Karst

In Great Britain, gypsum karst is widespread in the Late Permian (Zechstein) gypsum of north-eastern England. Here and offshore, a well-developed palacokarst with large breccia pipes was formed by dissolution of the underlying Permian gypsum. Farther south, around Ripon, the same rocks are still being dissolved, forming an actively evolving phreatic gypsum-maze cave system. This is indicated by the presence of numerous active subsidence hollows and sulphate-rich springs. In the English Midlands, gypsum karst is locally developed in the Triassic deposits south of Derby and Nottingham. Where gypsum is present, its fast rate of dissolution and the collapse of overlying strata lead to difficult civil-engineering and construction conditions; these can be further aggravated by water abstraction. Salt (halite) occurs within British Permian and Triassic strata, and has a long history of exploitation. The main salt fields are in central England and the coastal areas of northwest and northeast England. In central England, saline springs indicate that rapid, active dissolution occurs that can cause subsidence problems. In the past, subsidence was aggravated by shallow mining and the uncontrolled extraction of vast amounts of brine. This has now almost stopped, but there is a legacy of unstable buried salt karst, formed by both natural and induced dissolution. The buried salt karst occurs at depths ranging from about 40 m to 130 m; above these depths, the overlying strata are foundered and brecciated. In the salt areas, construction and development are hampered by both abandoned mines and by natural or induced brine runs, with their associated unstable ground.

Tracer techniques were used to study infiltration losses into a dry wadi bed. In order not to be fully dependent on rarely occurring natural flood events, an artificial flash flood was studied in a small arid stream channel, Nahal Shahmon, Israel. A reservoir was built, filled with water (550 m3) and breached artificially. Three different artificial tracers were injected at different times during the flood. At two locations downstream surface water samples were taken. The water moving within the alluvium was also sampled with the help of fluocapteurs distributed at different locations within the alluvial body. The fluocapteurs enabled the different pathways of the two dye tracers downstream to be identified and the maximum depth of infiltration to be approximated. This sampling technique is promising for future studies in arid rivers, since fluocapteurs can stay for a long time without any maintenance. Towards the end of flow, exfiltration from the channel alluvium was observed. The...

Using artificial tracer tests, this study confirms the presence of a single basal aquifer feeding the springs in the wide and complex hydrogeological boundary of the Sibillini Mountains of central Italy. The tracer was introduced into the sinkhole of the Castelluccio di Norcia plain. The tracer test results, observed at the studied springs, highlight the changes induced by the 2016/2017 earthquake in the water circulation of the aquifer system. In particular, the seismic events increased the hydraulic conductivity of the basal aquifer, with a consequent increase in the springs’ flow rates at the western hydrogeological boundary and a decrease in the flow rates at the eastern Adriatic hydrogeological boundary. This phenomenon is in accordance with the hydro-structural framework of the area. The study also investigated the relation between groundwater circulation and tracer behaviour in the springs during the pre- and post-earthquake periods. The tracer test results led to the formula...

Krasno polje is one of the less typical karst poljes within the Dinaric Mountains. It is situated within Velebit Mountain. Our research utilized morphographic, morphostructural and morphometric analysis of the polje to present its mor phogenetic characteristics. It is completely filled with gravel and lacking any surface flows. Slopes above the polje were severely altered by glacial action during the colder periods of the Pleistocene. As a result, proglacial fans filled the karst depression, creating a piedmont type polje. Glacial evidence suggests that there were at least two separate phases of in tense proglacial deposition within the polje.

The vulnerability of four European aquifers with different hydrogeological and climatic characteristics was evaluated using the COP method. The results obtained were statistically analyzed by determination coefficients to measure which factor has greater importance in the vulnerability index. Furthermore, a new parameter has been designed to measure the vulnerability for the whole of the aquifer. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration. The results obtained are coherent with the conceptual model of each pilot aquifer and the available hydrogeological information (hydrographs, isotopic data, tracer tests). Fissured carbonate aquifers (diffuse flow systems) are less vulnerable than karst aquifers (conduit flow systems) and the vulnerability index is more positively correlated with the O factor (unsaturated zone protection capacity) in the first case. The karst aquifers are more vulnerable than fissured aquifers and they show a higher correlation between the C factor (karst features) and the vulnerability index. Climatic variation (precipitation for example) influences the final vulnerability index of the aquifers according to the weight in the index and the spatial distribution.

