Acta Carsologica

Formation of clastic sediments in the Atl cave of the Sierra Zongolica, Veracruz Mexico, and their relationship to the soil cover

2024-12-04T09:15:43+01:00

Allochthonous cave sediments contain important paleontological and archaeological records as well as indicators of recent ecological processes. Correct interpretation of these records requires knowledge about the sediment sources and deposition processes, in particular the interrelation of vertical and lateral sediment transport. Compared to platform karst, knowledge about tropical mountainous karstic geosystems is quite limited. To trace the origin and transportation pathways of sediments, we investigated Atl Cave in the Sierra Zongolica Mountain range, Veracruz, Mexico. Field exploration and mapping have shown that the cave presents two horizontal stages representing phreatic conduits and ancient stability stages and is an epigenetic cave with a point recharge zone at the entrance, which is fed by a stream. A comparative study of the surface soil profiles and the diamicton facies of the cave floor deposits included field morphological description, micromorphological observations, grainsize analysis, colorimetry, bulk chemical composition via XRF, and clay mineral identification by XRD. The results demonstrate that the cave deposits have more similarities with the young alluvial and colluvial soils near the entrance than with mature Terra Rossa developed over the limestone formation that hosts the cave. This proves the predominant role of the lateral alluvial transport by high energy events in the formation of the cave diamicton with very restricted contribution of the vertical erosion of Terra Rossa. The main source rock for alluvial and colluvial materials transported to the cave are siliciclastic sediments of the Necoxtla formation, whereas Terra Rossa soils were formed from tephra of the Orizaba volcano. High CIA values, high clay content with a predominance of kaolinite, point to greater weathering of Terra Rossa in comparison with other studied surface and underground materials.

Factors influencing the groundwater circulation in Mali me Gropa karst massif, Central Albania

2025-03-17T07:49:16+01:00

There are 23 carbonate karst areas in Albania with a total area of 6440 km², or 24% of the country’s territory. Karst aquifers are the richest in the country and about 80% of the water supply for the population living in cities is supplied by karst water. One of the most interesting karst massifs of Albania is called Mali me Gropa (MMG) with a total surface area of 157 km². It is the subject of this paper. Although this massif has attracted attention due to its exceptional development of surface karst landforms (karst pits, sinkholes, swallow holes) and its large and high-quality groundwater resources, it has not been the subject of comprehensive research. In this paper, for the first time, is a summary of the results of a combination of specialized studies, including geomorphological characterization, analysis of long-term groundwater regime observations in relationship with meteorological data, water balance studies applying the recently developed WaterbalANce software method, assessment of groundwater quality and its variability, determination of the groundwater flow velocity with an artificial tracer, and the use of hydrochemistry and runoff data to determine groundwater flow patterns and sensitivity of spring water to contamination. The results of the multi-method studies conducted on the MMG karst massif will inform future studies of the numerous carbonate karst regions in Albania. A final important objective of this article is to raise public awareness about the vulnerability of karst waters and the need to protect the associated ecosystem, especially now that the MMG karst massif is in the spotlight for tourism development.

Characteristics and reasons for the discharge interruption of the Iskrets karst spring (Western Balkans, Bulgaria)

2025-04-22T11:50:52+02:00

The Iskrets spring is one of the most significant karst springs in Bulgaria. А specific feature of this spring are irregular and abrupt reductions of its discharge after some earthquakes as well as other reasons related to the recharge. This study aims to present a reasonable hypothesis for the reasons of the discharge interruptions. A main feature of the Iskrets karst system is the fact that it is dominated by unconfined water flow in the unsaturated zone with velocities varying in a wide range. This creates conditions for significant erosion, transport and redeposition of the fluvial cave sediments. As a result, in the zones where there is a sharp decrease in the water velocity, a considerable accumulation of sediments occurs which can even fill the entire section of the passage-way and leads to a temporary blocking of the spring discharge. It is supposed that an appropriate section where this happens is located near to the discharge point of the spring. Most likely the main reason for the cave deposit displacement is the soil liquefaction caused by the seismic impact. It has been found that the duration of the discharge interruption period is longer at low water flow rates.

