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 active cave is 1. cave containing a running stream. 2. cave in which speleothems are growing. (less common and less desirable usage.) compare live cave [10].?

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

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 flow velocity (Keyword) returned 38 results for the whole karstbase:
Showing 31 to 38 of 38

The characteristics of flow from the landfill near Sežana in the area of Kras were studied by the use of tracer test. In well permeable fissure on the karren surface near the landfill the fluorescent dye uranine was injected in order to study the directions and velocities of its flow through the karst aquifer. Monitoring of tracer concentrations in the period of one year and a half enabled us to make some conclusions about the dynamics of groundwater flow in the directions towards the Timava, Brojnica and Sardoč springs. Detailed observations were organised also at the Klariči pumping station, which is the main source of drinking water for the Kras region. Increased concentrations of tracer were measured only during extremely high waters. Different explanations are possible, but we can not exclude the possibility of a weak, not permanent underground water connection with the landfill. Calculation of the amount of recovered tracer confirmed the main flow direction towards the Timava springs (recovery rate 93%) and a secondary direction with lower flow velocity towards the Brojnica and Sardoč springs. Outflow through the Klariči pumping is estimated to only 0.003% of injected uranine.

Chemical and isotopic (d18O%, d2H%, d13C%, 222Rn%) multi-tracing for groundwater conceptual model of carbonate aquifer (Gran Sasso INFN underground laboratory central Italy), 2008, Adinolfi Falcone R. , Falgiani A. , Parisse B. , Petitta M. , Spizzico M. , Tallini M.

A hydrochemical and isotope study was conducted on the drainage waters of an underground laboratory, located inside the Gran Sasso massif (central Italy). The study was expected to improve the conceptual model of groundwater circulation at the base of an over 1000-thick unsaturated zone in the Gran Sasso partitioned karst aquifer. This lithostratigraphically and tectonically complex aquifer is typical of Africa–Europe thrust-andfold collision belt in the Mediterranean area. In this case, investigations on water–rock interactions during recharge in complex aquifers, overlaid by a thick unsaturated zone, have been made thanks to the strategic location of the Gran Sasso underground laboratories, located in the core of a huge carbonate aquifer. Knowledge of the local basic hydrogeological setting was the starting point for a detailed hydrogeochemical and isotopic study, which was carried out at the aquifer scale and at the fine scale in the underground laboratories. The water–rock interaction processes were investigated both spatially and in temporal sequences, analysing recharge waters and groundwater in the underground laboratories by multitracing techniques, including major ions and d18O&, d2H& and d13C& stable isotopes. Use of 222Rn provides information on transit time in the aquifer. Processes proved to be typical of carbonate rocks, with clear influence of vertical movement of water on chemical–physical parameters through the unsaturated zone. Conversely, in the saturated zone, these processes proved to be dominantly affected by local geological–structural conditions. A conceptual model with dual flow velocity is proposed, directly related to the local geological-structural setting. 222Rn decay enables to calculate an effective velocity of around 10 m/day for the fracture network, through the sequence of less permeable dolomites and underlying limestone. Lag time between recharge and chemical changes in the saturated zone testifies to an effective velocity of about 35 m/day for fast flow through recent and active extensional faults

Periodic breakthrough curve of tracer dye in the Gelodareh Spring, Zagros, Iran, 2009, Karimi, Haji And Javad Ashjari.
The Patagh Dam is under construction in the Kermanshah province in the west of Iran. The right abutment of the dam is located on Ilam-Sarvak limestone, which has the potential of karstification. This limestone is drained by several springs including Gelodareh Spring. In order to study possible leakage through the dam, a dye tracing test was organized in borehole PC208 near the dam. The recession coefficients and hydrochemical data of the Gelodareh Spring show that the flow regime of the area is of diffuse type. The dye appeared in the water samples from borehole PC206 and Gelodareh Spring, which are located downstream of the dam. This demonstrates a hydraulic connection between the injection well and these points. Therefore, there is the potential for seepage through the right abutment of the dam. The measured mean flow velocity to borehole PC206 (0.86 m/h) indicates a diffuse flow regime. The breakthrough curve of the Gelodareh Spring shows multiple peaks without significant tail except the last one. Additionally, the high flow velocity (11.8 m/h) is at odds with a diffuse flow regime. The ambiguous behaviour of the dye breakthrough curve of the Gelodareh Spring is explained by a combination of siphon and diffuse flow systems. Existence of a siphon flow system explains the multiple periodic peaks of the breakthrough curve and the lack of tails. The tail on the last peak is the result of diffuse flow system. A neck, close to the spring or the main conduit, which conveys water to the spring, might be causing the pseudo-steady state behaviour of spring discharge and diminishes the periodic discharge fluctuation, which is created by a siphon. It is probable that the siphon level is situated in the zone of water level fluctuation.

