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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 B-horizon is illuvial horizon in which soluble material from the overlying ahorizon has been deposited [16].?

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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 limestone dissolution (Keyword) returned 47 results for the whole karstbase:
Showing 16 to 30 of 47
Role of mixing corrosion in calcite-aggressive H2O-CO2-CaCO3 solutions in the early evolution of karst aquifers in limestone, 2000, Gabrovsek F, Dreybrodt W,
Two cave-forming mechanisms in limestone are discussed currently. First, when two H2O-CO2-CaCO3 solutions, saturated with respect to calcite but with different chemical compositions mix, renewed aggressiveness to limestone dissolution occurs. This process called mixing corrosion [Bogli, 1964, 1980], in combination with linear dissolution kinetics, has been suggested as cave forming. Second, it has been shown that solely the action of nonlinear dissolution kinetics can generate extended karst conduits. This paper combines both mechanisms. By digital modeling of the evolution of the aperture widths of a confluence of two fractures into a third one it is shown that the first mechanism does not create large cave conduits. The combination of mixing corrosion and nonlinear kinetics, however, considerably intensifies karstification, compared to that of nonlinear kinetics solely. The times to terminate early evolution of karst are significantly reduced when the CO2 concentrations of the inflowing solutions differ by no more than 30%. We discuss the underlying mechanisms by inspection of the time dependence of the evolution of aperture widths, flow rates through them, and of the renewed undersaturation of the mixed solution at the confluence of two fractures. Finally, the evolution of a karst aquifer on a two-dimensional percolation network is modeled when mixing corrosion is present, and compared to that on an identical net with identical nonlinear dissolution kinetics, but mixing corrosion excluded. Large differences in the morphology of the net of cave conduits are found and also a reduction of the time of their evolution. From these findings we conclude that climatic changes, which influence the p(CO2) in the soil, can divert the evolving cave patterns

Limestone dissolution rates in karst environments, 2000, Dreybrodt W. , Eisenlohr L.
The removal of limestone from the bedrock at the surface and below ground by CO2-containing aqueous solutions sculptures karst landscapes and complex karst aquifers. To understand the evolution of such karstic features requires the knowledge of dissolution rates under various hydrogeological conditions. These rates are controlled by several complex mechanisms: 1) The rate equations of Plummer et al. (1978), from which surface reaction rates can be obtained when the concentrations of reacting species at the surface are known. 2) The slow reaction of CO2 to H+ and HCO3, which provides the H+ ion for converting carbonate to bicarbonate ions. 3) Mass transport by diffusion, either in laminar or turbulent flow. 4) Inhibition of surface reaction rates by the presence of impurities in natural carbonate minerals. 5) Open- or closed-system conditions with respect to CO2, under which dissolutional removal of limestone is active. Depending on the actual conditions each of these processes can greatly effect dissolution rates. This paper addresses these problems and provides data, which can be used to obtain realistic dissolution rates, when solutions flow laminarly in narrow fractures, but also for turbulent flow in large conduits, and a variety of other different hydrogeological conditions. These data are also necessary as input for modeling the evolution of karst.

Dynamics of the evolution of single karst conduit, 2000, Dreybrodt W. , Gabrovsek F.
The evolution of karst conduits by calcite-aggressive water flowing in initially narrow fractures require a non-linear rate law FSUBn(c)=kSUBn(1-c/cSUB eg)SUPn for limestone dissolution close to equilibrium with respect to calcite. A mathematical analysis of the evolution of limestone dissolution rates of water in such early, narrow fractures as a function of the distance from the input reveals an exponential decrease of the dissolution rates for linear dissolution rate laws (n=1), such that subsurface karstification is prevented. For non-linear kinetics (n>2), however, the decrease of rates proceeds by a hyperbolic relation, such that dissolution rates at the exit of the fracture are still sufficiently high to create a feedback mechanism by which after a long time of gestation a dramatic increase in the widths of the conduits is established. After this breakthrough event, uniform widening along the entire channel determines the further evolution. The time to achieve breakthrough is given by T=aSUB0/2gammaF(L,0), where 2gammaF(L,0) is the initial widening in cm/year at the exit of the conduit. This however is only true when the inflow solution is at less than 99% of saturation. Otherwise the positive feedback loop is switched off and the conduit widens evenly along its entire length with rates of 10SUP-9 cm/year to enlarge extremely narrow fractures with initial widths of several ten microns over distances of kilometers to sizes of about 0.1mm within several ten millions of years. This provides a general explanation for the concept of inception horizons, where usually other mechanisms have been assumed.

