MWH Global

Enviroscan Ukrainian Institute of Speleology and Karstology


Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/template/toolbar_left.php on line 5
Community news

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 critical depth is the depth of flow in open channels when specific energy is minimum [16].?

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


Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/template/toolbar_right.php on line 7
What is Karstbase?

Search KARSTBASE:

keyword
author

Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
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;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for groundwater (Keyword) returned 958 results for the whole karstbase:
Showing 916 to 930 of 958
Isotopes of Carbon in a Karst Aquifer of the Cumberland Plateau of Kentucky, USA, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Florea Lee J.

In this study, the concentration and isotopic composition of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are measured in the karst groundwater of the Otter Creek watershed of the Cumberland Plateau of Kentucky, USA. Comparisons among these data and with the geochemistry of carbonate and gypsum equilibrium reactions reveal that DOC concentration is inversely related to discharge, multiple reaction pathways provide DIC with isotopic enrichment that may be directly related to mineral saturation, and oxidation of reduced sulfur is possible for dissolution. DOC is derived from C3 vegetation with an average δ13C DOC of ‒27‰. DIC in groundwater is derived from both pedogenic CO2  and HCO3 - from dissolved carbonate. At input sites to the karst aquifers DIC concentrations are expectedly low, less than 1 mmol/L, in waters that are undersaturated with respect to calcite. At the output of these karst aquifers DIC concentrations reach 3 mmol/L in waters that are at or above calcite saturation. Values of δ13C DIC range between ‒6.3 and ‒12.4‰ with CO2 degassing and calcite precipitation at some sites obfuscating a simple relationship between δ13C DIC, discharge, and mineral saturation. In addition, concentrations of DIC in sulfur seeps within the watershed range between 2–7 mmol/L with δ13C DIC values in some samples skewed more toward the anticipated value of carbonate bedrock than would be expected from reactions with carbonic acid alone. This suggests that the oxidation of reduced sulfur from shallow oilfield brines liberates bedrock DIC through reactions with sulfuric acid.


Interpretation of hydrogeological functioning of a high karst plateau using the KARSYS approach: the case of Trnovsko-Banjška planota (Slovenia), 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Turk Janez, Malard Arnauld, Jeannin Pierreyves, Vouillamoz Jonathan, Masini Jean, Petrič Metka, Gabrovšek Franci, Ravbar Nataša, Slabe Tadej

The high karst plateau of Trnovsko­Banjška planota is one of the most important reservoirs of karst water in Slovenia. Almost all important karst springs in this area are captured for water supply. A sustainable management of this source of groundwater is of strategic importance, not only as drinking water supply but also for the economy. For these reasons, many hydrogeological monitoring studies have been carried out over the last decades. However, no consistent regional overview of the hydrogeological functioning of Trnovsko­Banjška planota was available and we decided to study this area with more direct approach based on 3D geological and hydrogeological models. The so called KARSyS approach was developed in Switzerland and applied primarily to characterize groundwater reserves within a karst massif, and to sketch the main flow­paths carrying groundwater from recharge areas to the respective springs. The delineation of spring catchment areas in karst regions was better defined and interactions between catchments were interpreted. These results can be used to improve the management of karst waters in the studied area.


Hydrodynamic modeling of a complex karst-alluvial aquifer: case study of Prijedor Groundwater Source, Republic of Srpska, Bosnia and Herzegovina, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Polomčić Dušan, Dragišić Veselin, Živanović Vladimir

Middle Triassic fractured and karstified limestone and dolomite form a karst aquifer in the Sana River Valley near the town of Prijedor. As a result of intensive tectonic movements, carbonate rocks are mostly below the Sana River level, covered by younger Pliocene and alluvial deposits. The main source of groundwater recharge is infiltration from the Sana River through its alluvium over most of the aquifer. The main objective of the research reported in this paper was to evaluate the hydraulic relationships of the alluvial, Pliocene and karst aquifers in order to better understand the water supply potential of the karst aquifer. Although the use of hydrodynamic modeling is not very common with karst aquifers, the developed model provided significant and useful information on the groundwater budget and recharge type. The influence of fault zones and spatial anisotropy of the karst aquifer were simulated on the hydrodynamic model by varying permeability on the xand y­axes of the Cartesian coordinate system with respect to the fault, the main pathway of groundwater circulation. Representative hydraulic conductivities were Kx

 = 2.3·10­3

 m/s and Ky

 = 5.0·10­3

 m/s in the faults of Nw to SE direction, and Kx

 = 2.5·10­3

 m/s and Ky

 1.2·10­3

 m/s in the faults of Sw to NE trend. Model research showed that the karst aquifer can be used in the long term at maximal tested capacities and that current groundwater exploitation is not compromised in dry periods when the water budget depends entirely on recharge from the Sana River.


