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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. ...

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That snowdrift is snow accumulation due to wind transport [16].?

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Karst environment, Culver D.C.
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Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
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Your search for karst genesis (Keyword) returned 30 results for the whole karstbase:
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A New Equation Solver for Modeling Turbulent Flow in Coupled Matrix‐Conduit Flow Models, ,

Karst aquifers represent dual flow systems consisting of a highly conductive conduit system embedded in a less permeable rock matrix. Hybrid models iteratively coupling both flow systems generally consume much time, especially because of the nonlinearity of turbulent conduit flow. To reduce calculation times compared to those of existing approaches, a new iterative equation solver for the conduit system is developed based on an approximated Newton–Raphson expression and a Gauß–Seidel or successive over-relaxation scheme with a single iteration step at the innermost level. It is implemented and tested in the research code CAVE but should be easily adaptable to similar models such as the Conduit Flow Process for MODFLOW-2005. It substantially reduces the computational effort as demonstrated by steady-state benchmark scenarios as well as by transient karst genesis simulations. Water balance errors are found to be acceptable in most of the test cases. However, the performance and accuracy may deteriorate under unfavorable conditions such as sudden, strong changes of the flow field at some stages of the karst genesis simulations.

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Le systme souterrain du Sornin (Berger-Fromagre, Vercors, Isre), 1983, Delannoy, J. J.
THE UNDERGROUND SYSTEM OF PLATEAU DU SORNIN (VERCORS, FRANCE): THE GOUFFRE BERGER AND THE SCIALET DE LA FROMAGERE - Gouffre Berger (-1198m) and Scialet de La Fromagre (-902m) are the two main drains of an important underground complex, which develops 26 km inside Sornin table-land, massif du Vercors, Isre. The glaciers have left deep prints in the surface morphology (Schichttreppenkarst) and have played an important role in the genesis of the underground complex of Sornin. Most of morphological elements and dated witnesses (speleothems) testify to the primacy of this morphoclimatic term. Under present bioclimatic conditions (discontinuous forest - Raw weather climate, T? = 4?C, P = 1700mm), the specific dissolution is estimated to 120mm/ky. This dissolution is important in winter (2,5 times more than in summer). Sornin plateau belongs to an intermediary case between forests mountainous karsts and high karsts regarding the spatial distribution of the dissolution.

Les karsts du gypse dans la dpression de l'Ebre, 1985, Guttierez M. , Ibanez M. J. , Pena J. L. , Rodriguez J. , Soriano M. A.
A FEW EXAMPLES OF GYPSUM KARSTS IN THE EBRO DEPRESSION (SPAIN) - Three areas where dissolution processes in gypsum formations have taken place, are studied. They show different geologic arrangements, one of them being folded, another in a flat--lying strata, and the third one covered by a thick unit of alluvials of the Ebro river. The climatic conditions are similar for these areas. Several kinds of dolines morphology, uvalas and large depressions similar to poljes can be distinguished. It seems to be established in the origin of some of these landforms, an interrelation between the fluvial processes and the dissolution ones.

Le systme souterrain de la Dent de Crolles, Isre, 1985, Marchand, Th.
THE UNDERGROUND SYSTEM OF DENT DE CROLLES (ISERE, FRANCE) - The Dent de Crolles plateau (highest point: 2062m asl.) is the southermost part of the great syncline of the eastern Chartreuse. This syncline stretches from Grenoble to Mont Granier, above Chambery. The karst of Dent de Crolles develops in urgonian limestone, and in spite of little surface (2km2), it contains the most important underground system of the French Alps (about 52km). In spite of important oceanic rainfall, underground flows only drain some small galleries. Karst genesis is related to the glaciers.

