Journal of

GEOsciences

  (Formerly Journal of the Czech Geological Society)

Original Paper

Havlíček, Vaněk, Vokáč

Discovery of the fossiliferous middle Berounian Vinice Formation at Cekov (Ordovician, western part of the Prague Basin)

Journal of the Czech Geological Society, volume 41 (1996), issue 1-2, 55 - 59

Occurrence of the fossiliferous Vinice Formation in a highway cutting at Cekov is remarkable in that it was omitted in all geological maps so far published. The black shales of the Vinice Formation are squeezed between the quartzites and sandstones of the Libeň Formation, and the dark clayey shales of the Dobrotivá Formation. The Letná Formation, which underlies the Vinice Formation almost everywhere in the Prague Basin, is either reduced to a few meters or it is absent totally. This anomalous development may be explained by extension of the Cerhovice flexure zone toward south-west up to the Cekov-Kařez area, where this structure acquired in the lower Berounian a form of a rising elevation distinguished by a strongly reduced sedimentation on its top; after this short-lasting rising episode, the marine sedimentation re-appeared again in the middle Berounian. Few typical trilobites and brachiopods are figured to support outr idea about the mid-Berounian age of the fossiliferous sequence.