As far as Austria is concerned, the Bohemian Massif mainly consists of granites and gneisses that originate from several orogeneses. The Moldanubicum, which comprises the large western part of the Bohemian Massif, was thrust over the small eastern part, called Moravicum, during the Variscian Orogenesis (Devonian to Carboniferous). This process caused the melting of the subducted Moravicum and huge plutones (about 380 to 320 million years old) formed within the Moldanubicum. The country rocks of the plutones are gneisses and schists of previous orogeneses (Caledonian, Cadomian and even earlier orogeneses).
The oldest rocks are the Dobra Gneiss between Gföhl and Zwettl (1,380 million years) and the Bittesch Gneiss E of Horn (800 million years). However, also younger sediments occur within the Bohemian Massif. In the Boskovice Graben and near Zöbing at Kamp River, clastics of the Variscian Mountains were sedimented during the Carboniferous and Permian. From the Upper Cretaceous until the Lower Tertiary, the northern parts of the Bohemian Massif were flooded and transgressive sediments (mostly sandstones) formed. They can be found between Gmünd and Czeské Budejovice, for example. In the middle Tertiary, sands and clays formed at some locations in the south.
E of Aggsbach-Dorf (NE of Melk), there is a serpentinite body within the Gföhl Gneiss of the Dunkelstein Wood. It has been divided into several parts due to erosion. Those parts encircle the upper Mitterbach Valley. Viewed clockwise, the first is S of Polakenkopf, the next on Bärenköpfl, followed by those W of Gurhof, N of Altwieshof and at the N slope of the Herrn Wood.
For their origin, see Alpine serpentinites.
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Last modified: Sept 09, 2009