No abstract

Na dinarskih kraških planotah Kočevskega Roga in Kočevske Male gore se je na kontaktu med kraškim in fluvialnim geomorfnim sistemom oblikoval t.i. kontaktni kras. Preučene so bile geomorfološke oblike in procesi na štirih območjih kontaktnega krasa. Na stiku med nekarbonatnimi in karbonatnimi kamninami so se razvile ponikve, slepe doline (aktivne in fosilne), konkavne oblike v bližini kontakta pa so zapolnjene z nekarbonatnimi sedimenti. Na kontaktu med različnimi karbonatnimi kamninami (dolomiti in apnenci) so reliefne oblike kontaktnega krasa manj jasno izoblikovane, mdr. ponori (aktivni in fosilni), ponorni zatrepi ter suhe doline.

Within the area of Upper Pivka there is a number of intermittent lakes because of oscillation of water table level close to the surface i.e. shallow karst. Our survey was focused on morphogenetic interpretation of depressions hosting intermittent lakes by means of classic morphographic mapping and sediment analyses that was supported by electrical resistivity tomography. We can interpret at least two different morphogenetic types of depressions. One type are depressions which are periodically inundated uvalas positioned in-between conical hills. The second type are circular depressions within karst plain that are collapse dolines filled with extensive flood deposits up to several metres thick.

Ilič: Vršaji na kontaktnem krasu: primer iz Matarskega podolja, SlovenijaNa slovenskem krasu je več različnih tipov kontaktnega krasa. Najpogostejši je ponorni tip kontaktnega krasa, ki se navadno pojavlja med fliši in apnenci. Najdaljši kontakt te vrste v Sloveniji je na območju Matarskega podolja v zahodni Sloveniji, kjer se pojavljajo mnoge kraške kotanje, ki so značilne za kontaktni kras. Na severozahodnem delu Matarskega podolja se pojavljata dva tipa vršajev. En vršaj z aktivnim procesom sedimentacije rečnih nanosov na površju in ima obliko, ki je značilna za vršaje v fluvialnem geomorfnem sistemu. Drug tip predstavljajo reliktni vršaji na kontaktnem krasu. To so površinske oblike podobne vršajem na karbonatni matični podlagi. Njihov nastanek je vezan na postopno denudacijo rečnih naplavin na območjih, ki so jih prekrivali vršaji, in kemično denudacijo karbonatne matične podlage. Podrobneje so bile proučene geomorfne oblike in procesi na vršajih ter vpliv vršajev na razvoj kontaknega krasa.

Patterned ground is a characteristic periglacial landform in polar and alpine environments but has not been systematically studied in karst caves. Here we characterize the periglacial environment and sorted stripes within the Ledenica pod Hrušico ice cave, western Slovenia. The stripes were mapped, sediment depth and grain size were measured, and cave and outside air temperatures were monitored together with ground temperatures. Eleven sorted stripes of coarse limestone debris had developed on 1 m thick silt‐rich sediment, underlain by limestone bedrock. Silt‐rich cave sediments can accumulate as insoluble carbonate residue or during flood events, whereas coarse debris may result from frost shattering. Cold winter air entered the ice cave, but little air exchange occurred during summer, when the cave air temperature slowly rose to a maximum of 5°C. Winter temperature oscillations propagated efficiently to the snow‐free cave floor. Fourteen freeze‐thaw cycles were observed at the patterned‐ground surface during winter 2015/2016 and may cause the differential frost heaving necessary for sediment sorting. Such periglacial conditions and mixtures of silty and coarse sediments can produce sorted patterns in karst caves.