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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 solute is the substance present in a solution in the smaller amount. for convenience, water is generally considered the solvent even in 'concentrated' solutions with water molecules in the minority [22].?

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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 karst evolution (Keyword) returned 58 results for the whole karstbase:
Showing 31 to 45 of 58
Modeling the influence of epikarst evolution on karst aquifer genesis: A time-variant recharge boundary condition for joint karst-epikarst development, 2005, Bauer S, Liedl R, Sauter M,
The epikarst, a zone of increased weathering near the land surface, determines the distribution of recharge to a karst aquifer in both space and time. It links climatic and near-surface geological conditions with the karstification of a limestone aquifer, defining both the hydraulic and the chemical boundary conditions for the development of the karst system. Realistic modeling of the epikarst is therefore a prerequisite for the simulation of karst aquifer genesis. A conceptual model of the joint karst-epikarst evolution is presented in this paper. An epikarst module is developed and implemented in a numerical continuum-discrete conduit flow model for karst genesis, which accounts for the joint evolution of the epikarst and the main karstic conduit network under unconfined conditions. The influence of epikarst genesis on the evolution of the underlying karst aquifer is investigated in four scenarios. It is found that only the interaction of epikarst and initial heterogeneity in the underlying carbonate rock leads to the development of a dendritic cave system. If no heterogeneity in the initial conduit network or in the recharge distribution is included, maze-type caves develop

Processes of Speleogenesis: a Modeling Approach, 2005, Dreybrodt W. Gabrovsek F. , Romanov D.

This book draws together the major recent advances in the modeling of karst systems. Based on the dissolution kinetics of limestone, and flow and transport processes in its fractures, it presents a hierarchy of cave genetic situations that range from the enlargement of a single fracture to the evolution of cavernous drainage patterns in confined and unconfined karst aquifers. These results are also applied to the evolution of leakage below dam sites in karst. The book offers a wealth of information that helps to understand the development of cave systems. It addresses geologists, hydrologists, geomorphologists, and geographers. It is also of interest to all scientists and engineers who have responsibilities for groundwater exploration and management in karst terrains.

?Processes of Speleogenesis: a Modeling Approach is an exciting book that brings together and displays the products of the first and second generations of karst cave and aquifer computer modeling in a succinct fashion, with excellent illustrations and stimulating contrasts of approach. It is a ?benchmark? publication that all who are interested in speleogenesis should read. It will be a very useful volume for teaching, not only in karst and hydrogeology, but for others who use computer modeling in the physical and spatial sciences.? (From the foreword by D.C. Ford)

?This book is an extraordinary achievement that warrants close attention by anyone interested in speleogenesis??This book is ideal for researchers in speleogenesis who have a solid grasp in technical aspects. Most of the necessary background information is outlined in the first chapter, but subtle aspects will be clear only to those who already have a good background in geochemistry and computer modeling especially when interpreting the figures. This book is not aimed at groundwater hydrologists, although the results would be eye-opening to anyone in that field who denies the importance of solution conduits in carbonate aquifers.? (From book review by A.N. Palmer, JCKS, Volume 67, No.3, 2005)

?To specialists the book is very helpful and and up-to-date, providing many ideas and answering many questions.? (From book review by P. Hauselmann, Die Hohle, Volume 56, 2005)

CONTENTS

  1. Introduction
  2. Equilibrium chemistry and dissolution kinetics of limestone in H2O-CO2 solutions
  3. The evolution of a single fracture
  4. Modeling karst evolution on two-dimensional networks: constant head boundary conditions
  5. Unconfined aquifers under various boundary conditions
  6. Karstification below dam sites
  7. Conclusion and future perspectives
  8. Bibliography

GUEST CHAPTER by Sebastian Bauer, Steffen Birk, Rudolf Liedl and Martin Sauter
Simulation of karst aquifer genesis using a double permeability approach investigation for confined and unconfined settings

GUEST CHAPTER by Georg Kaufmann
Structure and evolution of karst aquifers: a finite-element numerical modeling approach


Investigation of Morphology Hydrogeology Relations in Harmanköy Beyyayla (Bilecik, Turkey) Karst System, PhD thesis, 2005, Aydin, H.