An understanding of what influences sinkhole formation and the ability to accurately predict sinkhole hazards is critical to environmental management efforts in the karst lands of southeastern Minnesota. Based on the distribution of distances to the nearest sinkhole, sinkhole density, bedrock geology and depth to bedrock in southeastern Minnesota and northwestern Iowa, a decision tree model has been developed to construct maps of sinkhole probability in Minnesota. The decision tree model was converted as cartographic models and implemented in ArcGIS to create a preliminary sinkhole probability map in Goodhue, Wabasha, Olmsted, Fillmore, and Mower Counties. This model quantifies bedrock geology, depth to bedrock, sinkhole density, and neighborhood effects in southeastern Minnesota but excludes potential controlling factors such as structural control, topographic settings, human activities and land-use. The sinkhole probability map needs to be verified and updated as more sinkholes are mapped and more information about sinkhole formation is obtained.

Sixteen karst áreas, developed in limestone that ranges in age from Cretaceous to Pleistocene, are known to exist in Costa Rica. Whereas their geologic setting is known as a result of regional stratigraphic reconnaissance, detailed exploration of most of the karst áreas has not been accomplished, with one exception. Information on basic geologic conditions, geomorphology, speleology, ecology, and hydrogeology is available for the Barra Honda karst. General developmentof karst systems in Costa Rica has reached the young to moderately mature stage. They exhibit many of the classic karst features. The available data suggest that many more discoveries are waiting to be made.

Karst environments are characterized by distinctive landforms related to dissolution and a dominant subsurface
drainage. The direct connection between the surface and the underlying high permeability aquifers makes karst
aquifers extremely vulnerable to pollution. A high percentage of the world population depends on these water
resources. Moreover, karst terrains, frequently underlain by cavernous carbonate and/or evaporite rocks, may
be affected by severe ground instability problems. Impacts and hazards associatedwith karst are rapidly increasing
as development expands upon these areas without proper planning taking into account the peculiarities of
these environments. This has led to an escalation of karst-related environmental and engineering problems
such as sinkholes, floods involving highly transmissive aquifers, and landslides developed on rocks weakened
by karstification. The environmental fragility of karst settings, togetherwith their endemic hazardous processes,
have received an increasing attention from the scientific community in the last decades. Concurrently, the interest
of planners and decision-makers on a safe and sustainable management of karst lands is also growing. This
work reviews the main natural and human-induced hazards characteristic of karst environments, with specific
focus on sinkholes, floods and slope movements, and summarizes the main outcomes reached by karst scientists
regarding the assessment of environmental impacts and their mitigation.

The article deals with the archaeological material from the archaeological excavations made in 2010 inside the Štanjel castle. The excavated cellar was probably part of a bigger
building inside which were the living and the working area. Ceramics analysis shows that this basement was used in the early Iron Age (6th –5th century BC). Radiocarbon dating gives date of the basement’s collapse at the turn of the 4th century BC.

TAZA cave I is located on the national coast road, linking the town of Bejaia and Jijel. And composed by an archaeological deposit of middle Paleolithic and Epi-paleolithic. This study concerns a morphotechnological analysis stone artifacts assigned to the Iberomaurusian culture(Lower level),is attributed  to ancient phase, characterized by a high backed bladelets,end-scrapers, notches, denticulates,burins and microburins frequencies. Composed of one large group of raw material (flint rocks), this industry shows three operative schemes to produce flakes ,blades and bladelets. Backed bladelets are calibrated, almost standardized and piercing armatures. The faunal remains indicate a specialized seasonal hunt of Barbary sheep. The flint armatures are viewed here as a consequence of this situation and of the cultural standard of Iberomaurusian hunters at TAZA I.

Significance of hydrological variability in karst is presented, which also discusses factors inducing such variability and consequences it may cause. Groundwater flow in karst aquifers is often characterized by strong variability of flow dynamics in response to different hydrologic conditions within a short time period. Consequently, water table fluctuations are often in the order of tens of meters, differences in flow velocities between low- and high-flow conditions can reach ten or even more times. In dependence to respective hydrologic conditions groundwater flow also results in variations of flow directions, and thus in contribution of different parts of the aquifer to a particular spring. The described hydrological variability has many implications for contaminant transport, groundwater availability and vulnerability. Groundwater level rising reduces thickness of the unsaturated zone and decreases protectiveness of the overlying layers. Higher water flow velocities reduce underground retention. Due to more turbulent flow, transport and remobilization of solute and insoluble matter is more effective. During high-flow conditions there is usually more surface flow and hence more concentrated infiltration underground. Particularly in karst systems that show very high hydrologic variability, this should be considered to correctly characterize, understand or predict the aquifers’ hydrological behaviour and to prepare proper protection strategies.

