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Speleology in Kazakhstan

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

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That vadose cave is 1. a cave that underwent most of its development above the water table. within the vadose zone, drainage is freeflowing under gravity, and cave passages therefore have air above any water surface. the gravitational control of vadose flow means that all vadose cave passages drain downslope, they exist in the upper part of a karst aquifer, and they ultimately drain into the phreatic zone or out to the surface. active stream caves, explorable by non-diving cavers, are by definition vadose (though they generally have phreatic origins). characteristics of vadose caves are uneroded ceilings (except for immature phreatic features pre-dating the vadose conditions) and continuous downhill gradients (unless interrupted by short perched sumps). the main passage forms are canyons, with meanders and potholes, broken by subcylindrical, spray-corroded shafts that may demonstrate waterfall retreat. some of the caves of monte canin, italy, are spectacularly long and deep vadose systems [9]. 2. older, higher cave passages found in the vadose zone; usually vadose caves have been abandoned by the ground water except in times of extreme aquifer recharge. passages are usually appear as canyons and keyholes.?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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 exhumation (Keyword) returned 14 results for the whole karstbase:

Within the Franco-Belgian segment of the Hercynian orogen, two thick Dinantian anhydritic formations are known, respectively in the Saint-Ghislain (765 m) and Epinoy 1 (904 m) wells. Nevertheless, occurrences of widespread extended breccias and of numerous pseudomorphs of gypsum/anhydrite in stratigraphically equivalent carbonate deposits (boreholes and outcrops), suggest a larger extent of the evaporitic conditions (fig. 1, 2). The present distribution of evaporites is controlled by palaeogeographical differentiation and post-depositional parameters such as tectonics and dissolution. These latter have dissected the deposits formerly present in all the structural units. By using depositional, diagenetic and deformational characters of these formations, the article provides a model for the reconstruction of a dislocated evaporitic basin. This segment of the Hercynian chain is schematically composed of two main units (fig. 1, 3) : (1) the autochthonous or parautochthonous deposits of the Namur synclinorium, (2) the Dinant nappe thrusted northward over the synclinorium of Namur. The major thrust surface is underlined by a complex fault bundle (faille du Midi) seismically recognized over more than 100 km. A complex system of thrust slices occurs at the Hercynian front. Except for local Cretaceous deposits, most of the studied area has been submitted to a long period of denudation since the Permian. Sedimentary, faunistic and geochemical data argue for a marine origin of the brines which have generated the evaporites interbedded with marine limestones. Sedimentary structures. - The thick evaporitic formations are composed of calcium-sulfates without any clear evidence of the former presence of more soluble salts (with the exception of a possible carbonate-sulfate breccia in the upper part of the Saint-Ghislain formation). As in all the deeply buried evaporitic formations, the anhydrite is the main sulfate component which displays all the usual facies : pseudomorphs after gypsum (fig. 4A, B), nodular and mosaic (fig. 4C), laminated. The gypsum was probably an important component during the depositional phase despite the predominant nodular pattern of the anhydrite. Early diagenetic nodular anhydrite may have grown during temporary emersion of the carbonates (sabkha environments), but this mechanism cannot explain the formation of the whole anhydrite. So, most of the anhydrite structures result from burial-controlled gypsum --> anhydrite conversion and from mechanical deformations. Moreover, a complex set of diagenetic processes leads to various authigenic minerals (celestite, fluorite, albite, native sulfur, quartz and fibrous silica) and to multistaged carbonate <> sulfate replacements (calcite and dolomite after sulfate, replacive anhydrite as idiomorphic poeciloblasts, veinlets, domino-like or stairstep monocrystals...). These mineral transformations observed ill boreholes and in outcrops have diversely been controlled during the complex evolution of the series as : depositional and diagenetic pore-fluid composition, pressure and temperature changes with burial, bacterial and thermochemical sulfate reduction, deep circulations favored by mechanical brecciation, mechanical stresses, role of groundwater during exhumation of the series. Deformational structures. - A great variety of deformational structures as rotational elongation, stretching, lamination, isoclinal microfolding, augen-like and mylonitic structures