Výpustek Cave - Natural conditions
GEOLOGICAL DEVELOPMENT OF THE AREA
The Moravian Karst is formed by limestones – 360–370 millions of years old organogenous sea sediments from the Middle to Late Devonian. Their evolutionary phases formed the Josefov, Lažánky, Vilémovice and Křtiny formations of limestones with a total thickness estimated at 500–1000 m. In the west, the limestones lie on old deep-mined volcanic rocks – granodiorites of the Brno Massif; in the east they are overlapped by younger Culm greywackes and shales of Carboniferous age.
After the Palaeozoic sea dereliction and mighty Variscan folding which hit the whole Bohemian massif, the exposed limestone mountains began to undergo intensive karstification. The karst process during the Mesozoic and Tertiary eras was interrupted by short-term sea floods, which reflected orogenic unrest of the mighty neighbouring Alpine folding. The Mesozoic Sea also left its carbonate sediments with fossils of ammonites, belemnites and other sea animals, e.g. in the surroundings of Olomučany. Vari-coloured layers of kaolinitic sands and clays filling deep karst depressions (so-called sand pipes) survived from the Early Cretaceous Period in the surroundings of the village of Rudice.
They are remainders from continental sedimentation under a tropical climate. The following development of the Moravian Karst was markedly influenced by the sea (Badenian) flooding in the Tertiary. Deep karst canyons with the oldest cave systems at that time were filled with young clay sediments from the Vienna Basin, which basically changed the hydrographic development of the whole region. From the middle Tertiary, the Moravian Karst gradually changed to the present form.
STALACTITE DECORATION
In the areas of the Výpustek Cave open to the public, the original stalactite decoration was barbarously destroyed. The Liechtensteins removed the stalactites to decorate the interiors of their artificial caves in Lednice Castle. Neither the phosphate clay mining in the 1920s nor the German underground factory contributed to conservation of natural values and that was another devastating period in the history of the cave. The final blow was the fire set in April 1945. On the dark ends of the old stubs relatively rapid formation of young white stalactites, especially in the ceiling parts of the corridor, can currently be seen. Fortunately, the less accessible spaces such as the Nízká chodba corridor and Salmův Výpustek (Salm's Omission) were not markedly devastated by human activity. There is still rich and exquisite stalactite decoration in some parts of these areas that are not open to the public.