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Speleology in Kazakhstan

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

Speleology in Kazakhstan

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

Speleology in Kazakhstan

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

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That anticline is upfolded stratum [16].?

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Your search for sequences (Keyword) returned 190 results for the whole karstbase:
Showing 181 to 190 of 190
Hydrogeological approach to distinguishing hypogene speleogenesis settings, 2013, Klimchouk, A. B.

The hydrogeological approach to defining hypogene speleogenesis (HS) relates it to ascending groundwater flow (AF). HS develops where AF causes local disequilibria conditions favoring dissolution and supports them during sufficiently long time in course of the geodynamic and hydrogeological evolution. The disequilibrium conditions at depth are invoked by changing physical-chemical parameters along an AF paths, or/and by the interaction between circulation systems of different scales and hydrody-namic regimes. The association of HS with AF suggests a possibility to discern regulari-ties of development and distribution of HS from the perspectives of the regional hy-drogeological analysis. In mature artesian basins of the cratonic type, settings favorable for AF and HS, are as follows: 1) marginal areas of discharge of the groundwaters of the 2nd hydrogeological story (H-story), 2) zones of topography-controlled upward cir-culation within the internal basin area (at the 1st and, in places, at the 2nd H-stories; 3) crests of anticlinal folds or uplifted tectonic blocs within the internal basin area where the upper regional aquitard is thinned or partially breached; 4) linear-local zones of deep-rooted cross-formational faults conducting AF from internal deep sources across the upper H-stories. Hydrodynamics in the 3rd and 4th stories is dominated by ascending circulation strongly controlled by cross-formational tectonic structures. Specific circula-tion pattern develops in large Cenozoic carbonate platforms (the Florida-type), side-open to the ocean, where AF across stratified sequences in the coastal parts, driven by both topography-induced head gradients and density gradients, involves mixing with the seawater. The latter can be drawn into a platform at deep levels and rise in the plat-form interior (the Kohout’s scheme). In folded regions, AF and HS are tightly con-trolled by faults, especially those at junctions between large tectonic structures. In young intramontaine basins with dominating geostatic regime, HS is favored at margin-al discharge areas where circulation systems of different origins and regimes may inter-act, such as meteoric waters flows from adjacent uplifted massifs, basinal fluids expelled from the basin’s interiors, and endogenous fluids rising along deep-rooted faults. Spe-cific and very favorable settings for HS are found in regions of young volcanism with carbonate formations in a sedimentary cover


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


Speleogenesis of an exhumed hydrothermal sulphuric acid karst in Cambrian carbonates (Mount San Giovanni, Sardinia), 2013, De Waele Jo, Forti P. , Naseddu A.

n the past few years the systematic study of caves intercepted by mine workings in southwest Sardinia has permitted us to observe morphologies due to rare speleogenetic and minerogenetic processes related to ancient hydrothermal activity. These relic morphologies are slowly being overprinted by recent speleogenetic processes that tend to obscure the hypogene origin of these caves. A combined geomorphological and mineralogical investigation has permitted a fairly detailed reconstruction of the various phases of evolution of these caves. Cave formation had already started in Cambrian times, but culminated in the Carboniferous, when most of the large voids still accessible today were formed. A key role in carbonate dissolution was played by sulphuric acid formed by the oxidation of the polymetallic ores present in the rocks since the Cambrian. During the Quaternary a variety of minerals formed inside the caves: calcite and aragonite, that yielded sequences of palaeo-environmental interest, and also barite, phosgenite, hydrozincite, hemimorphite and many others. These minerals are in part due to a phreatic thermal hypogenic cave forming phase, and in part to later epigene overprinting in an oxidizing environment rich in polymetallic ores. Massive gypsum deposits, elsewhere typical of this kind of caves, are entirely absent due to dissolution during both the phreatic cave formation and the later epigenic stage.


THE ROLE OF SULFATE-RICH SPRINGS AND GROUNDWATER IN THE FORMATION OF SINKHOLES OVER GYPSUM IN EASTERN ENGLAND, 2013, Cooper A. H. , Odling N. E. , Murphy Ph. J. , Miller C. , Greenwood Ch. J. , Brown D. S.