are generated by compressive tectonic stresses (fig. 4D to J). The similarities between tectonic-generated structures and sedimentary (lamination) or diagenetic (pseudo-nodules) features could lead lo misinterpretations. The calcareous interbeds have undergone brittle deformation the style and the importance of which depend of their relative thickness. Stretching, boudins, microfolds and augen structures F, H. I) affect the thin layers while thicker beds may be broken as large fractured blocks dragged within flown anhydrite leading to a mylonitic-like structure (fig, 4G). In such an inhomogeneous formation made of interlayered ductile (anhydrite) and brittle (carbonate) beds, the style and the intensity of the deformation vary with respect to the relative thickness of each of these components. Such deformational features of anhydrite may have an ubiquitous significance and can result either from compressive constraints or geostatic movements (halokinesis). Nevertheless, some data evidence a relation with regional tangential stresses: (1) increase of the deformation toward the bottom of the Saint-Ghislain Formation which is marked by a deep karst suggesting the presence of a mechanical discontinuity used as a drain for dissolving solutions (fig. 3, 4); (2) structural setting (reversed series, internal slidings) of the Epinoy 1 formation under the Midi thrust. However, tectonic stresses also induce flowing deformations which have contributed to cause their present discontinuity. It can be assumed that the evaporites played an active role for the buckling of the regional structure as detachment or gliding layers and more specifically for the genesis of duplex structures. Breccia genesis. - Great breccia horizons are widely distributed in outcrops as well as in the subsurface throughout the greater part of the Dinant and Namur units (fig. 2). The wide distribution of pseudomorphosed sulfates in outcrops and the stratigraphical correlation between breccia and Saint-Ghislain evaporitic masses (fig. 2) suggest that some breccia (although not all) have been originated from collapse after evaporites solution. Although some breccia may result from synsedimentary dissolution, studied occurrences show that most of dissolution processes started after the Hercynian deformation and, in some cases, were active until recently : elements made of lithified and fractured limestones (Llandelies quarries) (fig. 5A), preservation of pseudomorphs of late replacive anhydrite (Yves-Gomezee) (fig. 5B, C), deep karst associated with breccia (Douvrain, Saint Ghislain, Ghlin boreholes) (fig. 3, 4, 5D)). Locally, the final brecciation may have been favored by a mechanical fragmentation which controlled water circulations (fig. 5E). As postulated by De Magnee et al. [19861, the dissolution started mostly after the Permian denudation and continued until now in relation with deep circulations and surface weathering (fig. 6). So, the above-mentioned occurrences of the breccia are logically explained by collapse after dissolution of calcium-sulfates interbeds of significant thickness (the presence of salt is not yet demonstrated), but other Visean breccia may have a different origin (fig. 5F). So, these data prove the extension of thick evaporitic beds in all the structural units including the Dinant nappe, before dissolution and deformation. Implications. - Distribution of Visean evaporites in northern France and Belgium is inherited from a complicated paleogeographic, tectonic and post-tectonic history which has strongly modified their former facies, thicknesses and limits (fig. IA, 6). Diversified environments of deposition controlled by both a palaeogeographical differentiation and water level fluctuations led to the deposition of subaqueous (gypsum) or interstitial (gypsum, anhydrite) crystallization. Nevertheless, most of the anhydrite structures can be interpreted as resulting from burial conversion of gypsum to anhydrite rather than a generalized early diagenesis in sabkha-like conditions. Deformation of anhydrite caused by Hercynian tangential stresses and subsequent flow mechanisms, have completed the destruction of depositional and diagenetic features. The tectonic deformations allow us to consider the role of the evaporites in the Hercynian deformations. The evaporites supplied detachment and gliding planes as suggested for the base of the Saint-Ghislain Formation and demonstrated by the structural setting of Epinoy 1 evaporites in reverse position and in a multi-system of thrust-slices below the Midi overthrust (fig. 7). So, although the area in which evaporation and precipitation took place cannot be exactly delineated in geographic extent, all the data evidence that the isolated thick anhydritic deposits represent relics of more widespread evaporites extending more or less throughout the different structural units of this Hercynian segment (fig. 1B). Their present discontinuity results from the combination of a depositional differentiation, mechanical deformations and/or dissolution

