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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 karst valley is 1. valleys in karst are normally distinctive due to the lack of integrated surface drainage. most are either blind (due to being closed where the drainage sinks underground), headless or pocket (where a river emerges from a spring) or dry (where surface flow has been lost due to underground capture). the exception is the allogenic valley, where a river completely traverses a karst, normally because underground conduits at or below valley floor level are immature. fine examples of allogenic karst valleys are dove dale in the peak district and france's tarn gorge [9]. 2. elongated solution valley in limestone [20]. 3. valley produced by collapse of a cavern roof [10]. synonyms: (french.) vallee karstique; (german.) karsttal, karstgabe; (greek.) karstiki kilas; (italian.) valle carsica; (russian.) karstovaja dolina; (spanish.) valle karstico; (turkish.) karst vadisi; (yugoslavian.) krska (kraska) dolina.?

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.

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Texas A&M University
2005, p. 1-138
Calcite dissolution kinetics and solubility in Na-Ca-Mg-Cl brines of geologically relevant composition at 0.1 to 1 bar pCO2 and 25 to 80°C. Doctoral dissertation, Texas A&M University.
Abstract:
Sedimentary basins can contain close to 20% by volume pore fluids that are commonly classified as brines. These fluids can become undersaturated with respect to calcite as a result of processes such as migration, dispersive mixing, or anthropogenic injection of CO2. This study measured calcite solubility and dissolution rates in geologically relevant Na-Ca-Mg-Cl synthetic brines (35 to 200 g L-1 TDS). In brines < 50 g L-1 TDS, the EQPITZER calculated calcium carbonate ion activity product (IAP) at steady-state was in reasonable agreement (±10%) with the thermodynamic solubility constant for calcite (Kc). However, the IAP systematically exceeded Kc in more concentrated brines. The deviation was strongly correlated with calcium concentration and also was observed in magnesium-free solutions. This is interpreted as an uncertainty in the carbonate ion activity coefficient, and minor adjustment in stoichiometric association constants (K*M2+CO30) for the CaCO30 or MgCo30 ion pairs would correct for the error. The dissolution rate dependency on brine composition, pCO2 (0.1 to 1 bar), and temperature (25.0 to 82.5 °C) was modeled using the empirical rate equation ()nkRΩ−=1 where R is the rate, k and n are empirical fitting terms, and Ω the degree of disequilibrium with respect to calcite. When Ω was defined relative to an apparent kinetic solubility, n could be assumed first-order over the range of Ω investigated (Ω = 0.2 to 1.0). Rates increased with increasing pCO2 as did the sensitivity to brine concentration. At 0.1 bar, rates were nearly independent of concentration (k = 13.0 ±2.0 x 10-3 moles m-1 hr-1). However, at higher CO2 partial pressures rates became composition dependent and the rate constant, k, was shown to be a function of temperature, pCO2, ionic strength, and calcium and magnesium activity. The rate constant (k) can be estimated from a multiple regression (MR) model of the form k = B0 + B1(T) + B2(pCo2) + B4(aCa2+) + B5(aMg2+). A relatively high activation energy (Ea = 20 kJ mol-1) was measured, along with a stirring rate independence suggesting the dissolution is dominated by surface controlled processes at saturation states Ω > 0.2 in these calcium-rich brines. These findings offer important implications to reaction-transport models in carbonate-bearing saline reservoirs.