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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. ...

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That anion is a negatively charged ion that migrates to an anode, as in electrolysis [6].?

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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 fracturation (Keyword) returned 16 results for the whole karstbase:
Showing 1 to 15 of 16
Fracturation and Karstification of a Massif: the example of the Azerou El Kebir (Northern Algeria)., 1978, Coiffait P. E. , Quinif Yves
The fracturation of the sub-autochthonous massif of the Azerou el Kebir is not fundamentally different from that of the adjoining allochthonous massif; where the structures are due to an Alpine phase, known as the Atlas phase. As with all fractures, karstification only exploits certain of them, without having any linkage to their statistical importance, caves have developed following fractures which are qualitatively important, but are poorly represented quantitatively. The study of the karstification therefore, confirms his complementary to the structural analysis in order to elucidate the technical problems of fracturation in the region.

Structures des aquifres carbonats d'aprs les donnes de captages d'eau, 1984, Pulidobosch A. , Castillo E.
STRUCTURE OF CARBONATE AQUIFERS IN EASTERN SPAIN FROM THE DATA DERIVED FROM WELLS - From a statistical analysis of the data from several wells, pumping the carbonate materials of Creu Formation (Cenomanian-Senonian), in an area in Eastern Spain, it can be deduced that the yield and specific capacity fits well to a log-normal theoretical distribution. The biggest capacity of the wells located in discharge areas respect to the wells situated in recharge areas is interpreted as a result of the "hierarchical" role of karstification processes.

Le massif du Parmelan, Haute-Savoie, relations fractura-tion-karstification, 1985, Masson, M.
THE MASSIF OF PARMELAN, HAUTE-SAVOIE, FRANCE: RELATIONS BETWEEN FRACTURATION AND KARSTIFICATION - The massif of Parmelan (Haute-Savoie), encloses a well-karstified and highly organised perched aquifer. Its simple geological structure and easy-speleological penetration (more than 45km are known) have allowed a statistical study of the fracturation and karstification parameters at different scales. This study shows that the karst has developed on the most frequent fracturation directions (study of the cumulated lengths), whereas its directional distribution in frequency is relatively homogeneous; the most used fractures are the tension faults, linked with the folding of the massif.

Les surfaces karstiques du plateau de Montrieux (Var), tude quantitative de la fracturation, 1990, Blanc J. J. , Nicod J.
THE KARSTIC SURFACES OF MONTRIEUX PLATEAU (VAR) - Statistical analysis of the jointing. Network jointing analysis in relation to the karstic areas with dolomitized Upper Jurassic and Lower Cretaceous limestones (Valbelle, Montrieux and Morieres forest). Statistical results show some networks and tectonic occurrences correlated with an anisotropic status. Stresses repartition in space and time are linked to an ancient polygenic evolution. Data treatment outputs mark some relations with the quantitative spectrum of jointing extension, dolomitic surface morphology and eventual water drains.

IMPACT OF PAST SEDIMENT ECOLOGY ON ROCK FRACTURATION AND DISTRIBUTION OF CURRENT ECOSYSTEMS (JURA, FRANCE), 1991, Gaiffe M, Bruckert S,
Differences in the fracture type of limestone rocks have resulted in the formation of several main plant soil ecosystems in the montane and subalpine zones of the Jura (800-1 700 m). The sites were on stable landscape with slope < 5%. Locations were chosen to reflect the variation in physical properties of the bedrock and lithic contact. The rock fractures (densities and size), the shape and size of the fragments and the hydraulic conductivities were described and analyzed to characterize the 3 main bedrocks in the area studied (table 1): 1), lapiaz, ie, large rock fragments separated from each other by wide fractures (figs 1-2), 'broken' rocks traversed by numerous fine fractures (fig 2-3), paving-stones crossed by infrequent narrow fractures (fig 3). The effects of rock fracturing on vegetation (table II) and soil formation were significant in reference to porosity and permeability relationships (figs 6-7). Under similar precipitation, meteoric waters flow through the soil and porosity is relative to fracture systems (figs 4, 5). The weathering of cobbles in the soil profiles and along the lithic contacts maintains different soil solution Ca levels and is an important variable in soil and ecosystem formation (table III). Regarding the regional orogenic phases and the tectonic origin of the fractures, we postulate that the different types of fracturation originated from the different chemical and mineralogic composition of the rocks. Significant differences exist in both the calcite and dolomite content, in the insoluble residue content (table IV) and in the percentage of organic matter of the carbonate-free residues (table V, fig 8). The results indicate that the differences in rock composition arose early at about the period of sedimentation. The origin of the differentiation might be due to the sedimentation conditions and environment (fig 9). It is concluded that the present-day plant soil ecosystems may be related to the marine sediment environments of the Jurassic period (fig 10)