Les karsts portugais, problmes et perspectives, 1996, Cunha, L.
The Portuguese karsts owing to their geomorphological, speleological, hydrogeological and environmental problems, deserve to be better known and studied by the international scientific and speleological community. We present a brief synthesis of the Portuguese karsts in three parts: 1) the presentation of the main scientific works, mainly from the pionner thesis written by Alfredo Fernandes Martins in 1949 on the Estremadura limestone massif, which was the starting point of karst geomorphological studies in Portugal; 2) a brief description of the main characteristics of the karst areas in the western Mesozoic border (Sico and Estremadura), especially the pre--Cretaceous paleokarsts (recent and incomplete exhumation) and the importance of endokarst and exokarst (Estramadura); 3) some further research approaches are proposed, aiming at a deeper and more synthetical knowledge of the Portuguese karsts.

Les Forts de Pierre ou Stone forests de Lunan (Yunnan, Chine), 1996, Ford D. , Salomon J. N. , Williams P.
"Stone forests " are well known in Southern China. We describe the type site in Lunan County on the Yunnan Plateau at about 1800 m. "Stone forests " are a spectacular form of karren, similar to the "tsingy" of Madagascar or pinnacles of Mulu. In Yunnan they are developed in massive Permian limestones and dolomites. The "Stone forests" are high fluted towers, typically more ruiniform in dolostones, that attain 20-30m in height, exceptionally 40m. They occur in patches of several square kilometres in extent in a rolling polygonal karst landscape with about 150 m local relief Three phases of evoluti6n are recognized spanning 250 Ma from the Permian until the present: 1) Mid Permian karstification and burial by Upper Permian continental basalts, 2) Mesozoic erosion and re-karstification, then burial in the Eocene by thick continental deposits, 3) Late Tertiary and Quaternary exhumation and re-karstification. No other "Stone forests" in the world show this complexity of evolution.

Types of karst and evolution of hydrogeologic settings, 2000, Klimchouk A. , Ford D.
Karst is treated as a specific kind of fluid circulation system capable to self-development and self-organization. Active karst may evolve at wide range of geological environments, from deep-seated (without any apparent relation to the surface) to sub-surface, and be represented by confined and unconfined circulation systems. Extrinsic factors and intrinsic mechanisms of karst development change regularly and considerably within the general cycle of geological evolution of a soluble rocks or, more specifically, within hydrogeologic cycle. The latter encompasses a period of exposure between major transgressions and is characterized by progressively expanding meteoric groundwater circulation. A broad evolutionary approach is therefore needed to differentiate between karst types, which concurrently represent distinct stages of karst development. This is also a mean to adequately classify speleogenetic settings. Evolutionary typology of karst considers the whole cycle of a formation's life, from deposition (syngenetic karst) through deep burial to exposure and denudation. The group of intrastratal karst types includes deep-seated, subjacent, entrenched and denuded karst, the latter also fall into the group of exposed karst types. Exposed karst includes also open karst which represents the pure line of exposed development, that is karst evolved solely when the soluble rock has been exposed to the surface. Exposed karst development can be interrupted by a subsequent burial (buried karst), with paleokarst formed in result, and rejuvenated by exhumation. The types of karst are marked by characteristic associations of structural prerequisites for groundwater flow and speleogenesis, flow regime, recharge mode and recharge/discharge configurations, groundwater chemistry and a degree of inheritance. Consequently, these associations generate particular types of caves.

Paleokarst: cessation and rebirth?, 2003, Osborne, R. A. L.

