite/phlogopite granitoids, often with quartz syenite and quartz monzonite compositions, designated as durbachites, represent important rock-types in the Moldanubian Zone of the Variscan orogenic belt (von Raumer et al 2014;Žák et al 2014;Tabaud et al 2015). Following the most plausible interpretation, the rocks crystallized from hybrid magmas (Holub 1997;Gerdes et al 2000;Janoušek and Holub 2007).…”