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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. ...

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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 hydrogen sulfide (Keyword) returned 28 results for the whole karstbase:
Showing 16 to 28 of 28
Sulfuric Acid Caves, 2012, Palmer A, Hill C.

Most caves owe their origin to carbonic acid generated in the soil. In contrast, sulfuric acid caves are produced by the oxidation of sulfides beneath the surface. Although sulfuric acid caves are relatively few, they include some large and well-known examples, such as Carlsbad Cavern, New Mexico. They also provide evidence for a variety of deep-seated processes that are important to petroleum geology, ore geology, tectonic history, and the nascent field of karst geomicrobiology.

Sulfuric acid caves: Morphology and evolution, 2013, Palmer, A. N.

Many hypogene caves are formed by sulfuric acid produced by the oxidation of sulfides, particularly hydrogen sulfide. This cave development can take place below, at, or above the water table. Most cave enlargement is subaerial, in water films and droplets that absorb gaseous hydrogen sulfide and oxygen. Sulfuric acid caves have irregular patterns with large variations in cross section and elevation, with relatively few subhorizontal passages formed along the water table. Cave origin is scattered, localized, and sporadic. Sulfuric acid caves provide evidence for regional geomorphic and tectonic history, groundwater flow patterns, and redox geochemistry.

Karst Geomorphology: Sulfur Karst Processes, 2013, Hose, L. D.

Recognition and understanding of the important role of sulfur redox processes in developing karst has grown over the last25 years with the discovery of remarkable sulfur-rich caves worldwide and advances in geomicrobiology. Recent work hasshown that microbes interact with hydrocarbons, calcium sulfate bedrock, magmatic fluids, and sulfide ore minerals toreduce gypsum/anhydrite to calcite, produce hydrogen sulfide and sulfuric acid, convert limestone to gypsum, in crease porosity in carbonate bedrocks, precipitate massive sulfur, and deposit Mississippi Valley-Type (MVT) ores. These processesare most active in the shallow phreatic and vadose-phreatic subsurface, where transitions between aerobic and anaerobicconditions exist.

Sources of water aggressiveness the driving force of karstification, 2013, 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.

Hypogene speleogenesis in Italy, 2013, Menichetti, M.

Through more than one century of speleological research in Italy, many hypogenic limestone caves have been explored, mapped and studied. These caves are characterized by a variety of patterns and morphological sizes including three-dimensional maze sys-tems and deep shafts, with both active endogenic CO2 and H2S vents.
An integrate approach taking in account geological, hydrological and geochemical set-tings permit to recognize the main hypogenic speleogenetic process. The H2S oxidation to sulfuric acid, by oxygen-rich groundwaters as well as in the atmosphere is actually the main active hypogenic cave-forming processes. Both phreatic and vadose corrosion reactions involve chemotropic microbial activity, with sulfur-redox bacterial communi-ties that generate sulfuric acid as metabolic product. The bedrock corrosion produce sulfate ions in the phreatic zone and gypsum replacement in the limestone walls of the vadose sectors of the caves. The caves are characterized by both fossil and active pas-sages in which water rich in H2S as well as endogenic CO2 plays a determinant role in speleogenesis. Although sulfuric acid-related speleogenesis typically produces gypsum deposits, in caves where the karstification processes are driven by subterranean CO2 sources, voids and speleothems are the only final products.
In Italy all the end-members of the karst processes can be found, from solution caves to outcrop of carbonate travertine. The hypogenic caves are concentrated for largest and both fossils and active systems in the Tuscany, Umbria, Marche and Latium regions (Menichetti, 2009). These consist of few tens of kilometers of solutional passages with galleries and shafts, which are characterized by large rooms, cupola and blind pits, anas-tomotic passages, bubble trails roof pendants, knife edges, and phreatic passages. Ac-tive smaller karst systems are known in Southern Italy in Apulia, Campania and Sicily, related to the geothermal anomaly associated with CO2 and H2S vents.

Marine seismic-reflection data from the southeastern Florida Platform: a case for hypogenic karst, 2013, Cunningham, Kevin J.