Influence of fracture roughness on karstification times, 2000, Dreybrodt W. , Gabrovsek F.
Karst aquifers develop along water-transmitting fractures which are rough by nature. Most numerical models on the evolution of the widths of those fractures by limestone dissolution, however, approximate such rough fractures by two parallel smooth planes. Here we investigate the influence of fracture roughness on the breakthrough time of conduits. All results show that even when the flow through a fracture is reduced by its roughness by a factor of ten in comparison to a corresponding smooth fracture, breakthrough time is increased only by a factor of 4. This gives a first answer to the influence of natural fracture roughness on the evaluation of karst and shows that extreme roughness, unlikely in nature, is necessary to exert significant influence on karstification time.

Dissolution of salt, 2000, Frumkin A.
Halite, the mineral of sodium chloride, dissolves by simply dissociating to Na+ and Cl-. Special features such as density stratification within water may arise from the high solubility, 360 g/L, while the rapid kinetics promotes intense karstification within a short time. Salt water enhances limestone dissolution by the ionic-strength effect. Other soluble chlorides reduce halite solubility through the common-ion effect.

Acidic bog drainage and limestone dissolution, Mammoth Cave National Park., 2000, Timmons J. , Groves C. , Meiman J.

A model of the early evolution of karst aquifers in limestone in the dimensions of length and depth, 2001, Gabrovsek F, Dreybrodt W,
A new model of the early evolution of limestone karst aquifers in the dimensions of length and depth is presented. In its initial state the aquifer consists of a rock massive with evenly spaced fractures of about 50 [mu]m aperture widths with an hydraulic conductivity of 10-7 ms-1. In addition to this a coarser network of prominent fractures with aperture widths of several 100 [mu]m is also present. Boundary conditions of constant recharge 450 mm/year, or constant head from the input of allogenic streams are imposed. First the position of the water table in the aquifer is calculated, then dissolutional widening during a time step in all the fractures below the water table is found by use of the well-known nonlinear dissolution kinetics of limestone. This is iterated and the position of the water table as well as the fracture widths are found as a function of time. In the case of constant recharge to a karst plateau, the water table in any case drops to base level and conduits there propagate from the spring headwards. If constant head conditions are valid the position of the water table remains almost stable and conduits propagate along the water table from the input towards the spring. There is competition between conduit evolution along prominent fractures and along tight fissures close to the water table. In any case under constant head conditions one of these pathways wins, and early karst evolution is terminated by a breakthrough event with an explosive increase of the flow through the aquifer until constant head conditions break down. Depending on the boundary conditions of constant head or constant recharge or a combination of both it is possible to describe models of cave genesis, which have been derived from field evidence, such as the water table models of Swinnerton and Rhoades as well as the four-state model by Ford and Ewers (Can. J. Earth Sci., 15 (1978) 1783)

The processes dominating Ca dissolution of limestone when exposed to ambient atmospheric conditions as determined by comparing dissolution models, 2002, 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

Could Mammoth Cave be reduced to a single equation?, 2003, Groves C. G. , Meiman J.

Since the evolution of any cave system is largely deterministic, in theory the processes responsible for this development could be described mathematically. In a practical sense, we will never have such a model to realistically describe the evolution of the Mammoth Cave System in detail. However, the search itself can provide a framework within which to understand what processes are important. This can guide the design of rate process studies that would eventually be coupled to provide a comprehensive understanding of the cave's evolution. Data gaps, as well, are identified during this process.
The geometry of a cave system depends on the individual growth rates of sequential sets of passage cross-sections. The growth of each of these cross-sections is determined by a set of coupled processes, the rates of which are related to well-defined variables. Major processes include limestone dissolution and precipitation (dependent on water and rock chemistry, flow characteristics, wetted passage perimeter, and temperature), sediment entrainment, deposition, and abrasion (dependent on flow velocity distributions and properties of the sediment supply), and breakdown processes (dependent on fracture characteristics). Our ability to model the complete picture depends on our grasp of these individual behaviors, as well as their interactions.
A long-term study of the behaviors of two single active passage cross-sections is underway in the Right and Left forks of Hawkins River of Mammoth Cave, where continuous water quality data are being obtained through two 145 m deep wells. Experiments are currently underway to determine storm- and seasonal-scale changes in limestone dissolution rates. Planned studies will explore sediment dynamics and the impact of sediment masking on dissolution rates, as well as potential impacts of sediment abrasion on passage growth. Complete understanding of a single cave slice is an important step to understanding cave evolution in general.


Interaction of Fracture and Conduit Flow in the Evolution of Karst Aquifers, 2003, Romanov D. , Dreybrodt W. , Gabrovsek F.

