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Community news

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 damping is the process of gradually reducing amplitude of a periodic event such as acoustic oscillations in velocity logging [16].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms


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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
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 scenario (Keyword) returned 76 results for the whole karstbase:
Showing 31 to 45 of 76
The Messinian salinity crisis in the Mediterranean basin: A reassessment of the data and an integrated scenario, 2006,
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Rouchy Jean Marie, Caruso Antonio,
After a long period of controversial debate about the interpretation of the Messinian salinity crisis (MSC), a near consensus existed since the ODP Leg 42A for a model keeping the major lines of the deep basin-shallow water model initially proposed by Hsu et al. (1973). The knowledge of the crisis was improved since the 1995s by the availability of a very accurate astronomically calibrated timescale. The debate about its interpretation was then reactivated by several new scenarios that questioned most the major aspects of the previous classical models. The updated re-examination of the most salient features along with consideration of the hydrological requirements for evaporite deposition allow us to assess the viability of the new models. We propose an integrated scenario that revives the key points of the previous model with new statements about the chronology, depositional settings, hydrological mechanisms, consequences and correlations with the global changes. A model implying two main stages of evaporite deposition that affected successively the whole basin with a slight diachronism matches better the whole dataset. The distribution of the evaporites and their depositional timing were constrained by the high degree of paleogeographical differentiation and by the threshold effects that governed the water exchanges. It is assumed that the central Sicilian basin was a deep basin located in a marginal position with regard to the deepest central basins. The restriction of the Mediterranean was predominantly under a tectonic control, but the complex development of the evaporitic crisis implied the interplay of both glacio-eustatic changes and fluctuations of the circum-Mediterranean climate.The first evaporitic stage (lower evaporites) that includes the deposition of the thick homogeneous halite unit with K-Mg salt interbeds in the deepest basins is correlated with the major evaporative drawdown and higher aridity, and occurred during the glacial period recorded in the ocean sediments between 6.3 and 5.6 Ma. The deposition of the potash in Sicily is tentatively linked to the two major glacial peaks TG 20 and TG 22, while the end of this first stage is linked to the peak TG 12. The second stage (upper evaporites) correlates with the interval of warming and global sea level rise recorded in the ocean since 5.6-5.5 Ma onwards. During this second stage, freshwater contribution increased and culminated by the latest Messinian dilution, i.e. the Lago-Mare event, as the result of the worsened tectonically driven closure of the Atlantic gateways combined to an evolution towards wetter climate conditions at least on the mountainous peripheral areas. In fact, reduced inputs of seawater continued to enter at least episodically the basin through the MSC explaining the sporadic presence of marine organisms. These inputs reached their lowest value and practically ceased during the latest Messinian dilution, just before the abrupt restoration of stable open marine conditions at the beginning of the Zanclean.A polyphased erosional surface affected the Mediterranean margins during the MSC with several critical episodes. The major episode related to the greatest water level fall, more than 1000 m, occurred during the deposition of the lower evaporites, from the onset of the evaporite deposition till the end of the first stage. Erosional processes remained active during the second evaporitic stage especially whenever the basin dried-up and a last important event marked by the karstification of the evaporites developed during the latest Messinian dilution just before the Early Zanclean reflooding that filled the erosional morphology

Modle dvolution de paysages, application aux karsts en cockpit de Jamaque, 2007,
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Fleurant Cyril , Tucker Gregory, Viles Heather
LANDSCAPE EVOLUTION MODEL, EXAMPLE OF COCKPIT KARST TERRAINS, JAMAICA. A model of cockpit karst landscape evolution is presented. After explaining implementation of dissolution processes of limestone in the landscape evolution model CHILD, we develop a model of limestone denudation based on epikarst theory processes. The model takes into account an anisotropic dissolution in space and time according to what is observed in reality or described by scenarios of cockpit karst landscape evolution. This model requires a fractures network to take into account subsurface flow. Then, dissolution and thus fractures widening are computed and show a positive feedback between dissolution and flow. The relation between subcutaneous dissolution of fractures and denudation of the topography is introduced by means of an empirical equation associated with epikarst processes: the denudation is taken to be proportional to the dissolution in the subcutaneous zone. Simulated cockpit karst terrains are compared with real landscapes by means of morphometric criteria. Results of the model are very close to reality which hence confirms the importance of anisotropic dissolution processes and above all could be a numerical validation of the epikarst processes to describe cockpit karst genesis.

