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Speleology in Kazakhstan

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

Speleology in Kazakhstan

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

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That aquifer stimulation is a type of development that is done in semiconsolidated and completely consolidated formations to alter the formation physically to improve its hydraulic properties [6].?

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Your search for epiphreatic zone (Keyword) returned 21 results for the whole karstbase:
Showing 1 to 15 of 21
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.


Unusual flooding in the Calernakm shaft (Alpes-maritimes, France) Origin and consequences of the phenomen on the deep drainage organisation, 1998, Audra Ph.
The Calernakm shaft is located in the Southern french Alps, near Nice It contains large galleries reaching -478 m deep During unusual high waters, the lower part floods over 100 m height The flooding is linked to a semi-dammed karst structure The galleries organisation proves that the karstification privileges subhorizontal conduits in the epiphreatic zone, without favouring any deep phreatic passages The origin of deep phreatic karsts is discussed

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.

Plio-Quaternary karst development in the French Prealps: Speleogenesis and significance of cave fills, 2000, Audra P.
Three French cave systems in the Prealps in the Vercors and Devoluy mountain areas are described. It is possible to reconstruct their evolution by analyzing their morphology and by dating the karst fill using paleomagnetism and U/Th. Cave development began at the end of the Miocene during uplift when inclined tubes formed in the epiphreatic zone. Later the tubes were partially blocked by weathered detritus from the surface. Uplift diverted former recharge away from the caves and extensive calcite deposition occurred. The cave systems were reactivated during glaciations, with flooding to considerable depths. The epiphreatic zone was blocked with calcareous varves from meltwater. During interglacial periods, either calcite deposition or dissolution occurred, depending on the altitude and density of the soil cover.

Les stalagmites d'argile, indicateurs de mises en charge, 2001, Audra Ph.
Detailed morphological description and growing processes linked to backflooding in the epiphreatic zone. These are climatic records, particularly concerning rare floodings.

The genesis of the Tennengebirge karst and caves (Salzburg, Austria), 2002, Audra, Ph. , Quinif, Y. , Rochette, P.
Research has been carried out in the Tennengebirge Massif (Salzburg, Austria) with specific attention to karst morphology, cave systems, and sediments. This study reveals the genesis of the karst and the underground systems of the Tennengebirge, since the Oligocene. Large horizontal systems, which date back to the Miocene, were studied through the example of the caves Hornhhle and Eisriesenwelt, which respectively represent Ruinenhhlen (cave ruins) and Riesenhhlen (giant caves). The Cosa-Nostra - Bergerhhle System is typical of a mostly vertical, large, high-relief, alpine cave. The main characteristic of this network is major development in the vadose zone. Shaft morphology is in stairs beneath a faulted roof. At greater depth, they connect to a perched epiphreatic zone, which is typical of a dammed karst. The main underground sediments are of paleoclimatic and hydrodynamic significance, corresponding to hot, stable, or unstable environments (flowstones, reworked weathered rocks) and cold environments (carbonate varves, glacial pebbles). A preliminary study of the Tennengebirge sediments reveals significant information about its evolution throughout Pliocene-Quaternary time. Hhlen- und Karstgenese im Tennengebirge (Salzburg, sterreich) Es handelt sich um Erforschungen des unterirdischen Hhlensystems im Tennengebirge mit Hilfe der Erforschung der Karstsedimente. Durch die Beobachtung der Morphologie und der Ausfllungen kann die Geschichte der verschiedenen Hhlenorganisationen nachgezeichnet werden. Wir haben die groen horizontalen Hhlensysteme des Miozns anhand der Hornhhle und der Eisriesenwelt studiert, die wiederum ein Beispiel fr Ruinen- und Riesenhhlen sind. Das Cosa-Nostra - Bergerhhle System ist ein Beispiel fr die groen vertikalen Alpenschchten, das an seiner ausgeprgten Entwicklung der vadosen Zone erkenntlichist. Die Schchte haben die Morphologie von Treppen unter einem Kluftdach. Sie sind tief unten mit einer gestuften phreatischen Zone verbunden, die einen abgedmmter Karst enthllen. Die wichtigsten unterirdischen Sedimente haben eine Bedeutung auf dem Gebiet der Paloklimatologie und der hydrodynamik. Sie entsprechen entweder warmen und bestndigen oder kalten Umgebungen oder einer Umbegung in der das natrliche Gleichgewicht unterbrochen wurde (Sinterformation, vernderte Sedimente aus Alteriten, Karbonatwarven, glazial Schotter). Die Erforschung der Sedimenten in der Bergerhhle bringt wichtige Informationen ber die Entwicklung der Hhlensysteme im Plio-Quartr. Durch die gesamte Erforschung kann die Entstehung der Hhlen- und Karstgenese im Tennengebirge seit dem Oligozn nachgezeichnet werden.

