Kalendář věků National Nature Monument

The Kalendář věků NNM – “Calendar of Ages” is located on the floor and walls of abandoned brickpit on the eastern edge of the village of Dolní Věstonice in the Jihomoravský kraj – South Moravian Region. The protected area was declared in 2005 on an area of 0.45ha and lies at elevations of 180-205 metres above sea level. This stratotype of the Upper Pleistocene in a facia of dry loess is exposed in profile on the northern foot of the Pavlovské vrchy limestone ridge.
 
A terrace system of fluvial accumulations gradually developed along the Dyje river, which already flowed through its current valley and the Věstonická brána Gate between the Lower Pleistocene to the Holocene periods. This Quaternary covering is built of Pleistocene fluvial sediments (sandy gravels) at several height levels and deluvial and eolic sediments (loess, airblown sands) with fossil soils PI-X. Cryogenic phenomena are common in these soils. Together with the pre-Quaternary basement these strata are prone to landslides. Well-developed exposed loess strata can be found in the Kalendář věků abandoned brickpit, where the former quarrying work uncovered a profile of around 20 metres in height. After the extraction finished a vertical cut (rectangular in shape) was made in the centre of the pit wall.
 
This vertical cut enables us to see the exposed loess strata of Upper Riss age with remnants of mollusc fauna on the wall of the former brickpit. Well developed brown earth or Cambisol lies on top of this loess (soil complex III-R/W) and on top of this we can observe three brown-black horizons of humus-rich black earth of Chernozem (soil complex II), which are separated by wash sediments and loess. The para-brownearthdoes not contain fossils or pollen, whereas the complex of Chernozems and their intermediate layers contain steppe fauna. In the lower Chernozem and in the loess between the lower and middle black earths we can find the shells of thermophilous molluscs. Soil complexes II and III are overlain by a thick complex of the youngest loesses, which are separated by a thin light-brown layer which can be regarded as soil complex I. This youngest soil complex is of stratigraphic importance because the Gravetienne (Pavlovienne) horizon (29-22 thousand years ago) lies on its surface. Evidence of fir and spruce trees is typically found in the Pavlovienne cultural layer. Less resistant steppe elements are occasionally found in soil complex I, although this layer is predominantly sterile due to decalcification. These absent steppe elements are replaced by tundra species which are bound to the greyish horizon of the initial Pseudogley. Recently developed Chernozem can be found at the surface. Remains of fauna from the Würm period, such as mammoths, woolly rhinoceros, reindeer, wolves and foxes are often found in the accompanying loess horizons.
 
Boreholes made in the floor of the brickpit provided evidence that there is a further 15-metre-deep complex of loess, slope sediments and fluvial sands with occasional gravels and with two soil complexes.
 
Speleological research in the surroundings of the Calendar of Ages included the mapping of the previously known underground spaces close to the U Langrů wine bar, which is known as the Netopýří jeskyně – Bat’s Cave. This cave is around 70 metres long and 20 metres deep. Further underground cavities and other pseudokarst phenomena were also discovered during this research process in the surroundings of the monument.
 
Partially trampled grassland grows on the floor of the brickpit and includes thermophilous ruderal species. Part of the pit floor and the south wall are covered with false acacia (Robinia pseudoacacia) stands. Notable herbs in the protected area include the white-flowered poppy Papaver maculosum and the rocket Hesperis sylvestris.
 
The locality is notable for the occurrence of many hymenoptera insects, especially solitary bees such as Andrena morawitzi, the tawny mining bee (Andrea fulva) and Osmia leucogastra. Individual hibernating lesser horseshoe bats (Rhinolophus hipposideros) have been found in the neighbouring underground spaces.
 
Brick-making clay was previously extracted on the site of the current Kalendář věků NNM and later material to build the dam wall of the Nové Mlýny reservoir was also taken from the pit. After quarrying was stopped the pit was occasionally used as a campsite, but now it is used and maintained by the local hunting club.
 
The actual loess profile has been affected by local landslides caused by weathering. The speed of the landslides and destruction of the profile was worsened by water which penetrated the strata in the profile from the open ventilation shafts of a collapsed wine cellar, which came to the surface several metres below the upper edge of the pit. These ventilation shafts have now been blocked and rainwater is probably unable to penetrate the profile in this way.
 
Young growths of “tree of heaven” (Ailanthus altissima) were cut back on the north-east wall of the brickpit in 2004. Around 0.1 hectares of tree stands (predominantly false acacia – Robinia pseudoacacia) remain on the floor and south wall of the pit and it will be necessary to remove them. The Kalendář věků NNM is easily accessible from the road and an information panel is provided for visitors.