Apports des datations U/Th dans la karstogense de la Grande Moucherolle-Rochers de la Balme (Vercors), 1986, Delannoy J. J. , Holliger Ph.
234 U - 230 Th DATING OF SPELEOTHEMS AND KARSTOGENESIS OF THE "GRANDE MOUCHEROLLE-ROCHERS DE LA BALME" (VERCORS) - In this article, is presented a first geomorphological and speleological synthesis of the subalpine karst of the Grande Moucherolle (2285 m) - Rochers de Ia Balme. This area of Vercors (Alps), which has 8 caves deeper than 300m (Antre des Damns -720m; Clos de La Fure -580m...) is surely the most promising sector from a speleological point of view. Through the study of the glacio-karstic landforms and the distri-bution of the great caves, it seems that there is a real relation between these two parameters. In order to evaluate the contribution of quaternary glaciations in the genesis of caves, isotopic dating (234U-230Th) have been performed on underground carbonated deposits. After a presentation of the chronometric method 234U-230Th, the results are analysed according to their speleological environment. A paleogeographic reconstitution through the middle and recent Quaternary is proposed for the geosystem of the Grande Moucherolle - Rochers de la Balme.

Le karst pliocne de la rgion de Safi (Maroc atlantique), 1987, Weisrock A. , Lunski S.
POST-PLIOCENE KARST OF SAFI AREA (ATLANTIC MOROCCO) - The karst of Safi area is developed in bioclastic calcarenites of Plio-Moghrebian upon Mesozoic limestones, marls and gypsum. Dolines, uvalas and poljes are found along faults N170-N195, N040-N070, N080-N115, which are mainly " Mesetian " and " Atlasic " tectonic directions of Atlantic Morocco. Two points are developed upon this karst genesis: 1/ the relations between post-pliocene karstic landforms and paleokarst in limestones and gypsum; 2/ the recent karstic developments occur during the periods wetter than today (310 mm/y), for example Upper Pleistocene, as it is showed by dating of charcoal in dolines filling.

Les karsts des Pyrnes-Orientales, 1989, Salvayre, H.
The karsts of Eastern Pyrenees (France) - Karsts in the Eastern Pyrenees occur in Palaeozoic limestones (syncline of Villefranche-de-Conflent) or in Mesozoic limestones. Horizontal caves of several kilometres (En Gorner, Fuilla, Les Ambullas) are found in the Palaeozoic; but the numerous shafts are in the Mesozoic limestones. The subterranean waters circulate freely in the upper parts of the massif (Fontrabiouse), while there are many saturated karst in coastal areas (Font-Estramar). Classical types of surface karst features develop in the Corbires massif; elsewhere, in the Palaeozoic limestones, this karst morphology does not exist or is hidden under covers.

Notectonique dans le karst du N-O du lac de Thoune (Suisse), 1990, Jeannin, P. Y.
Neotectonic in the karst north of Lake Thoune (Switzerland) - The karstic area north of Lake Thoune is part of the "Border Chain" of the Swiss Alps (Cretaceous, Helvetic). It comprises large caves coming from two catchments. The first one pours out at the Beatushhle; more than 15 km of galleries are known in this area. The second one contains the Sieben Hengste - Hohgant - Hohlaub - Schrattenfluh region, it pours out at the Btterich and Gelberbrunnen springs, by Lake Thoune. It includes the very large "Sieben Hengste - Hohgant cave System" (length: 115 km; depth: 1050 m); the Brenschacht (length: >10 km; depth: 950 m), as well as several other important caves more than 1 km length. Recent shifts along faults were mainly measured in the Sieben Hengste Cave System. Neotectonic indication were of the following types: gallery sections displaced by the fault shifts, displaced pillar structures or shifted, inclined or broken speleothems. The fault movements were placed on a time scale according to the genetic evolution of the region. It indicates that there were three phases of movement, which greatly affected the underground flows and karstification. The geometric and dynamic analysis of the measured shifts and slikken-slides also indicates three phases of movements. The strain direction, causing these movements, was determined. Thus, three plio-quaternary tectonic phases were found: an alpine compressive SSE-NNW phase, followed by an extensive SSE-NNW phase and then again by a compressive one.