Le palokarst littoral de Provence (Estaque, Calanques et zone de Bandol), 1993, Blanc, J. J.
The general features of coastal paleokarst in Provence are describes: suspended gallery sections and drain-pipes cut across by fracturations or fault reactivation. The types of deformations and breaking observed are tilting, stalactite fall, extension fault sealing, reactivation and speleothem shearing, coastal wall and karstic cleft collapse as well as network deformation. The influence of structural environment is represented by overlapping strata, coastal faults and crossed-fault systems. Emphasis has been laid on the tectonic inheritance as well as the geodynamic context. To conclude, the importance of provenal-ligurian rifting mechanisms and the transition to faulted and distorted margin is underlined.

INFLUENCE OF THE FRACTURATION IN THE PRECAMBRIAN BASEMENT AND OF DISSOLUTION PHENOMENA IN THE LITHOMARGIN ON THE GEOMORPHOLOGICAL EVOLUTION IN WEST NIGER, 1993, Willems L. , Lenoir F. , Levecq J. M. , Vicat J. P. ,
The observation of several forms in the Precambrian formations, in Tertiary and Quaternary deposits brings us to propose a model of topographic evolution mainly generated by a pseudo-karst. This latter is developed in sedimentary deposits and in the lithomargin, in relation with fracturation of the basement

Prhistoire et karst littoral : la grotte Cosquer et les calanques mar_seillaises (Bouches-du-Rhne, France), 1996, Collinagirard, J.
The Cosquer Cave is a French palaeolithic painted and engraved cave (27000/ 18500 BP) which is located under the sea, in the urgonian limestones of Cap Morgiou ("Massif des Calanques"; Marseille). The en trance was submerged at the end of the last glacial stage and is presently 37 m under sea level. A synthesis about the Cosquer cave environmental studies is presented here. Structural studies show that cave planimetry is determined by Cap Morgiou fracturations (mainly NW/SE and N/S vertical faults). Through archaeological studies, a concretion breaking period can be dated between 27000 and 18000 BP. Geomorphological study of the continental shelf at the foot of the Cosquer cave area shows fossils shorelines at -36 m, -50/55 m, -90 m, -100 m depth. Radiocarbon datings from shells collected in 100m sediments yielded a date of 13 250 BP. Direct scuba diving observations and submarine clive profiles sketching show several eustatic stand-still levels between -36 m and the sea surface indicating a probable tectonic stability during the last 10000 years.

