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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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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 keyhole passage; keyhole is 1. this very descriptive name derives from the crosssectional shape of a cave passage that consists of a phreatic tube with a vadose canyon cut in its floor. it is the classic example of a two-phase cave passage that originated and began its development in the phreas and was then modified by vadose entrenchment. as this sequence is the result of water table lowering by normal surface erosion, keyholes are common. some keyholes are so small that the lower slot is impassable and the caver has to squeeze along the upper tube; others are very large. spectacularly long is the 5km of keyhole forming the fissures in castleguard cave, canada. a tube 6m in diameter tops an irregular tapering canyon 15m deep that must be traversed on sloping ledges at mid-level [9]. 2. a small passage or opening in a cave; in cross section, rounded at the top, constricted in the middle, and rectangular or flared out below [10]. they appear as keyholes when viewed in cross section. they are formed when underground streams flowing in a tubular passage begin downcutting to form a canyon passage [15]. see also canyon passage; passage; tubular passage; vertical shaft.?

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

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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 heterogeneous media (Keyword) returned 6 results for the whole karstbase:
Determining karst transmissivities with inverse modeling and an equivalent porous media, 1999, Larocque M. , Banton O. , Ackerer P. , Razack M. ,
Flow simulation is difficult to implement in heterogeneous media such as karst aquifers, primarily because the structure of the rock is extremely complex and usually unknown. The aim of this study was to verify the possibility of using inverse modeling and an equivalent porous media to identify transmissivities in a slightly karstified aquifer, the La Rochefoucauld karst (Charente, France), Different simulation scenarios were tested: using two spatial discretizations with different finite-element cell sizes and using measured or interpolated heads. The inverse modeling was performed with the downscaling parameterization procedure, using a finite-element representation of bidimensional ground water flow. The inverse modeling converged satisfactorily with all scenarios: head residuals were small and spring flow rates and the river/aquifer exchanges were adequately stimulated. The scenario using small cells and measured heads generated a highly heterogeneous transmissivity field, indicating an overparameterization of the problem. The calibrated transmissivities and simulated heads of this scenario proved less reliable overall than those of the other scenarios. The use of interpolated heads generated more uniform transmissivities as a result of the head smoothing. A rotation of the initial parameter mesh showed that the scenarios using interpolated heads generate the most stable and reliable results. The scenarios with interpolated heads could therefore be used when head measurements are limited or are unevenly distributed over the aquifer. Overall, the calibrated transmissivities reproduced the entire range of transmissivities measured in the field using different methods. The results indicate that inverse modeling and an equivalent porous media can be used to determine transmissivities in a moderately karstified aquifer

Groundwater modelling in aquifers with highly karstic and heterogeneous characteristics (KHC) in Palestine, 2002, Froukh Lj,
Groundwater modelling is hindered by the lack of adequate information about the groundwater system and hence the need for an interactive and efficient system for data preparation and results analysis. Such a lack of information usually necessitates the use of tedious iterative methodology within a sensitivity analysis scheme. The heterogeneous aquifer systems complicate the issue since more data is required to simulate the system. This study demonstrates the integrated approach to bridge the gap between data handling and modelling. The karst cretaceous aquifer system (complex aquifer system) of the Eastern Basin in the West Bank is used to illustrate this approach. The groundwater modelling approach integrates the outputs from different programs for data preparation and analysis. These include (1) Groundwater Database (GWW) (2) Geographic Information System (GIS) (3) Groundwater Modelling System (GMS). In addition, the paper will summarize the data collection efforts, problems faced and experience gained working with heterogeneous media. This involves linking the results from various field investigations for groundwater development programs in the West Bank

2D and 3D GPR imaging of sinkholes and dissolution features in Jandaíra karst of Fazenda Belém oil field, Potiguar Basin-CE, northeast of Brazil, PhD Thesis, 2005, Xavier Neto, Pedro

In Fazenda Belém oil field (Potiguar Basin, Ceará State, northeast Brazil) occur frequently sinkholes and sudden terrain collapses associated to an unconsolidated sedimentary cap covering the Jandaíra karst. This research was carried out in order to understand the mechanisms of generation of these collapses. The main tool used was Ground Penetrating Radar (GPR). This work is developed twofold: one aspect concerns methodology improvements in GPR data processing whilst another aspect concerns the geological study of the Jandaíra karst. This second aspect was strongly supported both by the analysis of outcropping karst structures (in another regions of Potiguar Basin) and by the interpretation of radargrams from the subsurface karst in Fazenda Belém.


