The paper discusses problem of deep meteoric speleogenesis. Relatively uncritically hypothesis of Worthington states that deep flow pathways are favourable to speleogenesis because the viscosity of water decreases with temperature, which increases with depth. This concept was tested with numerical model where other depth-depended variables were considered. It turned out that the effects which hinder deep speleogenesis, play far more important role. Among these is a decrease of initial fracture widths with depth due to lythostatic pressure and decrease of calcite solubility with increasing temperature.
COBISS.SI-ID: 37575981
Shallow subterranean habitats (SSHs) are areas of habitable space that are less than 10 metres in depth beneath the surface. They range from large areas such as lava tubes, to tiny areas such as cracks in cave ceilings (epikarst) or pore spaces in soil. From an ecological, biological, evolutionary, conservation and geographical view are also presented other habitats: seepage springs or hypotelminorheic, intermediate-sized terrestrial SSHs, intertitial habitats along rivers and streams, and shallow carbonate aquifers in arid regions of Australia. Their study calls into question the prevailing view that subterranean habitats are extreme, nutrient-limited environments with no light and no daily or annual cycle. Shallow subterranean habitats have little in common with caves except for the absence of light and a specialized fauna with typical ‘cave’ morphology. Fascinating habitats in their own right, they also hold the key to understanding adaptation to subterranean environments in general.
COBISS.SI-ID: 36933421
Air and groundwater temperatures were measured in a rimstone pool in Postojna Cave, to advise evaluation of the impact of natural and anthropogenic influences related to heat being initially transmitted into cave air by visitors. Such heat can accumulate both in the rock mass and in water. Results show that attention must be paid to temperature changes of rimstone pool water rather than those of cave air, especially during the winter. Due to good ventilation deep inside the cave, short term air temperature increases related to higher visitor numbers have not influenced flowstone precipitation or the cave fauna. However, this situation might change if winter visitor numbers increased greatly. This study does not support a suggested increase in winter visits (currently the tourism lowseason) and reduction of summer visits (currently the tourism highseason).
COBISS.SI-ID: 35783725
Caves are linked with ancient relief and can be dated by means of the sediments they contain. In Snežna jama U/Th dating, palaeomagnetic analysis of flowstone and sediment profiles, cosmogenic dating of quartz pebbles and mammalian dating allowed a robust estimate of speleogenesis. Sediment deposition indicate that was formed in the Miocene, received its sedimentary deposits during the Pliocene in a rather low-lying, hilly landscape, and became inactive due to uplift at the beginning of the Quaternary. The information contained within it makes it an important site for explanation of tectonic and geomorfic evolution of the Southern Alps.
COBISS.SI-ID: 38033197
The processes influencing the solute transport in the karst vadose zone were studied by long-term tracer tests with artificial tracers. The results of three successive tracer tests with different modes of injection were compared. Tracer breakthrough curves were monitored at three drips of different hydrological types inside one of the cave galleries of the system of Postojnska Jama over several years. Comparison of the results indicates the highly significant influence of preceding hydrological conditions, injection mode and geologic heterogeneities within the vadose zone on solute transport. Long-continued sampling in each of the tests proved to be important for reliable characterization of the long-term solute transport dynamics.
COBISS.SI-ID: 37575725