Este artigo propõe uma avaliação qualitativa e
quantitativa do valor geopatrimonial de nascentes cársicas
localizadas no bordo do Maciço Calcário Estremenho
(MCE). Primeiro, identificaram-se as nascentes cársicas
perenes principais, sendo a sua inventariação e classificação,
relativa aos tipos de valores patrimoniais associados,
realizada através do preenchimento de fichas-inventário
efectuadas no campo para as exsurgências dos
rios Alviela, Almonda, Lis, Alcoa, Baça, Lena, Maior e
ribeira de Alcobertas. Para avaliar o seu potencial geopatrimonial
foram utilizados parâmetros de avaliação do
seu valor científico (raridade, representatividade, integridade
e vulnerabilidade), bem como de valores adicionais
que acrescentam importância às nascentes cársicas
consideradas (histórico-culturais, económico-sociais,
estéticos e ecológicos). Por fim, procedeu-se à apresentação
de propostas de geoconservação, valorização e
promoção sustentável das nascentes.

Hypogenic speleogenesis is the formation of solution-enlarged permeability structures by waters ascending to a cave-forming zone from below in leaky confined conditions, where deeper groundwaters in regional or intermediate flow systems interact with shallower and more local groundwater flow systems. This is in contrast to more familiar epigenic speleogenesis which is dominated by shallow groundwater systems receiving recharge from the overlying or immediately adjacent surface.Hypogenic caves are identified in various geological and tectonic settings, formed by different dissolutional mechanisms operating in various lithologies. Despite these variations, resultant caves demonstrate a remarkable similarity in patterns and meso-morphology, which strongly suggests that the hydrogeologic settings were broadly identical in their formation. Hypogenic caves commonly demonstrate a characteristic suite of cave morphologies resulting from rising flow across the cave-forming zone with distinct buoyancy-dissolution components. In addition to hydrogeological criteria (hydrostratigraphic position, recharge–discharge configuration and flow pattern viewed from the perspective of the evolution of a regional groundwater flow system), morphogenetic analysis is the primary tool in identifying hypogenic caves.Cave patterns resulting from ascending transverse speleogenesis are strongly guided by the permeability structure in a cave formation. They are also influenced by the discordance of permeability structure in the adjacent beds and by the overall hydrostratigraphic arrangement. Three-dimensional mazes with multiple storeys, or complex 3-D cave systems are most common, although single isolated chambers, passages or crude clusters of a few intersecting passages may occur where fracturing is scarce and laterally discontinuous. Large rising shafts and collapse sinkholes over large voids, associated with deep hydrothermal systems, are also known.Hypogenic caves include many of the largest, by integrated length and by volume, documented caves in the world. More importantly, hypogenic speleogenesis is much more widespread than it was previously presumed. Growing recognition of hypogenic speleogenesis and improved understanding of its peculiar characteristics has an immense importance to both karst science and applied fields as it promises to answer many questions about karst porosity (especially as deep-seated settings are concerned) which remained poorly addressed within the traditional epigenetic karst paradigm.

Tuban sudah memiliki dua korporasi semen level multinasional, ditambah puluhan industri menengah ke bawah baik yang legal maupun ilegal, yang setiap harinya merusak kawasan karst. Selain karst tentu vegetasi alami berupa hutan yang telah rusak, akan turut berpengaruh dalam pelestarian lingkungan hidup di Kabupaten Tuban. Karst Tuban kembali mengalami ancaman yang cukup serius, mengenai ekspansi korporasi semen asal China. Rencananya wilayah Tuban akan dieksploitasi oleh Abadi Cement yang berlokasi di desa Sugihan Kecamatan Merakurak dan Unimine Cement di wilayah Tambakboyo serta Kerek. Unimine sendiri rencananya akan membangun pabrik dengan luas 761 Ha. Tersebar di Kecamatan
Tambakboyo meliputi Desa Sotang, Cokrowati, Mander, Plajan, Klutuk, Gadon dan Dasin dan Kecamatan Kerek meliputi Desa Wolu Tengah dan Kedung Rejo, dan Kecamatan Bancar meliputi Dusun Doro Desa Latsari, Kabupaten Tuban Propinsi Jawa Timur.

Sinkholes usually have a higher probability of occurrence and a greater genetic diversity in evaporite terrains than in carbonate karst areas. This is because evaporites have a higher solubility and, commonly, a lower mechanical strength. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes are only well understood in a few areas. To deal with these hazards, a phased approach is needed for sinkhole identification, investigation, prediction, and mitigation. Identification techniques include field surveys and geomorphological mapping combined with accounts from local people and historical sources. Detailed sinkhole maps can be constructed from sequential historical maps, recent topographical maps, and digital elevation models (DEMs) complemented with building-damage surveying, remote sensing, and high-resolution geodetic surveys. On a more detailed level, information from exposed paleosubsidence features (paleokarst), speleological explorations, geophysical investigations, trenching, dating techniques, and boreholes may help in investigating dissolution and subsidence features. Information on the hydrogeological pathways including caves, springs, and swallow holes are particularly important especially when corroborated by tracer tests. These diverse data sources make a valuable database—the karst inventory. From this dataset, sinkhole susceptibility zonations (relative probability) may be produced based on the spatial distribution of the features and good knowledge of the local geology. Sinkhole distribution can be investigated by spatial distribution analysis techniques including studies of preferential elongation, alignment, and nearest neighbor analysis. More objective susceptibility models may be obtained by analyzing the statistical relationships between the known sinkholes and the conditioning factors. Chronological information on sinkhole formation is required to estimate the probability of occurrence of sinkholes (number of sinkholes/km2 year). Such spatial and temporal predictions, frequently derived from limited records and based on the assumption that past sinkhole activity may be extrapolated to the future, are non-corroborated hypotheses. Validation methods allow us to assess the predictive capability of the susceptibility maps and to transform them into probability maps. Avoiding the most hazardous areas by preventive planning is the safest strategy for development in sinkhole-prone areas. Corrective measures could be applied to reduce the dissolution activity and subsidence processes. A more practical solution for safe development is to reduce the vulnerability of the structures by using subsidence-proof designs.

