KARST OF THE KRKONOŠE MOUNTAINS AND THEIR FOOTHILLS

They have been formed for  millions of years by water in relatively small bodies of crystalline limestones and dolomites situated in a mighty formation of phyllites and other metamorphosed rocks of the Krkonoše-Jizera crystalline unit. The series of moderate karst bodies emerge here on the Earth’s surface in two discontinuous bands in the west-east direction.

The caves were found here especially in the surroundings of Železný Brod, Bozkov, Jesenný, Poniklá, Vrchlabí, Svoboda nad Úpou and Horní Albeřice, more to the north than in the surroundings of Rokytnice nad Jizerou and Strážné. The Bozkov Dolomite Caves are the largest of them.

DOLOMITE (calcareous dolomite)

It is a carbonate rock composed of a mixture of minerals, calcite (CaCO₃) and dolomite (CaMg(CO₃)₂). It was formed by the conversion of sedimented limestone rocks of ancient seas with the addition of magnesium (Mg). In addition to that, the dolomite body in Bozkov underwent strong silification during repeated orogenic processes.

BOZKOV DOLOMITE CAVES

• They are situated on the northern edge of the village of Bozkov on the slope of the plateau called Na Vápenci (485 m a.s.l.);
• They were formed due to a strong corrosive activity of the underground water in the lentil of calcareous metamorphosed dolomites, in some parts strongly silificated;
• They consist of two relatively independent systems of cave corridors and halls, which were connected with trenches and a long tunnel at the times when the cave was made accessible;
• They are permanently flooded with water in the lowest parts, forming underground lakes – the largest in Bohemia;
• They are also unique with an unusual extent of selective corrosion of walls and ceilings, and with rare forms of these formations;
• They are, with their total length of all the spaces known today – 1,060 m – and with denivelation of 43 m, the longest dolomite caves in the Czech Republic;
• There is a 350 m long route open to the public with a tour duration of 45 minutes;
• There is an air temperature of 7.5–9 °C (ca 47°F), relative humidity 96–100 % and temperature of water in lakes 8 °C;
• They were declared a National Natural Monument in 1999;
• They are annually visited by about 70 thousand visitors from all over the world.