Resolving the Variscan evolution of the Moldanubian sector of the Bohemian Massif: the significance of the Bavarian and the Moravo-Moldanubian tectonometamorphic phases
Abstract
The Variscan evolution of the Moldanubian sector in the Bohemian Massif consists of at least two distinct tectonometamorphic phases. The Moravo-Moldanubian Phase involved the overthrusting of the Moldanubian over the Moravian Zone, and also the exhumation of the HP-HT rocks of the Gföhl Unit into the Moldanubian middle crust, represented by the Monotonous and Variegated series.
The tectonic emplacement of the HP-HT rocks was accompanied by intrusions of distinct magnesio-potassic granitoid melts (the 335-338 Ma old Durbachite plutons), which contain components from a strongly enriched lithospheric mantle source. The Bavarian Phase (330-315 Ma) represents a fully independent stage defined by a significant reheating (LP-HT regional metamorphism combined with voluminous granitic plutonism)and a tectonic remobilisation of crust in the south-western sector of the Bohemian Massif.
These processes were most likely triggered by a Late Variscan delamination of mantle lithosphere.