Interprtation morphomtrique et splo_gense : exemple de rseaux karstiques de Basse-Provence (directions de galeries, modle et maillage structural), 1997, Blanc Jeanjoseph, Monteau Raymond
Successive tectonic phases on limestone massifs are at the origin of a fracturation grid with several pattern dimensions, and linear or organized drain directions. Mechanical reactivations are observed from Oligocene until Plio-Quaternary on a former "pyreneo-provenale" structure (Eocene). Statistical analysis of gallery and fracture directions, cave levels and descent stages (overdeepening) show several erosional stages occurring after the formation of the Antevindobonian erosional surface. The active speleogenesis during Oligocene and Miocene was controlled by tectonics in connection with European rifting and mediterranean opening. In Messinian a short and significant lowering of mediterranean base level (and water table) made drastic erosion and created vertical pits. The horizontal cave level dug during the stabilization phase of Pliocene, now perched over underground rivers, shows a new overdeepening because of glacio-eustatic Quaternary oscillations. Compressive or distensive mechanical reactivations (Upper Miocene, Pliocene, Quaternary) modified the drainage and consequently the cave organization: self-piracy, confluence and diffluence. In the endokarst, the drainage inversion can be detected in late Upper continental Miocene and early Messinian (6,5 Ma), in correlation with the tilting and extension of the continental margin. Five caves in Provence are studied: Sabre, Petit Saint-Cassien, Rampins, Planesselve river, and Tete du Cade networks.

Relation entre ecoulements et fractures ouvertes dans un systeme aquifere compartimente par des failles et mise en evidence d'une double porosite de fractures, 1999, Bruel T, Petit Jp, Massonnat G, Guerin R, Nolf Jl,
Hydrodynamic characterisation of real fracture systems is necessary to improve modelling of fracture reservoirs as well as nuclear waste disposal sites. This characterisation is usually considered globally and theoretically but very few studies have aimed to identify the real physical environment of flow (matrix, faults, joints etc.) before establishing hydrodynamical models. We present a case study in a fractured reservoir aiming to give an example of how and why fluids actually flow within a given fracture at the various scales of fracturation of a fracture network. This study demonstrates that the determination of type and orientation of fractures actually supporting flow is necessary for accurate interpretation of the pumping tests within a fractured reservoir. It also shows that there is no simple relationship between the fault offset and the importance of flow, probably due to the influence of in situ stress. It is shown that the combination of various methods can be used to determine the fracture-flow relationship and behaviour at subseismic scale in subsurface conditions

Exploitation of massif fracturation by karstification: example of the Causse de I'Hortus (Herault, France), 1999, Boinet N,
The Causse de l'Hortus is a particularly well adapted massif to the survey of the fracturation and to its interdependences with karstification. The on-going realisation of a hydrogeological and speleological monograph of the massif, as well as the existence of more than twenty kilometers of prospected channels belonging to the active networks, provide new data which can be compared with previous surveys carried out in this field. The comparison of the directions of fracturation, visible on aerial photographs with directions currently exploited by the karstic channels on the whole Causse, show the effect of the greater fractures and the influence of the hydraulic gradient on the exploitation of the fracture spectrum. To sum up, the display of the relationships between the dextral disconnecting faults and the temporary emergences of the 'boulidou' type, results in concrete applications for speleological and hydrogeological aspects. The survey of these 'boulidous' provides new information about the vertical structuration of the karst. (C) Elsevier, Paris

