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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 wetland is a general term used for a group of wet habitats, in common use by specialists in wildlife management. it includes areas that are permanently wet and/or intermittently water-covered, especially coastal marshes, tidal swamps and flats, and associated pools, sloughs, and bayous [1].?

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 ridge (Keyword) returned 154 results for the whole karstbase:
Showing 136 to 150 of 154
New insights into the carbon isotope composition of speleothem calcite : an assessment from surface to subsurface, 2012,
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Meyer, Kyle William

The purpose of this study was to provide new insights into the interpretation of speleothem (cave calcite deposit) δ13C values. We studied two caves in central Texas, which have been actively monitored for over 12 years. We compared δ13C values of soil CO2 (δ13Cs), cave drip water (δ13CDIC), and modern cave calcite (δ13Ccc). Measured average δ13C values of soil CO2 were -13.9 ± 1.4‰ under mixed, shallowly-rooted C3-C4 grasses and were -18.3 ± 0.7‰ under deeply-rooted ashe juniper trees (C3). The δ13CDIC value of minimally-degassed drip water in Natural Bridge Caverns was -10.7 ± 0.3‰. The carbon isotope composition of CO2 in equilibrium with this measured drip water is -18.1 ± 0.3‰. The agreement between juniper soil CO2 and drip water (within ~0.2‰) suggests that the δ13C value of drip water (δ13CDIC) that initially enters the cave is controlled by deeply-rooted plants and may be minimally influenced by host-rock dissolution and/or prior calcite precipitation (PCP). At Inner Space Caverns, δ13CDIC values varied with vegetation above the drip site, distance from the cave entrance, and distance along in-cave flow paths. Whereas CO2 derived from deeply-rooted plants defines the baseline for drip water δ13CDIC entering the caves, kinetic effects associated with the degassing of CO2 and simultaneous precipitation of calcite account for seasonal variability in δ13CDIC and δ13Ccc. We documented increases in δ13CDIC at a rate of up to 0.47‰/hour during the season of peak degassing (winter), suggesting that δ13CDIC variations may be controlled by total elapsed time of CO2 degassing from drip water (Ttotal). We also observed seasonal shifts in the δ13C values of modern calcite grown on glass substrates that are correlated with shifts in drip water δ13CDIC values and drip-rate. Therefore, we suggest that increased aridity at the surface above a given cave results in, slower drip-rates, higher Ttotal, and therefore higher δ13CDIC values. We propose that large variability (>2‰) in speleothem δ13Ccc values dominantly reflect major vegetation changes, and/or increasing Ttotal by slowing drip-rates. Based on these findings, variability in speleothem carbon isotope records may serve as a proxy for paleoaridity and/or paleovegetation change.


Karst and caves of headstreams of the Lena River, 2012,
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Philippov V. M. , Filippov A. G. , Indyukov A. E.

Karst phenomena of headstreams of the Lena River in Eastern Siberia between junctions of the Zolotokan Creek and Chanchur River are described in the paper. Wide spreading of karst is determined by: areal occurrence of marine carbonate rocks of the Lower and Middle Cambrian, their monoclinal bedding, increased tectonical fracturing of karstiferous rocks, relatively high roughness of surface topography, flattened dividing ranges, relatively humid climate (precipitation 400-500 mm per year), and long history of continental regime of the area. The relics of ancient gently sloped river valleys at dividing ranges are the most karstified. There is no surface drainage in their limits, and groups of dolines up to 40-80 individuals per square kilometer are common. Karst development determines an existence of vast meadows covered with the dwarf birch, reindeer moss and herbs (Trollius asiaticus, Scutellaria baialensis, Rhodiola rosea, Veratrum lobelianum, Gentiana sp., Allium sp. .) among stocked coniferous taiga at the altitude of 1080-1150 m a.s.l. at the watershed divides of the Lena and Levaya Tongoda rivers (Mongolian Steppe Stow), and Lena and Pankucha-2nd rivers. On the rest of the territory, dolines do not form large groups, but they occur as isolated individuals or scattered clusters consisting of 3 to 5 individuals. Karst dry valleys are widely spread. Their total length is not less than 397 km, and 126 km of them belongs to the watershed of the Yukhta-1st River. Residual hills having morphology of pillars, towers and ridges were observed. Descriptions of two karst caves and two crevice caves are given.


Dealing with gypsum karst problems: hazards, environmental issues, and planning, 2013,
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Cooper A. H. , Gutierrez F.

