MWH Global

Enviroscan Ukrainian Institute of Speleology and Karstology

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 5
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 cano is (spanish.) stream. see also stream.?

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

Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 7
What is Karstbase?



Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

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;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for rates (Keyword) returned 712 results for the whole karstbase:
Showing 706 to 712 of 712
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943

Tectonic research and morphologi calobservations were carried out in six caves (Kalacka, Goryczkowa, Kasprowa Ni¿na, Kasprowa OErednia, Kasprowa Wy¿nia and Magurska) in the Bystra Val ley, in the Tatra Moun -tains. There are three cave lev els, with the youn gest ac tive and the other two in ac tive, re flect ing de vel op ment partly un der epiphreatic and partly un der phreatic con di tions. These stud ies dem on strate strong con trol of the cave pat tern by tec tonic fea tures, in clud ing faults and re lated frac tures that orig i nated or were re ju ve nated dur ing up lift,last ing from the Late Mio cene. In a few lo cal cases, the cave pas sages are guided by the com bined in flu ence of bed ding, joints and frac tures in the hinge zone of a chev ron anticline. That these cave pas sages are guided by tec tonic struc tures, ir re spec tive of lithological dif fer ences, in di cates that these proto-con duits were formed by “tec tonic in cep tion”. Dif fer ences in the cave pat tern be tween the phreatic and epiphreatic zones at a given cave level may be a re sult of mas sif re lax ation. Be low the bot tom of the val ley, the ef fect of stress on the rock mass is re lated to the re gional stress field and only in di vid ual faults ex tend be low the bot tom of the val ley. Thus in the phreatic zone, the flow is fo cused and a sin gle con duit be comes en larged. The lo cal ex ten sion is more in tense in the epiphreatic zone above the val ley floor and more frac tures have been suf fi ciently ex tended to al low wa ter to flow. The wa ter mi grates along a net work of fis sures and a maze could be form ing. Neotectonic dis place ments (of up to 15 cm), which are more re cent than the pas sages, were also iden ti fied in the caves. Neotectonic ac tiv ity is no lon ger be lieved to have as great an im pact on cave mor phol ogy as pre vi ously was thought. Those faults with dis place ments of sev eral metres, de scribed as youn ger than the cave by other au thors, should be re clas si fied as older faults, the sur faces of which have been ex posed by speleogenesis. The pos si ble pres ence of neotectonic faults with greater dis place ments is not ex cluded, but they would have had a much greater mor pho log i cal im pact than the ob served fea tures sug gest.

Tectonic control of cave development: a case study of the Bystra Valley in the Tatra Mts., 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Szczygieł Jacek, Gaidzik Krzysztof, Kicińska Ditta

Tectonic research and morphological observations were carried out in six caves (Kalacka, Goryczkowa, Kasprowa Niżna, Kasprowa Średnia, Kasprowa Wyżnia and Magurska) in the Bystra Valley, in the Tatra Mountains. There are three cave levels, with the youngest active and the other two inactive, reflecting development partly under epiphreatic and partly under phreatic conditions. These studies demonstrate strong control of the cave pattern by tectonic features, including faults and related fractures that originated or were rejuvenated during uplift, lasting from the Late Miocene. In a few local cases, the cave passages are guided by the combined influence of bedding, joints and fractures in the hinge zone of a chevron anticline. That these cave passages are guided by tectonic structures, irrespective of lithological differences, indicates that these proto-conduits were formed by "tectonic inception”. Differences in the cave pattern between the phreatic and epiphreatic zones at a given cave level may be a result of massif relaxation. Below the bottom of the valley, the effect of stress on the rock mass is related to the regional stress field and only individual faults extend below the bottom of the valley. Thus in the phreatic zone, the flow is focused and a single conduit becomes enlarged. The local extension is more intense in the epiphreatic zone above the valley floor and more fractures have been sufficiently extended to allow water to flow. The water migrates along a network of fissures and a maze could be forming. Neotectonic displacements (of up to 15 cm), which are more recent than the passages, were also identified in the caves. Neotectonic activity is no longer believed to have as great an impact on cave morphology as previously was thought. Those faults with displacements of several metres, described as younger than the cave by other authors, should be reclassified as older faults, the surfaces of which have been exposed by speleogenesis. The possible presence of neotectonic faults with greater displacements is not excluded, but they would have had a much greater morphological impact than the observed features suggest.

Stable isotope data as constraints on models for the origin of coralloid and massive speleothems: The interplay of substrate, water supply, degassing, and evaporation, 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Caddeo Guglielmo Angelo, Railsback Loren Bruce, De Waele Jo, Frau Franco

Many speleothems can be assigned to one of two morphological groups: massive speleothems, which consist of compact bulks of material, and coralloids, which are domal to digitate in form. Faster growth on protrusions of the substrate occurs in the typical growth layers of coralloids (where those layers are termed “coralloid accretions”),

but it is not observed in the typical layers of massive speleothems, which in contrast tend to smoothen the speleothem surface (and can therefore be defined as “smoothing accretions”). The different growth rates on different areas of the substrate are explainable by various mechanisms of CaCO3 deposition (e.g., differential aerosol deposition, differential CO2 and/or H2O loss fromacapillary filmof solution, deposition in subaqueous environments).