Karst aquifers in their initial state consist of a net of fractures with largely differing aperture widths. As a most simple example we investigate the evolution of a karst aquifer where a wide fracture with aperture width A0 = 0.03 cm is embedded into a dense net of narrow fractures of aperture widths a0 < A0. The aim of this work is to investigate the influence of the hydraulic coupling between these fractures to the evolution of the karst aquifer. The modelling domain consists of a confined aquifer, which is divided into a square network consisting of narrow fractures. In its center a straight wide fracture leads from the input at hydraulic head h to the output at head zero. We have computed the breakthrough times of this aquifer as a function of a0. For a0 = 0 the breakthrough time is that of an isolated one-dimensional fracture. As a0 is increased the breakthrough times drop until at about a0 > 0.02 cm they are reduced significantly by almost one order of magnitude. This is caused by the following mechanism. As the central tube gets enlarged into a funnel like shape from its entrance water from its tip is injected into the fine net of fractures. Therefore more aggressive solution enters into the central fracture and enhances dissolutional widening there. By this way aquifers with wide fractures embedded into a continuum of fine fractures experience accelerated karstification.


Surface sediment characteristics and tower karst dissolution, Guilin, southern China, 2003, Tang Tao,
Dissolution of extensive outcrops of limestone and dolostone in humid tropical and subtropical southern China produced numerous caves and residual hills that are referred as tower karst. This study identifies and relates the physical and chemical characteristics of the surface sediment with the limestone bedrock in Guilin to assess the influence of the limestone dissolution process on sediment composition.The results of this study indicated that (i) both limestone and dolostone of the region are very pure (99.5% and 98.5% of CaCO3 and MgCO3, respectively); (ii) the material composition of limestone and dolostone is different from that of soil and sediment of the region: constituents of surface sediments are highly related with the clastic sedimentary rocks, such as the mudstone, but show negative correlation with limestone and dolostone; (iii) the limestone formations are highly resistant to physical weathering and disintegration; their durability versus physical weathering and their high susceptibility to chemical dissolution account for why residual towers can form and persist; (iv) a dual-zone environmental structure exists vertically downward from the surface in Guilin: the zone of unconsolidated clastic sediments that is predominantly acidic, and the zone of karstified limestone that is predominantly basic. The evidence suggests that the environment and processes differ in these two zones. The chemical dissolution of limestone that formed tower karst of the region is not mainly responsible for the accumulation of clastic sediment on the surface

A conceptual model of flow and transport in a karst aquifer based on spatial and temporal variations of natural tracers, 2003, Perrin, Jerome

Karst aquifers represent an important groundwater resource world-wide. They are highly vulnerable to contamination due to fast transport through the system and limited attenuation of contaminants. The two main hydrogeological approaches developed for studying flow and transport are: inference of the
system structure from karst spring hydrographs and chemographs; numerical modelling of flow and transport using a theoretical distribution of flow and transport field parameters. These two approaches lack of validation by detailed field measurements and observations. The main objective of this thesis is to “fill the gap” existing between field and model data. Observations of flow and transport parameters at several locations within the system were used to develop a conceptual model. This model was then compared to the existing models.
The main field test site is the Milandre karst aquifer, located in the Swiss tabular Jura. Natural tracers (major ions, oxygen-18, specific conductance) and discharge were measured on the underground river, its main tributaries, percolation waters, and the main spring. These data were collected on a long-term basis in order to assess the spatial variability of the parameters, and on a short time scale (i.e. flood events) in order to investigate the dynamic processes. Complementary sites (Brandt and Grand Bochat) were used for more observations at the base of the epikarst.
The proposed conceptual model considers four sub-systems: the soil zone, the epikarst, the unsaturated zone, and the phreatic zone. Each has its own specificity with respect to flow and transport. The soil zone controls the actual infiltration into the system. It contributes efficiently to groundwater storage. It mixes quickly stored water with fresh infiltrated water. Its thickness determines land-use: thick soils are generally cultivated whereas thin soils are under forested areas. The solutes concentration of soil waters depends on land-use for pollution-related parameters (nitrate, chloride, sulfate, potassium, sodium). Moreover the soil zone is the main source of CO2 which controls the limestone dissolution-related parameters. The epikarst zone contributes largely to groundwater storage. It distributes groundwater into vadose flow through conduits, and base flow through low permeability volumes (LPV) in the unsaturated zone. It is the sub-system where dissolution-related parameters are mostly acquired.
The unsaturated zone is seen as a transmissive zone connecting the epikarst to the horizontal conduit network of the phreatic zone. In case of flood events, some dissolution still occurs in this sub-system.
The phreatic zone is the partly flooded conduit network draining groundwater to the spring. It collects waters issued from the unsaturated zone, mixes the tributaries, and drain the water towards the discharge area. The role of phreatic storage appears to be limited for both hydraulics and transport.
Tributary mixing is a prominent process that shapes spring chemographs during flood events. In steady-state conditions, base flow is mainly sustained by the epikarst reservoir. Tracer concentrations are stable as the chemical equilibrium is already reached in the epikarst. Waters issued from the different tributaries mix in the conduit network, and the spring chemistry is the result of this mixing.
During flood events, transient flow induces non-linear mixing of the tributaries. The respective contributions of the tributaries change throughout the flood, and the spring chemographs vary accordingly. In case of important recharge, waters issued from other sources than the epikarst participate to the flood. First, soil water reaches the phreatic zone. Its characteristics are a dampened isotopic signal, and ionic concentrations differing from those of the epikarst. Second, fresh water directly issued from rainfall, may reach the phreatic zone. Its characteristics are a varying isotopic signal, and diluted ionic concentrations. The mixing components participating to the flood are controlled by the actual infiltration volume (or height). The limestone dissolution process is effective for the fresh and soil components of flow. However mixing processes play a more important role than dissolution for shaping the spring chemographs.
From a practical point of view, the project confirmed the prominent role of the soil zone and the epikarst on the solute transport in karst systems. This was already integrated in karst vulnerability mapping methods recently developed (EPIK, PI, VULK).