Recent acquisition of twenty marine seismic-reflection profiles suggests a hypogenic karst origin for the Key Biscayne sinkhole located on the seafloor of Miami Terrace at the southeastern part of Florida Platform. Analysis of the seismic-reflection data strongly suggest the submarine sinkhole was produced by dissolution and collapse of Plio(?)-Pleistocene age carbonate strata. A complex fault system that includes compres-sional reverse faults underlies the sinkhole, providing a physical system for the possible exchange of groundwater with the sinkhole. One seismic profile is suggestive of a mas-ter feeder pipe beneath the sinkhole. The feeder pipe is characterized by seismic-reflection configurations that resemble megabreccia and stratal collapse. The sinkhole is located at a depth of about 365 m below sea level. The record of sea-level change dur-ing the Plio(?)-Pleistocene and amount of subsidence of the Florida Platform during this span of time indicates that the sinkhole has always been submerged at a water depth of about 235 m or more. Thus, the near-surface epigenic karst paradigm can be ruled out. Possible hypogenic models for sinkhole formation include ascending fluids along the fault system, such as, dissolution related to the freshwater/saltwater mixing at a regional groundwater discharge site, or processes related to gases derived from gener-ation of hydrocarbons within deep Mesozoic strata. Hydrocarbon-related karstification provides several possible scenarios: (1) oxidation of deep oil-field derived hydrogen sulfide at or near the seafloor to form sulfuric acid, (2) reduction of Cretaceous or Paleocene anhydrite or both by oil-field methane to form hydrogen sulfide and later oxidation to form sulfuric acid, and (3) carbon-dioxide charged groundwater reacting to form carbonic acid. Further, anerobic microbes could form methane outside of a hy-drocarbon reservoir that ascends through anhydrite to form hydrogen sulfide and later oxidized to sulfuric acid.

Hypogene speleogenesis in Italy, 2013, Menichetti, Marco



Hypogean speleogenesis is the main cave formation process in the Frasassi area. The carbon flux represents an important proxy for the evalution of the different speleogenetic processes. The main sources of CO2 in the underground karst system are related to endogenic fluid emissions due to crustal regional degassing. Another important CO2 source is hydrogen sulfide oxidation. A small amount of CO2 is also contributed by visitors to the parts of the cave open to the public.


Karst development in Permian Castile evaporites has resulted in complex speleogenetic evolution with multiple phases of diagenetic overprinting. More than 10,000 surficial features, primarily sinkholes, occur throughout Culberson County, Texas, and Eddy County, New Mexico, based on GIS-analyses where laminated Castile sulfates crop out. Cave development is largely the result of hypogene processes, where ascending fluids from the underlying Bell Canyon Formation migrate near vertically through the Castile Formation, creating caves up to 100 meters deep and over 500 meters long, which have been breached through a combination of collapse and surface denudation. Numerous small and laterally limited epigene features occur throughout the region, as well as the anomalously large Parks Ranch Cave System with more than 6.5 kilometers of cave development and multiple large, incised, sinkhole entrances. Hypogene caves exhibit varying degrees of epigenic overprinting as a result of surficial breaching.

Water resources in the Castile Formation are directly related to karst development with extremely heterogeneous flow networks. Most springs in the region discharge sulfate-rich waters, contain high levels of hydrogen sulfide, and support sulfate-reducing bacterial colonies. Isolated stream passages in northern Culberson County provide locally significant water resources that do not exhibit elevated hydrogen sulfide concentrations. Local water tables vary greatly over the region and few caves access base-level conditions. Upward migration of hydrocarbons complicates regional hydrology and diagenesis, resulting in extensive evaporite calcitization, which greatly modifies both fluid / rock interaction and permeability structures.


In The Bahamas, caves and blue holes provide clues to the geologic and climatic history of archipelago but are now emerging as windows into the ecological and cultural past of islands. Cave environments in The Bahamas alternate cyclically between vadose and phreatic conditions with sea-level change, thereby providing unique but ephemeral fossil capture and preservation conditions.