The transformation of active karst into paleokarst by burial, isolation or cessation of process is not necessarily permanent. Paleokarst structures and landforms can be and are exhumed or reactivated, sometimes on numerous occasions. There is not a great deal of similarity between the localities where exhumation and reactivation of paleokarst has been reported. Exhumation and reactivation however have not been reported in many karsts that are similar to those where they have been reported. Exhumation and reactivation appears to be favoured in four situations: - the margins of sedimentary basins overlying grand unconformities, the axes of anticlines, narrow steeply-dipping impounded karsts and where paleokarst fill contains unstable minerals. Six processes are principally responsible for exhumation and reactivation: - per-ascensum speleogenesis, eustatic sea level changes, paragenesis, high density speleogenesis, glaciation, and large-scale meteoric speleogenesis. On some occasions karst landforms, particularly caves or segments of caves, may survive intact and unfilled for geologically significant periods of time. These may be completely isolated from the surface environment, or become reactivated by entrance formation due to breakdown, surface lowering or headward erosion. The intersection and reactivation of ancient open cavities and of exhumed cavities by “modern” caves may be much more common than is currently recognised. If caves have histories as long and as complex as the karsts in which they are developed then many “modern” caves will be composite features composed of interconnected “modern”, relict and exhumed cavities excavated at different times by different processes. Unravelling these histories is the new challenge facing cave science. It will require caves to be studied in a much more detailed, thorough and systematic manner and will also require the application of new technologies in surveying, analysis and dating

Geomorphic constraints on surface uplift, exhumation, and plateau growth in the Red River region, Yunnan Province, China, 2004, Schoenbohm L. M. , Whipple K. X. , Burchfiel B. C. , Chen L. ,
Field observations, digital elevation model (DEM) data, and longitudinal profile analysis reveal a perched low-relief upland landscape in the Red River region, Yunnan Province, China, which correlates to an uplifted, regional low-relief landscape preserved over the eastern margin of the Tibetan Plateau. As with other major rivers of the plateau margin, the Red River has deeply incised the low-relief upland landscape, which we interpret to be the remnants of a pre-uplift or relict landscape. We examine longitudinal river profiles for 97 tributaries of the Red River. Most profiles consist of three segments separated by sharp knickpoints: an upper, low-gradient channel segment, a steeper middle channel segment, and a very steep lower channel segment. Upper channel segments correspond to the relict landscape and have not yet experienced river incision. Steeper middle and lower segments indicate onset of rapid, two-phase river incision, on the basis of which changes in external forcings, such as climate or uplift, can be inferred. In terms of two end-member scenarios, two-phase incision could be the result of pulsed plateau growth, in which relatively slow uplift during the first phase is followed by rapid uplift during the second phase, or it could reflect adjustments of the main channel to changing climate conditions against the backdrop of steady plateau growth. Reconstruction of the paleo-Red River indicates [~]1400 m river incision, 1400-1500 m surface uplift, and a maximum of 750 m vertical displacement across the northern Red River fault, elevating the northern Ailao Shan range above the surrounding relict landscape. On the basis of stratigraphic constraints, incision along the Red River likely began in Pliocene time

Geomorphological evolution of the Podgorski Karst, SW Slovenia: contribution of magnetostratigraphic research of the Črnotiče II site with Marifugia sp., 2004, Bosá, K Pavel, Mihevc Andrej, Pruner Petr

The sequence of interior cave facies 9 m high is composed of cyclically arranged fluvial sediments (conglomerates, sands, silts, clays) in the lower part and by laminated to banded silts to clays in the upper part. Both parts are separated by pronounced unconformity associated with deep erosion of the lower part of the profile and tectonic tilting. The fill is covered by chaotic flowstone boulder breccia with red loamy matrix. One segment of the cavity wall was covered by tiny tubes of polychates worms comparable to recent fresh-water Marifugia cavatica. Both profiles show normal magnetozone with only one narrow reverse excursion in each. The correlation of the obtained magnetostratigraphy log can indicate the Gauss chron (ca 2.5 to 3.6 Ma) or the other long normal chron. Črnotiče II site was filled in a substantially short time. Gemorphological evolution of the Podgorski karst plateau (Classical Karst, Karst Edge) since Miocene underwent complicated development with distinct phases of repeating phreatic speleogenesis (horizontal caves), vadose evolution (drawdown shafts), filling, fossilisation, exhumation, block tilting and rotation, uplift and planation.