Gypsum dissolves rapidly underground and at the surface, forming gypsum karst features that include caves, subsidence areas, and sinkholes. Mapping these landforms, understanding the gypsum karst and local hydrogeology, and producing sinkhole susceptibility and hazard maps are crucial for development and public safety. Situations that change the local hydrogeology, such as dams, water abstraction, or injection/drainage, can accelerate dissolution and subsidence processes, increasing the severity of the problems; dams and canals built on gypsum karst can leak or fail catastrophically. Gypsum karst problems can be mitigated by careful surveying and scientific investigation followed by phased preventive planning, ground investigation, and construction incorporating sinkhole-proof designs. Towns and cities, including parts of Paris (France), Dzerzhinksk (Russia), Madrid and Zaragoza (Spain), Birzai (Lithuania), and Ripon and Darlington (UK), are developed on such ground requiring local planning guidelines and special construction methods. Roads, railways, pipelines, and bridges are particularly vulnerable to such subsidence and require special consideration. 


Hydrogeology of gypsum Formations in Iran, 2013,
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Raeisi E. , Zare M. , Aghdam J. A.

The gypsum formations in Iran are mainly Upper Red (URF), Gachsaran (GF), and Sachun. The GF is divided into salt (SGF) and its non-salt equivalents (NSGF). The conductivity of the spring’s water in Sachun, URF and NSGF is below 3500 mS cm21, but the conductivity of the SGF varies from 2400 to 400,000 mS cm21. Three different sites, Tangsorkh (NSGF), Ambal and Salbiz (SGF), were selected for further studies. The Tangsorkh area is composed of alternating units of marlstone and gypsum. The hydraulic connections between these units are broken by the marls and no sub-aquifer is developed in the gypsum units due to their small catchment area and lack of karst development. The Ambal area, adjacent to the large Karun River, consists of units of marl, anhydrite, and halite. Sinkholes cover all parts of the area. Contact of Karun River with the Amble ridge causes the chemistry of the river to evolve from bicarbonate type to chloride type. The presence of the Karun River inside this ridge formed a network of karstic conduits and sinkholes, which causes the marly layers to collapse such that the Ambal area cannot be considered to have several independent subaquifers. The Salbiz site is composed of alternating units of marl-marlstone and gypsum without any sinkholes or exposed salt layers. It consists of independent sub-aquifers with general flow directions parallel to the strike. The study indicates that the GF is mainly composed of small independent sub-aquifers due to its alternative marl or marlstone layers, resulting water flows parallel to the strike, except in the SGF under specific conditions.


Mineralogical researches at Snezhnaya-Mezhennogo-Illuzia cave system (Bzibskiy ridge, Western Caucasus): preliminary results and directions for future researches, 2013,
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Bazarova E. P. , Mazina S. E. , Hodyreva E. V.

Isotopically altered wallrock of the hypogene conduits in the Crimean Piedmont, Ukraine, 2013,
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Klimchouk A. , Dublyansky Y. , Tymokhina E. , Sptl Ch.

The Crimean Piedmont stretches along the tectonic suture separating the fold-and-thrust structure of the Crimean Mountains from the Scythian Plate. It comprises two cuesta-like ridges whose structural slopes are built up of homoclinal limestone beds of the Paleocene- Eocene (the Inner Range), and the Neogene (the Outer Range) ages. Abundant relicts of the hypogene karst have been identified recently in steep cuesta cliffs of the Piedmont. The hypogene cavities formed in confined to semi-confined hydrological conditions due to interaction of the deep-seated waters, ascending along cross-formational fracture conduits, with the strata-bound lateral filtration flow. The ongoing geomorphological dissection of the stratified structure of the Piedmont com-monly follows the pre-formed hypogene conduits, resulting in the development of the pronounced cuesta relief with steep cliffs featuring massive exposure of the hypogene karst conduit paleo-walls with specific morphologies.
Movement of deep-seated fluids through carbonate wallrock may cause isotopic altera-tion of the later. We have studied isotopic composition of C and O along nine cores drilled into the walls of the cliffs decorated with hypogene solutional features, as well as in two hypogene caves. Data from all cores show the presence of a wide isotopic altera-tion halo, whose thickness exceeds the core length (max. 40 cm). In this zone, the rock is slightly depleted in δ18 (ca. 1 -2 ‰) relative to the “pristine”, unchanged values of a given rock unit. In most cores the rock is also depleted in 13 but two cores show high-er 13C values. In addition to this low-gradient alteration, most of the cores also show a narrow (4-50 mm) zone of the high-gradient alteration, across which δ18 and δ13 drop by respectively, 2.0–4.9 ‰ and 0.7–4.5 ‰. At three localities, the walls of the hypogene cavities were coated with phreatic calcite. Isotopic composition of this calcite corresponds to the lowermost values of the altered rock. In one core, the rock in the high-gradient alteration zone is depleted in 18 but enriched in 13. In yet another core the rock is enriched in both 18 and 13. The results corroborate the hypogenic origin of conduits and suggest that the wallrock was exposed to, and interacted with, geo-chemically different waters after the main volume of cavities had been created by disso-lution.