Harmanköy – Beyyayla Karst System (HBKS) forms the highlands in the Central Sakarya Basin. HBKS which is made of Jurassic Bilecik limestone is located within the province boundaries of Bilecik and Eskişehir and extends over a surface area of 49.5 km2. In this study, the HBKS whose boundary conditions are well defined was investigated in terms of morphology – hydrogeology relationships. Within this context, hydrogeological conceptual model of the study area was developed based on the physical parameters such as geology, tectonic, morphology and dynamic properties such as precipitation regime, infiltration, recharge, flow and storage.
Upon the evaluation of morphological, hydrologic, hydrogeological and hydrodynamic properties, it was concluded that HBKS consists of three distinct subsystems, namely the Beyyayla, Döşkaya and Nardın subsystems. It was further determined that Beyyayla and Döşkaya subsystems are similar by the properties mentioned above, while the Nardın subsystem differs from these two subsystems.
Recharge in HBSK occurs in two different forms; allogenic-point and autogenic-diffuse. Surface waters which are drained from Paleozoic age granites located in Beyyayla and Döşkaya subsystems’ recharge these systems as allogenic-point from Beyyayla and Tozman sinkholes. On the other hand, precipitation which falls on the limestone rock-mass supplies the autogenic diffuse recharge to the systems. Recharge to the Nardın subsystem on the other hand, is autogenic diffuse from direct precipitation on to the limestone area. The Qmax/Qmin ratio and the variation coefficient (CV) of chemical compositions of the springs which drain these subsystems, imply that concentrated flow is dominant in all these three systems. In addition, trace experiments carried out in Beyyayla and Döşkaya subsystems suggest that the flow is turbulent and rapid within the well-developed karstic channels. Advective-dispersive transport is controlling the solute transport in the system.
It was speculated that the energy gradient is more important than tectonic, lithologic characteristics and climatic changes in karst evolution Beyyayla and Döşkaya subsystems. Lowering of erosion base caused exposure of granites which consequently supplied the allogenic-point recharge to these subsystems. This was resulted in distinct morphologic, hydrologic and hydrodynamic properties of the subsystem.
Advisor: Assoc. Prof. Dr. Mehmet EKMEKÇİ, Hacettepe University, Department of Geological Engineering, Hydrogeological Engineering Division


Variation in rates of Karst processes, 2007, Palmer, A. N. ,

The development of karst is not a linear process but instead takes place at irregular rates that typically include episodes of stagnation and even retrograde processes in which the evolution toward maturity is reversed. The magnitude and nature of these irregularities differs with the length of time considered. Contemporary measurements in caves show fluctuations in dissolution rate with changes in season, discharge, and soil conditions. Dissolution is sometimes interrupted by intervals of mineral deposition. Observed dissolution rates can be extrapolated to obtain estimates of long-term growth of a solution feature. But this approach is flawed, because as the time scale increases, the rates are disrupted by climate changes, and by variations that are inherent within the evolutionary history of the karst feature (e.g., increased CO2 loss from caves as entrances develop). At time scales of 105-106 years, karst evolution can be interrupted or accelerated by widespread fluctuations in base level and surface river patterns. An example is the relation between karst and the development of the Ohio River valley in east-central U.S.A. At a scale of 106-108 years, tectonic and stratigraphic events cause long-term changes in the mechanism and style of karst development. For example, much of the karst in the Rocky Mountains of North America has experienced two phases of pre-burial Carboniferous karst, mineral accretion during deep burial from Permian to Cretaceous, extensive cave development during Paleocene-Eocene uplift, and stagnation and partial mineral deposition caused by late Tertiary aggradation. At such large time scales, it is difficult to determine rates of karst development precisely, if at all. Instead it is appropriate to divide the evolutionary history into discrete episodes that correlate with regional tectonic and stratigraphic events.


The age of Karst relief in west Slovenia, 2007, Mihevc, A.