La karstification de l'le haute carbonate de Makatea (Polynsie franaise) et les cycles eustatiques et climatiques quaternaires, 1991, Dessay J. , Pouchan Y. , Girou A. , Humbert L. , Malezieux J.
THE KARST 0F MAKATEA ISLAND (FRENCH POLYNESIA) AND THE CLIMATIC AND GLACIO-EUSTATISM SETTING - Located in the Central Pacific, in the northwestern part of the Tuamotu Archipelago, Makatea island (148 15 W - 15 50 S) is an uplifted, karstic, carbonate construction of Early Miocene age, which reaches 113m in height. From 1906 to 1966, phosphate deposits were exploited on Makatea Island. These phosphate deposits (apatite) overlaid the Miocene series and filled the karstic cavities in the higher regions of the island. Several traces of ancient shorelines can be observed on Makatea: 1/ three different reef formations, which reach about +27m, +7m, +1m above the present mean sea level and respectively dated 400,000 100,000 yr BP, 140,000 30,000 yr BP, between 4,470 150 yr BP and 3,720 13O yr BP; 2/ four distinct marine notch lines on the Early Miocene cliff at about +1m, +7m, +27m and +56m (or +47m on the west coast caused by tilt) above the present mean sea level; 3/ two exposed marine platforms respectively at +29m and +7m above the present mean sea level. The ages of the former makatean shores are inferred by using: (1) the Pacific glacio-eustatic sea-level curve for the last 140,000 yr BP, (2) the Pacific oxygen isotope curve for the last 900,000 yr BP, and (3) a constant uplift rate during the Pleistocene. In this way, according to their age and elevation, the sea-level indicators at about +1m, +7m and +27m (+29m) above the present mean sea level can be respectively related to the Holocene transgression (Flandrian) dated between 6,000 and 1,500 yr BP, to the last Pleistocene interglacial period (Sangamon) dated between about 130,000 and 110,000 yr BP, and to a Middle Pleistocene interglacial period (Yarmouth) dated between about 315,000 and 485,000 yr BP. If we assume that a sea level similar to the present occurred during the Yarmouth inter-glacial period, the uplift rate is valued at 0.085 mm/yr to 0.056 mm/yr. Thus the sea-level associated with the marine notch at about +56m (+47m) may be about 650,000 yr to 1 M.y. old and can be associated with another Pleistocene interglacial period (Aftonian). Consequently, as indicated by the former shores, the sea level fluctuations can be related to the major glacio-eustatic quaternary events. This climatic and eustatic setting is used to explain the karst observed on the Makatea island. Carbonate dissolution and essentially vertical karst genesis were the result of the superposition of several cycles. Each cycle was initially composed of a solution of the carbonates during an interglacial period, followed by a drainage of the saturated solutions during the marine regression associated with the consecutive glacial period. Nevertheless, this scheme is not enough to explain the specific morphology of the makatean karstic cavities and we suggest using insular phosphatisation to explain this karst genesis. It is generally accepted that phosphate rock deposits on coral reef islands are the result of chemical reaction between seabird guano and reef limestone. Furthermore, petrographic and stable isotope studies suggest several generations of phosphorite formation and reworking episodes in the history of these deposits. The primary deposition of phosphates must have begun during a glacial period. This deposition was followed by some redistribution of phosphorites during the interglacial period and by additional precipitation of apatite from meteoric waters. This assumed process of phosphogenesis is consistent with both the field observations and the geodynamic evolution of Makatea. Thus, the particular morphology of the makatean karst can be the result of the dissolution of the carbonates caused by phosphoric acid etching. This acid is derived from the evolution of the phosphorites during the pleistocene interglacial periods.

