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Enviroscan Ukrainian Institute of Speleology and Karstology


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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 mechanical ascender is a mechanical device that is the same as an ascender, but is used to clarify the use of a mechanical device instead of a rope ascender knot [13]. see also ascender.?

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.
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

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Your search for cd (Keyword) returned 34 results for the whole karstbase:
Showing 16 to 30 of 34
Fens in karst sinkholes - Archives for long lasting 'immission' chronologies, 2003,
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Hettwer K. , Deicke M. , Ruppert H. ,
Fens in karst sinkholes are excellent archives for the reconstruction of vegetation, land use and emission rates over millennia. The reasons are the usually good preservation of pollen, the high portion of low density organic material with very low background concentrations of heavy metals, and the circum-neutral pH-values in most of these mires preventing migration of heavy metals. Immissions of dust and of harmful elements can easily be correlated with changes in vegetation ('immission' is a synonym for the deposition or impact of pollutants from the atmosphere on a receptor surface). One 13 m core from a similar to5000 yr old karst sinkhole fen (Silberhohl, western margin of the Harz Mountains, central Germany) was investigated by geochemical analysis, pollen analysis and dated by C-14 and palynological data. The core consists of organic material with a few percent of CaCO3 precipitated from groundwater and a small amount of atmospheric detritus. As early as the Iron Age (first pre-Christian millennium), slight but significant enrichments of Pb, Zn, Cu and Cd are observed. After 400 AD stronger enrichments occurred culminating in the High Middle Ages (similar to1200-1300 AD). Maximum values are 1250 mug g(-1) Pb, 214 mug g(-1) Cu, 740 mug g(-1) Zn, and 3.8 mug g(-1) Cd. The enrichments are caused by emissions during smelting of sulfidic lead-zinc ores from the adjacent Hercynian deposits to extract Ag and Cu. Except for cadmium, these values were never exceeded in modern times. Since the Iron Age 23 g technogenic Pb, 5.3 g Cu, 27 g Zn and 0.2 g Cd have been deposited per square meter. Palynological investigations show a strong correlation between decreasing red beech pollens (Fagus sylvatica) and increasing demand on wood for smelting in the Middle Ages. Simultaneously, the pollen share of pioneer trees such as birch (Betula pubescens) and of cereal grains (e.g. Secale) increases. Since the beginning of the 14th century, the decline of agriculture and population is reflected in the decreasing contents of Secale and heavy metals in the fen deposits

Das Untertagelabor in den Obir-Hhlen., 2004,
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Sptl, Ch.
The Obir Caves in the southern part of the province of Carinthia are among the best known dripstone caves in Austria. These caverns were only discovered as a result of mining operations during the 19th century and parts of them were adapted as a show cave which was opened in 1991. In a cave system adjacent to the show cave and not open to the public, an underground research station was set up in 1998 and has been in operation since then. This laboratory encompasses a total of six automatic drip water measurement stations in two cave chambers, as well as air temperature data loggers. On regular cave visits every one to two months since 1998, a series of manual measurements (e.g., partial pressure of CO2) and water and cave air samples have been taken. Compositional parameters determined on site include pH, electric conductivity and carbonate alkalinity. Parameters determined in laboratories elsewhere include cations (Na, K, Ca, Mg, Sr), anions (Cl, F, NO3, SO4), dissolved silica and stable isotopes (dD, d18O, d13CDIC, d13Cair). These measurements are complemented by soil studies above the cave (soil temperature and soil water chemistry, rainwater composition).[Obir-Hhlensystem]

Contribution to knowledge of the content of heavy metals (Pb, Cu, Zn and Cd) in speleological objects in the Risnjak national park (Croatia), 2004,
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Vrbek Boris, Buzjak Nenad

Samples of silt were taken from six speleological objects in the Risnjak National Park in Gorski kotar area (NW Croatia). The samples were taken from almost inaccessible rock fissures and shafts in order to find the most natural sediment outside the reach of anthropogenic pollution. The samples were examined in the Laboratory of the Forest Research Institute, where standard pedological analyses were performed, and the content of several heavy metals (Pb, Cu, Zn and Cd) was determined. The results indicate relatively low values of the content of lead, copper and zinc, while the values of cadmium in the sediment were increased above the limit level of 2 mgkg-1 in the majority of speleological objects. The content of other heavy metals (Pb, Cu and Zn) in mgkg-1 was lower than previously determined in samples taken from other speleological objects on the Croatian territory. Also, the content of heavy metals was lower in relation to surface soil samples taken from the humus horizon and mineral part of the soil under the parent rock of limestone, when sampling the soils of the Risnjak National Park