The age of a karst can be defined as the time when the karst rocks were uplifted out of the sea. The other view of the age of karst is to define the age of certain karst features or assemblages of karst features. On the Kras plateau there is a variety of forms that were formed at quite different times, but due to karst evolution, they coexist in today’s relief. On the plateau, that is slowly rising, the hydrological zones in karst surface are moving downwards. Streams from the side ceased to flow on the karst and former leveled surface that was formed in conditions of high ground water is dissected by numerous dolines. Blind valleys are incised at the side and some of them show the influence of recent tectonics. The lowering of relief by corrosion exposes caves that have formed deep beneath the surface and creates unroofed caves that become a part of the surface topography. From the morphological comparison of the unroofed caves, blind valleys and levelled surfaces and by dating of the sediment and considering the age of tectonic phases we can reconstruct the evolution and estimate the age of the karst landscape.


Cave and Karst evolution in the Alps and their relation to paleoclimate and paleotopography, 2007, Audra P. , Bini A. , Gabrovš, Ek F. , Hä, Uselmann P. , Hoblé, A F. , Jeannin P. Y. , Kunaver J. , Monbaron M. , Š, Uš, Terš, Ič, F. , Tognini P. , Trimmel H. , Wildberger A.

Progress in the understanding of cave genesis processes, as well as the intensive research carried out in the Alps during the last decades, permit to summarize the latest knowledge about Alpine caves. The phreatic parts of cave systems develop close to the karst water table, which depends on the spring position, which in turn is generally related to the valley bottom. Thus, caves are directly linked with the geomorphic evolution of the surface and reflect valley deepening. The sediments deposited in the caves help to reconstruct the morphologic succession and the paleoclimatic evolution. Moreover, they are the only means to date the caves and thus the landscape evolution. Caves appear as soon as there is an emersion of limestone from the sea and a water table gradient. Mesozoic and early tertiary paleokarsts within the alpine range prove of these ancient emersions. Hydrothermal karst seems to be more widespread than previously presumed. This is mostly due to the fact that usually, hydrothermal caves are later reused (and reshaped) by meteoric waters. Rock-ghost weathering is described as a new cave genesis agent. On the contrary, glaciers hinder cave genesis processes and fill caves. They mainly influence cave genesis indirectly by valley deepening and abrasion of the caprock. All present datings suggest that many alpine caves (excluding paleokarst) are of Pliocene or even Miocene age. Progress in dating methods (mainly the recent evolution with cosmogenic nuclides) should permit, in the near future, to date not only Pleistocene, but also Pliocene cave sediments absolutely.


Aspects of the evolution of an important geo-ecosystem in the Lessinian Mountain (Venetian Prealps, Italy), 2007, Latella L. , Sauro U.

The Grotta dell’Arena (476 V/VR), located in the Lessinian Mountain, at the elevation of 1512 m a.s.l., is a very important underground karst system. Although it is only 74 m long, several of the geological, geomorphological and environmental features of the High Lessinian underground karst are present in this cave. The Grotta dell’Arena shares some common geological and faunistic characters with other important and well known karst systems. This cave has also one of the highest number of troglobitic species in all Venetian Prealps and some of them possibly originated in the pre-Qquaternary. From the geological point of view the cave is the expression of a contact karst, where different limestone types come in contact both stratigraphically and along tectonic structures. The Grotta dell’Arena is located at the stratigraphic contact between the “Calcari del Gruppo di San Vigilio” and the “Rosso Ammonitico” and it is very close to a fault plane putting in vertical contact the two above formations with the “Biancone”, a kind of limestone closely stratified and densely fractured, very sensible to frost weathering. It is interesting to note the presence of a good number of species of Tertiary, or more generally pre-Qquaternary, originate in the Grotta dell’Arena. This presence is possibly related to the geology of caves. In this paper the different kinds of underground karst systems in the Grottta dell’Arena and Lessinian Mountain, are analyzed and the relation with the cave fauna distribution are taken in consideration.