Climate influence on geochemistry parameters of waters from Santana?Pérolas cave system, Brazil, 2007,
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Karmann Ivo, Cruz Francisco W. Jr. , Viana Oduvaldo Jr. , Burnsb Stephen J.
A four-year study of water geochemistry and hydrology was performed in a relatively deep cave system (overlying bedrock thickness varies from 100 to 300 m) as part of two monitoring programs, from June 1990 to February 1992 and from March 2000 to March 2002. The pH, saturation index for calcite, Ca and SO4 concentrations, and elemental ratios of Mg/Ca and Sr/Ca were measured in surface, well and drip waters throughout the system. Despite local hydrological and geological differences among sampling sites, the monitoring revealed significant synchronous intersite variations in these parameters that are related to seasonal changes in rainfall recharge, suggesting that element ratios of speleothems formed in deep caves are capable of recording short-term climate variations. Groundwater residence time appears to be the main factor affecting the water composition in the epikarst. Epikarstic waters are always undersaturated with respect to calcite but both saturation index (S.I.) and dissolved solids content increase substantially during drier periods because of longer residence times and longer interaction between meteoric water and limestone. By contrast, results from cave drips and rimstone pools indicate constant supersaturation for calcite and demonstrate that a major control on trace element ratios of waters in the deep vadose zone is the degree of prior calcite precipitation. This mechanism is more effective during drier periods when higher Mg/Ca and Sr/Ca values are observed in all drip and pool sites. However, variations do occur independently of the general trend of drip discharge, which suggest non-linear features in cave seepage water geochemistry. In addition, synchronous variations in SO4 and Cl concentration indicate high connectivity between different water flow pathways characterized by similar response to interseasonal changes in vadose water level. Fluctuations in trace element ratios of cave streams appear to reflect increased contribution of waters flushed from the vadose fissure aquifer during very wet periods by a piston flow mechanism. Flushing episodes are also responsible for maintaining more positive saturation indices in streams even during periods of high river discharge. Our results suggest that trace elements are a potential proxy for past rainfall changes but they also reveal different scenarios for interpreting trace elements ratios of speleothems and freshwater tufa deposited in a deep cave systems located in tropical humid areas.

Sinkholes in Italy: first results on the inventory and analysis, 2007,
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Nisio S. , Caramanna G. , Ciotoli G. ,
The Italian Geological Survey (APAT) carried out field surveys and analysis of collapse phenomena (sinkholes) in Italy. The main goal of the project is to collect geological, geomorphological, geochemical and hydrogeological data about the sinkhole-prone areas in Italy in order to develop a spatial database of the characteristics of each phenomenon. The preliminary results of this study provide information on the distribution, geological setting, and monitoring and remediation actions associated with these natural collapses in Italy. Many Italian regions are affected by these natural disasters. Some of them are caused by karst collapses or anthropic activity. However, some occur in areas characterized by buried carbonate bedrock (up to 190 m), as well as by peculiar geological-structural and geochemical scenarios. In these areas it is not reasonable to ascribe the formation mechanism to karst activity. Instead, these types of cavities quickly develop in terrains with a variable granulometry, often in connection with upwelling fluids. In this work some natural specific cases have been studied in order to define the relationships between the geology (regional tectonic elements, mineral spring waters and strong gas vents) and the genesis of the sinkholes. A first attempt of sinkhole classification is also presented

Visões do relevo cárstico na mídia: literatura, filmes e notícias, 2007,
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Travassos, L. E. P.
This work aims at summarize the main topics addressed in the lecture "Visions of karst in the media: literature, movies and news" given to Undergraduate Geography students from the 3rd year (5th period) of PUC Minas University (Coração Eucarístico Campus). The work explores the little known field of study of karst areas and caves: the humanistic study of karst. The work presents examples of how karst scenarios are usually portrayed in the media.

Updating of a DRASTIC-based method for specific vulnerability assessment in carbonate aquifers, 2007,
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Celico F. , Petrella E. , Naclerio G.

Some methodological modifications are suggested to improve a DRASTIC-based method as a reliable predictor of microbial contamination in extensively fractured and subordinately karstified carbonate aquifers. Those modifications will allow a better assessment of vulnerability induced by the concentrated infiltration of surface runoff in two different scenarios: (a) when the karst system is entirely located within an unsaturated aquifer and (b) when the karst system is partially located within a saturated medium. The effectiveness of the update method has been experimentally verified by comparing the vulnerability values with the results of a hydrogeological and microbiological study ad a test site.


Karsts des craies et calcarénites de la Montagne Saint-Pierre (BasseMeuse liégeoise), 2007,
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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.

NON-SPECIALISTS PERCEPTION ABOUT ENDOKARST AND EXOKARST SCENARIOS: VISIONS FROM HIGH SCHOOL STUDENTS, 2007,
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Travasos L. E. P. , Travassos E. G. , Travassos L. P. , Travassos L. C. P.