Das Untertagelabor in den Obir-Hhlen, 2004,
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Sptl, Ch.
The Obir Caves in the southern part of the province of Carinthia are among the best known dripstone caves in Austria. These caverns were only discovered as a result of mining operations during the 19th century and parts of them were adapted as a show cave which was opened in 1991. In a cave system adjacent to the show cave and not open to the public, an underground research station was set up in 1998 and has been in operation since then. This laboratory encompasses a total of six automatic drip water measurement stations in two cave chambers, as well as air temperature data loggers. On regular cave visits every one to two months since 1998, a series of manual measurements (e.g., partial pressure of CO2) and water and cave air samples have been taken. Compositional parameters determined on site include pH, electric conductivity and carbonate alkalinity. Parameters determined in laboratories elsewhere include cations (Na, K, Ca, Mg, Sr), anions (Cl, F, NO3, SO4), dissolved silica and stable isotopes (dD, d18O, d13CDIC, d13Cair). These measurements are complemented by soil studies above the cave (soil temperature and soil water chemistry, rainwater composition).

Protection of Karst in the Philippines., 2006,
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Restificar S. D. F. , Day M. J. , Urich P. B.
The article presents an overview of the current status of karst protection in the Philippines. Prior studies indicate that of the 35,000km2 of karst landscape in the country, about 29% is protected . However, protection of karst has not to date been a priority of the Philippine government, and the country has no existing legislation that is directly decreed for protection and conservation of karstlands. Most contemporary karst protection is indirect, in that the karst is located within protected areas established for other, although often related reasons, such as ecological conservation, water supply protection and tourism. However, it appears that the Philippine government is gradually recognizing explicitly the need to protect karst landscapes. The establishment of the National Caves and Cave Resources Management and Protection Act in 2001 and the inclusion of karst water resources in the countrys National Action Plan (NAP) under the United Nations Convention to Combat Desertification (UNCCD) are significant steps towards explicit protection of karst areas. Although the existing legislation only addresses specific facets of karst landscape, it may stimulate additional programs and legislation that will more broadly protect karst landscapes nationally. Philippines, karst, caves, protected areas, environmental legislation