The genesis of the Tennengebirge karst and caves (Salzburg, Austria), 2003, Audra Ph, Quinif Y. , Rochette P.

Research has been carried out in the Tennengebirge Massif (Salzburg, Austria) with specific attention to karst morphology, cave systems, and sediments. This study reveals the genesis of the karst and the underground systems of the Tennengebirge, since the Oligocene. Large horizontal systems, which date back to the Miocene, were studied through the example of the caves Hornhohle and Eisriesenwelt, which respectively represent Ruinenhohlen (“cave ruins”) and Riesenhohlen (“giant caves”). The Cosa-Nostra - Bergerhohle System is typical of a mostly vertical large high-relief, alpine cave. The main characteristic of this network is major development in the vadose zone. The shafts' morphology is in “stairs beneath a faulted roof.” At greater depth, they connect to a perched epiphreatic zone, which is typical of a dammed karst. The main underground sediments are of paleoclimatic and hydrodynamic significance, corresponding to hot, stable, or unstable environments (flowstones, reworked weathered rocks) and cold environments (carbonate varves, glacial pebbles). A preliminary study of the Tennengebirge sediments reveals significant information about its evolution throughout Pliocene-Quaternary time.


Kitzsteinhorn high alpine karst (Salzburg, Austria): Evidence of non-glacial speleogenesis., 2004, Audra, Ph.
Cave and karst development in a recently deglaciated alpine area (Kitzsteinhorn, Salzburg, Austria) is examined and compared to presently and previously glaciated karst regions elsewhere. Field evidence suggests that cave genesis occurs mainly during warm, interglacial periods when vegetation and soil formation provide chemically aggressive runoff during the melting season. During periods of extensive glacier coverage, the glacial contribution to karst development is restricted to surface abrasion, shaft development in pre-existing vadose caves and infill of fine-grained sediment in the epiphreatic zone. [Feichtner-Schachthhle (2573/3)]

Kitzsteinhorn high alpine karst (Salzburg, Austria): Evidence of non-glacial speleogenesis, 2004, Audra, Ph.
Cave and karst development in a recently deglaciated alpine area (Kitzsteinhorn, Salzburg, Austria) is examined and compared to presently and previously glaciated karst regions elsewhere. Field evidence suggests that cave genesis occurs mainly during warm, interglacial periods when vegetation and soil formation provide chemically aggressive runoff during the melting season. During periods of extensive glacier coverage, the glacial contribution to karst development is restricted to surface abrasion, shaft development in pre-existing vadose caves and infill of fine-grained sediment in the epiphreatic zone.

CAVE SEDIMENTS FROM THE POSTOJNSKAPLANINSKA CAVE SYSTEM (SLOVENIA): EVIDENCE OF MULTI-PHASE EVOLUTION IN EPIPHREATIC ZONE, 2008, Zupan Hajna N. , Pruner P. , Mihevc A. , Schnabl P. , BosÁ, K P.

The Postojnska jama–Planinska jama cave system and number of smaller adjacent caves are developed in the Postojnski kras. These caves are located between two dextral strike-slip fault zones oriented in the Dinaric direction. The caves contain lithologically diversified cave fill, ranging from speleothems to allogenic fluvial sediments. The allogenic clastic material is derived from a single source, Eocene siliciclastics of the Pivka Basin. Small differences in mineral/petrologic composition between the sediments can be attributed to different degrees of weathering in the catchment area and homogenization of source sediments. Thick sequences of fine-grained laminated sediments, deposited from suspension are common. The depositional environment was mostly calm, but not completely stagnant. Such a sedimentary environment can be described as cave lacustrine, with deposition from pulsed flow. The homogeneity of the palaeomagnetic data suggests rapid deposition by a number of short-lived single-flood events over a few thousand years. This depositional style was favourable for recording of short-lived excursions in the palaeomagnetic field. The sediments were originally not expected to be older than Middle Quaternary in age (i.e. about 0.4 Ma). Later numerical dating (Th/U and ESR) indicated ages older than 0.53 ka. New palaeomagnetic data from selected sedimentary profiles within the cave system detected normal polarization in much of the profiles studied. Reverse polarized magnetozones, interpreted mostly as short- lived excursions of magnetic field, were detected in only a few places. Therefore, we interpreted most of the sediments as being younger than 0.78 Ma, belonging to different depositional phases within the Brunhes chron. Palaeomagnetic properties of two profiles in caves intersected by the artificial tunnel between Postojnska jama and Črna jama had reverse polarized magnetozones and of sediments in Zguba jama, may indicate an age much greater than 0.78 Ma. The cave system has evolved over a long period of time, governed by the functioning of Planinsko polje in the relation to the evolution of the resurgence area in Ljubljana Moor further to the east. General stabilization of the hydrological system with low hydraulic head led to the evolution of caves in epiphreatic and paragenetic conditions over a long time-span. Individual cave segments or passages were completely filled and exhumed several times during the evolution of the cave. Alternation of depositional and erosional phases may be connected with changing conditions within the cave system, the functioning of the resurgence area, collapse, climatic change, tectonic movement and the intrinsic mechanisms of contact karst.