The aim of this work is to recover some methodological aspects of the study about the mind representations of caves in Brazil. The basis of this research consisted of one essay, approaching the social representations of a particular group of high school students on the exokarst and the endokarst. The results showed that the meanings vary only slightly, however, the most inter­esting result was due to the fact that students, who had already visited caves in some period of their lives, still held “negative” concepts regarding this environment even before visual stimu­lations. About 640 words associated with the exokarst and the endokarst were mentioned, emphasizing: fear, dark, shadowy, skull, hidden places, fantastic and beauty, which helped iden­tifying relations between the cultural and psychological as­pects of the group, mainly general views about the obscure and mysterious aspects of this landscape and its prominence over natural beauties. Analyzed data showed that the development of new research on mind representations of caves is very impor­tant, mainly for environmental education programs promoting adequate concepts about caves and extending activities of edu­cational ecotourism in Brazilian caves.


Hydrodynamic aspect of caves, 2008,
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Prelovek M. , Turk J. And Gabrovek F.
From a hydrological point of view, active caves are a series of connected conduits which drain water through an aquifer. Water tends to choose the easiest way through the system but different geological and morphological barriers act as flow restrictions. The number and characteristics of restrictions depends on the particular speleogenetic environment, which is a function of geological, geomorphological, climatological and hydrological settings. Such a variety and heterogeneity of underground systems has presented a challenge for human understanding for many centuries. Access to many underground passages, theoretical knowledge and recent methods (modeling, water pressure-resistant dataloggers, precise sensors etc.) give us the opportunity to get better insight into the hydrodynamic aspect of caves. In our work we tried to approach underground hydrodynamics from both theoretical and practical points of view. We present some theoretical background of open surface and pressurized flow in underground rivers and present results of some possible scenarios. Moreover, two case studies from the Ljubljanica river basin are presented in more detail: the cave system between Planinsko polje and Ljubljansko barje, and the cave system between Bloko polje and Cerkniko polje. The approach and methodology in each case is somewhat different, as the aims were different at the beginning of exploration. However, they both deal with temporal and spatial hydrodynamics of underground waters. In the case of Bloko polje-Cerkniko polje system we also explain the feedback loop between hydrodynamics and Holocene speleogenesis.

Solid waste disposal in the Environmental Protected Area of the Lagoa Santa Karst, Minas Gerais State, Brazil, 2008,
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Travassos L. E. P, Sampaio J. L. D, GuimarÃ, Es R. L. , Kohler H. C.

The State of Minas Gerais, Brazil, has approximately 580,000 sq km. From this total, it?s believed that at about 29,000 sq km are composed by carbonatic rocks.With a total of 853 municipalities and some noticeable environmental problems, the biggest problem is the proper final waste disposal. This work is intended to demonstrate the potential pollution of karst aquifers due to leachate?s percolation from improper waste disposal sites. In Brazil, it was established three categories to designate them. From the most environmentally incorrect sites for waste disposal to the better suitable for these activities it is possible to identify the waste dumps (lixões), controlled landfills (aterros controlados) and sanitary landfills (aterros sanitários). In each Brazilian State, around 80% of their municipalities have less than 20,000 inhabitants and no sufficient financial resources required to construct a sanitary landfill. It is also observed a certain degree of lack of political will from some municipal administrations to execute these projects. Unfortunately, some of these areas are located in karst terrains and therefore it is important to observe that an effective environmental control is not always made. The region of Lagoa Santa, State of Minas Gerais, is developed on metasediments of the Bambui Group, Sete Lagoas Formation (Upper Proterozoic). This rock Formation favors the development of expressive superficial and underground karst features. Moreover, the region presents great paleontological, archaeological, historical and speleological potential, which must also be protected from quarrying, pressures from population growth and uncontrolled touristic activities. In 1990 this scenario favored the creation of an Environmental Protected Area (Área de Proteção Ambiental - APA) to preserve local fauna and flora as well the physical environment. However, for many years the APA?s municipalities and its surroundings had installed waste dumps (lixões) since the end of the 70´s.With the State Guideline nº 52 (Deliberação Normativa nº 52) from December 2001, the State Government decreed the adequacy of such irregular dumps. The Guidelines clearly states that the waste must be deposit in a site with soil and/or low permeability rocks, with less than 30% steep angles, a minimum distance of 300m from water sources and 500m distant from core population. Furthermore, the standardization requires the municipalities to implement rainwater drainage systems around the site to reduce water percolation. The Document also obligates the municipality to compact and cover the waste cells at least three times a week, isolating the area to avoid human and animal access. In 2005, the state had registered 25 sanitary landfills, 199 controlled landfills and 549 waste dumps. In February 2007 the State Environmental Agency (FEAM) pointed out the same number of landfills, 207 controlled landfills and still a large amount of waste dumps: 519. Sadly, these inappropriate dumps (lixões) that were controlled in or near karst areas still poses as a threat to the environment since all the contamination comes from at least 25 years ago.


