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Enviroscan Ukrainian Institute of Speleology and Karstology

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Speleology in Kazakhstan

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

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That flux is see specific discharge.?

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

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KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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 thinning (Keyword) returned 7 results for the whole karstbase:
Groundwater circulation and geochemistry of a karstified bank-marginal fracture system, South Andros Island, Bahamas, 1997,
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Whitaker Fiona F. , Smart Peter L. ,
On the east coast of South Andros Island, Bahamas, a major bank-marginal fracture system characterised by vertically extensive cavern systems (blue holes) is developed sub-parallel to the steep-sided deep-water re-entrant of the Tongue of the Ocean. In addition to providing a discharge route for meteoric, mixed and geochemically evolved saline groundwaters, a strong local circulation occurs along the fracture system. This generates enhanced vertical mixing within voids of the fracture system, evidenced by the increasing mixing zone thickness, and the thinning and increasing salinity of brackish lens waters from north to south along the fracture system. Furthermore, tidally driven pumping of groundwaters occurs between the fracture and adjacent carbonate aquifer affecting a zone up to 200 m either side of the fracture.The resultant mixing of groundwaters of contrasting salinity and within and along the fracture system and with the surrounding aquifer waters, together with bacterial oxidation of organic matter, generates significant potential for locally enhanced diagenesis. Undersaturation with respect to calcite within the fresh (or brackish)-salt water mixing zone is observed in the fracture system and predicted in the adjacent aquifer, while mixing between the brackish fracture lens and surrounding high fresh waters causes dissolution of aragonite but not calcite. The latter gives rise to considerable secondary porosity development, because active tidal pumping ensures continued renewal of dissolutional potential. This is evidenced by calcium and strontium enrichment in the brackish lens which indicates porosity generation by aragonite dissolution at a maximum rate of 0.35% ka-1, up to twice the average estimated for the fresh water lens. In contrast saline groundwaters are depleted in calcium relative to open ocean waters suggesting the formation of calcite cements.The development of a major laterally continuous cavernous fracture zone along the margin of the carbonate platform permits enhanced groundwater flow and mixing which may result in generation of a diagenetic `halo' at a scale larger than that generally recognised around syn-sedimentary fractures in fossil carbonates. This may be characterised by increased secondary porosity where a relative fall in sea-level results in exposure and formation of a meteoric groundwater system, or cementation by `marine' calcite both below this meteoric system, and where the bank surface is flooded by seawater

Stability appraisal of the Medvedova Konta pothole, 2002,
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Kortnik Joze
Until 1956 the underground details of areas around Pokljuka were practically unknown due to the area's non-karstic outward appearance. However, the presence of karst phenomena on this Alpine plain is undoubtedly indicated, primarily by the absence of a surface drainage network. A mathematical model was made of the Medvedova konta pothole, in which two different sets of material properties were used, corresponding to the Triassic limestone that forms the bedrock under the greater part of Pokljuka. The model simulates the gradual thinning of the ceiling of the underground hall, from the surface downwards, until its collapse. The paper presents a stability appraisal of the Medvedova konta pothole in Pokljuka.

Sedimentary evidence for a rapid, kilometer-scale crustal doming prior to the eruption of the Emeishan flood basalts, 2003,
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He B. , Xu Y. G. , Chung S. L. , Xiao L. , Wang Y. ,
Biostratigraphic and sedimentologic investigations in 67 sections have been carried out for the Middle Permian Maokou Formation that immediately underlies the Emeishan flood basalts in southwest China. The results suggest a domal crustal thinning before the emplacement of the Emeishan large igneous province. Variably thinned carbonates in the Maokou Formation are capped by a subaerial unconformity, which is generally manifested by karst paleotopography, paleoweathering zone, or locally by relict gravels and basal conglomerates. Provenance analysis indicates that these gravels and conglomerates were mainly derived from the uppermost Maokou Formation. Therefore, the stratigraphic thinning likely resulted from differential erosion due to regional uplift. Iso-thickness contours of the Maokou Formation delineate a subcircular uplifted area, in accordance with the crustal doming caused by a starting mantle plume as predicted by experimental and numerical modeling. The duration of this uplift is estimated to be less than 3 Myr and the magnitude of uplift is greater than 1000 m. The sedimentary records therefore provide independent supporting evidence for the mantle plume initiation model for the generation of the Emeishan flood basalts. (C) 2003 Elsevier B.V. All rights reserved