Exhumation of Messinian evaporites in the deep-sea and creation of deep anoxic brine-filled collapsed basins, 2006, Cita Mb,
The first part of the paper summarizes some basic concepts concerning (a) the distribution of Messinian evaporites in the deepest parts of the Mediterranean Sea and (b) the Mediterranean Ridge accretionary wedge and its peculiar characteristics deriving from the presence of a substantial evaporitic body in the deforming sedimentary prism.Then five brine-filled anoxic collapsed basins (Tyro, Bannock, Urania, Atalante and Discovery), discovered from 1983 to 1994, are presented and discussed in their physiographic, geologic, hydrologic and geochemical characters. High density brines deriving from submarine dissolution of outcropping or subcropping evaporites accumulate at the bottom of collapsed basins, if they are not swept away by submarine currents. The interface separating normal sea-water from high density brines is sharp with a density contrast of about 20% and lies at 3200-3500[no-break space]m below sea level. Strong bacterial activity is developing at the interface and living bacteria have been recovered from the anoxic salty brines. Thickness of the brines may be up to 500[no-break space]m. Thermal stratification has been observed in three brine lakes. Exhumation and dissolution of Messinian evaporites in the Mediterranean Ridge occur in different tectonic settings: pull-apart basin (Tyro), subducting seamount close to the outer deformation front (Bannock Basin), top of a backstop (Urania, Atalante and Discovery Basins).Chemistry of the brines is strongly variable and suggests dissolution of different layers or levels of the Messinian suite. Discovery brines are the saltiest ever recorded in natural environment. Their saturation in Mg chloride (bischofite), the end product of sea-water evaporation, suggests that the deepest parts of the eastern Mediterranean were close to dryness at the end of the salinity crisis, strongly supporting the deep basin desiccation model

Cathedral Cave, Wellington Cave, New South Wales, Australia. A multiphase, non-fluvial cave., 2007, Osborne R. A. L.
Cathedral Cave is an outstanding example of a class of multiphase caves with largely non-fluvial origins. It contains large cavities such as cathedrals and cupolas, characteristic of excavation by convection currents in rising waters. Smaller-scale features such as rising half-tubes, pseudonotches, curved juts, projecting corners, blades and bridges indicate intersection and exhumation of older cavities during the formation of younger ones. It is possible to recognize at least ten significant phases of speleogenesis by morphostratigraphy, in addition to the four generations of cave-filling palaeokarst deposits intersected by the cave. The cave we see today results from the progressive integration of a number of previously disconnected or poorly connected solution cavities.

Speleothems and mountain uplift, 2011, Meyer Michael C. , Cliff Robert A. , Spö, Tl Christoph

Ancient speleothems were recovered from caves that today are situated in a high-alpine cirque landscape at 2500 m altitude at the northern rim of the European Alps. U-Pb ages date speleothem deposition to the early Quaternary (between 2.16 and 2.12 Ma and ca. 2.00 Ma), i.e., well before the onset of major alpine and Northern Hemisphere glaciations. Using a stable isotope–based modeling approach, we quantitatively estimate the paleoelevation of both the caves and their former catchment area, which in turn allows us to calculate rates of rock and surface uplift (and hence erosion) since 2 Ma. We show that for the frontal part of the Alps, rates of rock uplift and erosion were ∼0.75 and ∼0.5 mm/yr, respectively, and further suggest that isostatic uplift of mountain peaks of as much as ∼500 m in response to enhanced glacial erosion occurred during the Quaternary. This study highlights the potential of U-Pb-dated speleothems for reconstructing paleoaltimetry, particularly in calcareous mountain ranges, where a standard thermochronologic assessment of exhumation and erosion is generally not feasible.

