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Enviroscan Ukrainian Institute of Speleology and Karstology

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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That closed traverse is a traverse which begins and ends at survey points with known co-ordinates and orientation or at the same point [25].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

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What is Karstbase?



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KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for acidity (Keyword) returned 9 results for the whole karstbase:
Geomicrobiology of caves: A review, 2001,
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Northup D. E. , Lavoie K. H. ,
In this article, we provide a review of geomicrobiological interactions in caves, which are nutrient-limited environments containing a variety of redox interfaces. Interactions of cave microorganisms and mineral environments lead to the dissolution of, or precipitation on, host rock and speleothems (secondary mineral formations). Metabolic processes of sulfur-, iron-, and manganese-oxidizing bacteria can generate considerable acidity, dissolving cave walls and formations. Examples of possible microbially influenced corrosion include corrosion residues (e.g., Lechuguilla and Spider caves, New Mexico, USA), moonmilk from a number of caves (e.g., Spider Cave, New Mexico, and caves in the Italian Alps), and sulfuric acid speleogenesis and cave enlargement (e.g., Movile Cave, Romania, and Cueva de Villa Luz, Mexico). Precipitation processes in caves, as in surface environments, occur through active or passive processes. In caves, microbially induced mineralization is documented in the formation of carbonates, moonmilk, silicates, clays, iron and manganese oxides, sulfur, and saltpeter at scales ranging from the microscopic to landscape biokarst. Suggestions for future research are given to encourage a move from descriptive, qualitative studies to more experimental studies

The processes dominating Ca dissolution of limestone when exposed to ambient atmospheric conditions as determined by comparing dissolution models, 2002,
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Cardellfernandez C, Vleugels G, Torfs K, Van Grieken R,
In order to gain a clearer understanding of the decay mechanisms operating in limestones, and to determine the main damage factors at different exposure environments, calcite-dissolution models from the literature were compared. The models recognise three major stone decay mechanisms: attack by air pollutants (dry deposition), dissolution in clean rain (karst effect) and dissolution caused by neutralisation of rain acidity (acidity effect), These models were fitted to experimental data obtained from the run-off water analysis running over the so-called Massangis limestone, exposed under ambient conditions in five sites in Belgium. The models demonstrate that different processes dominate the limestone dissolution at the different sites, with dry deposition of air pollutants (especially SO2) being the principal process involved

The influence of bedrock-derived acidity in the development of surface and underground karst: Evidence from the Precambrian carbonates of semi-arid northeastern Brazil, 2003,
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Auler As, Smart Pl,
Very extensive cave systems are developed in Precambrian Una Group carbonates in the Campo Formoso area, eastern Brazil. In contrast, the area is largely devoid of significant surface karst landforms, as would be expected given its semi-arid climate. The caves in the area display many morphological features characteristic of deep-seated hypogenic caves, such as lack of relationship with the surface, ramiform/network pattern, abrupt variations of passage cross-sections and absence of fluvial sediments, but do not show evidence of vertical passages marking the ascending path of acidic water nor present extensive gypsum or acid clay mineral deposits. Hydrochemical analyses of present-day ground water indicate that oxidation of bedrock sulphide is an active process, and sulphuric acid may be the main agent driving carbonate dissolution in the area. A shallow mode of speleogenesis is thus proposed, in which sulphuric acid produced through the oxidation of sulphide beds within the carbonates controls cave initiation and development. Moreover, the geological situation of the area in an ancient stable passive margin precludes the possibility of deep-seated sources of acidity. Under dry climate, due to the absence of recharge, solutional landforms will be largely subdued in the surface. Hypogenic processes, if present, are likely to predominate, producing a landscape characterized by a marked disparity in the comparative degree of development between surface and underground landforms. Rates of karst landform development have traditionally been analysed through a climatic perspective, runoff being the main controlling factor in promoting karst development. This view needs to be reassessed in the light of the growing awareness of the importance of climate-independent processes related to hypogenic sources of acidity.

The nature and distribution of flowing features in a weakly karstified porous limestone aquifer, 2012,
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Maurice L. D. , Atkinson T. C. , Barker J. A. , Williams A. T. , Gallagher A. J.

The nature and distribution of flowing features in boreholes in an area of approximately 400 km2 in a weakly karstic porous limestone aquifer (the Chalk) was investigated using single borehole dilution tests (SBDTs) and borehole imaging. One-hundred and twenty flowing features identified from SBDTs in 24 boreholes have densities which decrease from _0.3 m_1 near the water table to _0.07 m_1 at depths of more than 40 m below the water table; the average density is 0.20 m_1. There is some evidence of regional lithological control and borehole imaging of three boreholes indicated that most flowing features are associated with marls, hardgrounds and flints that may be developed at a more local scale. Borehole imaging also demonstrated that many flowing features are solutionally enlarged fractures, suggesting that even in carbonate aquifers where surface karst is developed on only a small scale, groundwater flow is still strongly influenced by dissolution. Fully connected solutional pathways can occur over 100s, sometimes 1000s of metres. However, conduits, tubules and fissures may not always be individually persistent along a flowpath, instead being connected together and also connected to unmodified fractures to create a relatively dense network of voids with variable apertures (<0.1 cm to >15 cm). Groundwater therefore moves along flowpaths made up of voids with varying shape and character. Local solutional development of fractures at significant depths below the surface suggests that mixing corrosion and in situ sources of acidity may contribute to solutional enhancement of fractures. The study demonstrates that single borehole dilution testing is a useful method of obtaining a large dataset of flowing features at catchment-regional scales. The Chalk is a carbonate aquifer with smallscale surface karst development and this study raises the question of whether other carbonate aquifers with small-scale surface karst have similar characteristics, and what hydrological role small-scale dissolutional features play in highly karstic aquifers.