NA JAVORCE CAVE A NEW DISCOVERY IN THE BOHEMIAN KARST (CZECH REPUBLIC): UNIQUE EXAMPLE OF RELATIONSHIPS BETWEEN HYDROTHERMAL AND COMMON KARSTIFICATION, 2013,
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Dragoun J. Ž, á, K K. Vejlupek J. Filippi M. Novotný, J. Dobeš, P.

 

The Na Javorce Cave is located in the Bohemian Karst, Czech Republic, near the Karlštejn castle, about 25 km SW of Prague. The cave was discovered as a result of extensive exploration including cave digging and widely employed capping of narrow sections. Exploration in the cave has already lasted 20 years. The cave is fitted with several hundred meters of fixed and rope ladders and several small fixed bridges across intra-cave chasms. Access to the remote parts of the cave is difficult because of long narrow crawl passages and deep and narrow vertical sections. The Na Javorce Cave became the deepest cave discovered to date in Bohemia with the discovery of its deepest part containing a lake in 2010. The cave was formed in vertically dipping layers of Lower Devonian limestone; it is 1,723 m long and 129 m deep, of which 9 m is permanently flooded (data as of December 2012). The cave is polygenetic, with several clearly separable evolutionary stages. Cavities discovered to date were mostly formed along the tectonic structures of two main systems. One of these systems is represented by vertical faults of generally N-S strike, which are frequently accompanied by vein hydrothermal calcite with crystal cavities. The second fault system is represented by moderately inclined faults (dip 27 to 45°, dip direction to the W). Smaller tube-like passages of phreatic morphology connect the larger cavities developed along the two above-mentioned systems. The fluid inclusion data obtained for calcite developed along both fault systems in combination with C and O stable isotope studies indicate that the hydrothermal calcite was deposited from moderately saline fluids (0.5 to 8.7 wt. % NaCl equiv.) in the temperature range from 58 to 98 °C. The fluids were NaCl-type basinal fluids, probably derived from the deeper clastic horizons of the Barrandian sedimentary sequence. The age of the hydrothermal processes is unknown; geologically it is delimited by the Permian and Paleogene. The hydrothermal cavities are small compared to cavities formed during the later stages of karstification. The majority of the known cavities were probably formed by corrosion by floodwater derived from an adjacent river. This process was initiated during the Late Oligocene to Early Miocene, as was confirmed by typical assemblage of heavy minerals identical in the surface river sediments and in clastic cave sediments. The morphology of most cavities is phreatic or epiphreatic, with only local development of leveled roof sections (“Laugdecken”). The phreatic evolution of the cave is probably continuing into the present in its deepest permanently flooded part, which exhibits a water level close to that of the adjacent Berounka River. Nevertheless, the chemistry of the cave lake differs from that of the river water. The cave hosts all the usual types of cave decoration (including locally abundant erratics). The most interesting speleothem type is cryogenic cave carbonate, which was formed during freezing of water in relation to the presence of permafrost during the Glacial period. The occurrence of cryogenic cave carbonate here indicates that the permafrost of the Last Glacial period penetrated to a depth of at least 65 m below the surface.


