Barrandovské skály National Nature Monument

The Barrandovské skály – Barrandov Cliffs contain a very instructive stratigraphic profile, especially of the early Paleozoic formation of the Devonian with typically disharmonic folding.
 
The national nature monument lies in the parishes of Hlubočepy and Malá Chuchle in the south of the city of Prague. The monument was declared in 1982 on an area of 11.5ha at elevations of 196-270 metres above sea level. Barrandovské skály is in fact the oldest Czech geological reserve - it was donated by the owner for preservation to the National Museum as early as in 1884.
 
On the basis of their stratigraphy we can divide the profile under Barrandov into four basic sections. These are the Zlíchov limestone, the boundary between the Dvorecko-Prokopský and the Zlíchov limestones, the Kaplička – Chapel section and the Barrandova skála – Barrandov Rock.
 
The profile under Barrandov – Zlíchov limestones
The sequence of layers of the Zlíchov limestones is exposed below the Barrandov bridge, where they are distinctly layered, mostly fine-grained, bioclastic and micrite, and contain hornfels. The Zlíchov limestone beds are around 100 metres in thickness, but these layers are very poor in paleontological materials. However, when they are processed in a laboratory, microfauna such as conodonts can be found in the limestone.
 
The profile under Barrandov – boundary between the Dvorecko-Prokopský limestone and the Zlíchov limestone.
This exposure is of stratigraphical significance as it was recognized by the 1st International Symposium for Silurian and Devonian Stratigraphy as the original stratotype of the base of the Zlíchov Formation in 1958. In the left-hand section of the profile we can see the grey, Dvorecko-Prokopský limestones with a slab-like structure, with bodies of calcareous shales and imperfectly-developed hornfels. These limestones belong to the Prague Formation and are paleontologically very poor. These limestones are sharply overlain by dark-grey bioclastic limestone of the Zlíchov Formation with an abundance of black hornfels. These begin with a 1.4-metre-thick interval of layered limestones with a slippery texture which developed on a sloping sea bottom where the layers were not sufficiently stabilized during the period of the Devonian sedimentation. An 8-metre-thick bed of coarser bioclastic limestones and sedimentary breccia, which contains many various fragments of rounded limestones and remnants of marine fauna lies sharply on the layered limestones. These positions are known as the “Coral Horizon by the Chapel”. The weathered broken limestones (known as “white layers”) contain more than 250 fossil species. The way in which these organic remnants are preserved and laid down provides evidence that they were transported from different parts of a coral reef, which did not survive until the present day.
 
Profile under Barrandov Chapel
Benches of very fine-grained micrite, grey Dvorecko-Prokopský limestones with a bench-like structure are exposed in the old quarries. These layers are simply tilted towards the north-west and are more than 150 metres thick. These limestones are paleontologically poor and only contain ichnofossils – the contents of worm burrows. In the “Chapel” quarry we can find a historically valuable building, which was originally built as a gunpowder store by the French Army in 1742, but was later converted into a chapel.
 
Profile under Barrandov – Barrandova skála Rock
The Barrandov Rock is built of intensively folded rocks of the Lochkov Strata, which belongs to the lowest Devonian. These are block limestone with very thin layers of calcareous shales and contain an abundance of irregular agglomerations of dark-coloured hornfels. The Barrandov Rocks are notable for their complex folded sedimentary rocks which were formed during the Hercynian mountain-building movements. Especially in the central part of the exposure below the Barrandov memorial tablet the rocks are folded in many different ways – often in a zig-zag pattern, overlapping and deformed in various ways. The deformation of the limestones on the Barrandov rocks is a “textbook” example of disharmonic folding which mostly occurred in the Prague region in platy or laminar limestones, which differ from the surrounding units as they were more prone to folding and their plasticity under the effects of tectonic pressure. A memorial to the geologist and palaeontologist Joachim Barrande can be found on the Barrandov Rocks. The memorial was installed by members of the Natural History Society of the National Museum in 1884, one year after Barrande’s death. The exposures at the Barrande Rock are only of natural origin in their upper section, but were uncovered in the lower sections when the French Army blasted them away to construct a road along the rocky bank of the Vltava river in 1742. The cliffs were cut further back to make way for a railway line in 1862.
 
The Barrandovské skály NNM is also of botanical and zoological importance. Thermophilous rocky grasslands mostly grow on the open sections of the cliffs, although they are in danger of becoming overgrown with shrubs and false acacias (Robinia pseudoacacia). The open rocky areas are also the home of relict thermophilous invertebrate species – gastropods, beetles, both species of swallowtail butterflies, the sloe hairstreak (Satyrium acaciae) and chequered blue (Scolitantides orion) butterflies. The occurrence of the ladybird spider Eresus cinnaberinus is also notable.