Datierung fluviatiler Hhlensedimente mittels kosmogener Nuklide am Beispiel des Grazer Berglandes, 2011, Wagner, T.
The Central Styrian Karst north of Graz comprises a great number of caves of which many are of phreatic origin. Due to a clustering of caves at certain elevations above the current base level, the Mur River, these caves can be assigned to distinct levels. Caves cannot be older than the rock in which they formed, i.e. in the case of the region studied here not older than about 400 Ma (million years ago). Cave deposits on the other hand allow to infer a minimum age of cave formation, because they are deposited in the cave during or (mostly) after its development. Besides numerous autochthonous (i.e. in situ) sediments and speleothems, also a number of allochthonous (transported into the cave from the surface) sediments are encountered. Burial ages of several quartz-rich allochthonous cave sediments were determined using the radioactive cosmogenic nuclides 26Al and 10Be. The present article provides an insight into this rela tively new dating method (burial age dating) to constrain the age of cave deposits. The current state of knowledge about the timing of cave formation in the Grazer Bergland (Highland of Graz) will be discussed by summarizing the results of two recent papers (Wagner et al., 2010, 2011). Based on these results, conclusions are drawn about the age of the cave levels, relative incision rates of the River Mur and the landscape evolution of the eastern rim of the Alps in general. Sedimentation ages of 0 to about 5 Ma ago are in good agreement with increasingly higher cave levels above the present base level. This in turn reflects the stepwise relative incision of the River Mur. Based on the oldest samples, the onset of karstification and thus the exhumation of the Central Styrian Karst occurred at least 4-5 Ma ago. The oldest level, assigned to an age of at least 4 Ma, is situated some 500 m above the current valley bottom. Therefore, a relative incision rate of the River Mur in the order of only about 100 meters per million year (m/Myr) for the last 4-5 Ma is inferred. A more detailed examination of the levels reveals on average a decrease in the incision rate. Burial ages of ~2.5 Ma are determined only 100 m above the current base level. Moreover, the formation of planation surfaces and terraces in the Grazer Bergland is constrained by the correlation with cave levels and as such an important contribution to the understanding of landscape evolution of this region is made.

Preservation and burial of ancient karst., 2013, Osborne, R. A. L.

Ancient karst features can be preserved by burial, filling, or by occurring in areas with extremely slow denudation. Although the terms ‘paleokarst’, ‘relict karst’,‘buried karst’, and ‘fossil karst’ have caused much confusion, paleokarst, buried karst, and relict karst can be defined in terms useful to karst geomorphologists and cave scientists. The term ‘fossil karst’ is best abandoned. Burial and paleokarstification are not necessarily the end of karst. Ancient features may be exhumed and reactivated. Karst ends with denudation at the Earth’s surface. Unroofed caves are a particular feature of karst denudation. Most ancient karst features may be preserved by filling, burial, and exhumation. In unusual conditions, karst features have survived at the surface since the Mesozoic. Burial, exhumation, and slow denudation may not be sufficient for extreme survival; relative vertical movement may be required. As caves and many other karst landforms are negative features, they are prone to filling by a range of materials, making cave sediments and paleokarst deposits quite diverse. Whole karst landscapes can be buried and evidence of burial can be recorded in the diagenesis of sediments. Although filled and unfilled caves can survive shallow burial, deep burial can crush caves, forming crackle breccia. Exhumation can occur from the surface following uplift or from below following hypogene speleogenesis. Preservation, burial, and exhumation of ancient karst have two unexpected consequences. Caves can be older than the landscapes in which they occur and stalagmites can be the longest surviving karst features

Focused Groundwater Flow in a Carbonate Aquifer in a Semi-Arid Environment, 2014, Green R. T. , Bertetti F. P. , Miller M. S.

An efficient conveyance system for groundwater is shown to have formed in a carbonate aquifer even though it is situated in a semi-arid environment. This conveyance system comprises preferential flow pathways that developed coincident with river channels. A strong correlation between high capacity wells and proximity to higher-order river channels (i.e., within 2.5 km) is used as evidence of preferential flow pathways. Factors that contributed to development of the preferential flow paths: (i) karst development in carbonate rocks, (ii) structural exhumation of a carbonate plateau, and (iii) the requirement that the groundwater regime of the watershed has adequate capacity to convey sufficient quantities of water at the required rates across the full extent of the watershed. Recognition of these preferential pathways in proximity to river channels provides a basis to locate where high capacity wells are likely (and unlikely) and indicates that groundwater flow within the watershed is relatively rapid, consistent with flow rates representative of karstic aquifers. This understanding provides a basis for better informed decisions regarding water-resource management of a carbonate aquifer in a semi-arid environment.

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