Palaeomagnetism and Magnetostratigraphy of Karst Sediments in Slovenia, 2008, Zupan Hajna Nadja, Mihevc Andrej, Pruner Petr, Bosk Pavel

Results of more than 10 years intensive study of palaeomagnetic properties and magnetostratigraphy of karst sediments in Slovenia are summarized. The research covered the most important karst regions, from lowlands to high mountains. It included both well-known and documented sites, and relatively unknown or newly found locations in caves and surface karst sediments. The territory of Slovenia, with its numerous karst regions, long history of karst evolution and relatively good knowledge of the karst sediments represents an ideal testing ground for comprehensive research on individual infilling processes, their stages and periods. The questions concentrated to the time span of karst evolution in Slovenia, age of karst surfaces, speleogenesis and rates of processes. The majority of karst sediment dating has been carried out in south-western Slovenia (in the north-western part of the Dinaric Karst, which is known as the Kras) where Eocene flysch is the last marine deposit preserved in the geologic record. The Oligocene to Quaternary period represented mostly terrestrial phase with prevailing surface denudation and erosion processes. Therefore only karst sediments preserved on karst surface and in subsurface can yield some facts and ideas of karst evolution and its age. In the book 21 locations are described, 19 from Slovenia and two Italian Karst. Each location is placed in space describing geological, karstological and speleological properties. A precise description of studied sediment profile with lithological and mineralogical composition follows obtained by various research methods. Every profile contains also the palaeomagnetic results with magnetostratigraphic and palaeomagnetic properties.

Dating of cave sediments by the application of the palaeomagnetic method is a difficult and sometimes risky task, as the method is comparative in its principles and does not provide numerical ages. Repeated sampling in some profiles have shown that only dense sampling (high-resolution approach with sampling distance of 2?4 cm), can ensure reliable results. Correlation of the magnetostratigraphic results we obtained, and the interpretations tentatively placed upon them has shown that in the majority of cases, application of an additional dating method is needed to either reinforce the palaeomagnetic data or to help to match them with the geomagnetic polarity timescale.

The most important result is the discovery that cave fills have substantially older ages than generally expected earlier (max. about 350 ka). Palaeomagnetic data in combination with other dating methods, especially biostratigraphy, have shifted the possible beginning not only of the speleogenesis but also of the cave filling processes in Slovenia far below the Tertiary/Quaternary boundary. Results suggest that there were probably some distinct phases of massive deposition in caves. The oldest one took place from about 1.8 to more than 5.4 Ma (with two phases at 1.8 ? 3.6 and about 4.1 ? 5.4 Ma). The data support and better define the estimated ages of the surface and cave sediments that were based on geomorphic evidences, especially from unroofed caves.

The evolution of the caves took part within one karstification period, which began with the regression of Eocene sea and exposing of limestones at the surface within complicated overthrusted structure, which formed principally during Oligocene to early Miocene.


The impact of glacier ice-contact and subglacial hydrochemistry on evolution of maze caves: A modelling approach, 2010, Skoglund Rannveig Ovrevik, Lauritzen Steinerik, Gabrovsek Franci

Labyrinth and maze cave networks are a conspicuous feature in formerly glaciated stripe karst in Scandinavia. Often found in topographically “impossible” situations, their genesis is attributed to glacial ice-contact conditions. This is further supported by observing that individual networks may either be influent, effluent or through-flow; depending on the attitude of the host rock and former glacier directions. The ice-contact hypothesis is tested by using a finite difference, fracture network model where chemical and hydrological conditions can be varied. Subglacial chemistry alone (low partial pressure of CO2, low temperature) is not sufficient to favour mazes over linear caves. However, when coupled with high input saturation ratio, high and varied hydraulic gradients and glacial hydrology, the model produced cave patterns comparable in scale and complexity to our field examples.


Evolutionary typology of karst, 2010, Klimchouk A. B.