HYDROLOGIC CONNECTIONS AND DYNAMICS OF WATER MOVEMENT IN THE CLASSICAL KARST (KRAS) AQUIFER: EVIDENCE FROM FREQUENT CHEMICAL AND STABLE ISOTOPE SAMPLING, 2008, Doctor, D. H.

A review of past research on the hydrogeology of the Classical Karst (Kras) region and new information obtained from a two- year study using environmental tracers are presented in this paper. The main problems addressed are 1) the sources of water to the Kras aquifer resurgence zone—including the famous Timavo springs—under changing flow regimes; 2) a quantification of the storage volumes of the karst massif corresponding to flow regimes defined by hydrograph recessions of the Timavo springs; and 3) changing dynamics between deep phreatic conduit flow and shallow phreatic and epiphreatic storage within the aquifer resurgence zone as determined through changes in chemical and isotopic composition at springs and wells. Particular focus was placed on addressing the long-standing question of the influence of the Soča River on the ground waters of the aquifer resurgence zone. The results indicate that the alluvial aquifer supplied by the sinking of the Soča River on the northwestern edge of the massif contributes approximately 75% of the mean annual outflow to the smaller springs of the aquifer resurgence zone, and as much as 53% to the mean annual outflow of the Timavo springs. As a whole, the Soča River is estimated to contribute 56% of the average outflow of the Kras aquifer resurgence. The proportions of Soča River water increase under drier conditions, and decrease under wetter conditions. Time series analysis of oxygen stable isotope records indicate that the transit time of Soča River water to the Timavo springs, Sardos spring, and well B-4 is on the order of 1-2 months, depending on hydrological conditions. The total baseflow storage of the Timavo springs is estimated to be 518 million m3, and represents 88.5% of the storage capacity estimated for all flow regimes of the springs. The ratio of baseflow storage volume to the average annual volume discharged at the Timavo springs is 0.54. The Reka River sinking in Slovenia supplies substantial allogenic recharge to the aquifer; however, its influence on the northwest resurgence zone is limited to the Timavo springs, and is only a significant component of the spring discharge under flood conditions for relatively brief periods (several days to weeks). Sustainability of the trans-boundary aquifer of the Kras will benefit from maintaining high water quality in the Soča River, as well as focused water tracing experiments within the epiphreatic zone of the aquifer to better delineate the recharge zone and to identify sources of potential contamination to the Brestovica water supply well.


Structure des rseaux karstiques: les contrles de la splogense pigne, 2011, Audra P. , Palmer A. N.

Cave development is related to the geomorphic evolution. Their morphology, preserved far longer than correlative surface features allows reconstructing the regional history of the surrounding landscape. Modeling shows that initial cave development occurs along the water table with loops in the phreatic zone along fractures. Consequently, cave profiles and levels reflect the local base level and its changes. Cave profile is controlled by timing, geological structure, and recharge. In first exposed rocks, juvenile pattern displays steep vadose passages. In perched aquifers, vadose erosion produces large passage along aquiclude. In dammed aquifers, the main drain is established at the water table when recharge is fairly regular. But when irregular recharge causes backflooding, looping profiles develop throughout the epiphreatic zone. Interconnected cave levels correspond to some of the largest cave systems in the world. The oldest abandoned highest levels have been dated beyond 3.5 Ma (Mammoth Cave). However, when base level rises, the deepest parts of the karst are flooded; the flow rises along phreatic lifts, and discharges at vauclusian springs. In the epiphreatic zone, floodwater produces looping tubes above the low-flow water table. In such a case of baselevel rise, per ascensum speleogenesis can produce higher-elevation passages that are younger than passages at lower elevations. base-level rises occur after tectonic subsidence, filling of valleys, or sea-level rise, as for instance around the Mediterranean in response to the Messinian Crisis. Deep-phreatic karst, if not hypogenic, can generally be attributed to flooding by a base-level rise. 


