The Koněprusy Caves are a karst cave system in the south-western part of the Bohemian Karst, in the Karlštejnská pahorkatina, inside the hill of Zlatý kůň.[1][2] According to the Správa jeskyní České republiky, they belong among caves formed by the action of water in soluble rocks, in Czechia mostly in limestones.[2]
Bohemian Karst
The Bohemian Karst lies between Prague and Zdice in the central part of the Barrandian, over an area of about 144 km². It is made up of Paleozoic deposits of Silurian and Devonian age, a discontinuous belt of mostly limestone rocks about 32 km long and up to 8 km wide. Its elevation ranges from 209 m above sea level at the surface of the Berounka near Karlštejn to 498.9 m above sea level on the hill of Bacín. About 680 caves are recorded in the Bohemian Karst, from rock shelters to complex shaft-like systems, and many of them are archaeological sites. Since 1972 the area has been a protected landscape area covering 12,823 ha.[2]
Origin of the caves
Ideas about how the caves formed differ. There is agreement that they are at least tens of millions of years old and have been developing since the Tertiary at the latest. The initial vertical cavities, to whose formation thermal waters from the depths may also have contributed, were, according to the administration, gradually reshaped by atmospheric water as the river network cut deeper. The higher levels are older, the lower ones youngest. The present form of the spaces was created mainly by corrosion, in many places also by the collapse of limestone beds and by a large quantity of sedimentary fillings, that is cave loams and clays. In the course of their development, parts of the caves were flooded with water, filled with sediments and emptied again.[2]
The caves have three known levels. The highest, smallest and apparently oldest level, Mincovna, formed in coloured Suchomasty limestones, and its tall passages of oval cross-section developed along vertical tectonic faults. The most extensive middle level, with wide passages and spacious halls, follows the boundary between the Koněprusy limestones below and the Suchomasty limestones above. The gentle dip of this boundary caused the whole level to tilt to the north and the ceilings to collapse extensively in the southern parts of the system. The lower level is less extensive, and its passages follow vertical faults in massive Koněprusy limestones, so they are mostly narrow and tall. All the levels are connected by vertical chimneys or shafts. Exploratory probes have shown that most of the system is filled with sediments and that today's open spaces are only a fraction of the cavities that formed in the Zlatý kůň massif.[2]
Prehistoric finds
The thick loamy fillings of the caves preserved evidence of prehistoric life on Zlatý kůň. The oldest dated bones come from the earliest part of the Quaternary, about 1.5 million years ago, and were found in the Proškův dóm. They belong mainly to bats, voles, dormice and other rodents and document life in a warm period. Slightly younger are skeletons of bears of the species Ursus deningeri together with small fauna.[1]
Most skeletal finds come from the surface of the debris cone beneath the chimneys in the Proškův dóm and the Pustý dóm and date from the last glacial period and the older Holocene. Bones of large vertebrates predominate, for example woolly rhinoceros, horses, deer, wolves, chamois, ibexes and cave hyenas. At that time the caves were open to the surface through chimneys into which animals fell, and some species fed on their remains in the caves.[1]
Human remains were also found on the loams of the Proškův dóm: a mandible, fragments of a skull and of cheekbones, and ribs and vertebrae belonged to a woman who lived in the Bohemian Karst area more than 45,000 years ago. They are the remains of one of the oldest known modern humans in Eurasia. The grave goods were apparently three stone tools, a perforated shell of a marine bivalve and a bone flake with a notch. The grave was apparently located in an upper part of a chimney and later collapsed into the caves.[1]
History of exploration
The Koněprusy Caves were known as early as the 15th century. According to one legend, a shepherd boy climbed down into a hole, where he saw a robber counting money. He received a handful of coins from him but revealed the secret in the village, and when the villagers set out for the hill, the hole could not be found. After the upper level was discovered, it turned out that the legend had a rational core.[1]
The oldest written report comes from the book Versuch einer Naturgeschichte Böhmens by Laurenz Albert Dlask, dating from 1822, and shows that the spaces which quarry workers from Koněprusy gradually discovered in 1950 had already been known at the beginning of the 19th century.[1] The first explorations were attended by quarrymen who cooperated with J. Petrbok, and by scientific staff. After an accident in the Letošníkova propast, the quarry administration closed the caves and permitted access only to specialists.[1]