Interaction between a dam site and karst springs: The case of Supramonte (Central-East Sardinia, Italy), 2008,
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De Waele Jo, Forti Paolo

Sardinia is one of the Italian regions with the greatest number of dams per inhabitants, almost 60 for a population of only 1.5 million people. Many of these dam sites are located on non-carbonate rocks along the main rivers of the Island and their waters are used for irrigation, industrial, energy supply, drinking and flood regulation purposes.  The Pedra 'e Othoni dam on the Cedrino river (Dorgali, Central-East Sardinia) is located along the threshold of the Palaeozoic basement on the Northern border of the Supramonte karst area, where water is forced to flow out of the system through several resurgences, the most famous of which is the Su Gologone vauclusian spring, used for drinking water supply. The other main outflows of the system, Su Tippari and San Pantaleo springs, are at present almost permanently submerged by the high water level of the Pedra 'e Othoni dam. In the near future water will be supplied also to other communities with a possible increase of water taken from the spring.

The dam, originally meant to regulate the flooding of Cedrino river but actually used for all sorts of purposes (electricity supply, drinking water, irrigation of farmlands, industrial uses), has a maximum regulation altitude of 103 m a.s.l., only slightly less than a meter below the Su Gologone spring level (103.7 m), and 4 and 9 m respectively above the submerged Su Tippari and San Pantaleo springs.

During floods of the Cedrino river, occurring on average twice a year, also the Su Gologone spring becomes submerged by the muddy waters of the lake for a time ranging between a couple of hours up to several days, making water supply impossible. 

The analysis of the available meteorological and hydrogeological data relative to the December 2004 flood, one of the severest of the past 100 years, suggests that the reservoir is filled in a few days time. Several flooding scenarios have been reconstructed using digital terrain models, showing that backflooding submerges most of the discharge area of the aquifer, having important repercussions also on the inland underground drainage system. The upstream flood prone areas prevalently comprise agricultural lands with some sparse houses, but also highly frequented tourist facilities. Fortunately flooding occurs outside the tourist season, thus limiting risk to a limited number of local inhabitants. Massive discharge at the dam site, instead, determines a more hazardous situation in the Cedrino coastal plain, where population density in low lying areas is much higher. To avoid flooding hazard upstream the water level in the lake should be regulated, keeping it low in the flood prone seasons, and having it filled from the end of the winter in order to have enough water stocked before the beginning of the summer. Discharge at the dam site, instead, should be done cautiously, preventing severe flooding of the coastal Cedrino plain.


Hydrodynamic aspect of caves, 2008,
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Prelovek M. , Turk J. , Gabrovek F.

From a hydrological point of view, active caves are a series of connected conduits which drain water through an aquifer. Water tends to choose the easiest way through the system but different geological and morphological barriers act as flow restrictions. The number and characteristics of restrictions depends on the particular speleogenetic environment, which is a function of geological, geomorphological, climatological and hydrological settings. Such a variety and heterogeneity of underground systems has presented a challenge for human understanding for many centuries. Access to many underground passages, theoretical knowledge and recent methods (modeling, water pressure-resistant dataloggers, precise sensors etc.) give us the opportunity to get better insight into the hydrodynamic aspect of caves. In our work we tried to approach underground hydrodynamics from both theoretical and practical points of view. We present some theoretical background of open surface and pressurized flow in underground rivers and present results of some possible scenarios. Moreover, two case studies from the Ljubljanica river basin are presented in more detail: the cave system between Planinsko polje and Ljubljansko barje, and the cave system between Bloško polje and Cerkniško polje. The approach and methodology in each case is somewhat different, as the aims were different at the beginning of exploration. However, they both deal with temporal and spatial hydrodynamics of underground waters. In the case of Bloško polje-Cerkniško polje system we also explain the feedback loop between hydrodynamics and Holocene speleogenesis.