Structural framework of the Edwards Aquifer recharge zone in south-central Texas, 2004,
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Ferrill Da, Sims Dw, Waiting Dj, Morris Ap, Franklin Nm, Schultz Al,
The Edwards Aquifer, the major source of water for many communities in central Texas, is threatened by population growth and development over its recharge zone. The location of the recharge and confined zones and the flow paths of the aquifer are controlled by the structure of and deformation processes within the Balcones fault system, a major system of predominantly down-to-the-southeast normal faults. We investigate the geologic structure of the Edwards Aquifer to assess the large-scale aquifer architecture, analyze fault offset and stratigraphic juxtaposition relationships, evaluate fault-zone deformation and dissolution and fault-system architecture, and investigate fault-block deformation and scaling of small-scale (intrablock) normal faults. Characterization of fault displacement shows a pattern of aquifer thinning that is likely to influence fault-block communication and flow paths. Flow-path constriction may be exacerbated by increased fault-segment connectivity associated with large fault displacements. Also, increased fault-zone deformation associated with larger-displacement faults is likely to further influence hydrologic properties. Overall, faulting is expected to produce strong permeability anisotropy such that maximum permeability is subhorizontal and parallel to fault-bedding intersections. At all scales, aquifer permeability is either unchanged or enhanced parallel to faults and in many cases decreased perpendicular to faults

Navier-Stokes flow and transport simulations using real fractures shows heavy tailing due to eddies, 2007,
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Cardenas M. B. , Slottke D. T. , Ketcham R. A. , Sharp Jr. J. M.

Two-dimensional Navier-Stokes flow and transport simulations are conducted for a 15-cm long fracture mapped via X-ray computed tomography. (1) The actual fracture with irregular aperture, (2) a truncated fracture where the largest aperture area is excluded from the domain, (3) the truncated fracture with further thinning of other large aperture areas, and (4) a fracture with uniform vertical aperture equal to the actual fracture’s mean aperture, are subjected to the same pressure gradient. Slight variations in fracture characteristics result in significantly different flow and transport behavior. Flux is much larger for the uniformaperture fracture compared to the actual fracture. A pronounced eddy is present at the largest aperture zone of the actual fracture resulting in a power-law tail absent in other cases. The uniform aperture fracture has the largest effective dispersion coefficient estimated via inversion of a 1D analytical model. The analytical model fit to the other cases is not as robust as in the uniform aperture case

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Bayari S. , Ozyurt N. , Pekkans E.

Assessment of the tectonic, geologic and hydrogeologic processes reveal that the Obruks, mega collapse dolines located in the central Anatolia-Turkey, are products of hypogenic karsti?cation. Obruks are characterized by their cylindrical or truncated cone shapes with diameters and depths reaching several hundreds of meters. Geological, geophysical and hydrogeological data, along with the groundwater’s chemical and isotopic composition suggest a hypogene karsti?cation process that seems to be driven by the upward migration of a deep-seated carbon dioxide ?ux supplied by an asthenospheric rise. The linear distribution of obruks through the suture zone of a former oceanic subduction and their association with young volcanism reveal a tecto-genetic origin that is related to the extensional thinning of the upper lithosphere due to orogenic collapse of the Taurus Mountain Range, which is a part of the Alpine-Himalayan Orogenic Belt.

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Galdenzi S.

In the Apennine Mountains many examples of hypogene caves are known, generally related to present or past rise of sulfidic water that, mixing with oxygenated water of shallow flow systems, causes the sulfuric acid dissolution of limestone. The hypogene caves are generally located in small limestone outcrops covered by rocks of low permeability that in?uence the groundwater flowpaths. Some caves, however, are known also in hydrogeological massifs, where epigenic caves prevail. The hypogene caves show different patterns, ranging from phreatic to pure water table caves. The former prevail when karst evolved below the water table in structures almost completely covered by low permeability units; the latter occur in zones where a fast recharge of freshwater can reach the sulfidic water from the karst surface. The progressive lowering, thinning and removal of the low-permeability covers by non-karstic erosion processes can cause the progressive evolution from phreatic to water table caves. Active speleogenetic processes due to H2 S oxidation can be directly observed in different hydrogeologic settings: in highly permeable aquifers with ready recharge of freshwater (Frasassi caves), in thermal caves, below low permeability cover (Acquasanta Terme), or in marine thermal caves with salt water intrusion (Capo Palinuro).

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