The paper reveals the hydrogeological essence of karst, provides its definition, substantiates the evolutionary approach to karst typology and offers a respective classification. The evolutional typology of is based on consideration of geological evolution of a body of karstified rocks (unit, formation) and evolution of a groundwater circulation system. It reflects such basic  regularities of geological evolution as directed development and cyclicity. Different stages of post-sedimentary transformation of rocks and of the development of a geohydrodynamic systems are characterized by certain steady combinations of lithologic and structural pre-requisites for groundwater flow and speleogenesis, the mode of groundwater flow, recharge and discharge conditions, thermobaric and geohydrochemical conditions. Such combinations result in formation of karst systems with certain characteristic properties – i.e. types of karst. The directed development – results in regular changes of karst types. Changes of one type of karst into another is conditioned by the processes of tectonic and geomorphological evolution, which determine change of border conditions for groundwater flow and speleogenesis.

Within the framework of the proposed classification, the types of karst correspond to the successive stages of its evolution, between which boundary conditions of groundwater flow and speleogenesis, external factors and internal mechanisms of karstification (speleogenesis) differ considerably and in a regular manner.  The evolutional types of karst integrally characterize the most substantial properties of karst systems (structure of secondary porosity and permeability, degree and character of karst manifestation in surface relief, hydrogeologic features, potential for collapse and subsidence hazard, etc.), speleogenetic environments and dominant mechanisms, as well as potential of inheritance of porosity and permeability structures from the previous stages of development. This allows using this classification for resolving of broad range of scientific and practical problems, related to karst.


Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy), 2010, Chiesi Mauro, De Waele Jo, Forti Paolo

Poiano is the largest karst spring of the Emilia Romagna region (northern Italy). It drains an aquifer of unique properties composed of anhydrite with halite lenses at depth and gypsum at the surface (both with high NaCl content). Hydrogeological research has been undertaken using automatically recorded hourly data on temperature, electrical conductivity, and water level. Water feeding the Poiano spring is restricted within the gypsum/anhydrite outcrop between the Lucola, Sologno and Secchia rivers.

Karstification in the Upper Secchia Valley only concerns the gypsum rocks mainly present along the border and in the shallower parts of the sulfate outcrop and does not appear to occur at depth. Data strongly support the hypothesis that the salt content in the spring water derives from active halokinetic movements. For the first time, the fundamental hydrogeological importance of the anhydrite part inside the sulfate rocks is demonstrated. If gypsum prevails over anhydrite the karst drainage network can extend deep into the rocks following a network of fractures and fissures. Instead, if in the deep parts of the aquifer anhydrite prevails over gypsum, the karst evolution cannot take place at depth and the structure of the underground drainage paths only follows near-surface paths in gypsum. 


Karstification beneath dam-sites: From conceptual models to realistic scenarios, 2011, Hiller Thomas, Kaufmann Georg, Romanov Douchko

Dam-sites and reservoirs located above soluble rock are often damaged by increased leakage through the sub-surface within the life-time of the structure. The high hydraulic gradients driving the water through the fracture and fissure system of the bedrock have a strong impact on the aquifer evolution. The increased permeability, if not prevented, leads to an imminent danger of high leakage rates (breakthrough) as well. As a result, the structural safety of the dam-site itself is at risk. Past experience has shown that this may have large environmental and economical consequences.

For a better understanding of the evolution of karst aquifer systems in the vicinity of dam-sites, a three-dimensional conceptual model is presented. We show the evolution of the karst aquifer for simple three-dimensional dam-site setups. Keeping the symmetry and simplicity of the models we can relate our results to the two- and one-dimensional scenarios presented in the past. Implementing a statistical fracture network and topographic information to this basic setup we show that these complex three-dimensional properties of the real aquifers, have a significant influence on the karstification, and cannot always be addressed by two -and one-dimensional models.

Research highlights
- Three-dimensional karst evolution modeling of dam-sites. - Relating the 3D models to former 2D and 1D models. - Implementation of statistical fracture network and topography.