Evolution des karsts Ocaniens (Karsts, bauxite et phosphates), 1992, Bourrouilhlejan, Fr.
EVOLUTION OF THE PACIFIC OCEAN KARSTS - Karst phenomena constitute one of the main characteristics of the "high carbonate islands" of the Pacific Ocean. They are the key to the under-standing of the geological evolution, the stratigraphy, from Lower Miocene to Pleistocene and mid-Holocene, the diagenesis, mainly dolomitization and the current economic interest based on bauxite and phosphate. The eustatic variations have been numerous over the past 25 million years and can be added or substracted from the emersion and submersion movements of the plate supporting these carbonate platforms. Each island therefore has its own complex geological background with dolomitization, calcrete, bauxitic soils, fossil marine notches and karst surface either submerged or filled with phosphate, which can be mined for profit. Thanks to a thorough study of these platforms, it has been possible to establish an evolution of karst genesis in accordance with the evolution of the Pacific lithosphere and also to draw up a new model of phosphate genesis linked to phosphato-bauxitic soils and meromictic anoxic lakes.

Les karsts dans le Jurassique ardchois, 1992, Marchand, Th.
ARDECHE KARSTS IN THE JURASSIC LIMESTONES - The southern part of the department of the Ardeche consists of numerous karstic zones. In these places, there are several caves, some of which are well-known: The Sauvas-Cocalieres cave, St Marcels cave... But speleological and scientific studies have mainly focused on the Cretaceous karst. The Ardche gorges cut through this area. The Jurassic karsts although lesser known deserve to be studied in depth for their hydrogeological and geomorphologic interest. The surface landforms show evidence of the intense karstification, but it is deep down underground that these phenomena are most impressive. Four elements characterise the originality of these plateaus: the very strong amplitude of outflows in relation to the structure, the active grinding and the neotectonic affect most of the caves, the importance of the fillings which are sometimes allochtonous and the probable age of the caves. In most cases, investigating them means using subterranean diving techniques.

Structure et comportement hydraulique des aquifers karstiques, DSc thesis, 1996, Jeannin, P. Y.