Limitations of hendy test criteria in judging the paleoclimatic suitability of speleothems and the need for replication, 2009,
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Dorale J. A. And Liu Z.
Carbon and oxygen isotopes in calcite speleothems are powerful proxies for understanding past climate change. For calcite deposited under isotopic equilibrium conditions, variations in d18 O values directly reflect changes in cave temperature and the isotopic composition of meteoric water. Speleothem d13 C values have bedrock, atmospheric, and soil gas sources. Soil gases can be traced to the overlying vegetation, which is related to climate. Both d13 C and d18 O values are therefore potentially powerful tracers of climate change. Processes that could alter speleothem d13 C and/or d18 O values, and thereby mask primary environmental signals, fall in the categories of 1) kinetic processes, including deposition of calcite out of isotopic equilibrium, and 2) vadose processes, including evaporation of water at or near the land surface. In truth, there is no absolute test for the absence of these kinetic/vadose-zone processes. However, the Hendy Test is widely used for assessing whether isotopic equilibrium existed during the time of calcite deposition. Criterion (1) of the Hendy Test (i.e., that d18 O values remain constant along a single growth layer) may not be a valid control of equilibrium conditions because isotopic equilibrium could theoretically occur in the center of the speleothem at the same time that kinetic fractionation occurs at the flanks. Moreover, the concept of sampling along a single growth layer is flawed in both theory and practice. Criterion (2) of the Hendy Test (i.e., that there is no relationship between d13 C and d18 O) is based on the assumption that speleothem d13 C values are not linked to climate. However, speleothem d13 C values may well be linked to climate because climate provides a first-order control on soil productivity and the type of vegetation. Therefore, Hendy Test criterion (2) is not a prerequisite to isotopic equilibrium in all cases. We propose instead the Replication Test (i.e., the demonstration of similar isotopic profiles among two or more speleothems) for evaluating the likelihood of calcite deposition under isotopic equilibrium conditions. Replication of isotopic profiles among two or more speleothems is possible only if kinetic/vadose-zone processes are either: 1) absent or 2) have affected spatially separated speleothems in exactly the same way. Because the second scenario is highly unlikely, we propose that the Replication Test is effectively sufficient in ruling out kinetic/vadose- zone overprinting processes. We further suggest that the Replication Test is far more robust in testing for the absence of the wide range of processes described above than is the traditional Hendy Test.

Oreonetides beattyi, a new troglobitic spider (Araneae: Linyphiidae) from eastern North America, and re-description of Oreonetides flavus, 2009,
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Paquin P. , Duprr N. , Buckle D. J. , And Lewis J. J.
A new troglobitic Linyphiidae, Oreonetides beattyi n.sp., is described from caves of eastern North America. The species is morphologically close to Oreonetides flavus Emerton and proposed as sister-species. Both species are described, illustrated and their distribution is documented. The intra-specific variation of O. beattyi is detailed: female genitalia display unusual variability, but males provided stable species level diagnosis. A male from Bull Cave (Tennessee) that shows significant genitalic variation is problematic, however. With limited sampling, the genetic bar-coding approach did not provide helpful insights to determine if this specimen belongs to a different species, is morphologically aberrant, or simply belongs to a population geographically distant enough to explain genetic variability. We propose the cryophilic affinities/relict population hypothesis to explain the ecological affinities of some Linyphiidae that are restricted to caves in most of their ranges, but occur on the surface at the northern edge of their distribution. We suggest an evolutionary scenario for the disjunct distribution of Oreonetides beattyi n.sp. in eastern caves and O. flavus in more northern latitudes on the west coast of North America.

Modelling karst geomorphology on different time scales, 2009,
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Kaufmann G.

The evolution and flow in a karst aquifer is studied with numerical simulations, based on the KARST model (Karst AquifeR Simulation Tool). The aquifer consists of a three-dimensional interconnected network of conduits representing fractures in the rock, and a porous rock matrix representing the finer fissured system in the rock. Flow through the aquifer can be driven by both diffuse recharge from precipitation and localised sinking streams, and the aquifer drains towards a large karst resurgence representing the base level. Superimposed onto the karst aquifer is a landscape, which can evolve with time by small-scale diffusive processes, large-scale river erosion, and karst denudation. Fractures in the aquifer are enlarged with time by chemical dissolution, enhancing the secondary porosity of the karst aquifer. The enlargement of fractures results in a dramatic increase of the aquifer conductivity over several orders of magnitude, and a change of flow patterns from an initially pore-controlled to a heterogeneous fracture-controlled aquifer. During the evolution, the water table is falling from an initially high position close to the land surface to a lower level coinciding with the actual base level. Two model scenarios are studied to elucidate the karst aquifer evolution in three dimensions. The evolution models are then complemented by event-type spring discharge modelling, which can be used as a predictive tool for karst spring discharge and contaminant transport.


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