Spreading of tracer plumes through confined telogenetic karst aquifers: A model, 2011, Gabrovsek Franci, Dreybrodt Wolfgang

To calculate spreading of a tracer or contaminant through an aquifer all details of the aquifer, e.g. distribution of hydraulic parameters, must be known. This is not possible in nature. To study the spreading of plumes through karst, we have used a digital model of a confined karst aquifer at different stages of early karstification. In these models all details such as fracture aperture widths, their lengths and widths, and the hydraulic boundary conditions are known. Therefore the flow velocity of water can be calculated in each fracture. Using this information a particle tracking method is employed to calculate the propagation and spreading of a plume caused by an instantaneous input pulse into selected regions of the aquifer. From this information the time dependence of the outflow of particles from any selected region is obtained. This function represents the transfer response function for an instantaneous Dirac ?-function input. Two digital karst models are designed. In the first, homogeneous one, the aperture widths of the fractures are statistically distributed but of similar width. In the second a coarse percolating net of prominent fractures with larger constant aperture width is embedded into the dense net of narrow fissures. Propagation of the plumes and the transfer-response function are presented at the onset of karstification and at different times of karst evolution. If particles are injected at the entrance of evolving karst channels propagating towards the output boundary tracer breakthrough times increase with increasing time of karst evolution until shortly before breakthrough of the karst conduit they drop to half of their maximal value. With increasing evolution of the karst aquifer the hydraulic heads are redistributed and regions of low hydraulic gradients in the upstream side of the aquifer are created. Particles injected into fractures which have stopped dissolutional widening of their aperture widths and are located in regions of low gradient are kept in these regions for long times in the order of 100 years until they have propagated towards regions of high hydraulic heads, where a “fan like” plume develops along the pathway of steepest gradient.

Stability of dissolution flutes under turbulent flow, 2011, Hammer . , Lauritzen S. E. , Jamtveit B.

Dissolution of a solid surface under turbulent fluid flow can lead to the formation of periodic ripple-like structures with a wavelength dependent upon flow velocity. A model coupling hydrodynamics with mass transport and dissolution kinetics shows that the shape stability of these structures can be explained from fundamental
principles. The effects of a subgrid diffusion boundary layer must be included in the dissolution model to produce realistic results. The importance of including not only the mean flow velocity, but also the turbulent component of flow, in the dissolution model is emphasized. The numerical experiments also compare dissolution profiles for gypsum and calcite.

Scallops, 2012, Murphy, Phillip J.

Solutional sculpturing of cave walls can provide information on both the direction and discharge of water flow in a cave passage. Their asymmetry indicates the direction of ground water flow and their wavelength is inversely proportional to the flow velocity. Laboratory and field investigations have enabled the calculation of mean flow velocity from scallop wavelength data and thus the calculation of discharge at the time of scallop formation. Other hydraulic parameters may also be estimated from scallop measurements.

Carbon cycle in the epikarst systems and its ecological effects in South China, 2012, Jiang Z. , Lian Y. , Qin X.

The carbon cycle in a global sense is the biogeochemical process by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the earth. For epikarst systems, it is the exchange of carbon among the atmosphere, water, and carbonate rocks. Southern China is located in the subtropical zone; its warm and humid weather creates favorable conditions for the dynamic physical, chemical, and ecological processes of the carbon cycle. This paper presents the mechanisms and characteristics of the carbon cycle in the epikarst systems in south China. The CO2 concentration in soils has clear seasonal variations, and its peak correlates well with the warm and rainy months. Stable carbon isotope analysis shows that a majority of the carbon in this cycle is from soils. The flow rate and flow velocity in an epikarst system and the composition of carbonate rocks control the carbon fluxes. It was estimated that the karst areas in south China contribute to about half of the total carbon sink by the carbonate system in China. By enhancing the movement of elements and dissolution of more chemical components, the active carbon cycle in the epikarst system helps to expand plant species. It also creates favorable environments for the calciphilic plants and biomass accumulation in the region. The findings from this study should help in better understanding of the carbon cycle in karst systems in south China, an essential component for the best management practices in combating rock desertification and in the ongoing study of the total carbon sink by the karst flow systems in China

Calculating flux to predict future cave radon concentrations, 2016, Rowberry Matt, Marti Xavi, Frontera Carlos, Van De Wiel Marco, Briestensky Milos

Cave radon concentration measurements reflect the outcome of a perpetual competition which pitches flux against ventilation and radioactive decay. The mass balance equations used to model changes in radon concentration through time routinely treat flux as a constant. This mathematical simplification is acceptable as a first order approximation despite the fact that it sidesteps an intrinsic geological problem: the majority of radon entering a cavity is exhaled as a result of advection along crustal discontinuities whose motions are inhomogeneous in both time and space. In this paper the dynamic nature of flux is investigated and the results are used to predict cave radon concentration for successive iterations. The first part of our numerical modelling procedure focuses on calculating cave air flow velocity while the second part isolates flux in a mass balance equation to simulate real time dependence among the variables. It is then possible to use this information to deliver an expression for computing cave radon concentration for successive iterations. The dynamic variables in the numerical model are represented by the outer temperature, the inner temperature, and the radon concentration while the static variables are represented by the radioactive decay constant and a range of parameters related to geometry of the cavity. Input data were recorded at Driny Cave in the Little Carpathians Mountains of western Slovakia. Here the cave passages have developed along splays of the NE-SW striking Smolenice Fault and a series of transverse faults striking NW-SE. Independent experimental observations of fault slip are provided by three permanently installed mechanical extensometers. Our numerical modelling has revealed four important flux anomalies between January 2010 and August 2011. Each of these flux anomalies was preceded by conspicuous fault slip anomalies. The mathematical procedure outlined in this paper will help to improve our understanding of radon migration along crustal discontinuities and its subsequent exhalation into the atmosphere. Furthermore, as it is possible to supply the model with continuous data, future research will focus on establishing a series of underground monitoring sites with the aim of generating the first real time global radon flux maps.

Results 31 to 38 of 38
You probably didn't submit anything to search for