Karst aquifer average catchment area assessment through monthly water balance equation with limited meteorological data set: Application to Grza spring in Eastern Serbia, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Vakanjac Vesna Ristić, Prohaska Stevan, Dušan Polomčić, Blagojević Borislava, Vakanjac Boris

In the absence of detailed exploration of karstic catchments, the calculation of available reserves and elements of the water balance equation frequently reflect the topographic size of the catchment area, and not the actual, active (underground) size. The two differ largely where karst is concerned. The paper deals with the problem of average catchment area size estimation in the situation when meteorological data are limited to precipitation and temperature, but discharge records are available for long period. Proposed methodology was applied to, calibrated, and validated on 15 karst springs in Serbia. Results obtained with the model differ up to 20% from hydrogeological exploration results. One of investigated springs is Grza karst spring, which belongs to the karstic formation of Kučaj and Beljanica (the Carpatho­Balkanide Arch of Eastern Serbia). In this paper, we used the Grza Spring to show model application and necessary improvements to progress from graphoanalytical to analytical model. The average catchment area is linked to the model parameter that reduces potential to real evapotranspiration on monthly bases. The model potential lies in the possibility to determine not only catchment area, but real evapotranspiration and dynamic volume of the porous ­ karst groundwater storage as well.


Biological Control on Acid Generation at the Conduit-Bedrock Boundary in Submerged Caves: Quantification through Geochemical Modeling, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Herman Janet S. , Hounshell Alexandria G. , Franklin Rima B, Mills Aaron L.

No-mount Cave, located in wekiwa Springs State Park in central Florida, USA, is an aphotic, submerged, freshwater cave in which large colonies of sulfur-oxidizing bacteria live in filamentous microbial mats. Upwardly discharging groundwater enters the cave from the Upper Floridan aquifer, specifically the Eocene-aged Ocala Limestone. we undertook a combined field, laboratory, and modeling study in which we sought to determine the amount of calcite dissolution attributable to the generation of protons by microbially mediated sulfide oxidation. The chemical compositions of groundwater within the limestone formation collected through a newly designed sampling device and of water in the cave conduit were used in geochemical modeling. we used the reaction-path model PHREEqCI to quantify the amount of calcite dissolution expected under various plausible scenarios for mixing of formation water with conduit water and extent of bacterial sulfide oxidation. Laboratory experiments were conducted using flow-through columns packed with crushed limestone from the study site. Replicate columns were eluted with artificial groundwater containing dissolved HS- in the absence of microbial growth. without biologically mediated sulfide oxidation, no measurable calcite dissolution occurred in laboratory experiments and no additional amount of speleogenesis is expected as formation water mixes with conduit water in the field. In contrast, significant calcite dissolution is driven by the protons released in the biological transformation of the aqueous sulfur species. Although a range of results were calculated, a plausible amount of 158 mg Ca2+ released to conduit water per liter of groundwater crossing the formation-conduit boundary and mixing with an equal volume of conduit water was predicted. Our modeling results indicate that significant cave development can be driven by microbially mediated sulfide oxidation under these hydrogeochemical conditions


An approach for collection of nearfield groundwater samples in submerged limestone caverns, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Mills Aaron L. , Tysall Terrence N. , Herman Janet S.

Walls of submerged caves feeding Florida springs are often lined with a heavy mat of filamentous bacteria, many of which are able to oxidize reduced sulfur in groundwater migrating from the porous bedrock into the cave conduit. To determine changes in water chemistry as water passes through the microbial mat, a simple device made from standard well screen and sealed with a rubber stopper and controllable vents was installed in a hole drilled in the wall of the cave passage. The sampler was sealed in place with marine epoxy. we measured anions in water from the sampler and from the water-filled conduit taken just outside the sampler. Most anions measured viz., Cl, NO3, and PO43−, increased slightly between the matrix and conduit waters. However, traces of sulfide were measured in the water from the rock matrix, but not in the conduit. SO4 2−concentrations in the conduit were about twice that measured in the water from the sampler, about 22 and 11 mg SO42− L−1, respectively, providing further evidence that sulfur oxidation is an important process in the bacterial mats attached to the limestone surfaces in these caves. An additional use of the sampling device is to measure discharge from the local bedrock into the cave conduit.


