Origin and development of an old alpine cave (Zadlaška jama, Julian Alps)
Martin Knez, Tadej Slabe - (28/1,1999)
The entrance into Zadlaška jama lies in Maastrichtian limestone breccias at the extreme northern border of the Outer Dinarid tectonic unit, from the presence of Megalodontid shells it is presumed that the northern parts of the cave developed in Upper Triassic limestones. Tectonically the Cretaceous and also Triassic carbonates are strongly broken. Several systems of former water passages controlled by geological factors are found in the cave. Two of them are more distinctive: one developed along bedding-planes or at the contact of beds parallel to bedding and the other along fissures and faults which are transverse to local bedding. The cave is an anastomosis network system of initial tubes that develop into passages. The first and the most important factor was water that slowly flowed through the passages. Later the cave was filled by fine-grained sediments. Water flowed above them leaving above-sediment rocky features. The parts of the lower lying passages from which the sediments had been removed were shaped by fast water flow after the lowering of the underground water level. Relatively soon the cave remained hanging in the slope and was dry. Then the rocky perimeter was partly reshaped by condensation water.