Kateřinská (Catherine) 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. According to evolutionary phases, it forms the Josefov, Lažánky, Vilémovice and Křtiny formations of limestones with the 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. During the Mesozoic and Tertiary eras it was again interrupted by short-term sea floods which reflected orogenic unrest of the main phases of mighty neighbouring Alpine folding. The Mesozoic Sea left its carbonate sediments here 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 then markedly influenced by the short-term marine flooding in the Tertiary (Badenian). 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 AND STALAGMITE DECORATION
The stalactite and stalagmite decoration of the Kateřina´s Cave was substantially influenced by ceiling breakdowns during formation of its big spaces. The old decoration was buried under debris and sinter coatings and sporadic stalactites and stalagmites preserved only on the walls. Nevertheless, a relatively rich stalactite and stalagmite decoration was preserved in the places where no breakdowns of ceilings occurred. It is first of all a part of the New Kateřina´s Cave behind Hlavní dóm - Main Dome. Slender stalagmites and columns grouped in the so-called Bambusový lesík - Bamboo Forest dominate here. Due to favourable conditions (constant dripping from a relatively small height) they have grown up to a height of three metres with a diameter of only 2–4 centimetres! Bambusový lesík thus belongs among the most remarkable parts of the underground of the Moravian Karst. There is also a very attractive symbol of the Kateřina´s Cave, the stalagmite formation Čarodějnice - Witch, which is lit by spot-lights of different colours.
Photo: Petr Zajíček