Variability of groundwater flow and transport processes in karst under different hydrologic conditions, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Ravbar, Nataša

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.


Flow characterization in the Santee Cave system in the Chapel Branch Creek watershed, upper coastal plain of South Carolina, USA., 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Edwards A. E. , Amatya D. M. , Williams T. M. , Hitchcock D. R. , James A. L.

Karst watersheds possess both diffuse and conduit flow and varying degrees of connectivity between surface and groundwater over spatial scales that result in complex hydrology and contaminant transport processes. The flow regime and surface-groundwater connection must be properly identified and characterized to improve management in karst watersheds with impaired water bodies, such as the Chapel Branch Creek (CBC), South Carolina watershed, which has a long-term sampling station presently listed on an EPA 303(d) list for phosphorous, pH, and nitrogen. Water from the carbonate limestone aquifer of the Santee Cave system and spring seeps in the CBC watershed were monitored to characterize dominant flow type and surface-groundwater connection by measuring dissolved calcium and magnesium, total suspended solids, volatile suspended solids, alkalinity, pH, specific conductance, and stable isotopes (d18O, d2H). These measurements indicated that the conduit flow to Santee Cave spring was recharged predominantly from diffuse flow, with a slow response of surface water infiltration to the conduit. Qualitative dye traces and stage elevation at Santee Cave spring and the adjacent Lake Marion (equal to the elevation of the flooded portion of CBC) also indicated a relation between fluctuating base level of the CBC reservoir-like embayment and elevation of the Santee Limestone karst aquifer at the spring. Methods described herein to characterize the flow type and surface-groundwater connection in the Santee Cave system can be applied not only to watershed management in the Chapel Branch Creek watershed, but also to the greater region where this carbonate limestone aquifer exists. 


Early-stage hypogene karstification in a mountain hydrologic system: A coupled thermohydrochemical model incorporating buoyant convection, 2013,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Chaudhuri A. , Rajaram H. , Viswanathan H

The early stage of hypogene karstification is investigated using a coupled thermohydrochemical model of a mountain hydrologic system, in which water enters along a water table and descends to significant depth (_1 km) before ascending through a central high-permeability fracture. The model incorporates reactive alteration driven by dissolution/ precipitation of limestone in a carbonic acid system, due to both temperature- and pressuredependent solubility, and kinetics. Simulations were carried out for homogeneous and heterogeneous initial fracture aperture fields, using the FEHM (Finite Element Heat and Mass Transfer) code. Initially, retrograde solubility is the dominant mechanism of fracture aperture growth. As the fracture transmissivity increases, a critical Rayleigh number value is exceeded at some stage. Buoyant convection is then initiated and controls the evolution of the system thereafter. For an initially homogeneous fracture aperture field, deep well-organized buoyant convection rolls form. For initially heterogeneous aperture fields, preferential flow suppresses large buoyant convection rolls, although a large number of smaller rolls form. Even after the onset of buoyant convection, dissolution in the fracture is sustained along upward flow paths by retrograde solubility and by additional ‘‘mixing corrosion’’ effects closer to the surface. Aperture growth patterns in the fracture are very different from those observed in simulations of epigenic karst systems, and retain imprints of both buoyant convection and preferential flow. Both retrograde solubility and buoyant convection contribute to these differences. The paper demonstrates the potential value of coupled models as tools for understanding the evolution and behavior of hypogene karst systems.


EARTH TIDE, A POTENTIAL DRIVER FOR HYPOGENIC FLUID FLOW: OBSERVATIONS FROM A SUBMARINE CAVE IN SW TURKEY, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Bayari C. S. , Ozyurt N. N.

Initiation and development of karstification requires a con­tinuous flushing of pore water in equilibrium with carbon­ate minerals. Under confined flow conditions, the energy required for pore water transport is supplied by external pressure sources in addition to the by earth’s gravity. Earth tides and water loads over the confined flow system are the main sources of ex­ternal pressure that drives the pore water. Earth tides, created by the sum of the horizontal components of tide generation forces of moon and sun, causes expansion and contraction of the crust in horizontal direction. Water load on top of the confined flow system causes vertical loading/unloading and may be in the form of recharge load or ocean loading in the inland and sub-oceanic settings, respectively. Increasing and decreasing tide generating force results in pore water transport in the confined system by means of contraction and expansion, respectively. Since these forces operate in perpendicular directions, pore water flushing by earth tides becomes less effective when water load on top of the confined flow system increases. Temporal variation of fresh­water content in a submarine cave is presented as an example of groundwater discharge driven by earth tides and recharge load.


