Acta Carsologica

The Traces of ancient glaciations in karst environment - a case study in the Venetian Prealps

2023-08-30T09:07:05+02:00

To reconstruct the ancient glaciations of a mountainous area, it is necessary to consider together, in their topographic contexts, the forms of erosion and those of accumulation, aiming to model the relative glacial systems, which can be understood on the basis of the interrelationships between the various forms. In the karst areas, the forms of glacial erosion are often easily recognizable, given that the geomorphological dynamic favours their conservation. The very ancient deposition forms, on the other hand, are hardly detectable or absent given that chemical erosion contributes to the decrease in volume of the moraines until their total disappearance. As an exemplary case, the relict forms of the ancient local glacial system of Valon del Malera, developed in jurassic limestone and Main Dolomite (Dolomia Principale), partly preserved in the Lessini Mountains (Prealpi Venete, NE Italy) and partly in the nearby Carega massif (Piccole Dolomiti), are illustrated. The forms of erosion document the dismantling of a segment of a glacial valley due to accelerated erosion phenomena attributable to active tectonics along an important fault system. Other segments of the trough-shaped glacial valley are very well preserved. On the other hand, forms resulting from the “over-imprinting” of some ancient morainic ridges are detectable, due to the fact that in favourable cases the morainic cover has reduced the rate of lowering at the cover-rock interface of the underlying limestone, in comparison with the surrounding rocky surfaces not covered by till deposits, causing the formation of rocky ridges. However, the temporary aquifer hanging within the moraine has favoured the development of grike type covered Karren in the limestone, with isolated spikes or pillars of rock. Ridges mainly or totally formed by rock in place are described, which, according to all evidence, seem to be the result of the “over-imprinting” by ancient moraine ridges partly or totally eroded.

Sulfuric acid speleogenesis in Greece

2024-07-28T20:49:33+02:00

Manifestations of sulfuric acid speleogenesis (SAS) documented in several caves in the areas of Aghia Paraskevi, Konitsa, W. Peloponnese, Elassona, Lavrion and Kammena Vourla in Greece are examined and discussed in this work. Carbonate and sulfate samples collected from caves in Aghia Paraskevi and western Peloponnese areas were investigated using methods, such as fluid inclusion, scanning electron microscopy, carbon, sulfur and oxygen stable isotopes, X-ray powder diffraction, and chemical analysis. The examined caves are mainly developed at or in the proximity of the local water table and they are related to hydrothermal springs and geothermal fields. In addition to the documentation of SAS in one case study from Aghia Paraskevi, calcite spar with a homogenization temperature peak at 280°C, indicates an early speleogenetic stage that involves meteoric-origin hydrothermal fluids under deep-seated settings. Sulfur isotope composition of sulfates (–4 ‰) is indicative for pyrite oxidation. The Konitsa caves represent a system developed at multiple altitudes that is related to the evolution of Sarantaporos River. The caves in West Peloponnese are located in two different geotectonic units. However, the caves in both units are active and share common characteristics, such as their development near sea level, morphology and fracture-guided pattern, and the presence of gypsum with δ³⁴S values (average –26 ‰) that are plausibly related to hydrocarbons and bacterial activity. Morphological and geochemical aspects of the caves in these two regions suggest long-lasting, multiphase speleogenetic systems.

Karren of Provence (France), Gréolières, Caussols, Tourrettes-sur-Loup and Luberon

2024-08-26T09:00:41+02:00

The rock relief of karst forms, either of surface forms or of caves which are forming on different carbonate rocks and under different conditions, is one of the most telling traces of their formation, along with the characteristic factors and development. Therefore, we meticulously studied and examined the geological features and rock formations, as well as how they fit into the rocky relief. The diverse shaping of the karst surface is revealed by the rock relief of selected karren on different carbonate rocks, fine-grained homogeneous and compact limestones, as well as porous fine-grained sandstones. We have also newly explained the formation of parallel channels on the inclined surfaces of denuded rock (Gréolières); the gradual reshaping of the rock surface from a subsoil one to one directly exposed to rain and water creeping along the gently sloping rock (Caussols). Furthermore, the unique shaping of carbonate sandstones, specifically such with large channels (Tourrettes-sur-Loup) is presented for the first time. The speed of karstification of younger carbonate rocks is revealed by channels on the walls of the palace in Avignon.

Topographic conditions for spatial distribution of dolines in Valjevo–Mionica karst, western Serbia

2024-08-18T21:29:05+02:00

Valjevo–Mionica karst is a limestone area within the easternmost flanks of the Internal Dinarides in western Serbia. In the spatial extent of 380 km2, it hosts typical karst landforms, primarily dolines, blind valleys, dry valleys and caves. Dolines are present on 75% of the total area, and the exact number of them within the area outline is 5319. The aim of the study is to determine the guidance factors for the spatial distribution of dolines, primarily morphological, while lithological, tectonic and climatic factors are presented at the basic level. Morphological factors in this study are analysed through morphometrical characteristics and calculations, which include the elevation, the mean topographical slope and the landform classification based on geomorphons. Digital elevation models with resolutions 90 m and 30 m are used. Data sources for doline positions were the topographical maps of 1:25,000 scale.
Spatial distribution of dolines in the study area is rather uneven. Three zones (clusters) of higher concentration may be distinguished, where 34% of the total study area hosts 72% of dolines. These three zones are the karsts of the villages Lelić, Bačevci and Robaje, divided by deep canyon valleys. Maximum density of dolines, judging by the Kernel density method, is 33 dolines per km2 in the zone of the Stapar village, at the northwestern outskirt of the study area. The main factors influencing the spatial distribution of dolines are the topographical slope and the phases of morphological/hydrographical evolution of the area.

20 years of LTER Slovenia

2023-12-04T18:49:42+01:00

Research infrastructures dedicated to long-term ecosystem research are important to support the assessment of the impacts of global change on landscapes, ecosystems and society. The European Long-Term Ecological Research Network (LTER Europe) is an initiative with the main objective of improving the understanding of the processes that shape ecosystems and socio-ecological systems under the influence of global change. In this paper we briefly present the twenty years of research since Slovenia joined this initiative and the main challenges and research activities carried out within the LTER Slovenia consortium.

IUGS Recognition of the Račiška Pečina Cave section as a Global Geological Heritage Site

2024-12-03T14:21:09+01:00

Račiška Pečina, a limestone cave in the Classical karst in southwestern Slovenia, which belongs to the External Dinarides (Slovenian Cave Register No. 935; 45°30’12.10’’N; 14°09’00.83’’E; 609 m a.s.l.), has received international recognition for its exceptional sedimentary section. The cave’s sediments, which span 3.4 Ma, provide a continuous and detailed record of climate, environmental and paleomagnetic changes. This unique archive of the Earth’s history has earned Račiška Pečina a place among the “Second 100 IUGS Geological Heritage Sites”, an award announced by the International Union of Geological Sciences (IUGS) at the 37th International Geological Congress in Busan, South Korea.

Interview with Prof France Šušteršič

2024-10-03T09:49:14+02:00

Professor France Šušteršič dedicated his professional career to the study of karst, & caves. He is renowned for his original research achievements and insightful reflections on the challenges and role of karstology in science.

Prof. Dr. Andrej Mihevc (1952–2024)

2024-12-04T16:51:45+01:00

Our dear friend and colleague, Prof. Dr. Andrej Mihevc, passed away in October 2024 after a long battle with an incurable illness.