Long-term tracing in karstic aquifer reservoir for drinking water:, 2006,
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Rino Semeraro, Massimiliano Baldassi, Luciano Ballarin, Clarissa Brun, Luca D?amelio, Fulvio Forti
The chain of the Musi Mt (1,869.4 m) is one of the most important karst massifs of the Western Julian Fore-Alps (Italy). It corresponds to an east-west unicline dipping north. The structural northern slope, having glaciokarst morphologies, is conditioned by karst in calcareous rocks (Raethian-Liassic); the southern dolomitic slope (Dolomia Principale, Norian-Raethian), is less karstified and is characterized by trenches. On the northern slope, the Barmàn spring is located; on the southern slope the Voidizza Springs and the Torre Springs are located. The Torre Springs, fed by both the alluvial aquifer of the upper valley of the Torre Stream and by the carbonate aquifer of the Musi, supply the waterworks of western Friuli region managed by ?CAFC Consorzio Acquedotti Friuli Orientale?. Almost the whole feeding basin of the above-mentioned springs is placed in a protected area, managed by ?Ente Parco Naturale delle Prealpi Giulie?. Therefore, the zone is an important example of an area having high vulnerability due to karst and it is strategic for the water supply for an important part of Friuli. Formerly, two tracing tests were carried out injecting Uranine into the Pahor Abyss on the northern slope. From these tests it results that the waters of the karst area drain in the Uragano Cave and in the underlying Barman Spring. Only during heavy low water, when the underground watershed of the massif lowers, is it possible to observe traces of Uranine in the Torre Springs, since the most northern underground regions of the massif are drained. In order to understand better the underground water flow, a long-term tracing was carried out injecting Uranine in the the Pahor Abyss on 11th October 2005. The tracer test was supported by a chemical-physical study of the underground waters of the massif, in the period from 28th September 2005 to 13th January 2006. In this study flow measurements (Q), physical-chemical measurements on the field (TC, pH, E.C.20C), chemical analysis (Tot. hardness, TDS180, Alk. CaHCO3-, K+, Na+, Ca2+, Mg2+, Cl-, SO42-, NO3-, NH4+, B, SiO2, Li+, Rb+, Sr2+, Cd, Co, tot. Cr, Ni, Pb, Mn, Fe, Cu, As, Zn) and the analysis of the stable isotopes (δ18O, δD) were carried out. As for the tracing test two fluorometer probes were positioned: one at the Barmàn Spring, the other in the mixer between the 21 drainages and the capture well of the Torre Springs. Moreover, the Voidizza Springs were checked and regularly sampled. Uranine was found at the Barmàn Spring after 12.26 hours with a distance of about 1,500 m. It probably flowed in large karst conduits, at a theoretical speed of 120 m/h (3.3 cm/s). The breakthrough curves are very quick: Uranine wave extinguished in only three days, thus confirming that it is a high mountain system that reacts to impulses immediately. The E.C.20C of the Barmàn Spring is almost constantly lower than that of the Torre and Voidizza Springs, whereas the temperature of the Voidizza Springs is always the highest of all the waters measured. δ18O of the Barmàn Spring (between -9.0 ? and -9.1?) is always inferior to that of the springs placed on the southern slope (between -8.0? and -8.7 ?) and δD of the Barmàn Spring ranges between -55? and -63?. E.C.20C of the Barmàn Spring (between μS/cm 128.7 and μS/cm 188.0) is almost always inferior to the E.C.20C of the springs of the southern slope (between μS/cm 139.9 and μS/cm 228.0). Ca2+ and Mg2+ are absolutely predominant in all the waters, where the Ca2+ values of the Barman Spring (around 30 mg/L) and of the springs of the southern slope (between 30 mg/L and 31.8 mg/L) are similar, whereas at the Barman Spring Mg2+ is always lower (about 4.9 mg/L) than that of the springs of the southern slope (between 9.0 mg/L and 16.2 mg/L). This confirms that the southern springs are fed by a predominantly dolomitic aquifer (in particular the Voidizza Springs) compared with that of the northern slope. Among the minor elements it is possible to observe Cu and Fe at the Torre and Voidizza Springs, whereas here Sr is remarkable (between 13.9 μg/L and 18.3 μg/L) and diffused in the whole aquifer. SO42- and NO3- are low in all the waters.

Variability in terrestrial and microbial contributions to dissolved organic matter fluorescence in the Edwards Aquifer, Central Texas, 2009,
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Birdwell J. E. And Engel A. S.
Most cave and karst ecosystems are believed to be dependent on an influx of allochthonous organic carbon. Although microbes are largely responsible for the fate of dissolved organic matter (DOM) in karst, the role of microbes in chemosynthetic (autochthonous) production and processing of DOM has received limited attention. Chromophoric dissolved organic matter (CDOM) is the fraction of DOM that absorbs ultraviolet and visible light, and differences in the fluorescence spectral characteristics of humic-like (terrigenous) and protein-like (microbially-derived) CDOM allow for tracing the relative contributions of allochthonous or autochthonous carbon sources, respectively, in water. We investigated CDOM in karst-aquifer well and spring waters along the fresh- to saline-water transition zone of the Edwards Aquifer, Central Texas, over a four year period. The groundwater fluorescence spectral characteristics were distinct from those generally observed in surface waters and soil porewaters. The dominant source of organic carbon in the aquifer waters may be a product of chemolithoautotrophic primary production occurring in situ. It is possible that the absence of a strong terrestrial CDOM signature may be due to filtering effects in the epikarst or rapid utilization by heterotrophs in the aquifer. Our results indicate that intense recharge following periods of drought may influence the intensity of microbial activity, either due to an influx of DOM or nutrients from the surface that was not quantified by our analyses or because of increased in situ autotrophic activity, or both. The variable contributions of allochthonous and autochthonous DOM during and after recharge events call into question whether karst aquifer ecosystems are necessarily dependent on allochthonous organic matter.