MORPHOLOGICAL EFFECTS OF CONDENSATION-CORROSION SPELEOGENESIS AT DEVILS HOLE RIDGE, NEVADA, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Dublyansky Y. , Spötl C.

The Devils Hole Ridge, a small block of Paleozoic carbonate rocks surrounded by the Amargosa Desert in southern Nevada, is located at the discharge end of the Ash Meadows regional groundwater flow system.
Continuous, long-term presence of slightly thermal (33.6°C) groundwater and the extensional tectonic setting, creating underground thermal lakes in open fractures, lead to intense dissolution above the water table. The morphology of the subaerial parts of the tectonic caves was slightly modified by condensation corrosion, and the Devils Hole Prospect Cave was almost entirely created by condensation corrosion. Caves and cavities in the Devils Hole Ridge are an interesting example of a hypogene speleogenesis by mechanism by condensation corrosion, operating above an aquifer which was demonstrably supersaturated with respect to calcite for hundreds of thousands of years.


HOW DEEP IS HYPOGENE? GYPSUM CAVES IN THE SOUTH HARZ, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Kempe, S.

Germany currently features 20 caves in sulfate rocks (gypsum and anhydrite) longer than 200 m. Most of them occur either in the Werra-Anhydrite or in the Hauptanhydrite of the evaporitic Zechstein series (Upper Permian). One occurs in the Jurassic Münder Mergel and two in the Triassic Grundgips. The longest, the Wimmelburger Schlotten, is 2.8 km long with a floor area of 24,000 m2. All caves, except four, occur in the South Harz, where the Zechstein outcrop fringes the uplifted and tilted Variscian Harz. These caves can be divided into three general classes: (i) epigenic caves with lateral, turbulent water flow, and (ii) shallow or (iii) deep phreatic caves with slow convective density-driven dissolution. The latter were discovered during historic copper-shale mining and called “Schlotten” by the miners; most of them are not accessible any more. Shallow phreatic caves occur in several areas, most notably in the Nature Preserve of the Hainholz/Beierstein at Düna/Osterode/Lower Saxony. Here, we sampled all water bodies in May 1973 and monitored 31 stations between Nov. 23rd, 1974, and April 24th, 1976, with a total 933 samples, allowing us to characterize the provenance of these waters. These monitoring results were published only partially (PCO2 data, see Kempe, 1992). Here, I use the data set to show that the Jettenhöhle (the largest cave in the Hainholz) has been created by upward moving, carbonate-bearing, groundwater of high PCO2. Even though the cave has now only small cave ponds and essentially is a dry cave above the ground water level, it is a hypogene cave because of the upward movement “of the cave-forming agent” (sensu Klimchouk, 2012). Likewise, the Schlotten are created by water rising from the underlying carbonate aquifer, but under a deep phreatic setting


HYPOGENE SPELEOGENESIS AND CO2: SUGGESTIONS FROM KARST OF ITALY, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Menichetti, M.

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.


HYPOGENE VS EPIGENE CAVES: THE SULFUR AND OXYGEN ISOTOPE FINGERPRINT, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
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).


HELIUM ISOTOPES AS INDICATOR OF CURRENT HYPOGENIC KARST DEVELOPMENT IN TAURIDS KARST REGION, TURKEY, 2014,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Ozyurt N. N. , Bayari C. S.

Hypogenic karst development by means of the aggressiveness of hydrothermal fluids driven and fed by mantle heat and mass flux is a known phenomenon. However, in cases when hydrothermal fluid cools down upon thermal conduction in the near-surface environment and is diluted by near-surface cool groundwater, evidences of this phenomenon may be erased completely. Recent data on the isotopes of helium dissolved in cool karst groundwater samples collected from three different karst aquifers in Turkey suggest an apparent mass flux from mantle, as well as from the crust. In the cases considered, helium content from the mantle increases with the increasing age of groundwater. All cases are located nearby the suture zones which may be easing the upward heat and mass flux. Despite sampling difficulties and high analysis costs, helium isotopes dissolved in cool karst groundwater seem to be useful tool to detect the current hypogenesis at the depths of karst aquifers


Results 916 to 930 of 958
You probably didn't submit anything to search for