Heavily karstified gypsum and dolomite aquifers occur in the Permian (Zechstein Group) of Eastern England. Here rapid active gypsum dissolution causes subsidence and abundant sinkholes affect an approximately 140-km by 3-km area from Darlington, through Ripon to Doncaster. The topography and easterly dip of the strata feed artesian water through the dolomite up into the overlying gypsum sequences. The shallow-circulating groundwater emerges as sulfate-rich springs with temperatures between 9-12 oC, many emanating from sinkholes that steam and do not freeze in the winter (such as Hell Kettles, Darlington). Water also circulates from the east through the overlying Triassic sandstone aquifer. Calcareous tufa deposits and tufa-cemented gravels also attest to the passage and escape of this groundwater.The sizes of the sinkholes, their depth and that of the associated breccia pipes are controlled by the thickness of gypsum that can dissolve and by the bulking factors associated with the collapsed rocks. The presence of sulfate-rich water affects the local potability of the supply. Groundwater abstraction locally aggravates the subsidence problems, both by active dissolution and drawdown. Furthermore, the gypsum and dolomite karstification has local implications for the installation of ground-source heat pumps. The sulfate-rich springs show where active subsidence is expected; their presence along with records of subsidence can inform planning and development of areas requiring mitigation measures.


Variability of groundwater flow and transport processes in karst under different hydrologic conditions, 2013, Ravbar, Nataša

Significance of hydrological variability in karst is presented, which also discusses factors inducing such variability and consequences it may cause. Groundwater flow in karst aquifers is often characterized by strong variability of flow dynamics in response to different hydrologic conditions within a short time period. Consequently, water table fluctuations are often in the order of tens of meters, differences in flow velocities between low- and high-flow conditions can reach ten or even more times. In dependence to respective hydrologic conditions groundwater flow also results in variations of flow directions, and thus in contribution of different parts of the aquifer to a particular spring. The described hydrological variability has many implications for contaminant transport, groundwater availability and vulnerability. Groundwater level rising reduces thickness of the unsaturated zone and decreases protectiveness of the overlying layers. Higher water flow velocities reduce underground retention. Due to more turbulent flow, transport and remobilization of solute and insoluble matter is more effective. During high-flow conditions there is usually more surface flow and hence more concentrated infiltration underground. Particularly in karst systems that show very high hydrologic variability, this should be considered to correctly characterize, understand or predict the aquifers’ hydrological behaviour and to prepare proper protection strategies.


The first cavernicolous Nicoletiidae (Insecta: Zygentoma) from The United Arab Emirates, 2013, Espinasa L. , Mendes L. F.

Lepidospora mazyadi, n. sp., is described and differentiated from all the other known Lepidospora s.s. The new species was collected from a cave in Jebel Hafeet in the United Arab Emirates. Morphology and preliminary analyses of 16S rRNA DNA sequences are described. The new species is unique because, unlike other species in the genus, it lacks sexually dimorphic terminal filaments. It is also the first nicoletiid reported from the United Arab Emirates and the second cave-adapted species from Arabia.


Microbial communities in a coastal cave: Cova des Pas de Vallgornera (Mallorca, Western Mediterranean), 2014, Busquets A. , Fornós J. J. , Zafra F. , Lalucat J. , Merino A.

As a part of an ongoing project on the role of microbes in the biogeochemistry of Majorcan caves, the species diversity of microbial communities present in cave pools of anchialine waters in the Cova des Pas de Vallgornera (Mallorca, western Mediterranean) is investigated by a culture-dependent method. Two-hundred and forty-eight strains isolated from this characteristic cave environment of the littoral karst are identified by whole-cell-MALDI-TOF mass spectrometry and phylogeneticaly by 16S rRNA gene sequences. Total cell counts and species diversity of the bacterial communities decreas with the distance to the entrance of the cave and to the sea. Strains are mainly identified as members of the Gammaproteobacteria and Actinobacteria. Around 20% of the isolates are able to precipitate carbonates. Calcite is the predominant phase, growing in all the precipitates, although struvite is also found in one Pseudomonas and in one Aspergillus cultures. Differences in crystal characteristics of external shape (habit) and growth are observed according to the bacterial species promoting the precipitates. Bacteria associated with multicolored ferromanganese deposits, present in several parts of the cave, are also studied and are identified as Pseudomonas benzenivorans and Nocardioides luteus. The preponderance of Pseudomonas species and the possible contribution of bacteria in calcite deposition are discussed.