Hypogean microclimatology and hydrogology of the 800-900 m asl level in the Monte Corchia cave (Tuscany, Italy): Preliminary considerations and implications for paleoclimatological studies, 2011,
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Ilaria Baneschi, Leonardo Piccini, Eleonora Regattieri, Ilaria Isola, Massimo Guidi, Licia Lotti, Francesco Mantelli, Marco Menichetti, Russell N. Drysdale & Giovanni Zanchetta:

The Monte Corchia Cave is one of the most promising sites for studying the paleoclimate of the Mediterranean basin, but its hydrology and hydrogeochemistry are still poorly known. In this paper, we report some meteoclimatic and hydrochemical data for different parts of the cave. Conductivity and water level data from La Gronda channel show that this system reacts rapidly to external meteoric events, indicating the presence of a conductive epikarst. Data on two different drips indicate that the physicochemical parameters, such as conductivity, pH, δ13CDIC and drip rate depend on the local structural setting and water path length. The data presented show that Galleria delle Stalattiti (the focus of the paleoclimate research) has the most stable conditions in terms of temperature, and the dripwaters show constant pH, electrical conductivity, alkalinity, calcium and magnesium content and δ18O. Drip rate is not affected by rain events and displays long-term trends that require a longer period of monitoring for elucidating their nature. The preliminary data presented here corroborate the hypotheses suggesting Galleria delle Stalattiti as a good example of a “deep” hypogean system of Fairchild et al. (2007).


Trace element and stable isotope data from a flowstone in a natural cave of the mining district of SW Sardinia (Italy): evidence for Zn⁺-induced aragonite precipitation in comparatively wet climatic conditions, 2011,
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Caddeo Guglielmo Angelo, De Waele Jo, Frau Franco, Railsback Loren Bruce

A speleothem from Crovassa Azzurra, a mine cave in SW Sardinia (Italy), has been analysed for mineralogy, minor and trace elements and stable isotopes. It is composed of layers of primary calcite and aragonite, with a region of secondary calcite. The primary carbonate is strikingly rich in Zn and Pb, presumably as the result of transport in solution from overlying Pb-Zn deposits. Immediately below the transition between calcite and aragonite, concentrations of Zn, Cd and P increase. At the transition between aragonite and Pb-rich aragonite, concentrations of Pb and P increase. Stable isotopes indicate an evolution toward more humid periods for these two transitions, conversely to what is normally observed in calcite-aragonite speleothems. The combined observation of increase in P and metals derived from oxidation of sulphides and the variation of isotopic composition of aragonite and calcite suggests that in this mine cave aragonite was deposited with increasing flowrate and thus more humid conditions. In addition, the effect of Zn2+ or Pb2+ in inhibiting precipitation of calcite appears to have been more important than that of Mg2+.


Ferruginous thermal spring complexes, northwest Tasmania: evidence that far-field stresses acting on a fracture mesh can open and maintain vertical flow in carbonate terrains, 2011,
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Davidson Garry J. , Bavea Michael, Harris Kathryn

Far-field stress changes in the southern Australian plate since 5 Ma have produced significant areas of uplift and seismicity. In northwest Tasmania, there is evidence that this stress reorientation to maximum horizontal NW–SE stress has influenced meteoricderived thermal (15–20°C) discharge patterns of confined karstic aquifers, by placing pre-existing NWtrending faults/fractures into a dilated state or a critically stressed state. Previous studies have shown that spring discharge has operated continuously for at least 65,000 years, and has transported large volumes of solutes to the surface to be deposited as mounds of calcite-goethite-silica up to 7 m high. The thermal spring chemistry at one site, Mella, is consistent with descent to at least 1.2–1.5 km, although the hinterland within 50 km is less than 500 m elevation. Thermal spring chemistry is consistent with most of the deep water–rock interaction occurring in low-strontium Smithton Dolomite. While some of this water is discharged at springs, some instead intersects shallow zones of NE-fracture-controlled rock (2×4 km in area) with karstic permeability where, although confined and subject to a NE-directed hydraulic gradient, it circulates and cools to ambient temperature, with only minor mixing with other groundwaters. 


Aqueous Geochemical Evidence of Volcanogenic Karstification: Sistema Zacaton, Mexico, 2011,
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Gary M. O. , Doctor D. H. , Sharp J. M.