Sources of water aggressiveness the driving force of karstification, 2013,
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Auler, A. S.

Chemically aggressive water is needed in order to promote bedrock dissolution and karstification. Aggressiveness is generated through a number of processes that include acids from the atmosphere and soil zone (epigenic acids) and from deep-seated mechanisms (hypogenic acids). Carbon dioxide and hydrogen sulfide are the main players, although additional acidity may be provided by processes that involve mixing of solutions with different degrees of saturation, temperature effects, and microbiological agents. Rainfall will generally have an acid pH due to natural CO2 and mostly anthropogenic gases such as H2S in the atmosphere. The soil zone will further boost acidity levels due to abundant CO2 production in the root and plant horizons. Although the buffering capacity of the carbonate will cause groundwater to quickly achieve saturation, mixing corrosion effects may rejuvenate aggressiveness in situations where waters of different chemistry are in contact. Bacterially mediated processes will both enhance and mediate processes of acid generation and dissolution. Mixing zones between fresh and salt water and between oxygen-rich groundwater (mostly epigenic) and rising thermal water will be important zones where increased levels of acidity will accelerate cave formation. The degree and effectiveness of aggressiveness will depend on a number of variables, such as the geological setting, solubility of the rock, position of the bedrock, and climate, sometimes operating together at various scales and strengths.

Environmental controls on organic matter production and transport across surface-subsurface and geochemical boundaries in the Edwards aquifer, Texas, USA, 2013,
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Hutchins Benjamin T. , Schwartz Benjamin F. , Engel Annette S.

Karst aquifer phreatic zones are energy limited habitats supported by organic matter (OM) flow across physical and geochemical boundaries. Photosynthetic OM enters the Edwards Aquifer of Central Texas via streams sinking along its northeastern border. The southeastern boundary is marked by a rapid transition between oxygenated freshwaters and anoxic saline waters where OM is likely produced by chemolithoautotrophic microbes. Spatial and temporal heterogeneity in OM composition at these boundaries was investigated using isotopic and geochemical analyses. δ13C values for stream fine particulate OM (FPOM) (−33.34‰ to −11.47‰) decreased during regional drought between fall 2010 and spring 2012 (p<0.001), and were positively related to FPOM C:N ratios (r2 =0.47, p<0.001), possibly due to an increasing contribution of periphyton. Along the freshwater-saline water interface (FwSwI), δ 13CFPOM values (−7.23‰ to −58.18‰) correlated to δ13C values for dissolved inorganic carbon (δ13C DIC) (−0.55‰ to −7.91‰) (r2 =0.33, p=0.005) and were depleted relative to δ13C DIC values by 28.44‰, similar to fractionation values attributed to chemolithoautotrophic carbon fixation pathways using DIC as the substrate. δ13CFPOM values also became enriched through time (p<0.001), and δ13C DIC values (r2 =0.43, p<0.001) and δ13CFPOM values (r2 =0.35, p=0.004) at FwSwI sites increased with distance along the southwest-northeast flowpath of the aquifer. Spatial variability in FwSwI δ13C DIC values is likely due to variable sources of acidity driving carbonate dissolution, and the temporal relationship is explained by changes to recharge and aquifer level that affected transport of chemolithoautotrophic OM across the FwSwI.

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Borges S. , Casarin C. , Menezes C. , Srivastava N. , Silva R. , Bezerra F. , Auler A.

The Toca da Boa Vista and Barriguda caves are located in Northeastern Brazil. They occur in the Neoproterozoic carbonates (limestones and dolomites) of the Salitre Formation, located at Irecê Basin. This set of rocks occurs within the São Francisco Craton, a region that was not affected by the Brasiliano-Pan-African orogeny (Pedreira et al., 1987). The caves occur at a dis­tance of approximately 300 m apart and there is a possibility of a link between them, but so far this has not been proven. Toca da Boa Vista has about 108 km of mapped passages and is therefore the largest cave in South America. Toca da Barriguda is smaller and has about 32 km of mapped galleries.