Fengcong, fenglin, cone karst and tower karst, 2011, Waltham, Tony

Fengcong and fenglin are the two major types of karst terrain as defined in Chinese literature. They correlate only loosely with the Western terms of cone and tower karst respectively. With its isolated towers rising from a karst plain, fenglin is the most extreme form of karst landscape, and much of it may evolve from fengcong where tectonic uplift is critically slow, but overall it appears to be polygenetic. It is suggested that fengcong and fenglin are more useful karst terms with genetic implications and should take precedence, while cones and towers should be used purely as descriptive terms.


Hypogenic caves in western Umbria (central Italy), 2011, Menichetti, Marco

Three karst areas located in the western sector of the Umbria Region (Central Italy) are here described: one north of Perugia, and the others to the south, close to Todi. All the end members of karst processes, from solution caves to quaternary travertine deposits, are present in this region, associated with CO2 and H2S emissions. The geological and hydrogeological aspects of the main karst systems are analyzed and their underground morphologies and patterns taken into account. Caves have different sizes and vary from a single conduit to complex systems, where the passages show features related to a possible hypogenic speleogenesis. In the area north of Perugia there are small horizontal and vertical solution caves developed in poorly karstified marly limestone, along fracture systems, where phreatic morphologies are prevalent. The endogenic CO2 emissions seem to drive the underground karst evolution. Pozzi della Piana, located west of the town of Todi, is a fossil branchform network cave system developed in a quaternary travertine and extending for more than 2500 m. The cave passages are arranged on at least two levels, with phreatic morphologies, cupola ceilings, and blind pits. Microcrystalline spalled gypsum blocks are associated with cusp features and wall pockets. The cave-forming process is believed to be linked to travertine deposition by supersaturated carbonate hydrothermal water rich in H2S. In the Parrano area, the underground karst system consists of solution caves extending for many hundreds of meters at different elevations in both sides of a small gorge. The cave patterns vary from single conduits to ramiform passages with anastomotic galleries and pits that intercept the water table with a temperature of 26°C, pCO2 of 0.1 atm, and H2S concentrations of 10 mg/l. Spongework, corrosion pockets, and cupola ceilings are common morphologies, with gypsum replacing limestone wall deposits. Cave formation by hypogenic speleogenesis is also well known in the Apennine karst system of M. Cucco and Frasassi, where both fossil and active processes are observable. The same processes are responsible for the genesis of these karst systems in different geological and hydrogeological contexts.


Spreading of tracer plumes through confined telogenetic karst aquifers: A model, 2011, Gabrovsek Franci, Dreybrodt Wolfgang

To calculate spreading of a tracer or contaminant through an aquifer all details of the aquifer, e.g. distribution of hydraulic parameters, must be known. This is not possible in nature. To study the spreading of plumes through karst, we have used a digital model of a confined karst aquifer at different stages of early karstification. In these models all details such as fracture aperture widths, their lengths and widths, and the hydraulic boundary conditions are known. Therefore the flow velocity of water can be calculated in each fracture. Using this information a particle tracking method is employed to calculate the propagation and spreading of a plume caused by an instantaneous input pulse into selected regions of the aquifer. From this information the time dependence of the outflow of particles from any selected region is obtained. This function represents the transfer response function for an instantaneous Dirac ?-function input. Two digital karst models are designed. In the first, homogeneous one, the aperture widths of the fractures are statistically distributed but of similar width. In the second a coarse percolating net of prominent fractures with larger constant aperture width is embedded into the dense net of narrow fissures. Propagation of the plumes and the transfer-response function are presented at the onset of karstification and at different times of karst evolution. If particles are injected at the entrance of evolving karst channels propagating towards the output boundary tracer breakthrough times increase with increasing time of karst evolution until shortly before breakthrough of the karst conduit they drop to half of their maximal value. With increasing evolution of the karst aquifer the hydraulic heads are redistributed and regions of low hydraulic gradients in the upstream side of the aquifer are created. Particles injected into fractures which have stopped dissolutional widening of their aperture widths and are located in regions of low gradient are kept in these regions for long times in the order of 100 years until they have propagated towards regions of high hydraulic heads, where a “fan like” plume develops along the pathway of steepest gradient.
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