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Enviroscan Ukrainian Institute of Speleology and Karstology

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Speleology in Kazakhstan

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

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That relict karst is a karst area that exists within the contemporary system, but has been removed from the situation in which they developed, usually as a result of baselevel changes.?

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

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What is Karstbase?



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

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Your search for prediction (Keyword) returned 70 results for the whole karstbase:
Showing 61 to 70 of 70
Improving sinkhole hazard models incorporating magnitudefrequency relationships and nearest neighbor analysis, 2011,
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Galve Jorge P. , Remondo Juan, Gutié, Rrez Francisco

This work presents a methodology for elaborating sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process. The proposed approach has been tested in a sector of the Ebro valley mantled evaporite karst, where sinkholes, largely induced by irrigation practices, have a very high occurrence rate (>50 sinkholes/km2/yr). In this area, covering 10 km2, a total of 943 new cover collapse sinkholes were inventoried in 2005 and 2006. Multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 sinkholes and different sets of variables, including the nearest sinkhole distance. The quantitative evaluation of the prediction capability of these models using the 2006 sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions. The incorporation of the indirect variable nearest sinkhole distance has contributed significantly to increase the quality of the models, despite simplifying the modeling process by using categorical rather than continuous variables. The best susceptibility model, generated with the total sinkhole population and the selected method and variables, has been transformed into a hazard model that provides minimum estimates of the spatial–temporal probability of each pixel to be affected by sinkholes of different diameter ranges. This transformation has been carried out combining two equations derived from the more complete 2006 sinkhole population; one of them expressing the expected spatial–temporal probability of sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces, which control the strength of the surface layer and the size of the sinkholes. The presented method could be applied to predict the spatial–temporal probability of events with different magnitudes related to other geomorphic processes (e.g. landslides).

Regularity and formation mechanism of large-scale abrupt karst collapse in southern China in the first half of 2010, 2011,
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Zhao Haijun, Ma Fengshan, Guo Jie

From winter 2009 to spring 2010, southern China suffered from an extensive and lengthy drought. Subsequently, southern China experienced torrential rains a dozen times during the flood season of April–June. The prolonged drought and subsequent intensive rainfall dramatically altered the hydrodynamic conditions of the karst areas, causing hundreds of widely distributed karst collapses, with extensive damage to houses and fields and necessitating the evacuation of many people. Understanding the causes of these collapses will provide a scientific basis for the prediction or prevention of the related risk. Thus, a geologic survey of karst collapses was performed that systematically allowed to analyze the basic geological conditions, groundwater hydrodynamic conditions, overlying strata properties, and environmental and climatic conditions in southern China. The results showed that environmental and climatic changes, especially the drastic changes in rainfall, gave rise to striking changes in karst hydrodynamic conditions that accelerated infiltration, suffosion, dissolution, and transportation rates and also changed the physical and mechanical properties of the strata overlying karst caves. These stressors triggered or facilitated both cave formation and collapse.

Carbonate porosity creation by mesogenetic dissolution: Reality or illusion?, 2012,
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Ehrenberg Stephen N. , Walderhaug Olav, Bjorlykke Knut

Many authors have proposed that significant volumes of porosity are created by deep-burial dissolution in carbonate reservoirs. We argue, however, that this model is unsupported by empirical data and violates important chemical constraints on mass transport. Because of the ubiquitous presence and rapid kinetics of dissolution of carbonate minerals, the mesogenetic pore waters in sedimentary basins can be expected to be always saturated and buffered by carbonates, providing little opportunity for the preservation of significantly undersaturated water chemistry during upward flow, even if the initial generation of such undersaturated pore water could occur. A review of the literature where this model has been advanced reveals a consistent lack of quantitative treatment. In consequence, the presumption of mesogenetic dissolution producing a net increase in secondary porosity should not be used in the prediction of carbonate reservoir quality. 

Entrances, 2012,
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White, William B.

Entrances are connections between an underlying cave passage and the surface above. Most cave entrances are statistical accidents where the breakthrough to the surface is caused by collapse, by valley deepening, or by human activities such as road cuts, quarries, and other excavations. The number of caves with a certain number of entrances decreases rapidly with the number of entrances, leading to the prediction of a large number of caves that have no entrances. Entrances range in size over several orders of magnitude but there is no relationship between the size of the entrance and the size of the cave.

Effective porosity of a carbonate aquifer with bacterial contamination: Walkerton, Ontario, Canada, 2012,
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Worthington S. R. H. , Smart C. C. , Ruland W.