This thesis aims to provide a better knowledge of karst flow systems, from a functional point of view (behaviour with time), as well as from a structural one (behaviour in space). The first part of the thesis deals with the hydrodynamic behaviour of karst systems, and the second part with the geometry of karstic networks, which is a strong conditioning factor for the hydrodynamic behaviour.
Many models have been developed in the past for describing the hydrodynamic behaviour of karst hydrogeological systems. They usually aim to provide a tool to extrapolate, in time and/or space, some characteristics of the flow fields, which can only be measured at a few points. Such models often provide a new understanding of the systems, beyond what can be observed directly in the field. Only special field measurements can verify such hypotheses based on numerical models. This is an significant part of this work. For this purpose, two experimental sites have been equipped and measured: Bure site or Milandrine, Ajoie, Switzerland, and Holloch site, Muotathal, Schwyz, Switzerland. These sites gave us this opportunity of simultaneously observe hydrodynamic parameters within the conduit network and, in drillholes, the "low permeability volumes" (LPV) surrounding the conduits.
These observations clearly show the existence of a flow circulation across the low permeability volumes. This flow may represent about 50% of the infiltrated water in the Bure test-field. The epikarst appears to play an important role into the allotment of the infiltrated waters: Part of the infiltrated water is stored at the bottom of the epikarst and slowly flows through the low permeability volumes (LPV) contributing to base flow. When infiltration is significant enough the other part of the water exceeds the storage capacity and flows quickly into the conduit network (quick flow).
For the phreatic zone, observations and models show that the following scheme is adequate to describe the flow behaviour: a network of high permeability conduits, of tow volume, leading to the spring, is surrounded by a large volume of low permeability fissured rock (LPV), which is hydraulically connected to the conduits. Due to the strong difference in hydraulic conductivity between conduits and LPV, hydraulic heads and their variations in time and space are strongly heterogeneous. This makes the use of piezometric maps in karst very questionable.
Flow in LPV can be considered as similar to flow in fractured rocks (laminar flow within joints and joints intersections). At a catchment scale, they can be effectively considered as an equivalent porous media with a hydraulic conductivity of about 10-6 to 10-7 m/s.
Flow in conduits is turbulent and loss of head has to be calculated with appropriate formulas, if wanting any quantitative results. Our observations permitted us to determine the turbulent hydraulic conductivity of some simple karst conduits (k', turbulent flow), which ranges from 0.2 to 11 m/s. Examples also show that the structure of the conduit network plays a significant role on the spatial distribution of hydraulic heads. Particularity hydraulic transmissivity of the aquifer varies with respect to hydrological conditions, because of the presence of overflow conduits located within the epiphreatic zone. This makes the relation between head and discharge not quadratic as would be expected from a (too) simple model (with only one single conduit). The model applied to the downstream part of Holloch is a good illustration of this phenomena.
The flow velocity strongly varies along the length of karst conduits, as shown by tracer experiments. Also, changes in the conduit cross-section produce changes in the (tow velocity profile. Such heterogeneous flow-field plays a significant role in the shape of the breakthrough curves of tracer experiments. It is empirically demonstrated that conduit enlargements induce retardation of the breakthrough curve. If there are several enlargements one after the other, an increase of the apparent dispersivity will result, although no diffusion with the rock matrix or immobile water is present. This produces a scale effect (increase of the apparent dispersivity with observation scale). Such observations can easily be simulated by deterministic and/or black box models.
The structure of karst conduit networks, especially within the phreatic zone, plays an important role not only on the spatial distribution of the hydraulic heads in the conduits themselves, but in the LPV as well. Study of the network geometry is therefore useful for assessing the shape of the flow systems. We further suggest that any hydrogeological study aiming to assess the major characteristics of a flow system should start with a preliminary estimation of the conduit network geometry. Theories and examples presented show that the geometry of karst conduits mainly depends on boundary conditions and the permeability field at the initial stage of the karst genesis. The most significant boundary conditions are: the geometry of the impervious boundaries, infiltration and exfiltration conditions (spring). The initial permeability field is mainly determined by discontinuities (fractures and bedding planes). Today's knowledge allows us to approximate the geometry of a karst network by studying these parameters (impervious boundaries, infiltration, exfiltration, discontinuity field). Analogs and recently developed numerical models help to qualitatively evaluate the sensitivity of the geometry to these parameters. Within the near future, new numerical tools will be developed and will help more closely to address this difficult problem. This development will only be possible if speleological networks can be sufficiently explored and used to calibrate models. Images provided by speleologists to date are and will for a long time be the only data which can adequately portray the conduit networks in karst systems. This is helpful to hydrogeologists. The reason that we present the example of the Lake Thun karst system is that it illustrates the geometry of such conduits networks. Unfortunately, these networks are three-dimensional and their visualisation on paper (2 dimensions) is very restrictive, when compared to more effective 3-D views we can create with computers. As an alternative to deterministic models of speleogenesis, fractal and/or random walk models could be employed.


Nouveau regard sur la splogense : le pseudo-karst du Tournaisis (Hainaut, Belgique), 1998, Vergari, Anne
In the paleokarstic features of the carboniferous limestones (Synclinorium of Namur Hainaut, Belgium) new endokarstic forms have been discovered and named "pseudo-endokarsts". From a morphological point of view, the pseudo-endokarst looks like a gallery. But, in fact, it results from an in-situ alteration: the "ghost rocks". The study of the sedimentary cross-section in the "pic--glace cave" described in this article offers new understanding of endokarst genesis. Dynamic flows are not any more the only way to initiate karstification.