Eiszeitliche Klimadynamik im Spiegel eines Stalagmiten aus dem Hlloch (Bayern/Vorarlberg) , 2011, Sptl C. , Boch R. , Wolf A.
A speleothem recovered from Hlloch Cave located at the border between Germany and Austria that was deposited during the Last Glacial shows prominent layers of silt and clay documenting episodes of extensive cave flooding. Such intermittent flooding events are not known from the modern cave system, although some galleries are situated in the epiphreatic zone. According to Uranium-Thorium age determinations of 13 calcite subsamples, stalagmite growth started around 62 kyr (= 62,000 years) before present and ended 40 kyr ago, i.e. the only 41 cm-tall stalagmite comprises a time interval of ca. 20 kyr during the Last Glacial. Fin-like extensions in the lower part of the stalagmite document calcite deposition competing with the aggradation of coarsegrained sand. U-Th dates in combination with the internal structure of the stalagmite constrain the age of this period of clastic sedimentation by the cave stream to between 62 and 46 kyr. In addition, the stalagmite also reveals several layers of silty clay documenting growth interruptions as a result of prolonged flood events. Highresolution oxygen isotope measurements along the stalagmite growth axis highlight abrupt alternations of warmer and colder climate conditions during the Last Glacial period. The flooding events occurred preferentially at the end of the relatively short warm phases (interstadials) and at the onset of the subsequent cooling episodes (stadials).

Large Epigenic Caves in High-Relief Areas, 2013, Hauselmann, Ph.

Although the two conditions given in the title, ‘Large Epigenic Caves’ and ‘High-Relief Area’, already considerably narrow down the caves that fall within these categories, it quickly becomes clear that the geomorphology of such caves is not clear from the beginning. A closer look into the literature actually reveals that diverse speleogenetic agents may influence the genesis of such caves. Vertical vadose passages as well as (epi) phreatic base-level control very commonly occur in large cavesin high-relief areas. The key to understanding the genesis of these caves is: (1) the notion of time (commonly such caves are old and may even present different distinct phases of evolution) and (2) the evolution of the surface around these caves. Commonly, caves in mountainous areas deliver hints to reconstruct the (spatial and temporal) evolution of the surface morphology. In that manner, caves in mountains and in lowlands are no different, but surface information within them ountains is generally much more rare because of the intensive erosional processes in such steeply sloping areas.


The vertical dimension of karst: controls of vertical cave pattern, 2013, Audra P. , Palmer A. N.

The vertical development of karst is related to the geomorphic evolution of the surrounding landscape. Cave profiles and levels reflect the local fluvial base level and its changes through time. These cave features tend to be preserved far longer than correlative surface features, which are more susceptible to weathering and erosion. As a result, cave morphology offers abundant clues that are helpful in reconstructing the regional geomorphic history. In the vadose zone, water is drawn downward by gravity along vertical fractures. In the phreatic zone, water follows the hydraulic gradient along the most efficient paths to available outlets in nearby valleys. Phreatic passages tend to have gentler gradients close to the water table, generally with some vertical sinuosity. Responding to irregular recharge rates, fluctuations in the water table define a transition zone, the epiphreatic zone, in which passages develop by floodwater flow. Free-surface flow in the vadose zone and full pipe flow in the phreatic zone produce distinctive passage morphologies. Identification of former vadose–phreatic transition zones makes it possible to reconstruct the position of former water tables that represent past static fluvial base levels. Early conceptual models considered cave origin mainly in relation to its position relative to the water table. Later, analytical and digital models showed that dramatic enlargement occurs when dissolutional enlargement of initial fissures is sufficient to allow rapid dissolution and turbulent flow to take place throughout the entire conduit length. Cave development is favored by the widest initial openings, and less importantly by the steepest hydraulic gradients and shortest flow distances. Consequently, most phreatic cave development takes place at or near the water table, but the presence of relatively wide fractures can lead to phreatic loops. Cave levels record successive base-level positions as valleys deepen. The oldest levels in Mammoth Cave (USA) and Clearwater Cave (Malaysia) have been dated beyond 3.5 Ma. However, when base level rises, the deepest parts of the karst are flooded and the flow follows phreatic lifts. In the epiphreatic zone, floodwater produces looping tubes above the low-flow water table. In these last two situations, high-level passages with large vertical loops are not necessarily the oldest. The juvenile pattern, composed of steep vadose passages, is common when soluble rock is first exposed. In perched aquifers, vadose erosion can produce very large cross sections. In dammed aquifers, the main drain is established at the water table. Irregular recharge causes backflooding, and passages develop throughout the epiphreatic zone, with looping profiles; however, when recharge is fairly regular, the passages develop along the stable water table. Interconnected cave levels correspond to some of the largest cave systems in the world. When base level rises, the karst is flooded; water rises through phreatic lifts and discharges at vauclusian springs. A per ascensum speleogenesis can produce higher-elevation passages that are younger than passages at lower elevations. Base-level rises occur after tectonic subsidence, filling of valleys, or sea-level rise, especially around the Mediterranean in response to the Messinian Salinity Crisis. Deep-phreatic karst, if not hypogenic, can generally be attributed to flooding by a base-level rise. 


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