Existence of karsts into silicated non-carbonated crystalline rocks in Sahelian and Equatorial Africa, hydrogeological implications, 2002, Willems Luc, Pouclet Andre, Vicat Jean Paul,
Various cavities studied in western Niger and South Cameroon show the existence of important karstic phenomena into metagabbros and gneisses. These large-sized caves resulted from generalized dissolution of silicate formations in spite of their low solubility. Karstification is produced by deep hydrous transfer along lithological discontinuities and fracture net works. The existence of such caves has major implications in geomorphology, under either Sahelian and Equatorial climate, and in hydrogeology and water supply, particularly in the Sahel area. Introduction. - Since a few decades, several karst-like morphologies are described in non-carbonated rocks (sandstones, quartzites, schistes, gneisses...) [Wray, 1997 ; Vicat and Willems, 1998 ; Willems, 2000]. The cave of Guessedoundou in West Niger seems to be due to a large dissolution of metagabbros. The cave of Mfoula, South Cameroon, attests for the same process in gneisses. This forms proof that big holes may exist deeper in the substratum even of non-carbonated silicate rocks. Their size and number could mainly influence the landscape and the hydrogeology, especially in the Sahelian areas. Guessedoundou, a cave into metagabbros in West Niger. - The site of Guessedoundou is located 70 km south-west of Niamey (fig. 1). The cave is opened at the top of a small hill, inside in NNE-SSW elongated pit (fig. 2 ; pl. I A). The hole, 3 to 4 m deep and 20 m large, has vertical walls and contains numerous sub-metric angular blocks. A cave, a few meters deep, comes out the south wall. Bedrocks consist of metagabbros of the Makalondi greenstone belt, a belt of the Palaeoproterozoic Birimian Formations of the West Africa craton [Pouclet et al., 1990]. The rock has a common granular texture with plagioclases, partly converted in albite and clinozoisite, and pyroxenes pseudomorphosed in actinote and chlorite. It is rather fairly altered. Chemical composition is mafic and poorly alkaline (tabl. I). A weak E-W schistosity generated with the epizonal thermometamorphism. The site depression was created along a N010o shear zone where rocks suffered important fracturation and fluid transfers, as shown by its silification and ferruginisation. The absence of human activity traces and the disposition of the angular blocks attest that the pit is natural and was due to the collapse of the roof of a vast cavity whose current cave is only the residual prolongation. To the vertical walls of the depression and at the cave entry, pluridecimetric hemispheric hollows are observed (pl. I B). Smooth morphology and position of these hollows sheltered within the depression dismiss the assumptions of formation by mechanical erosion. In return, these features are typical shape of dissolution processes observed into limestone karstic caves. That kind of process must be invoked to explain the opening of the Guessedoundou cave, in the total lack of desagregation materials. Dissolution of metagabbro occurred during hydrous transfer, which was probably guided by numerous fractures of the shear zone. Additional observations have been done in the Sirba Valley, where similar metabasite rocks constitute the substratum, with sudden sinking of doline-like depressions and evidence of deep cavities by core logging [Willems et al., 1993, 1996]. It is concluded that karstic phenomena may exist even in silica-aluminous rocks of crystalline terrains, such as the greenstones of a Precambrian craton. Mfoula a cave into gneisses in South Cameroon. - The cave of Mfoula is located 80 km north-east of Yaounde (fig. 3). It is the second largest cave of Cameroon, more than 5,000 m3, with a large opening in the lower flank of a deep valley (pl. I C). The cavity is about 60 m long, 30 m large and 5 to 12 m high (fig. 4; pl. I D). It is hollowed in orthogneisses belonging to the Pan-African Yaounde nappe. Rocks exhibit subhorizontal foliation in two superposed lithological facies: the lower part is made of amphibole- and garnet-bearing layered gneisses, and the upper part, of more massive granulitic gneisses. Average composition is silico-aluminous and moderately alkaline (tabl. I). The cave is made of different chambers separated by sub-cylindrical pillars. The ceiling of the main chamber, 6 m in diameter, is dome-shaped with a smooth surface (D, fig. 4). The walls have also a smooth aspect decorated with many hemispherical hollows. The floor is flat according to the rock foliation. They are very few rock debris and detrital fragments and no traces of mechanical erosion and transport. The general inner morphology is amazingly similar to that of a limestone cave. The only way to generate such a cavity is to dissolve the rock by water transfer. To test the effect of the dissolution process, we analysed a clayey residual sampled in an horizontal fracture of the floor (tabl. I). Alteration begins by plagioclases in producing clay minerals and in disagregating the rock. However, there is no more clay and sand material. That means all the silicate minerals must have been eliminated. Dissolution of silicates is a known process in sandstone and quartzite caves. It may work as well in gneisses. To fasten the chemical action, we may consider an additional microbial chemolitotrophe activity. The activity of bacteria colonies is known in various rocks and depths, mainly in the aquifer [Sinclair and Ghiorse, 1989 ; Stevens and McKinley, 1995]. The formation of the Mfoula cave is summarized as follow (fig. 5). Meteoric water is drained down along sub-vertical fractures and then along horizontal discontinuities of the foliation, particularly in case of lithological variations. Chemical and biological dissolution is working. Lateral transfers linked to the aquifer oscillations caused widening of the caves. Dissolved products are transported by the vertical drains. Regressive erosion of the valley, linked to the epeirogenic upwelling due to the volcano-tectonic activity of the Cameroon Line, makes the cavities come into sight at the valley flanks. Discussion and conclusion. - The two examples of the Guessedoundou and Mfoula caves evidence the reality of the karsts in non-carbonated silicated rocks. The karst term is used to design >> any features of the classical karst morphology (caves, dolines, lapies...) where dissolution plays the main genetical action >> [Willems, 2000]. Our observations indicate that (i) the karst genesis may have occurred into any kind of rocks, and (ii) the cave formation is not directly dependent of the present climate. These facts have major consequences to hydrogeological investigations, especially for water supply in Sahelian and sub-desertic countries. Some measurements of water transfer speed across either sedimentary pelitic strata of the Continental terminal or igneous rocks of the substratum in West Niger [Esteves and Lenoir, 1996 ; Ousmane et al., 1984] proved that supplying of aquifers in these silico-aluminous rocks may be as fast as in a karstic limestone. That means the West Niger substratum is highly invaded by a karstic net and may hidden a lot of discontinuous aquifers. The existence of this karst system can be easily shown by morphological observations, the same that are done in karstic limestone regions (abnormally suspended dry valleys, collapses, dolines...). Clearly, this must be the guide for any search of water, even in desertic areas where limestones are absent

