Pavel Herich’s research while affiliated with Comenius University Bratislava and other places

Because of the international significance of Dobšiná Ice Cave (Slovakia), it is important to have proper data about the state, movement, or decrease of the ice in which various information about past environments can be preserved. Thus, the goal of the study is to find out which of the 3D scanners used here is the most suitable for long-term monitoring of ice changes. A comparison of the 3D point clouds acquired from laser scanners Leica C10 and Leica RTC360 and the mobile scanners GeoSLAM Zeb Horizon and the iPhone 14 Pro to reference clouds from photogrammetry or tacheometry is provided, and also the process of data acquisition and registration is described. To catch the differences in point clouds according to different types of ice, cross-sections of the vertical and layered ice wall, horizontal ice surface, and artificial ice tunnel are analysed. Some remarkable but also unwanted properties of 3D scanners have been concluded, and the best compromise for 3D scanning of this ice cave has been chosen. According to the diversity of ice types and different layers occurring in Dobšiná Ice Cave, results could be partially helpful in choosing a suitable measurement technology for ice in other caves worldwide.

In January and May 2022 and June 2023, three unexpected caves (31m, 25 m, and 43 m long) were discovered during the construction of the D1 highway west of Hrboltová (a suburban part of the town of Ružomberok, the northern part of the Veľká Fatra Mountains). They formed in the lower Cretaceous bedded marly limestones of the Osnica Formation (approximately 47 % CaO, approximately 11 % SiO2), containing frequent irregular calcite veins. The bedding attitude of the host rocks is 50 – 60° to the NE. Observed frequent slickensides are likely related to the translation of the overriding nappe and later stages of deformation with a predominantly strike-slip movement sense. The cave spaces were predisposed mainly on the steep NE–SW to E–W-striking sinistral faults and NW–SE to N–S striking dextral faults. The strike-slip faults are likely related to the Central Slovak Fault System running through the area. The caves resulted from the corrosion caused by waters penetrating along structural discontinuities and partially dissolved marly limestones. The primary cavities probably originated under the phreatic conditions; no allochthonous fluvial sediments were found in these caves. Water penetrated the cave diffusely from the Váh River when a terraced surface was formed above the cave, probably in the later early or earlier Middle Pleistocene (currently, it is 57 m above the Váh river bed, about 535 m above sea level). Water from the small brook flowing through the tributary Kamenná dolina Valley could also have penetrated into the caves. Although the caves originated in marly limestone, a relatively rich secondary calcite decoration was present, mainly dripstones (straws, thin stalactites, conical and pagoda-like stalagmites, helictites), flowstones, and small rimstones. The seepage water dripping on the floor covered by unconsolidated fine-grained sediments, rock blocks, and debris is continuously drained downwards, only in some places of the Hrboltová 1 and 3 caves it accumulated in smaller rimstone pools. The analyzed waters in the Hrboltová 1 Cave (February 10, 2022) were alkaline, with low electrolytic conductivity (189 to 237 μS/cm). Two caves (Hrboltová 1 and 2) were destroyed by the ongoing highway construction in January and March 2023, and the majority of the third cave (Hrboltová 3) will probably be destroyed in the first half of 2024. The explored caves may represent a fragment of a larger cave developed at the mouth of Kamenná dolina to the Váh River valley, where there are more favourable lithological, hydrogeological and hydrographic conditions for the underground karstification of the marly limestones compared to the broader surroundings. The fauna survey was carried out in the hrboltová 1 and hrboltová 3 caves. In total, representatives of 10 invertebrate taxa were found there. Hypogean aquatic crustacean Bathynella sp. (Syncarida) is the most important of them. The individual was found in a small rim-stone pool situated in the back of hall no. III. in the hrboltová 1 Cave. We assume that the oligotrophic conditions and the long-term isolation of the cave (without entrances before its discovery) could have prevented the penetration of parietal and soil fauna, or bats, into the cave and the development of local biodiversity in general. The current findings of the majority of terrestrial invertebrates in the hrboltová 3 Cave are probably only a secondary penetration from the surface environment after the opening of cave spaces to the surface. The location of the caves near the bridge leading to the western portal of the Čebrať tunnel did not allow any change of the projected route of this highway section, which was significantly limited by the dissected relief (the deep antecedent valley of the váh River) and complicated geological conditions (landslides).