Preferential flow through solutionally enlarged fractures can be a significant influence on travel times and source area definition in carbonate aquifers. However, it has proven challenging to step beyond a conceptual model to implementing, parameterizing and testing an appropriate numerical model of preferential flow. Here both porous medium and preferential flow models are developed with respect to a deadly contamination of the municipal groundwater supply at Walkerton, Ontario, Canada. The preferential flow model is based on simple orthogonal fracture aperture and spacing. The models are parameterized from bore hole, gamma, flow and video logs resulting in a two order of magnitude lower effective porosity for the preferential flow model. The observed hydraulic conductivity and effective porosity are used to predict groundwater travel times using a porous medium model. These model predictions are compared to a number of independent estimates of effective porosity, including three forced gradient tracer tests. The results show that the effective porosity and hydraulic conductivity values closely match the preferential flow predictions for an equivalent fracture network of _10 m spacing of 1 mm fractures. Three tracer tests resulted in groundwater velocities of hundreds of meters per day, as predicted when an effective porosity of 0.05% was used in the groundwater model. These velocities are consistent with a compilation of 185 tracer test velocities from regional Paleozoic carbonate aquifers. The implication is that carbonate aquifers in southern Ontario are characterized by relatively low-volume dissolutionally enlarged fracture networks that dominate flow and transport. The porous matrix has large storage capacity, but contributes little to transport. Numerical models based on much higher porosities risk significantly underestimating capture zones in such aquifers. The hydraulic conductivity – effective porosity prediction framework provides a general analytical frame work for a preferential flow carbonate aquifer. Not only is the framework readily parameterized from borehole observations, but also it can be implemented in a conventional porous medium model, and critically tested using simple tracer tests.

Denudation and Erosion Rates in Karst, 2013,
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Gunn, J.

In many lithologies erosion (removal of material) and denudation (lowering of the land surface) are directly related butthis is not the case in karst where the majority of erosion is subsurface and only contributes to denudation over geological time. Dissolution is the dominant agent of both denudation and erosion although mechanical weathering of karst rock by clasts brought in by allogenic streams may contribute to the enlargement of cave passages. Most published ‘denudation’rates are actually corrosion rates and many were based on at most a few years of spot measurements at a spring or at a catchment outlet. Hence, considerable caution is necessary in interpreting the results. Cosmogenic nuclides could provide loner-term denudation estimates but have only rarely been applied to karst. Theoretical equations allow prediction of maximum erosion rates from runoff (water surplus), temperature, and carbon dioxide concentrations but field measurements indicate that erosion rarely operates at the maximal rate. Erosion rates vary spatially, with dolines a clear focus, and vertically, with most dissolution contributing to development of the epikarst rather than direct lowering of the land surface. Human activities, and particularly limestone quarrying, are potent erosive forces and in some areas more limestone was removed by quarrying in the twentieth century than by corrosion over the Holocene. Quarrying is also a direct agent of denudation, locally lowering land surface by tens or hundreds of meters

Deep hydrogeology: a discussion of issues and research needs, 2013,
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Tsang Chinfu, Niemi Auli

In this essay, “deep hydrogeology” is somewhat arbitrarily defined as hydrogeology in the subsurface deeper than 1 km, below which the effect of residual permeability at high stresses becomes evident (Neuzil 2003; Rutqvist and Stephansson 2003; Liu et al. 2009). Studies have shown that meteoric fluids are present in the earth’s crust from land surface to at least a depth of 10–15 km (Kozlowsky 1987; Taylor Jr 1990; Zharikov et al. 2003; Ge et al. 2003). At such depths, interaction with surface water and surface events over time periods of 100 or 1,000 years may be minimal, except in areas of very deep mining activities or where deep convection is enhanced by active magmatism. Deep drilling to several kilometers in depth is often done for petroleum and geothermal reservoir exploration and exploitation. The focus of such activities is reservoir identification, capacity evaluation, and fluid and heat extractability. However, it is largely an open area of research to understand the state, structure and evolution of deep hydrogeology over time scales of tens of thousands of years or more, especially in areas lacking petroleum and geothermal resources. Interest in attaining such an understanding has emerged from the need for long-term predictions related to nuclear waste disposal and from recognition of the role that hydrogeology may play in seismicity, orogenesis and various geological processes, as well as in global fluid and chemical cycles. A number of wide-ranging questions may be asked regarding deep hydrogeology, several of which are as follows: What are the current and past states of fluid pressure, temperature and chemical composition in deep formations? How does fluid transport mass and heat? What are the fluid sources and driving mechanisms? What are the magnitude and distribution of porosity and permeability? What are the occurrence and characteristics of large-scale flow, including thermally and chemically driven convection systems? What is the nature of local anomalous fluid pressures and what are their implications? The purpose of this essay is to discuss key issues and research needs in deep hydrogeology. It is based on a workshop on the subject held at Uppsala University in Sweden, with participants from 11 countries, including the USA, Russia, Japan and a number of European countries (Tsang et al. 2012). The following discussion will be divided into sections on permeability structures, driving forces, coupled processes, borehole testing and data analysis, followed by a few concluding remarks.