KARST DEVELOPMENT IN THE GLACIATED AND PERMAFROSTREGIONS OF THE NORTHWEST TERRITORIES, CANADA, 2013,
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Ford Derek

 

The Northwest Territories of Canada are ~1.2 million km2 in area and appear to contain a greater extent and diversity of karst landforms than has been described in any other region of the Arctic or sub-Arctic. The Mackenzie River drains most of the area. West of the River, the Mackenzie Mountains contain spectacular highland karsts such as Nahanni (Lat. 62° N) and Canol Road (Lat. 65° N) that the author has described at previous International Speleological Congresses. This paper summarizes samples of the mountain and lowland karst between Lats. 64–67° N that are located east of the River. The Franklin Mountains there are east-facing cuestas created by over-thrusting from the west. Maximum elevations are ~1,000 m a.s.l., diminishing eastwards where the cuestas are replaced by undeformed plateaus of dolomite at 300–400 m asl that overlook Great Bear Lake. In contrast to the Mackenzie Mountains (which are generally higher) all of this terrain was covered repeatedly by Laurentide Continental glacier ice flowing from the east and southeast. The thickness of the last ice sheet was >1,200 m. It receded c.10,000 years ago. Today permafrost is mapped as “widespread but discontinuous” below 350 m a.s.l. throughout the region, and “continuous” above that elevation. The vegetation is mixed taiga and wetlands at lower elevations, becoming tundra higher up. Access is via Norman Wells (population 1,200), a river port at 65° 37’N, 126° 48’W, 67 m a.s.l.: its mean annual temperature is -6.4 °C (January mean -20 °C, July +14 °C) and average precipitation is ~330 mm.y-1, 40 % falling as snow. In the eastern extremities a glacial spillway divides the largest dolomite plateau into “Mahony Dome” and “Tunago Dome”. The former (~800 km2) has a central alvar draining peripherally into lakes with overflow sinkholes, turloughs, dessicated turloughs, and stream sinks, all developed post-glacially in regular karst hydrologic sequences. Tunago Dome is similar in extent but was reduced to scablands by a sub-glacial mega-flood from the Great Bear basin; it is a mixture of remnant mesas with epikarst, and wetlands with turloughs in flood scours. Both domes are largely holokarstic, draining chiefly to springs at 160–180 m a.s.l. in the spillway. The eastern limit of overthrusting is marked by narrow ridges created by late-glacial hydration of anhydrite at shallow depth in interbedded dolostones and sulphate rocks. Individual ridges are up to 60 km long, 500–1,000 m wide, 50–250 m in height. They impound Lac Belot (300 km2), Tunago Lake (120 km2) and many lesser lakes, all of which are drained underground through them. In the main overthrust structures, the Norman Range (Franklin Mountains) is oriented parallel with the direction of Laurentide ice flow. It displays strongly scoured morphology with elongate sinkholes on its carbonate benches. In contrast, the Bear Rock Range is oriented across the ice flow, has multiple cuestas, is deeply furrowed and holokarstic but preserves pinnacle karst on higher ground due to karst-induced polar thermal (frozen-down) conditions at the glacier base there.


TRITIUM AND H, O AND C STABLE ISOTOPES AS A TOOL FOR TRACKING OF WATER CIRCULATION IN THE NIEDŹWIEDZIA CAVE SYSTEM (SUDETES, POLAND), 2013,
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Gą, Siorowski M. Hercman H.

 

Water circulation in Niedźwiedzia Cave system is complicated. The system is fed by direct infiltration of precipitation, infiltration from the surface stream and, possibly, by rising flow from deep sources. The cave is drained by system of karst springs in the Kleśnica stream valley, but some part of water flows across border ridge and occurs in Morava stream valley, Czech Republic (Ciężkowski et al. 2009). We tried to use tritium and stable isotopes to describe hydrology of the cave system and analyzed 155 water samples for stable isotopes and 38 water samples for tritium content. The Niedźwiedzia Cave system is composed of three levels of halls and galleries. In the upper level, stable isotope composition in drip water plots close to the local meteoritic water line (LMWL) on the δ18O vs δD diagram. It varies during the year similar to stable isotope composition of precipitation (i.e. low δ18O values during winters and higher δ18O during summers). The delay between isotopic signal in precipitation and drip water is ~10–14 days and this can be interpreted as a time of infiltration from the surface to the cave upper level. The correlation between isotopic composition of precipitation and drip water is not observed in the lower level of the cave system. There isotopic composition of drip water is more stable during the year. We use tritium dating method to estimate the age of this water. It has shown that infiltration time to the lower level is 1.4±0.3 year. The “oldest” water was found in karst spring draining the cave system. The estimated transit time is 3–4 years and suggest admixture of some “old” water that was not sampled in the cave.