http://doc.rero.ch/record/2604/files/these_PerrinJ.pdf


Weathering, geomorphic work, and karst landscape evolution in the Cave City groundwater basin, Mammoth Cave, Kentucky, 2005, Groves C. , Meiman J. ,
Following the pioneering work of Wolman and Miller [Wolman, M.G., Miller, J.P., 1960. Magnitude and frequency of forces in geomorphic processes. J. Geol., 68, 54-74.] in evaluation of geomorphic work and the frequencies and magnitudes of forces that drive it, a large number of quantitative studies have focused on the evolution of fluvial systems and transport of elastic sediment. Less attention has been given to understanding frequencies and magnitudes of processes in rock weathering, including investigation of rates at which solutes are removed from landscapes under various flow distributions as an analog to Wolman and Miller's [Wolman, M.G., Miller, J.P., 1960. Magnitude and frequency of forces in geomorphic processes. J. Geol., 68, 54-74.] concept of geomorphic work. In this work, we use I year of high-resolution flow and chemical data to examine the work done in landscape evolution within and at the outlet of Kentucky's Cave City Basin, a well-developed karst landscape/aquifer system that drains about 25 km(2). We consider both removal of solutes contributing to landscape denudation based on calcium mass flux as well as predicted dissolution rates of the conduit walls at the outlet of this basin based on limestone dissolution kinetics. Intense, short-duration events dominate. Storms that filled the Logsdon River conduit occurred < 5% of the year but were responsible for 38% of the dissolved load leaving the system and from 63% to 100% of conduit growth for various scenarios of sediment influence. Landscape denudation is a linear function of the amount of water moving through the system, but conduit growth rates, and thus rates of recharge area evolution from fluvial to karst surface landscapes, depend both on the amount of water available and the distribution of precipitation. © 2004 Published by Elsevier B.V

Limestone dissolution in phreatic conditions at maximum rates and in pure, cold, water., 2006, Faulkner T.
This paper reviews contemporary knowledge about the physical and chemical factors that govern the inception and enlargement phases of phreatic karst passages. A model is then presented to determine the conditions that allow dissolution at maximum rates. This builds on the known finding that wall retreat rates are dependent on the degree of saturation of the water, which in turn depends on the temperature and on the concentration of CO2 in the input stream. However, it also follows from the theoretical equations that conduits can enlarge at high rates if the flow through them is sufficiently great that the solution remains well-below saturation, even if the input contains no carbon dioxide at all, and especially at low temperature. Examples of fractures that achieved breakthrough and then enlarged at high rates to explorable dimensions in almost pure water at near-freezing temperatures are found in the metamorphic Caledonides, where many short caves formed phreatically during deglacial high-flow conditions at the start of the Holocene.

Extremely acidic, pendulous cave wall biofilms from the Frasassi cave system, Italy, 2007, Jennifer L. Macalady, * Daniel S. Jones And Ezra H. Lyon
The sulfide-rich Frasassi cave system hosts an aphotic, subsurface microbial ecosystem including extremely acidic (pH 0?1), viscous biofilms (snottites) hanging from the cave walls. We investigated the diversity and population structure of snottites from three locations in the cave system using full cycle rRNA methods and culturing. The snottites were composed primarily of bacteria related to Acidithiobacillus species. Other populations present in the snottites included Thermoplasmata group archaea, bacteria related to Sulfobacillus, Acidimicrobium, and the proposed bacterial lineage TM6, protists, and filamentous fungi. Based on fluorescence in situ hybridization population counts, Acidithiobacillus are key members of the snottite communities, accompanied in some cases by smaller numbers of archaea related to Ferroplasma and other Thermoplasmata. Diversity estimates show that the Frasassi snottites are among the lowestdiversity natural microbial communities known, with one to six prokaryotic phylotypes observed depending on the sample. This study represents the first in-depth molecular survey of cave snottite microbial diversity and population structure, and contributes to understanding of rapid limestone dissolution and cave formation by microbially mediated sulfuric acid speleogenesis.

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