Structure et comportement hydraulique des aquifers karstiques, DSc. Thesis, faculte des Sciences de l'Universite de Neuchatel., 1998, Jeannin Py.
This thesis aims to provide a better knowledge of karst flow systems, from a functional point of view (behaviour with time), as well as from a structural one (behaviour in space). The first part of the thesis deals with the hydrodynamic behaviour of karst systems, and the second part with the geometry of karstic networks, which is a strong conditioning factor for the hydrodynamic behaviour. Many models have been developed in the past for describing the hydrodynamic behaviour of karst hydrogeological systems. They usually aim to provide a tool to extrapolate, in time and/or space, some characteristics of the flow fields, which can only be measured at a few points. Such models often provide a new understanding of the systems, beyond what can be observed directly in the field. Only special field measurements can verify such hypotheses based on numerical models. This is an significant part of this work. For this purpose, two experimental sites have been equipped and measured: Bure site or Milandrine, Ajoie, Switzerland, and Holloch site, Muotathal, Schwyz, Switzerland. These sites gave us this opportunity of simultaneously observe hydrodynamic parameters within the conduit network and, in drillholes, the "low permeability volumes" (LPV) surrounding the conduits. These observations clearly show the existence of a flow circulation across the low permeability volumes. This flow may represent about 50% of the infiltrated water in the Bure test-field. The epikarst appears to play an important role into the allotment of the infiltrated waters: Part of the infiltrated water is stored at the bottom of the epikarst and slowly flows through the low permeability volumes (LPV) contributing to base flow. When infiltration is significant enough the other part of the water exceeds the storage capacity and flows quickly into the conduit network (quick flow). For the phreatic zone, observations and models show that the following scheme is adequate to describe the flow behaviour: a network of high permeability conduits, of tow volume, leading to the spring, is surrounded by a large volume of low permeability fissured rock (LPV), which is hydraulically connected to the conduits. Due to the strong difference in hydraulic conductivity between conduits and LPV, hydraulic heads and their variations in time and space are strongly heterogeneous. This makes the use of piezometric maps in karst very questionable. Flow in LPV can be considered as similar to flow in fractured rocks (laminar flow within joints and joints intersections). At a catchment scale, they can be effectively considered as an equivalent porous media with a hydraulic conductivity of about 10-6 to 10-7 m/s. Flow in conduits is turbulent and loss of head has to be calculated with appropriate formulas, if wanting any quantitative results. Our observations permitted us to determine the turbulent hydraulic conductivity of some simple karst conduits (k',turbulent flow), which ranges from 0.2 to 11 m/s. Examples also show that the structure of the conduit network plays a significant role on the spatial distribution of hydraulic heads. Particularity hydraulic transmissivity of the aquifer varies with respect to hydrological conditions, because of the presence of overflow conduits located within the epiphreatic zone. This makes the relation between head and discharge not quadratic as would be expected from a (too) simple model (with only one single conduit). The model applied to the downstream part of Holloch is a good illustration of this phenomena. The flow velocity strongly varies along the length of karst conduits, as shown by tracer experiments. Also, changes in the conduit cross-section produce changes in the (tow velocity profile. Such heterogeneous flow-field plays a significant role in the shape of the breakthrough curves of tracer experiments. It is empirically demonstrated that conduit enlargements induce retardation of the breakthrough curve. If there are several enlargements one after the other, an increase of the apparent dispersivity will result, although no diffusion with the rock matrix or immobile water is present. This produces a scale effect (increase of the apparent dispersivity with observation scale). Such observations can easily be simulated by deterministic and/or black box models. The structure of karst conduit networks, especially within the phreatic zone, plays an important role not only on the spatial distribution of the hydraulic heads in the conduits themselves, but in the LPV as well. Study of the network geometry is therefore useful for assessing the shape of the flow systems. We further suggest that any hydrogeological study aiming to assess the major characteristics of a flow system should start with a preliminary estimation of the conduit network geometry. Theories and examples presented show that the geometry of karst conduits mainly depends on boundary conditions and the permeability field at the initial stage of the karst genesis. The most significant boundary conditions are: the geometry of the impervious boundaries, infiltration and exfiltration conditions (spring). The initial permeability field is mainly determined by discontinuities (fractures and bedding planes). Today's knowledge allows us to approximate the geometry of a karst network by studying these parameters (impervious boundaries, infiltration, exfiltration, discontinuity field). Analogs and recently developed numerical models help to qualitatively evaluate the sensitivity of the geometry to these parameters. Within the near future, new numerical tools will be developed and will help more closely to address this difficult problem. This development will only be possible if speleological networks can be sufficiently explored and used to calibrate models. Images provided by speleologists to date are and will for a long time be the only data which can adequately portray the conduit networks in karst systems. This is helpful to hydrogeologists. The reason that we present the example of the Lake Thun karst system is that it illustrates the geometry of such conduits networks. Unfortunately, these networks are three-dimensional and their visualisation on paper (2 dimensions) is very restrictive, when compared to more effective 3-D views we can create with computers. As an alternative to deterministic models of speleogenesis, fractal and/or random walk models could be employed.