Quaternary dedolomitization along fracture systems in a Late Triassic dolomitized platform (western Southern Alps, Italy), 2004, Ronchi P. , Jadoul F. , Savino R. ,
The studied area belongs to a south vergent thrust and fold belt of the Southern Alps of central Lombardy where the norian Dolomia Principale crops out. This up to 2 km thick carbonate platform succession has been massively dolomitized from early to shallow burial diagenesis. Dark grey bedded dolostones (basal Dolomia Principale), outcropping along the both lower slopes of Iseo Lake (lower Camonica Valley), show a complex network of dedolomitized white-grey areas. The calcareous lenses show an irregular, elongated (up to few ineters large) shape; they are usually located along fault-fracture systems and extending along the strata bedding. Two main fabrics have been recognized: the fabric A is formed by a reticulate of small fractures filled by calcite and surrounded by fine grained calcitized halos, the fabric B is associated to more intense fracturation process that locally gave rise to breccia fabric; moreover a ochre-reddish internal sediment is locally present in small cavities or as a breccia matrix, a huge speleothem-like cementation is associated to these dedolomitized fabric. This study was aimed to reconstruct the dedolomitization process and to propose a relevant genetic model. The petrographic analyses, integrated using cathodoluminescence and electron scanning microscope allowed to find out that dedolomitization process is composed of a first phase of dolomite dissolution along permeable path ways, both at the macro and at the micro scale, followed by calcite precipitation in the pore spaces. The negative delta(13)O and delta(13)C values of the calcite cements and the calcitic fraction of the dedolomitized fabrics suggest precipitation in presence of meteoric water derived fluids. Radiometric absolute age determination (U-230/Th-234) indicates that calcite cements precipitated in the last 100000 years: age during which the area was subject to several advances and retreats of glacial tongues. The field mapping, analytical data and the geomorphology of the areas where the dedolomitized patches are more frequent, in correspondence of a narrow passage of the lower Camonica valley, allowed us to infer that the dedolomitization developed during glacial-interglacial phases particularly active in the region during the Pleistocene. In particular we propose that the fracturation and the first phase of dedolomitization (fabric A) occurred during the glacial period, while extensive calcite precipitation and brecciation (fabric B) formed during the interglacial periods, dominated by a warm climate during which extensive soil cover and karst processes developed

