Subhorizontal epiphreatic caves are good morphological markers of valley deepening or uplift processes, since they reflect the position of the spring, which is related to the valley bottom. In Northeast Slovenia, transpressional activity along the Periadriatic Fault System caused dextral strike-slip as well as possible uplift of the areas adjacent to the fault. The presence of four cave levels near the Periadriatic Fault System documents uplift processes; and, the datings presented here of two levels indicate a Plio-Pleistocene incision history. These dates are in accordance with cave and sediment datings in other parts of NE Slovenia, and they are in line with more recent activity of the conjugated Salzach-Enns-Mariazell-Puchberg (SEMP) Fault in the Northern Calcareous Alps. The major fault systems, therefore, seem to be active not only in the Miocene (as postulated elsewhere), but up to the recent Quaternary.
In a small, abandoned coal mine in northeastern Slovenia, there is an area with intensive flowstone deposition. We found about two hundred carcasses of the mosquito Culex pipiens s. l., as well as a few remains of a winter crane fly Trichocera sp., a rove beetle Atheta cf. spelaea, and a false diamondback moth Digitivalva pulicariae on the wall, partly or entirely embedded in the flowstone. We describe the initial taphonomic steps in these carcasses and discuss the probable reasons why the insect remains disintegrate completely, interrupting the process of fossilisation.
Recent technological advances have opened up new possibilities for collecting, analysing and sharing information about speleological sites. This study explores the integration of 360 degrees spherical imagery and Virtual Tours (VTs) to document five hard-to-access natural caves in the classic karst region. These immersive VTs experiences were embedded in the official speleological cadastre of the Friuli-Venezia Giulia Region, Italy (https://catastogrotte.regione.fvg.it/). The Autonomous Region of Friuli Venezia Giulia has officially integrated underground VTs into its institutional cave registry. This innovation not only improves the functionality of the cadastre but also sets a precedent for how immersive technologies can be effectively utilized within public geological and environmental databases. We analyse the benefits of integrating 360 degrees VTs into a regional cave cadastre from the perspective of scientific documentation, promotion of speleological heritage, knowledge dissemination and public engagement. We also address the technical challenges that have been encountered during acquisition and post-processing and provide guidelines and future perspectives for the application of these technologies in cave research and digital documentation.
The geology of the State of Qatar comprises large spans of carbonate rocks at the surface and evaporitic rocks at shallow depth, and a number karst features (depressions, caves) spread across the country that may cause challenges during land development or infrastructure construction. The government of Qatar has identified that existing geodatabases and geological and hydrogeological maps require improvement to mitigate this risk. In this framework, a thorough assessment of the karst geohazard has been performed including a karst features survey, geologic study of karstification, and an assessment of associated ground subsidence related to karst. The main findings indicate the existence of two types of caves: one corresponding to shallow subsurface dissolution caves developed under phreatic conditions in the past and truncated by erosion at a later stage, the other corresponding to large roof collapse caves originating at depth (intrastratal karst). These latter caves are systematically located on the edge of large depressions. In agreement with the existing literature, it is proposed that the depressions and collapse caves are part of a same collapse/sagging process caused by loss of material at depth (e.g., dissolution of evaporites, compaction of weathered dolostone, or incremental collapse of coalesced relict caves). To extract the karst collapse depressions among the large number of depressions mapped using a recent (2017) LiDAR DTM dataset, it is hypothesized that the karst depressions shall have the same geometrical characteristics (width, length, area, depth) than the few ones containing a roof collapse cave. This results in the identification and mapping of 3537 karst depressions spread across the entire Qatar peninsula. Presently, these karst features seem mostly inactive and thus inherited from a geoclimatic context, which was more favorable to karstification. Under the present geoclimatic conditions, the karst subsidence geohazard appears to be generally low, as caves are inherited, and ongoing karstification processes are limited. However, this geohazard is present across large spans of the territory and any future land development shall include plans and strategies to consider the presence of karstified rocks in the subsurface and ensure that karst is not reactivated by human activity.
The Südwandhöhle, located in the Dachstein karst massif, is a 12 km long cave system. It is primarily formed in dolomite (Middle Triassic Wetterstein Formation), a rare occurrence in the Northern Calcareous Alps. The cave is 509 m deep and notable for its rock overburden of 1.5 km, and its huge passage cross-sections of up to 250 m². In the remote parts, there is a 0.7 km-long tube that is almost entirely formed in lithified clastic cave sediments. The setting suggests that this relatively small tube (cross-sections: 0.5 to 2 m²) developed as a continuation of a large palaeo-phreatic gallery. The walls and ceilings of the tube are made up of well-lithified sandstone, which often shows erosional features. The sandstone components consist of calcite, partly dedolomite, as well as some quartz, small amounts of dolomite, and iron hydroxide. The cement is calcite, giving a total calcite content of 40–70% in the analysed thin sections. Unusually, the tube does not run along the ceiling of the corridor, as is common in many caves, but winds its way through the large, sediment-filled corridor. As there are no structures in the calcareous sandstone or active tectonics that could have acted as initial fissures, the formation of the proto-conduit is difficult to explain. One possible explanation is that the sand was cemented by pore water from the surrounding dolomite host rock, with parts inside being less lithified or not consolidated at all. Water migrating through this porous sand could have dissolved carbonate grains, and subsequent mechanical erosion and eventually piping could have created a tube. Due to the carbonate content, dissolution probably played only a limited role. Therefore, we interpret this tube as a pseudo-karst cave, that was formed primarily through mechanical erosion of sandstone that had deposited within a karst cave.
