Moldanubian Zone


The Moldanubian Zone is in the regional geology of Europe a tectonic zone formed during the Variscan or Hercynian Orogeny. The Moldanubian Zone crops out in the Bohemian Massif and the southern part of the Black Forest and Vosges and contains the highest grade metamorphic rocks of Variscan age in Europe.
The Moldanubian Zone was introduced by German geologist Franz Kossmat in 1927. It has a generally higher grade of metamorphism than the Saxothuringian Zone to the northwest. The contact between the two is a thrust over which the Moldanubian Zone moved over the Saxothuringian Zone during the Variscan Orogeny. In the east the Moldanubian Zone is thrusted over the Moravo-Silesian Zone, which is also generally lower grade.

Geology

The Moldanubian Zone of the Bohemian Massif can be divided into two tectonic units: the Teplá-Barrandian Zone and the Moldanubian Zone sensu stricto. The last contains large granitoid plutons and nappes.

Moldanubicum

The Moldanibicum or Moldanubian sensu stricto consists of high grade metamorphic rocks. The protoliths may have a Proterozoic age, but their origins or ages are mostly unknown.
The tectonostratigraphy of the Moldanubian Zone sensu stricto is divided into three main units:
These three tectonic units and their contacts are cut off by large batholith intrusions of late Variscan ages. The largest ones are the South Bohemian Batholith and the Central Bohemian Batholith. They consist of many different generations of intrusions often cutting through each other.

Tectonic history

The Moldanubian Zone is interpreted as the lower crust of a microcontinent called Cadomia or Armorica. This small piece of continental crust was sandwiched in between the larger continents of Laurussia and Gondwana during the Variscan Orogeny. Some authors think the microcontinent stretched far enough to also encompass the pre-Variscan basement of the Armorican Massif, others think a string of small microcontinents more reasonable.

Literature