Etude de la karstification partir des donnes de forages : le cas des Monts de Tlemcen (Algrie), 2007, Bensaoula Fouzia
STUDY OF KARSTIFICATION FROM BOREHOLE DATA. THE CASE OF THE TLEMCEN MOUNTAINS. The Tlemcen mountains are the second largest carbonate massif in the north-west of Algeria, after the one of the Saida mountains. It is a large horst structure trending NE-SW, composed mainly of Upper Jurassic and Lower Cretaceous formations. The aquifers within it constitute the main water resource of the area. They are tapped by more than 160 boreholes, which constitute a great tool for studying the karst, especially its phreatic part. In the holes made by conventional drills, the total loss of drilling mud indicate karstification. The registration of the altitude of those losses permit to recognize the fissured and karstified levels. Three different aspects of karstifications were observed: an important fracturation, seen by complete loss of drilling mud during the drilling, important caves, observed by the free fall of drilling tools, and caves filled by karstic sediments, found thanks to diagraphies and the study of material brought up by the drilling. A statistical analysis of these data permitted to evidence the following elements: The dolomitic facies is much more dominant than the limestone facies; The frequency of incidences slowly decreases with depth; The fracturation is most important in the first 120 to 130 m below the top of the karstified formations, although it does not disappear at depth. In the breakdown zone of Tlemcen, situated in the northern piedmont part of the Tlemcen mountain, 26 boreholes permitted to draw an isopach map of the thickness of the karstic cover as well as the top of the karstified formation. This one shows two hollow zones below 100 m depth in the SW and NE parts. The top of the jurassic carbonates shows a very irregular surface which might correspond to a karstic paleorelief that was drowned by the Miocene transgression. Finally, the last map shows a karstified surface that can possibly be connected to a pseudo-paleo-piezometric surface.

Karsts des craies et calcarénites de la Montagne Saint-Pierre (BasseMeuse liégeoise), 2007, Luc Willems Joë, L Rodet Camille Ek Michiel Dusar David Lagrou Matthieu Fournier Benoî, T Laignel And André, Pouclet
The ?Montagne Saint-Pierre? (Sint Pietersberg) is a separate part of the Hesbaye plateau, isolated between the lower valleys of the Geer and the Meuse rivers. It is exploited by a big open-air quarry and by numerous underground quarries developing galleries on hundreds of kilometers long. Excavated in Cretaceous chalk and calcarenite, these artificial networks allow an exceptional 3-D observation of karsts inside a very porous and permeable rock, less favourable to a concentrated solution. The most numerous of them are ?organ pipes? or ?earth pipes?. They are vertical tubular solution pipes that may exceed 60 m in depth. Sponge networks and subhorizontal caves occur, without any visible connection with fracturation. Finally, downwards to at least 20 m below the alluvial plain of the Meuse river, pluridecametric nodes of weathered chalk are found. By their size and rounded morphology, the nodes resemble to the natural caves occurring in the calcarenite and intersected by the underground quarries. All the studied karsts allow us to propose a scenario for the genesis of a polyphase karst system. Independently of surface conditions, caves are generated deeply in the phreatic zone (endokarsts). During the downcutting of theMeuse valley, and related to the fluvial terraces, solution pipes (input karsts) are generated. Due to the valley incision and to the lowering of the aquifer,theses solution pipes progress downward and cut the endokarsts. A concentrated water circulation takes place. In the dewatered upper part of the system, caves cut by solution pipes are rapidly filled by superficial deposits. The high porosity of the calcarenite makes it comparable to a sponge. The rock absorbs quickly the out-flows coming from the surface and causes a rapid deposit of the fine particles transported inside horizontal passages. The sealing of these conduits allows their conservation inside a very crumbly rock.

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