a phase of mountain building and accretion of terranes that resulted from the closing of the Rheic Ocean when the two paleocontinents Gondwana (in the south) and Laurussia (in the north) collided. Most of the Bohemian Massif is often supposed to belong to a terrane called Cadomia or Armorica, which also included the terranes of the Armorican Massif in western France. This supposedly formed a microcontinent that became sandwiched between the large continental masses north and south. The result of the Variscan Orogeny was that almost all continental mass became united in a supercontinent called Pangaea. From the Permian period onward the Variscan mountain belt eroded and became partly covered by younger sediments, with the exception of Variscan massifs like the Bohemian Massif. The basement rocks and terranes of the Bohemian Massif are tectonically part of three main structural zones, which differ in metamorphic degrees, lithologies and tectonic styles. This tectonic subdivision was formed during the Variscan Orogeny. The Saxothuringian Zone forms the northern parts of the massif. The northernmost part of the Saxothuringian Zone is the Mid-German Crystalline High, which is but rarely exposed in the Bohemian Massif. The northern boundary of this zone is assumed to be the Rheic suture which separates the former continental masses of Gondwana and Laurussia. The Moldanubian Zone forms the central parts of the massif and has generally a higher grade than the Saxothuringian Zone. It includes the Teplá-Barrandian Terrane, which is assumed to have been a small microcontinent. The southeast of the massif forms a third unit, the Moravian-Silesian Zone. This zone includes the Brunovistulian Block, an allochthonous unit thrusted over the Moravo-Silesian crystalline rocks. Contradictionary to most parts of the Bohemian Massif, the Brunovistulian was originally part of or close to the southern part of Laurussia. Resources Unlike other Variscan massifs in Central Europe the Bohemian Massif is not very rich in ores. The Harz Mountains further north in Germany, which are geologically part of the Rhenohercynian Zone, have more ore deposits. On the other hand, the Bohemian massif has many quarries where granite, granodiorite and diorite are won for use as decorative building stone. References Further reading ; 2000: The Brunovistulian: Avalonian Precambrian sequence at the eastern Bohemian Massif: speculations on palinsplastic reconstruction, in: (eds.): Orogenic Processes: Quantification and Modelling in the Variscan Belt, Geological Society of London Special Publication 179, pp 103–113. ; 1927: Gliederung des varistischen Gebirgsbaues, Abhandlungen