HYPOGENIC SPELEOGENESIS IN THE CRIMEAN FORE-MOUNTAINS (THE BLACK SEA REGION, SOUTH UKRAINE) AND ITS ROLE IN THE REGIONAL GEOMORPHOLOGY, 2013,
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Klimchouk A. , Amelichev G. , Tymokhina E. , Tokarev S.

 

The leading role in the geomorphic development of the Crimean fore-mountain region is played by the processes of dismemberment of “shielding” limestone layers of the monoclinal stratified structure through valley entrenchment, and by further retreat of vertical rocky outcrops via block-toppling mechanism. These processes are guided by the presense of hypogene karst structures, whose formation preceded the modern relief. Karstified fracture-karst zones, 100 to 400 m wide, in the Cretaceous-Paleogene strata controlled the entrenchment of valleys in the limestone layers. The basic elements of hypogenic karst structures, which form their spatial framework, are sub-vertical fracture-karst conduits (karst “rifts”). Denudational opening of vertical fracture-karst rift conduits in limestone layers set the cliff-like shape of valleys slopes, and presence of such rift conduits in the rear of cliffs of already incised valleys determines the block-toppling mechanisms of slope retreat. This maintains the verticality of cliff segments in the cuesta ridge and controls their position. Hypogenic sculptural morphology is extensively displayed in the exposed walls of cliffs (former conduit walls), which determines the originality and nomenclature of morphology of limestone cliffs of the Inner Ridge. In those areas of slopes where position of cliffs has stabilized for considerable time due to absence of new lines of block detachment in the rear, weathering becomes a significant process in the morphogenesis of surfaces. The abundance, outstanding expression, preservation and accessibility of relict hypogene karst features in the extensive cuesta cliffs of the Inner Ridge makes the region the foremost one for studying regularities of hypogene solution porosity development, the process currently ongoing in the adjacent artesian basin of the Plain Crimea.


GYPSUM KARST CAUSES RELOCATION OF PROPOSED CEDAR RIDGE DAM, THROCKMORTON COUNTY, TEXAS, 2013,
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Johnson K. S. , Wilkerson J. M.

Cedar Ridge Dam and Reservoir will be built to supply water for the city of Abilene, Texas. The original damsite (CR) was to be located on Clear Fork of Brazos River in Throckmorton County, but initial coring of the damsite encountered unsuspected gypsum beds in the Permian-age Jagger Bend/Valera Formation. Gypsum is a highly soluble rock that typically contains karst features, and its presence in a dam foundation or impoundment area could allow water to escape from the reservoir. A decision was made to look at potential sites farther upstream (to the southwest), where west-dipping gypsum beds would be deeper underground and karst problems would be minimized or eliminated.The first phase of the relocation was a comprehensive field study of Clear Fork Valley, upstream of the original damsite, to identify gypsum outcrops; gypsum was exposed at only one location, just above damsite CR. The second phase of the study was examination of nearly 100 petroleum-test geophysical logs to identify, correlate, and map the subsurface gypsum and associated rock layers upstream of the original damsite. The gypsiferous sequence is 30–45 m thick, and consists of 8 gypsum beds, mostly 1–3 m thick, interbedded with red-brown and gray shale units 1–10 m thick. Gypsum beds comprise 25–30% of the gypsiferous sequence. Gypsum beds dip uniformly to the west at about 7 m/km (about 0.4 degrees), and thus the uppermost gypsum is at least 23 m beneath the newly proposed damsite (A), about 8 km to the southwest.Subsequent coring and other studies of the new damsite A confirm that gypsum beds are 23 m beneath the newly proposed dam. There is no evidence of solution channels or other karst features beneath this site, and thus there is little likelihood of water loss from the reservoir at the new site due to gypsum karst.


Influence of meteorological variables to water quality in five lakes over the Aggtelek (Hungary) and Slovak karst regions – a case study, 2013,
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Samu Andrea, Csépe Zoltán, Báránykevei Ilona