Reduced soil quality with cultivation of calcareous soils in subtropical China karst region

2025-07-17T09:43:00+02:00

Cultivation practices significantly impact soil functionality and quality, however, the effects of different cultivation durations remain inadequately quantified in the fragile karst ecosystems of southwestern China. This study employed a chronosequence approach to assess agricultural soil quality changes and identify their key drivers. Five land-use stages were selected and sampled: a natural reserve forest (NR) as a reference, recently burned land (0 a), and cultivated lands with durations of 1, 5, 15, and 30 years (1 a, 5 a, 15 a, 30 a, respectively) in the subtropical karst region of southwestern China. The soil quality index (SQI) was constructed using both the Total Data Set (TDS) and Minimum Data Set (MDS) methods. Principal component analysis (PCA) identified calcium (Ca), silt content and silicon (Si) as the key indicators within the MDS. Both TDS and MDS assessments revealed a progressive decline in SQI with increasing cultivation duration following slash-and-burn practices (R²=0.67 between TDS- and MDS-derived SQIs), indicating that agricultural activities significantly alter soil physicochemical properties and lead to soil degradation. The observed decrease in soil quality may be explained by two main mechanisms: (1) depletion of the soil-forming matrix in shallow karst environments; and (2) accelerated loss of acid-insoluble residues due to enhanced weathering under cultivation. These findings highlight the high vulnerability of karst soils to long-term farming, where inherently limited pedogenic materials and intense chemical weathering collectively exacerbate quality decline. This study provides critical insights for developing sustainable land management strategies in karst regions, emphasizing the importance of practices that conserve soil fertility, reduce residue loss, and maintain essential ecosystem services. With the MDS model explaining 67% of the variance in the TDS-based SQI, it represents an efficient and practical tool for monitoring soil quality in fragile karst environments, thereby supporting evidence-based sustainable land use planning.

CO₂ and Temperature Variations During Peak Tourist Season in Lepe Jame (Postojna Cave, Slovenia)

2025-11-20T15:32:57+01:00

We present and analyze measurements of CO₂ concentration and air temperature taken during the peak tourist season of 2017 in Lepe Jame, a poorly ventilated passage within Postojnska Jama, Slovenia. During the study, the passage was visited by between 5500 and 6500 visitors per day. Both parameters show pronounced diurnal fluctuations, primarily driven by visitor activity. As part of our campaign, we tested and confirmed the effectiveness of enhanced ventilation—achieved by opening the artificial tunnel connecting Postojnska Jama to Črna Jama—in preventing excessively high CO₂ concentrations. The measure is, however, questionable, as it affects the microclimate in Črna Jama. Although CO₂ concentration and temperature are correlated, notable differences emerge in the shapes of their respective rise and recession curves. Temperature increases more rapidly with the arrival of visitors, while it decreases more slowly after visiting hours compared to CO₂. This lag is attributed to thermal storage: heat from visitors is absorbed by the cave walls during the day and gradually released into the cave during the night.

Interview with Professor Ira Sasowsky: Karstology is an integral part of geosciences

2025-11-14T11:02:00+01:00

Professor Ira Sasowsky is Professor of Geosciences at the University of Akron, USA, who has made many outstanding scientific contributions to the karstological community in karst hydrogeology, geomorphology, geochemistry and dating. He completed his undergraduate studies in geology at the University of Delaware and defended his doctoral thesis at Pennsylvania State University. He is known by his colleagues and students for his broad knowledge and experience gained during his extensive field work early in his career in oil fields and later in various parts of the world (Brazil, Croatia, Italy, Slovenia, Spain, USA). His research focuses on groundwater flow in carbonate aquifers, sediment transport and palaeomagnetic dating of cave deposits. He has authored numerous scientific papers and book chapters, edited several scholarly volumes and mentored many undergraduate and graduate students. He has received many honours, to name just few of them: Outstanding Teacher Award (Eastern Section American Association of Petroleum Geologists), Science Award (National Speleological Society), Distinguished Service Award (Geological Society of America, Hydrogeology Division), Presidential Citation (Association of Environmental and Engineering Geologists), and Service Recognition Award (Karst Waters Institute). Prof Sasowsky is active in many geoscience professional organisations in the USA and abroad.

UNESCO Proclaims the International Day of Caves and Karst: A Milestone in Global Recognition

2025-11-24T17:50:55+01:00

The proclamation of 13 September as the International Day of Caves and Karst (IDCK) by the UNESCO General Conference in Samarkand on 12 November 2025 represents a historic achievement for the international cave and karst community. The initiative, submitted by the Republic of Slovenia following the proposal of the International Union of Speleology (UIS), was developed through close cooperation with the Slovenian National Commission for UNESCO, the Republic of Slovenia Ministry of Natural Resources and Spatial Planning, the Permanent Delegation of Slovenia to UNESCO, and the Karst Research Institute ZRC SAZU in Postojna.