It was designed and tested an adequate flux to process GPR data which was adapted from an usual flux to process seismic data. The changes were introduced to take into account important differences between GPR and Reflection Seismic methods, in particular: poor coupling between source and ground, mixed phase of the wavelet, low signal-to-noise ratio, monochannel acquisition, and high influence of wave propagation effects, notably dispersion. High frequency components of the GPR pulse suffer more pronounced effects of attenuation than low frequency components resulting in resolution losses in radargrams. In Fazenda Belém, there is a stronger need of an suitable flux to process GPR data because both the presence of a very high level of aerial events and the complexity of the imaged subsurface karst structures. The key point of the processing flux was an improvement in the correction of the attenuation effects on the GPR pulse based on their influence on the amplitude and phase spectra of GPR signals. In low and moderate losses dielectric media the propagated signal suffers significant changes only in its amplitude spectrum; that is, the phase spectrum of the propagated signal remains practically unaltered for the usual travel time ranges. Based on this fact, it is shown using real data that the judicious application of the well known tools of time gain and spectral balancing can efficiently correct the attenuation effects. The proposed approach can be applied in heterogeneous media and it does not require the precise knowledge of the attenuation parameters of the media. As an additional benefit, the judicious application of spectral balancing promotes a partial deconvolution of the data without changing its phase. In other words, the spectral balancing acts in a similar way to a zero phase deconvolution. In GPR data the resolution increase obtained with spectral balancing is greater than those obtained with spike and predictive deconvolutions.


The evolution of the Jandaíra karst in Potiguar Basin is associated to at least three events of subaerial exposition of the carbonatic plataform during the Turonian, Santonian, and Campanian. In Fazenda Belém region, during the mid Miocene, the Jandaíra karst was covered by continental siliciclastic sediments. These sediments partially filled the void space associated to the dissolution structures and fractures. Therefore, the development of the karst in this region was attenuated in comparison to other places in Potiguar Basin where this karst is exposed. In Fazenda Belém, the generation of sinkholes and terrain collapses are controlled mainly by: (i) the presence of an unconsolidated sedimentary cap which is thick enough to cover completely the karst but with sediment volume lower than the available space associated to the dissolution structures in the karst; (ii) the existence of important structural of SW-NE and NW-SE alignments which promote a localized increase in the hydraulic connectivity allowing the channeling of underground water, thus facilitating the carbonatic dissolution; and (iii) the existence of a hydraulic barrier to the groundwater flow, associated to the Açu-4 Unity.


The terrain collapse mechanisms in Fazenda Belém occur according to the following temporal evolution. The meteoric water infiltrates through the unconsolidated sedimentary cap and promotes its remobilization to the void space associated with the dissolution structures in Jandaíra Formation. This remobilization is initiated at the base of the sedimentary cap where the flow increases its abrasion due to a change from laminar to turbulent flow regime when the underground water flow reaches the open karst structures. The remobilized sediments progressively fill from bottom to top the void karst space. So, the void space is continuously migrated upwards ultimately reaching the surface and causing the sudden observed terrain collapses. This phenomenon is particularly active during the raining season, when the water table – that normally is located in the karst – may be temporarily located in the unconsolidated sedimentary cap.


Characterization of Spatial Heterogeneity in Groundwater Applications , 2009, Trinchero, Paolo

Heterogeneity is a salient feature of every natural geological formation. In the past decades a large body of literature has focused on the effects of heterogeneity on flow and transport problems. These works have substantially improved the understanding of flow and transport phenomena but still fail to characterize many of the important features of an aquifer. Among them, preferential flows and solute paths, connectivity between two points of an aquifer, and interpretation of hydraulic and tracer tests in heterogeneous media are crucial points that need to be properly assessed to obtain accurate model predictions. In this context, the aim of this thesis is twofold:

· to improve the understanding of the effects of heterogeneity on flow and transport phenomena
· to provide new tools for characterizing aquifer heterogeneity

First, we start by theoretically and numerically examine the relationship between two indicators of flow and transport connectivity. The flow connectivity indicator used here is based on the time elapsed for hydraulic response in a pumping test (e.g., the storage coefficient estimated by the Cooper-Jacob method, Sest). Regarding transport, we select the estimated porosity from the observed breakthrough curve (Φ est) in a forced-gradient tracer test. Our results allow explaining the poor correlation between these two indicators, already observed numerically by Knudby and Carrera (2005).

