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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 stalactite is 1. speleothem, generally of calcite, formed by dripping water and hanging from a cave roof. stalactites embrace an enormous variety of sizes and shapes. they form where percolation water seeps from a cave ceiling and becomes saturated with respect to calcite due to loss of carbon dioxide into the cave air. calcite is precipitated round the rim of the water droplet and continued deposition creates a hollow tubular straw stalactite (soda straw). additional deposition of calcite on the outside of the initial cylinder creates an ordinary tapering stalactite. almost infinite variation in shape may be influenced by changes in water flow, cave air chemistry, evaporation, temperature or dissolved impurities, and by crystal growth blocking flow paths. they are the most common speleothem. though the single 7m long stalactite in ireland's poll an ionain is not the world's longest, it is uniquely spectacular against the dark chamber walls [9]. 2. conical deposit of calcite or aragonite often with a hollow center hanging from the roof of a cave or cavern formed by precipitation of carbonate due to escape of co2 from hanging water beads and to evaporation of part of the water [20]. 3. a cylindrical or conical deposit of minerals, generally calcite, formed by dripping water, hanging from the roof of a cave, generally having a hollow tube at its center. from greek word meaning exude drops [10]. synonyms: (french.) stalactite; (german.) tropfstein, stalaktit; (greek.) stalaktitis; (italian.) stalattite; (russian.) stalaktit; (spanish.) estalactita; (turkish.) sarkit (yugoslavian.) mosur, viseci kapnik, stalaktit.?

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

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PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Journal of Hydrology, 2001, Vol 241, Issue 0, p. 177-193
Dispersion, retardation and scale effect in tracer breakthrough curves in karst conduits
Abstract:
Characteristics of tracer breakthrough curves in karst conduits are examined and compared to results generated using well known equations applied to porous media. The equations of the turbulent dispersion lead to a transport equation similar to the classical advection-dispersion equation for porous media with a slightly different meaning for the dispersion and advection terms. For investigations at the meter length scale, we used a three-dimensional (3-D) computational fluid dynamics (CFD) code to simulate tracer transport in several conduit geometries. The simulations show that turbulent dispersion can be considered as Fickian at a meter length scale of observation and that turbulent dispersivity depends linearly on the average flow velocity in the range of observed velocities. The simulations show that pools induce retardation (tailing of the breakthrough curve) due to flow reversal in eddies. Retardation has a complex relationship with the pool dimensions. Irregularity of the conduit cross-section along the investigated section clearly produces retardation. This is obvious at the meter length scale but may still be visible 10(3) m downstream from the injection point. A transfer function ('black box') approach is used for upscaling from a meter to a 10(3) m length scale. Before applying it to natural examples, the transfer function approach is tested by using the 3-D CFD code and appears to perform well. Several tests, based on numerical, laboratory and held experiments, of conduit segments which includes various dispersive features indicate that retardation tends to be transformed to symmetrical dispersion with distance. At large scale it appears that the dominant dispersion factor is the irregularity of the conduit geometry, which produces an increase in dispersivity with distance ('scale effect'), similar to that observed in porous media. In conclusion this suggests that retardation and high dispersion provide evidence of an irregular conduit, including either numerous dispersive features or large-scale ones (pools for example). Conversely no retardation and moderate dispersion (close to 0.012 m) must result from turbulent Row through a smooth conduit. (C) 2001 Elsevier Science B.V. All rights reserved