Variability of karstic permeability between unconfined and confined aquifers, Grand Canyon region, Arizona, 2000, Huntoon P. W. ,
Most of the ground water in the Grand Canyon region circulates to springs in the canyon through the thick, deeply buried, karstified Cambrian-Mississippian carbonate section. These rocks are collectively called the lower Paleozoic carbonates and comprise the Redwall-Muav aquifer where saturated. The morphologies of the caves in the Grand Canyon are primarily a function of whether the carbonates are unconfined or confined, a distinction that has broad significance for ground-water exploration and which appears to be generally transferable to other carbonate regions. Caves in unconfined high-gradient environments tend to be highly localized, partially saturated, simple tubes, whereas those in confined low-gradient settings are saturated 2- or even 3-dimensional mazes. The highly heterogeneous, widely spaced conduits in the unconfined settings make for difficult drilling targets, whereas the more ubiquitously distributed mazes in confined settings are far easier to target. The distinctions between the storage characteristics within the two classes are more important. There is minimal ground-water storage in the unconfined systems because cave passages tend to be more widely spaced and are partially drained. In contrast, there is maximum storage in the saturated mazes in the confined systems. Consequently, system responses to major storm recharge events in the unconfined systems are characterized by flow-through hydraulics. Spring discharge from the unconfined systems tends to be both flashy and highly variable from season to season, but total dissolved solids are small. In contrast, the pulse-through hydraulics in the artesian systems cause fluctuations in spring discharge to be highly moderated and, in the larger basins, remarkably steady. Both total dissolved solids and temperatures in the waters from the confined aquifers tend to be elevated because most of the water is derived from storage. The large artesian systems that drain to the Grand Canyon derive water from areally extensive, deep basins where the water has been geothermally heated somewhat above mean ambient air temperatures. Karst permeability is created by the flow system, so dissolution permeability develops most rapidly in those volumes of carbonate aquifers where flow concentrates. Predicting where the permeability should be best developed in a carbonate section involves determining where flow has been concentrated in the geologic past by examining the geometry and hydraulic boundary conditions of the flow field. Karstification can be expected to maximize in those locations provided enough geologic time has elapsed to allow dissolution to adjust to the imposed boundary conditions. The rate of adjustment in the Grand Canyon region appears to be related to the degree of saturation. The artesian systems are far better adjusted to hydraulic gradients than the unconfined systems, a finding that probably implies that there is greater contact between the solvent and rock in the saturated systems. These findings are not arcane distinctions. Rather, successful exploration for ground water and management of the resource is materially improved by recognition of the differences between the types of karst present. For example, the unsaturated conduit karsts in the uplifts make for highly localized, high risk drilling targets and involve aquifers with very limited storage. The conduits have highly variable flow rates, but they carry good quality water largely derived from seasonal flow-through from the surface areas drained. In contrast, the saturated basin karsts, with more ubiquitous dissolutional permeability enhancement, provide areally extensive low risk drilling targets with large ground-water storage. The ground water in these settings is generally of lesser quality because it is derived mostly from long term storage

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