A comprehensive analysis of the increased pressure on karst landscapes due to expansive economic and urban development is presented with the aim of evaluating changes in land use and their deleterious effects on karst relief forms. The study focuses on two areas surrounding the relatively quickly growing settlements of Hrpelje-Kozina and Divača on the Kras plateau (Slovenia) that have been subjected to intensive urban and business development and traffic since the motorway was brought to their vicinity fifteen years ago. National legislation loopholes and technological improvement was the cause of the commonly unsupervised human encroachment which caused the widespread degradation of the landscape. By comparing different topographical and ortophotographical material from the past four decades and by detailed field inspection of land use and environmental changes, as well as the morphometrical characterization of dolines, the following results have been found: due to the population growth in the past four decades (39% and 50%, respectively), an increase of settlement area by 18 and 11 percentage points took place. Consequently, between 25 and 27% of dolines have disappeared or have been extensively modified (filled up and leveled). According to the local spatial plans, an additional 18% to 28% dolines are endangered. Broad human induced changes in the karst landscape have resulted in a noticeable increase in landscape deterioration, which is consistent with similar phenomena observed in other regions. Due to the extreme susceptibility of the karst to human activities that may lead to the degradation of its exceptional aesthetic and environmental value, the alteration of karst processes such as corrosion, endangering of unique habitats and the quality of non-renewable natural resources, it is necessary to promptly define measures for its protection at the national level.

Gypsum dissolves relatively quickly and gypsum karst can evolve on a rapid time scale that may be accelerated by human induced change, often resulting in severe subsidence damage. The area close to Inandık stream in Central Anato-lia, Turkey, is affected by subsidence in two ways: formation of collapse sinkholes on agricultural land and progressive subsidence in Inandık village that has damaged buildings. This study focuses on these subsidence phenomena. Seven large sinkholes were formed on a terrace where episodic incision of the fluvial system has led to reduced thickness and mechanical strength of the cavity roof; a process that also increases the hydraulic gradient and enhances cavity development in the terrace area. These processes formed a sinkhole-prone terrace surface. The other subsidence phenomena, which have increased progressively in the last decade, relate to human activity in Inandık village. Water consumption increased after domestic water service systems were installed in houses in 2007, and in 2012 a sewer system was built in the village. Due to cracks and breakage, leaking water from buildings and sewer pipes infiltrated the gypsum substratum, resulting in dissolution of the bedrock and superficial cavity formation, as shown by GPR and borehole data. The process leading to subsidence caused severe damage to buildings. Consequently, it was decided to relocate the village three km south of its current location because of the high level of damage.

Collapse dolines are closed karst depressions of various size and morphology, which can be found all over the Slovenian karst. A collapse of cave chamber roofs is the basic mechanism of their formation. Limited dimensions of cave chambers result only in the formation of small collapse dolines. The formation and allocation of collapse dolines of greater dimensions are closely related to specific underground hydrology in areas with concentrated underground water flow, water table oscillation and higher corrosion or erosion in cave passages. The analysis of collapse dolines morphology and the interpretation of processes lead to the understanding of dynamics and mechanisms of collapse dolines formation and transformation with various geomorphic processes. The dissertation introduces the new models of processes in collapse dolines, which can be used for the interpretation of collapse dolines development in time context or for interpretation of mechanics and dynamics of specific geomorphologic processes.

Dolines are regularly referred as diagnostic karst landforms, as their formation is usually attributed to chemical weathering or dissolution, which is the most typical karst process. In this paper, we re-evaluate the formation of the two most typical dissolution dolines,
provided by Cvijić. Within this study, we stated that both cases, which constitute the
foundations of interpretation of dissolution dolines formation, are actually not caused by dissolution of the surface. The purpose of the article is to provide a doubt about the understanding of formation of the most common karst landform.