A diverse assemblage of fossil plants and animals from Sawmill Sink, an inland blue hole on Abaco Island in the northern Bahamas, has revealed a prehistoric terrestrial ecosystem with exquisitely preserved fossil assemblages that result from an unusual depositional setting. The entrance is situated in the pine forest and opens into a flooded collapse chamber that intersects horizontal conduits at depths to 54 meters. The deepest passages are filled with sea water up to an anoxic mixing zone at depths of 14 to 9 meters and into the upper surface fresh-water layer. The collapse chamber is partially filled with a large talus pile that coincides with an anoxic halocline and direct sunlight for much of the day.

During glacioeustatic sea-level lowstands in the late Pleistocene, Sawmill Sink was a dry cave, providing roosting sites for bats and owls. Accumulations of bones deposited in depths of 25 to 30 meters were subsequently preserved by sea-level rise in the Holocene. The owl roost deposits are dominated by birds but also include numerous small vertebrate species that were actively transported by owls to the roost sites.

As sea levels rose in the Holocene, Sawmill Sink became a traditional passive pitfall trap. Significant quantities of surface derived organic material collected on the upper regions of the talus at the halocline where decaying plant material produced a dense layer of peat within an anoxic mixing zone enriched with hydrogen sulfide. Vertebrate species that drowned were entombed in the peat, where conditions inhibited large scavengers, microbial decomposition, and mechanical disarticulation, contributing to the superb preserva­tion of the fossil assemblage in the upper regions of the talus.


The carbon dioxide produced in the soil and dissolved in the percolation water is considered as the main agent for karstification in the carbonate rocks. Superficial morphologies and underground caves are product of the corrosion of the limestone, while carbonate speleothems is the other end member of the process.
Hypogene speleogenesis driven by deep seated fluids is the cave formation processes for the main karst systems in the Apennines of Italy. Hydrogen sulfide and endogenic carbon dioxide are the main agents for underground karst corrosion and the soil carbon dioxide plays a secondary rule. The limestone corrosion driven by hydrogen sulfide produces gypsum deposits in caves that could be assumed as the indicator of the hypogene speleogenesis. The action of endogenic carbon dioxide in the cave formation, especially if it operates at lower temperature, is not easy to detect and the resulting cave morphology is not helpful to recognize the cave formation process.
The main sources of carbon dioxide in the underground karst system in the Apennines of Italy can be related to different processes driven by the endogenic fluids emissions. The crustal regional degassing seems to be the prevalent source for carbon dioxide in the karst massifs with the main release in the groundwater. Hydrogen sulfide and methane oxidation, possibly mediated by bacteria activity, are other sources in the buried Cenozoic sediments. Releasing of carbon dioxide along the faults and in the fractures occurring in the carbonate rocks is an important source, especially in the seismically active area. Finally, thermogenic reactions with carbonate rocks are well known as one of the main production mechanism of carbon dioxide released in the atmosphere.
Data from carbon dioxide monitoring in several caves show a relevant contribution of the endogenic carbon dioxide (about 75 %) in the karst system which drives the speleogenesis reactions and shapes the underground morphologies.


