ORIGIN AND DEVELOPMENT OF THE NA ŠPIČÁKU CAVE
Tectonically disturbed layers of marbles that constitute the Velký Špičák Hill and its surroundings were significantly influenced by water from precipitations and surface streams. The karst joints were gradually widened due to calcite dissolution and underground channels were formed. Water ran through them into he resulting valleys and the cave labyrinth slowly evolved. Under the conditions seen in most of today's Czech Republic, the cave system below the Špičák Hill would probably consist of narrow fissure corridors that would maybe even be impenetrable for a man. Further development of the cave was however significantly influenced by the northern continental glacier, which especially in the next to last ice age (Saalian age) approximately before 150 thousand years ago was stopped as late as by today's Czech border mountains. The cave was even modelled by its melting water during warming and gradual recession of the glacier. The development of underground cavities was significantly accelerated by more aggressive glacier water and, considering the fact that permanent underground lakes were formed there for a very long time, the glacier water predominantly caused their widening. The limestone was dissolved most actively at lake surfaces, so that the underground corridors were formed into an unusual heart-shaped profile and an outstanding horizontal level of ceilings and niches was formed in the whole system. This genesis and modelling of caves is unprecedented in today's Czech Republic and even in other countries it is very rare. Thus, the example of the Na Špičáku Cave was the first time this phenomenon was introduced in the world's specialised literature.