Karst water resources in a changing world: Review of hydrological modeling approaches, 2014,
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Karst regions represent 7–12% of the Earth’s continental area, and about one quarter of the global population is completely or partially dependent on drinking water from karst aquifers. Climate simulations project a strong increase in temperature and a decrease of precipitation in many karst regions in the world over the next decades. Despite this potentially bleak future, few studies specifically quantify the impact of climate change on karst water resources. This review provides an introduction to karst, its evolution, and its particular hydrological processes. We explore different conceptual models of karst systems and how they can be translated into numerical models of varying complexity and therefore varying data requirements and depths of process representation. We discuss limitations of current karst models and show that at the present state, we face a challenge in terms of data availability and information content of the available data. We conclude by providing new research directions to develop and evaluate better prediction models to address the most challenging problems of karst water resources management, including opportunities for data collection and for karst model applications at so far unprecedented scales

Hydrogeological Characteristics of Carbonate Formations of the Cuddapah Basin, India, 2014,
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Farooq Ahmad Dar

Karst hydrogeology is an important field of earth sciences as the aquifers in carbonate formations represent vital resource of groundwater that feeds a large part of the world population particularly in semi-arid climates. These unique aquifers posses peculiar characteristics developed by dissolutional activities of water. Karst aquifers possess a typical hydrogeological setup from surface to subsurface. The aquifers are governed by slow groundwater flow in matrix porosity, a medium to fast flow in fractures and rapid flow in conduits and channels. This large variability in their properties makes the prediction and modeling of flow and transport very cumbersome and data demanding. The aquifers are vulnerable to contamination as the pollutants reach the aquifer very fast with little or no attenuation. The geomorphological and hydrogeological properties in these aquifers demand specific techniques for their study. The carbonate aquifers of the semi-arid Cuddapah basin were characterized based on geomorphological, hydrogeological and hydrochemical investigations. All the formations are highly karstified possessing one of the longest and deepest caves of India and few springs along with unique surface features. Karstification is still in progress but at deeper levels indicated by growing speleothems of different architectural size. Model of karstification indicates that lowering of base level of erosion resulted in the dissolution of deeper parts of the limestone as represented by paleo-phreatic conduits in the region. Moist conditions of the past were responsible for the karst development which has been minimized due to the onset of monsoon conditions. Karst has developed at various elevations representing the past base levels in the region.

The recharge processes in these aquifers are complex due to climatic and karst specificities. Point recharge is the major contributor which enters the aquifer as allogenic water. It replenishes the groundwater very rapidly. Diffuse recharge travels through soil and epikarst zone. Average annual recharge of semi-arid Narji limestone aquifer is 29% of the rainfall which occurs during 5-7 rain events in the year.

The hydrogeochemical characteristic of karst aquifers is quite varaible. A significant difference is observed in hydrochemistry. High concentrations of SO42-, Cl-, NO3- suggests the anthropogenic source particularly from agriculture. Local Meteoric Water Line of δ2H and δ18O isotopes of rain and groundwater shows a slope of 7.02. Groundwater isotope data shows more depletion in heavy isotopes -a result of high evaporation of the area. Groundwater samples show a trend with a slope of 4 and 3.1 for δ2H and δ18O respectively. Groundwater during dry months gets more fractionated due to higher temperature and little rainfall. The irrigated water becomes more enriched and then recharges the aquifer as depleted irrigation return flow. The isotopes show large variation in spring water. Few springs are diffuse or mixed type and not purely of conduit type in the area. Tracer results indicate that the tracer output at the sampling location depends on the hydrogeological setup and the nature of karstification.

The study has significantly dealt with in disclosing the typical characteristics of such aquifer systems and bringing out a reliable as well as detailed assessment of various recharges to the system. The groundwater chemistry has been elaborated to establish the nature of possible hydrochemical processes responsible for water chemistry variation in semi-arid karst aquifer. Such study has thrown light on the aquifers that are on one hand very important from social and strategic point of view and on the hand were left unattended from the detailed scientific studies.

A Three-dimensional Statistical Model of Karst Flow Conduits, 2016,
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Boudinet, P

It already exists several three-dimensional models dealing with groundwater circulation in karst systems. However, few of them are able either to give a large scale prediction of the repartition of the flow conduits or to make a comparison with real field data. Therefore, our objective is to develop a three-dimensional model about the early formation of karst flow conduits and to compare it with actual field data. This geometric and statistical model is based on percolation and random walks. It is computational and can be run on a personal computer. We examine the influence of fissures (joints and bedding planes) of variable permeability and orientations on the development or early flow conduits. The results presented here correspond to computations up to 2015. Because of long runtimes, we focused on some particular stereotypical situations, corresponding to some particular values of the parameters. Regarding the conduit patterns, the opening and directions of fissures have the same qualitative influence in the model than in actual systems. Two other predictions in good accordance with real karst are that flow conduits can either develop close to the water table or deeper, depending on the distribution of permeable fissures; and that, when viewed in the horizontal plane, conduits don't always develop close to the straight line between inlet and outlet. From a quantitative point of view, in the case of weak dips, our model predicts a realistic relationship between the stratal dip, the length of the system and the averaged depth of the conduits. Eventually, we show that the repartition of conduits depends not only on obvious geometrical parameters such as directions and sizes, but also also on other quantities difficult to measure such as the probability of finding open fissures. The lack of such data doesn't enable, at the present time, a whole comparison between model and reality.

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