Conspicuous brackish sulfidic springs have been described at the northern Sierra the Chiapas, Mexico. These springs are produced by a mixture between regional and local groundwater flow paths. The regional groundwater has an average Total Dissolved Ions of 3081 mg/L so it has a brackish composition. This brackish water is saturated with respect to calcite and dolomite but undersaturated with respect to gypsum, anhydrite and halite. The mass balance and the discharge rate are used to quantify the mass and volume of minerals that are dissolved by the brackish spring water following Appelo and Postma (1993). This quantification will allow comparing the various speleogenetic mechanisms in the area. This is considering the composition of the spring water is relatively constant over time, as it is suggested by periodic measurements at the Cueva de Villa Luz springs during the last 10 years.
Sulfur isotopes in the water are consistent with anhydrite dissolution as the main source of the sulfate to the brackish spring water. Thus, the average 6 mol/L of sulfate in the brackish springs are produced by dissolution of 6 mol of anhydrite after subtracting the sulfate that could result from evapotranspiration of rainwater. Each liter of brackish water dissolved an average of 882 mg of anhydrite, which are equivalent to dissolving 0.36 cm3 of this mineral considering a density of 2.981 g/cm3. Additionally, using the average brackish water discharge rate of 144 L/s, an average of 57 g of anhydrite are being dissolved each second per every liter of brackish water. This is a minimal value because some of the sulfate in the water is used by sulfate-reducing bacteria in the subsurface to produce the hydrogen sulfide in the spring water. The anhydrite subject to dissolution is found interbedded in the Cretaceous carbonates, either from the subsurface at 4,000 m below sea level to the carbonate outcrops.
Similarly, we can calculate the volume of halite that is being dissolved by the brackish springs, considering chloride is a conservative element and subtracting the chloride concentration from the rainwater from that of the spring water following Appelo & Postma (1993). The 22 mol/L of chloride in the brackish water can result from dissolution in the subsurface of 22 moles or 1.3 g of halite per liter of brackish water. This mass of halite dissolved is equal to 0.59 cm3 considering a density of 2.168 g/cm3. Alternatively, 118 g of halite are dissolved per second per each liter of brackish water if we use the average discharge rate of 144 L/s.
Even when the brackish springs are oversaturated with respect to calcite and dolomite, their dissolution is still possible due to the common ion-effect of calcium after anhydrite dissolution and by mixing of waters with different compositions. A range of 10 to 80 % of brackish water from the regional aquifers mixes with fresh water from the local aquifer based on their water chemistry. Additionally, sulfuric acid speleogenesis occurs due to the oxidation of hydrogen sulfide to sulfuric acid.
Finally, the increase in the chloride concentration of the fresh water springs with respect to the concentration in rainwater was used to estimate that from the 4000 mm/y of annual precipitation, only 4%, 158 to 182 mm/y, recharge the aquifers. This low percentage is slightly higher than the 3.3% recharge in marls, marly limestone, silts and clays (Sanz et al., 2011), probably because of the relatively small area of carbonate outcrops over the entire region and the lack of recharge in altitudes higher than 1500 m above sea level.
Sulfuric acid is the most obvious speleogenetic mechanism occurring in the caves of the northern Sierra de Chiapas, Mexico due to the high hydrogen sulfide concentration in the spring water. In addition, the location of the springs at a zone of regional and local discharge where waters from different composition converge and mix, and the amount of mixing calculated suggests mixing is also an important speleogenetic mechanism. However, the depth and the time constrains at which these two hypogenic mechanisms occur is still unknown. The relatively low rainwater recharge rate suggests epigenesis is limited. Most likely, the porosity created by dissolution of anhydrite and halite in the subsurface is occluded by the precipitation of calcite. Chemical modeling and petrography will help to elucidate the order of the reactions occurring in the subsurface.

Hydrogeology of northern Sierra de Chiapas, Mexico: A conceptual model based on a geochemical characterization of sulfide-rich karst brackish springs, 2014,

Conspicuous sulfide-rich karst springs flow from Cretaceous carbonates in northern Sierra de Chiapas, Mexico. This is a geologically complex, tropical karst area. The physical, geologic, hydrologic and chemical attributes of these springs were determined and integrated into a conceptual hydrogeologic model. A meteoric source and a recharge elevation below 1500 m are estimated from the spring water isotopic signature regardless of their chemical composition. Brackish spring water flows at a maximum depth of 2000 m, as inferred from similar chemical attributes to the produced water from a nearby oil well. Oil reservoirs may be found at depths below 2000 m. Three subsurface environments or aquifers are identified based on the B, Li+, K+ and SiO2 concentrations, spring water temperatures, and CO2 pressures. There is mixing between these aquifers. The aquifer designated Local is shallow and contains potable water vulnerable to pollution. The aquifer named Northern receives some brackish produced water. The composition of the Southern aquifer is influenced by halite dissolution enhanced at fault detachment surfaces. Epigenic speleogenesis is associated with the Local springs. In contrast, hypogenic speleogenesis is associated with the brackish sulfidic springs from the Northern and the Southern environments.

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