The architecture of the Toca da Boa Vista and Barriguda caves present both a 2D network and spongework type (Auler, 2009). The control of the conduits is related to faults, fractures and axial planes of antiforms. The general configuration of the caves seems to follow the Pacuí riverbed that has its channel located about 1km southeast. The origin of these hypogenic caves was first postulated by Auler & Smart (2004), who described some hypogenic features and reported a acid source (H2S) coming from existing pyrite in carbonates to explain the corrosion and dissolution of carbonate rocks. Klimchouk (2009) wrote about the need to investigate deeper this issue. He drew attention to the apparent feeders presence coming from the lower aquifer as well as to the importance of determi­nation of the source of acidity, since the amount of pyrite present doesn’t seem to be significant for the origin and development of the caves by hypogenic speleogenesis.

Although the origin and development of the caves are still under discussion, abundant hypogenic forms are present. Feeders, rising wall channels, half ceiling tubes, half wall tubes, ceiling cupolas, convection cupolas and wall niches are the major forms found. The linear geometry of caves suggests that they have a structural control. In addition, cavities generated at Toca da Boa Vista and Barriguda caves seem to follow the same stratigraphic level, as well as existing permeable structures such as fractures, faults and axial planes of antiforms. The process of ascending flow through these structures has resulted in the opening of the cavities by hypogenic dissolution as well as the collapse of blocks caused by the lack of sustainability of the layers generated by the voids left by the dis­solution. Outlets that would flow to levels above were not found. The origin and evolution of the cave system, however, needs further investigation.

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Galdenzi S. , Jones D. , Macalady J.

The condensation of acidic waters on subaerial carbonate surfaces (condensation corrosion) can be an important speleogenetic agent under certain conditions (Cigna and Forti, 1986; Sarbu and Lascu, 1997). Specific morphologies associated with condensation corrosion include notches, niches, cupolas, megascallops and domes (Audra, 2009), and have been recognized in many caves from different regions of the world and from different geologic settings. Condensation corrosion can be particularly important in thermal caves, where temperature differences facilitate air convection and water condensation, as well as in sulphidic caves, where degassing and subsequent oxidation of hydrogen sulphide (H2S) gas provides a ready source of acidity to the subaerial cave environment.
In pioneering studies on the formation of sulphidic caves, condensation corrosion via H2S degassing and oxidation to sulphuric acid was considered the primary mechanism for speleogenesis (Principi, 1931; Egemeier, 1981). However, recent research has cast doubt on the importance of subaerial H2S oxidation for sulphidic cave formation (Engel et al., 2004). In the Frasassi cave system, Italy, morphological evidence for both subaerial and subaqueous limestone dissolution has been extensively documented (Galdenzi, 1990; Galdenzi and Maruoka, 2003). In particular, corrosion above the water table has resulted in the formation of massive gypsum deposits as well as specific passage morphologies. Measured rates by Galdenzi et al. (1997) corroborated morphological evidence that condensation corrosion is important at least under certain conditions. Therefore, in order to better define the role of subaerial processes in the Frasassi cave system, we quantified sulphide flux to the cave atmosphere in the modern cave environment, and documented morphological evidence for subaerial corrosion in the past

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Onac, B. P.

The classical epigene speleogenetic model in which CO2 is considered the main source of acidity has been challenged over the last three decades by observations that revealed cave passages unrelated to groundwater drainage routes and surface topography. Most of these passages show unusual morphologies, such are cupolas, floor feeders (i.e., inlets for deep-seated fluids), and huge irregular-shaped rooms that terminate abruptly, and often a rich and diverse mineral association. A hypogenetic speleogenetic pathway was proposed for this group of caves.
The presence of abundant gypsum deposits in caves with one or more of the passage morphologies listed above, have prompted scientists to suggest a new theory (i.e., sulfuric acid speleogenesis, SAS) of cave development. In the hypogenic SAS model, the source of acidity is the sulfuric acid produced by oxidation of H2S (originating from sulfate reduction or petroleum reservoirs) near or at the water table, where it dissolves the limestone bedrock and precipitates extensive gypsum deposits. SAS is now thoroughly documented from numerous caves around the world, with the best examples coming from the Guadalupe Mountains (NM), Frasassi caves (Italy), selected caves in France, Cueva de Villa Luz (Mexico), and Cerna Valley (SW Romania).
To date, discrimination between epigene and hypogene speleogenetic pathways is made using cave morphology criteria, exotic mineral assemblages, and the predominantly negative δ34S values for the cave sulfates. This presentation highlights the role sulfur and oxygen stable isotope analyses have in discriminating between epigene and hypogene caves.
Based on a number of case studies in caves of the Cerna Valley (Romania), we found that relatively S-depleted isotopic composition of cave minerals alone does not provide enough information to clearly distinguish SAS from other complex speleogenetic pathways. In fact, δ34S values of SAS by-products depend not only on the source of the S, but also on the completeness of S redox reactions. Therefore, similar studies to this are needed to precisely diagnose SAS and to provide information on the S cycle in a given karst system.
Integrating cave mineralogy, passage morphology, and geochemical studies may shed light on the interpretation of polygenetic caves, offering clues to processes, mechanisms, and parameters involved in their genesis (sulfate-dominated).

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