Second, a geostatistical framework has been developed to delineate connectivity patterns using a limited and sparse number of measurements. The methodology allows conditioning the results to three types of data measured over different scales, namely: (a) travel times of convergent tracer tests, ta, (b) estimates of the storage coefficient from pumping tests interpreted using the Cooper-a Jacob method, S est, and (c) measurements of transmissivity point values, T. The ability of the methodology to properly delineate capture zones is assessed through estimations (i.e. ordinary cokriging) and sequential gaussian simulations based on different sets of measurements.


Third, a novel methodology for the interpretation of pumping tests in leaky aquifer systems, referred to as the double inflection point (DIP) method, is presented. The real advantage of the DIP method comes when it is applied with all the existing methods independently to a test in a heterogeneous aquifer. In this case each method yields parameter values that are weighted differently, and thus each method provides different information about the heterogeneity distribution. In particular, the combination of the DIP method and Hantush method is shown to lead to the identification of contrasts between the local transmissivity in the vicinity of the well and the equivalent transmissivity of the perturbed aquifer volume.

Fourth, the meaning of the hydraulic parameters estimated from pumping test performed in leaky aquifers is assessed numerically within a Monte Carlo framework. A synthetic pumping test is interpreted using three existing methods. The resulting estimated parameters are shown to be space dependent and vary with the interpretation method, since each method gives different emphasis to different parts of the timedrawdown data. Finally, we show that by combining the parameter estimates obtained from the different analysis procedures, information about the heterogeneity of the leaky aquifer system may be inferred.
Fifth, an unsaturated highly heterogeneous waste rock pile is modeled using a simple linear transfer function (TF) model. The calibration of the parametric model provides information on the characteristic time of the flow through the matrix and on the fraction of the water that, within each section, is channeled through the macropores. An analysis of the influence of the scale on the results is also provided showing that at large scales the behavior of the system tends to that of an equivalent matrix reservoir masking the effects of preferential flow.


Water exchange and pressure transfer between conduits and matrix and their influence on hydrodynamics of two karst aquifers with sinking streams, 2010, Baillycomte Vincent, Martin Jonathan B. , Jourde Hervé, , Screaton Elizabeth J. , Pistre Sé, Verin, Langston Abigail

Karst aquifers are heterogeneous media where conduits usually drain water from lower permeability volumes (matrix and fractures). For more than a century, various approaches have used flood recession curves, which integrate all hydrodynamic processes in a karst aquifer, to infer physical properties of the movement and storage of groundwater. These investigations typically only consider flow to the conduits and thus have lacked quantitative observations of how pressure transfer and water exchange between matrix and conduit during flooding could influence recession curves.

We present analyses of simultaneous discharge and water level time series of two distinctly different karst systems, one with low porosity and permeability matrix rocks in southern France, and one with high porosity and permeability matrix rocks in north-central Florida (USA). We apply simple mathematical models of flood recession using time series representations of recharge, storage, and discharge processes in the karst aquifer. We show that karst spring hydrographs can be interpreted according to pressure transfer between two distinct components of the aquifer, conduit and matrix porosity, which induce two distinct responses at the spring. Water exchange between conduits and matrix porosity successively control the flow regime at the spring. This exchange is governed by hydraulic head differences between conduits and matrix, head gradients within conduits, and the contrast of permeability between conduits and matrix. These observations have consequences for physical interpretations of recession curves and modeling of karst spring flows, particularly for the relative magnitudes of base flow and quick flow from karst springs. Finally, these results suggest that similar analyses of recession curves can be applied to karst aquifers with distinct physical characteristics utilizing well and spring hydrograph data, but information must be known about the hydrodynamics and physical properties of the aquifer before the results can be correctly interpreted.


Influence of conduit network geometry on solute transport in karst aquifers with a permeable matrix, 2013, Ronayne, M. J.

In karst aquifers with significant matrix permeability, water and solutes are exchanged between the conduits and carbonate matrix. Transport through the matrix increases thes pread of solutes and increases travel times. This study numerically evaluates advective solute transport in synthetic karst systems that contain 3D branching conduit networks. Particle tracking is performed to analyze the spatial and temporal transport history of solute that arrives at the conduit outlet. Three measures of transport connectivity are used to quantify the solute migration behavior: the skew ness of the particle arrival time distribution, the normalized fifth percentile of arrival times, and the fraction of the total travel time that occurs within conduits. All three of these metrics capture the influence of conduit network geometry on solute transport. A more tortuous network leads to enhanced conduit-matrix mixing, which reduces the transport connectivity and yields a broader distribution of solute arrival times. These results demonstrate that the conduit network geometry is an important control on solute transport in karst systems with a permeable matrix.


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