The formation of the pinnacle karst in Pleistocene aeolian calcarenites (Tamala Limestone) in southwestern Australia, 2015, Lipar Matej, Webb John A.

A spectacular pinnacle karst in the southwestern coastal part of Western Australia consists of dense fields of thousands of pinnacles up to 5 m high, 2 m wide and 0.5–5 m apart, particularly well exposed in Nambung National Park. The pinnacles have formed in the Pleistocene Tamala Limestone, which comprises cyclic sequences of aeolian calcarenite, calcrete/microbialite and palaeosol. The morphology of the pinnacles varies according to the lithology in which they have formed: typically conical in aeolianite and cylindrical in microbialite. Detailed mapping and mineralogical, chemical and isotopic analyses were used to constrain the origin of the pinnacles, which are residual features resulting mainly from solutional widening and coalescence of solution pipeswithin the Tamala Limestone. The pinnacles are generally joined at the base, and the stratigraphy exposed in their sides is often continuous between adjacent pinnacles. Some pinnacles are cemented infills of solution pipes, but solution still contributed to their origin by removing the surrounding material. Although a number of pinnacles contain calcified plant roots, trees were not a major factor in their formation. Pinnacle karst in older, better-cemented limestones elsewhere in theworld is similar inmorphology and origin to the Nambung pinnacles, but is mainly influenced by joints and fractures (not evident at Nambung). The extensive dissolution associated with pinnacle formation at Nambung resulted in a large amount of insoluble quartz residue, which was redeposited to often bury the pinnacles. This period of karstification occurred at around MIS 5e, and therewas an earlier, less intense period of pinnacle development duringMIS 10–11. Both periods of pinnacle formation probably occurred during the higher rainfall periods that characterise the transition from interglacial to glacial episodes in southern Australia; the extensive karstification around MIS 5e indicates that the climate was particularly humid in southwestern Australia at this time.


The influence of light attenuation on the biogeomorphology of a marine karst cave: A case study of Puerto Princesa Underground River, Palawan, the Philippines, 2015, Coombes Martin A. , La Marca Emanuela C. , Naylor Larissa A. , Piccini Leonardo, De Waele Jo, Sauro Francesco

Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site.

Organic growth at the entrance of the cave was abundant (100% occurrence) and complex, dominated by phototrophic organisms (green microalgae, diatoms, cyanobacteria, mosses and lichens). Thickness of this layer was 0.28 ± 0.18 mm with active endolith penetration into the limestone (mean depth = 0.13 ± 0.03 mm). In contrast, phototrophs were rare 50 m into the cave and biofilm cover was significantly thinner (0.01 ± 0.01 mm, p b 0.000) and spatially patchy (33% occurrence). Endolithic penetration here was also shallower (b0.01mm, p b 0.000) and non-uniform. Biofilm was found 250 m into the cave, but with a complete absence of phototrophs and no evidence of endolithic bioerosion.

We attribute these findings to light-induced stress gradients, showing that the influence of light on phototroph abundance has knock-on consequences for the development of limestone morphological features. In marine caves this includes notches, which were most well-developed at the sheltered cave entrance of our study site, and for which variability in formation rates between locations is currently poorly understood.


Initial conditions or emergence: What determines dissolution patterns in rough fractures?, 2015,

Dissolution of fractured rocks is often accompanied by the formation of highly localized flow paths. While the fluid flow follows existing fractures in the rock, these fissures do not, in general, open uniformly. Simulations and laboratory experiments have shown that distinct channels or “wormholes”develop within the fracture, from which a single highly localized flow path eventually emerges. The aim of the present work is to investigate how these emerging flow paths are influenced by the initial aperture field. We have simulated the dissolution of a single fracture starting from a spatially correlated aperture distribution. Our results indicate a surprising insensitivity of the evolving dissolution patterns and flow rates to the amplitude and correlation length characterizing the imposed aperture field. We connect the similarity in outcomes to the self-organization of the flow into a small number of wormholes, with the spacing determined of the longest wormholes. We have also investigated the effect of a localized region of increased aperture on the developing dissolution patterns. A competition was observed between the tendency of the high-permeability region to develop the dominant wormhole and the tendency of wormholes to spontaneously nucleate throughout the rest of the fracture. We consider the consequences of these results for the modeling of dissolution in fractured and porous rocks.


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