To identify the causes of formation of coralloids rather than massive speleothems, this article provides data about δ13C and δ18O at coeval points of both smoothing and coralloid accretions, examining the relationship between isotopic composition and the substratemorphology. In subaerial speleothems, data showenrichment in heavy isotopes both along the direction of water flow and toward the protrusions. The first effect is due to H2O evaporation and CO2 degassing during a gravity-driven flow of water (gravity stage) and is observed in smoothing accretions; the second effect is due to evaporation and degassing duringwatermovement by capillary action from recesses to prominences (capillary stage) and is observed in subaerial coralloids. Both effects coexist in smoothing accretions interspersed among coralloid ones (intermediate stage). Thus this study supports the origin of subaerial coralloids from dominantly capillary water and disproves their origin by deposition of aerosol fromthe cave air. On the other hand, subaqueous coralloids seem to form by a differential mass-transfer from a still bulk of water toward different zones of the substrate along diffusion flux vectors of nutrients perpendicular to the iso-depleted surfaces. Finally, this isotopic method has proved useful to investigate the controls on speleothem morphology and to obtain additional insights on the evolution of aqueous solutions inside caves.

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,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
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.

The role of condensation in the evolution of dissolutional forms in gypsum caves: Study case in the karst of Sorbas (SE Spain), 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Gazquez Fernando, Calaforra José Maria, Forti Paolo, De Waele Jo, Sanna Laura

The karst of Sorbas (SE Spain) is one of the most important gypsum areas worldwide. Its underground karst network comprises over 100 km of cave passages. Rounded smooth forms, condensation cupola and pendant-like features appear on the ceiling of the shallower passages as a result of gypsum dissolution by condensation water. Meanwhile, gypsum speleothems formed by capillarity, evaporation and aerosol deposition such as coralloids, gypsum crusts and rims are frequently observed closer to the passage floors. The role of condensation–dissolution mechanisms in the evolution of geomorphological features observed in the upper cave levels has been studied by means of long-term micro-erosion meter (MEM) measurements, direct collection and analysis of condensation waters, and micrometeorological monitoring. Monitoring of erosion at different heights on gypsum walls of the Cueva del Agua reveals that the gypsum surface retreated up to 0.033 mm yr−1 in MEM stations located in the higher parts of the cave walls. The surface retreat was negligible at the lowest sites, suggesting higher dissolution rates close to the cave ceiling, where warmer and moister air flows. Monitoring of microclimatic parameters and direct measurements of condensation water were performed in the Covadura Cave system in order to estimate seasonal patterns of condensation. Direct measurements of condensation water dripping from a metal plate placed in the central part of the El Bosque Gallery of Covadura Cave indicate that condensation takes place mainly between July and November in coincidence with rainless periods. The estimated gypsum surface lowering due to this condensation water is 0.0026 mm yr−1. Microclimatic monitoring in the same area shows differences in air temperature and humidity of the lower parts of the galleries (colder and drier) with respect to the cave ceiling (warmer and wetter). This thermal sedimentation controls the intensity of the condensation–evaporation mechanisms at different heights in the cave.

Long-term erosion rate measurements in gypsum caves of Sorbas (SE Spain) by the Micro-Erosion Meter method, 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943
Sanna Laura, De Waele Jo, Calaforra José Maria, Forti Paolo

The present work deals with the results of long-term micro-erosion measurements in the most important gypsum cave of Spain, the Cueva del Agua (Sorbas, Almeria, SE Spain). Nineteen MEM stations were positioned in 1992 in a wide range of morphological and environmental settings (gypsum floors and walls, carbonate speleothems, dry conduits and vadose passages) inside and outside the cave, on gypsum and carbonate bedrocks and exposed to variable degree of humidity, different air flowand hydrodynamic conditions. Four different sets of stations have been investigated: (1) the main cave entrance (Las Viñicas spring); (2) the main river passage; (3) the abandoned Laboratory tunnel; and (4) the external gypsum surface. Data over a period of about 18 years are available. The average lowering rates vary from 0.014 to 0.016 mm yr−1 near the main entrance and in the Laboratory tunnel, to 0.022 mm −1 on gypsum floors and 0.028 mm yr−1 on carbonate flowstones. 

The denudation data from the external gypsum stations are quite regular with a rate of 0.170 mm yr−1. The observations allowed the collecting of important information concerning the feeding of the karst aquifer not only by infiltrating rainwater, but under present climate conditions also by water condensation of moist air flow. This contribution to the overall karst processes in the Cueva del Agua basin represents over 20% of the total chemical dissolution of the karst area and more than 50% of the speleogenetically removed gypsum in the cave system, thus representing all but a secondary role in speleogenesis. Condensation–corrosion is most active along the medium walls, being slower at the roof and almost absent close to the floor. This creates typical corrosion morphologies such as cupola, while gypsum flowers develop where evaporation dominates. This approach also shows quantitatively the morphological implications of condensation–corrosion processes in gypsum karst systems in arid zones, responsible for an average surface lowering of 0.047 mm yr−1, while mechanical erosion produces a lowering of 0.123 mm yr−1.

Initial conditions or emergence: What determines dissolution patterns in rough fractures?, 2015,
Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/ on line 943

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.

Results 706 to 712 of 712
You probably didn't submit anything to search for