The main objective of this study is to analyse the effect of tendencies in the meteorological variables on the water quality on the example of five lakes in the Aggtelek and Slovak karst. The data set used eleven water quality parameters (oxygen saturation, chemical oxygen demand, nitrate, nitrite, orthophosphate, total phosphorus, ammonium, pH, conductivity, iron, manganese), as well as daily data of six climatic parameters from the period 2008­2010. A cluster analysis is performed in order to determine the climate impact on the water quality parameters. Furthermore, factor analysis with special transformation, as a novelty in the study, is implemented to find out the weight of the climate parameters as explanatory variables and hence their rank of importance in forming the given water quality parameter as an influencing variable. The study introduces a methodology for analysing the climate impact on the water quality parameters. In order to reduce the number of the water quality parameters, a so called two­stage factor analysis was performed, which is a novel procedure. Application of the two­stage factor analysis involves both benefits and disadvantages. Its benefit is that it substantially reduces the number of resultant variables. In this way, information loss of the retained factors is around 20%. As a result, we received that both positive and negative extreme values of water quality parameters can be associated with weak or breaking­up warm fronts passing through over the region. On the contrary, the role of anticyclones or anticyclone ridge weather situations is supposed to be irrelevant. Unstable and extreme weather conditions act in the direction of breaking up the balance that would support the good water quality. This process does not benefit the water use nor the sensitive karst hydrogeological system


Biologically influenced stalagmites in Niah and Mulu caves (Sarawak, Malaysia), 2013,
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Dodgewan Dominique, Deng Hui Min Angela

There are two significant karst regions in northern Sarawak (Malaysia): Niah and Mulu. Both are famous worldwide for their well developed caves. Here we document the presence of over twenty unusual stalagmites in six cave entrances in these two regions. One of the stalagmites has been previously described as a crayback stalagmite (Lundberg and McFarlane 2011) and they all show indications of biological influence. Our study aimed to establish the locations within the cave entrances where these stalagmites are present and to provide a preliminary overview of the stalagmite forms. The environment, and especially availability and direction of light, was also studied at several sites. Surface scrapings were examined for the presence of cyanobacteria. The morphology of the unusual stalagmites is variable and includes forms that are elongated and craybacklike and others that show features not previously described in craybacks: flat tops, bulbous protuberances, phototropic rims, irregular grooves and ridges and oriented coralloid growth. Several of these features are not found in abiotic stalagmites and suggest biological control. The findings of light surveys confirm that certain features of the stalagmites are phototropically controlled. Filamentous cyanobacteria with calcified sheaths and coccoid cyanobacteria are present. we propose that this diverse group of stalagmite be named “tufaceous stalagmite” of which craybacks are thought to be a sub­group.


MORPHOLOGICAL EFFECTS OF CONDENSATION-CORROSION SPELEOGENESIS AT DEVILS HOLE RIDGE, NEVADA, 2014,
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Dublyansky Y. , Spötl C.

The Devils Hole Ridge, a small block of Paleozoic carbonate rocks surrounded by the Amargosa Desert in southern Nevada, is located at the discharge end of the Ash Meadows regional groundwater flow system.
Continuous, long-term presence of slightly thermal (33.6°C) groundwater and the extensional tectonic setting, creating underground thermal lakes in open fractures, lead to intense dissolution above the water table. The morphology of the subaerial parts of the tectonic caves was slightly modified by condensation corrosion, and the Devils Hole Prospect Cave was almost entirely created by condensation corrosion. Caves and cavities in the Devils Hole Ridge are an interesting example of a hypogene speleogenesis by mechanism by condensation corrosion, operating above an aquifer which was demonstrably supersaturated with respect to calcite for hundreds of thousands of years.


Occurrence of diagenetic alunites within karst cavity infill of the Dammam Formation, Ahmadi, Kuwait: an indicator of hydrocarbon gas seeps, 2014,
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Khalaf F. I. , Abdullah F. A.

Alunite minerals occur as white powdery lumps and laminated coloured deposits within cavity and solution channel infill of the palaeokarst zone of the Upper Eocene Dammam Formation. This formation is exposed in a quarry located on the Al Ahmadi ridge within the Greater Burgan oil field in southern Kuwait. Field occurrences and sedimentary structures of the alunite deposits were described. Collected samples were petrographically described, and their mineralogy and geochemistry were determined using X-ray diffraction and X-ray fluorescence, respectively. Microfabrics were investigated using SEM, revealing that they are primarily composed of fibrous alunogen (hydrous aluminium sulphate) and pseudo-cubical K-alunite (hydrous potassium aluminium sulphate). Their mode of occurrence suggests a hypogenetic origin, where sulphide gases associated with hydrocarbon gases reacted with an Al-rich solution leached from clay minerals and feldspars of the cavity-fill muddy sand sediments. The hydrocarbon gases may have seeped from subsurface petroliferous formations within the Greater Burgan oil field along vertical fractures. This study suggests that these acidic seeps may have played a role in the development of the palaeokarst zone of the Dammam Formation


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