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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 well is 1. a shaft or hole sunk into the earth to obtain water, oil, gas, or minerals [10]. 2. a deep vertical rounded hole or shaft in the floor of a cave or at the bottom of a closed depression [10]. 3. a bored, drilled or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension [22].?

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

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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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Karst Waters Institute, Leesburg, Virginia
Hypogene Cave Morphologies. Selected papers and abstracts of the symposium held February 2 through 7, 2014, San Salvador Island, Bahamas. Karst Waters Institute Special Publication 18, 2014, p. 101-101
SPELEOGENESIS BY THE SULFIDIC SPRINGS AT NORTHERN SIERRA DE CHIAPAS, MEXICO, BASED ON THEIR WATER CHEMISTRY
Abstract:
Conspicuous brackish sulfidic springs have been described at the northern Sierra the Chiapas, Mexico. These springs are produced by a mixture between regional and local groundwater flow paths. The regional groundwater has an average Total Dissolved Ions of 3081 mg/L so it has a brackish composition. This brackish water is saturated with respect to calcite and dolomite but undersaturated with respect to gypsum, anhydrite and halite. The mass balance and the discharge rate are used to quantify the mass and volume of minerals that are dissolved by the brackish spring water following Appelo and Postma (1993). This quantification will allow comparing the various speleogenetic mechanisms in the area. This is considering the composition of the spring water is relatively constant over time, as it is suggested by periodic measurements at the Cueva de Villa Luz springs during the last 10 years.
Sulfur isotopes in the water are consistent with anhydrite dissolution as the main source of the sulfate to the brackish spring water. Thus, the average 6 mol/L of sulfate in the brackish springs are produced by dissolution of 6 mol of anhydrite after subtracting the sulfate that could result from evapotranspiration of rainwater. Each liter of brackish water dissolved an average of 882 mg of anhydrite, which are equivalent to dissolving 0.36 cm3 of this mineral considering a density of 2.981 g/cm3. Additionally, using the average brackish water discharge rate of 144 L/s, an average of 57 g of anhydrite are being dissolved each second per every liter of brackish water. This is a minimal value because some of the sulfate in the water is used by sulfate-reducing bacteria in the subsurface to produce the hydrogen sulfide in the spring water. The anhydrite subject to dissolution is found interbedded in the Cretaceous carbonates, either from the subsurface at 4,000 m below sea level to the carbonate outcrops.
Similarly, we can calculate the volume of halite that is being dissolved by the brackish springs, considering chloride is a conservative element and subtracting the chloride concentration from the rainwater from that of the spring water following Appelo & Postma (1993). The 22 mol/L of chloride in the brackish water can result from dissolution in the subsurface of 22 moles or 1.3 g of halite per liter of brackish water. This mass of halite dissolved is equal to 0.59 cm3 considering a density of 2.168 g/cm3. Alternatively, 118 g of halite are dissolved per second per each liter of brackish water if we use the average discharge rate of 144 L/s.
Even when the brackish springs are oversaturated with respect to calcite and dolomite, their dissolution is still possible due to the common ion-effect of calcium after anhydrite dissolution and by mixing of waters with different compositions. A range of 10 to 80 % of brackish water from the regional aquifers mixes with fresh water from the local aquifer based on their water chemistry. Additionally, sulfuric acid speleogenesis occurs due to the oxidation of hydrogen sulfide to sulfuric acid.
Finally, the increase in the chloride concentration of the fresh water springs with respect to the concentration in rainwater was used to estimate that from the 4000 mm/y of annual precipitation, only 4%, 158 to 182 mm/y, recharge the aquifers. This low percentage is slightly higher than the 3.3% recharge in marls, marly limestone, silts and clays (Sanz et al., 2011), probably because of the relatively small area of carbonate outcrops over the entire region and the lack of recharge in altitudes higher than 1500 m above sea level.
Sulfuric acid is the most obvious speleogenetic mechanism occurring in the caves of the northern Sierra de Chiapas, Mexico due to the high hydrogen sulfide concentration in the spring water. In addition, the location of the springs at a zone of regional and local discharge where waters from different composition converge and mix, and the amount of mixing calculated suggests mixing is also an important speleogenetic mechanism. However, the depth and the time constrains at which these two hypogenic mechanisms occur is still unknown. The relatively low rainwater recharge rate suggests epigenesis is limited. Most likely, the porosity created by dissolution of anhydrite and halite in the subsurface is occluded by the precipitation of calcite. Chemical modeling and petrography will help to elucidate the order of the reactions occurring in the subsurface.