The Sistema Zacatón karst area in northeastern Mexico (Tamaulipas state) is limited to a relatively focused area (20 km2) in a carbonate setting not prone to extensive karstification. The unique features found here are characteristic of hydrothermal karstification processes, represent some of the largest phreatic voids in the world, and are hypothesized to have formed from interaction of a local Pleistocene magmatic event with the regional groundwater system. Aqueous geochemical data collected from five cenotes of Sistema Zacatón between 2000 and 2009 include temperature (spatial, temporal, and depth profiles), geochemical depth profiles, major and trace ion geochemistry, stable and radiogenic isotopes, and dissolved gases. Interpretation of these data indicates four major discoveries: 1) rock-water interaction occurs between groundwater, the limestone matrix, and local volcanic rocks; 2) varying degrees of hydrogeological connection exist among cenotes in the system as observed from geochemical signatures; 3) microbially-mediated geochemical reactions control sulfur and carbon cycling and influence redox geochemistry; and 4) dissolved gases are indicative of a deep volcanic source. Dissolved 87Sr/86Sr isotope ratios (mean 0.70719) are lower than those of the surrounding Cretaceous limestone (0.70730-0.70745), providing evidence of groundwater interaction with volcanic rock, which has a 87Sr/86Sr isotope ratio of 0.7050. Discrete hydraulic barriers between cenotes formed in response to sinkhole formation, hydrothermal travertine precipitation, and shifts in the local water table, creating relatively isolated water bodies. The isolation of the cenotes is reflected in distinct water chemistries among them. This is observed most clearly in the cenote Verde where a water level 4-5 meters lower than the adjacent cenotes is maintained, seasonal water temperature variations occur, thermoclines and chemoclines exist, and the water is oxic at all depths. The surrounding cenotes of El Zacatón, Caracol, and La Pilita show constant water temperatures both in depth profile and in time, have similar water levels, and are almost entirely anoxic. A sulfur (H2S) isotope value of δ34S = -1.8 ‰ (CDT) in deep water of cenote Caracol, contrasted with two lower sulfur isotopic values of sulfide in the water near the surface of the cenote (δ34S = -7 ‰ and -8 ‰ CDT). These δ34S values are characteristic of complex biological sulfur cycling where sulfur oxidation in the photic zone results in oxidation of H2S to colloidal sulfur near the surface in diurnal cycles. This is hypothesized to result from changes in microbial community structure with depth as phototropic, sulfur-oxidizing bacteria become less abundant below 20 m. Unique microbial communities exist in the anoxic, hydrothermal cenotes that strongly mediate sulfur cycling and likely influence mineralization along the walls of these cenotes. Dissolved CO2 gas concentrations ranged from 61-173 mg/L and total dissolved inorganic carbon (DIC) δ13C values measured at cenote surfaces ranged from -10.9 ‰ to -11.8 ‰ (PDB), reflecting mixed sources of carbon from carbonate rock dissolution, biogenic CO2 and possibly dissolved CO2 from volcanic sources. Surface measurements of dissolved helium gas concentrations range from 50 nmol/kg to 213 nmol/kg. These elevated helium concentrations likely indicate existence of a subsurface volcanic source; however, helium isotope data are needed to test this hypothesis. The results of these data reflect a speleogenetic history that is inherently linked to volcanic activity, and support the hypothesis that the extreme karst development of Sistema Zacatón would likely not have progressed without groundwater interaction with the local igneous rocks 


Organic matter of fossil origin in the amberine speleothems from El Soplao Cave (Cantabria, Northern Spain), 2012,
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Gzquez Fernando, Jose Maria Calaforra, Fernando Rull, Paolo Forti, And Antonio Garcacasco.

Unusual amberine-coloured speleothems were recently found in El Soplao Cave (Cantabria, Spain). Chromophore elements such as Fe, Mn, Cd, Co or Ti were not present in significant quantities. Rather, our data show that their colour comes from leachates of fossilized organic material hosted in the carbonaceous Urgonian facies of the host rock. These leachates are related to the Cretaceous amber deposit that has been recently discovered in the vicinity of El Soplao Cave. The presence of humic and fulvic acids of fossil origin were confirmed by IR and Raman spectroscopic analysis of the carbonaceous strata and the speleothems. In addition, the mineralogy of the amberine speleothems was studied. Alternating bands made of calcite and aragonite reveal that periods of humidity and aridity occurred within the cave during the speleothem genesis.


Speleothem Deposition, 2012,
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Dreybrodt, Wolfgang

Speleothems in limestone caves may form spectacular underground landscapes. Stalagmites show a wide variety of forms, from slim candle stalagmites to massive cascading columns. How fast they grow and which principles determine their shapes can be explained by the physical chemistry of the system H2Osingle bondCO2single bondCaCO3. Precipitation rates of calcite from solutions supersaturated with respect to calcite, which flow as thin films of water on the surface of speleothems, are discussed. They are the fundamental tool to understand the shapes of ideal stalagmites and stalactites. Stalagmites are also important climate archives and conserve climate information from the last 400,000 years. To read this archive, a good understanding of their physics is important.


New insights into the carbon isotope composition of speleothem calcite: An assessment from surface to subsurface, 2012,
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Meyer, Kyle William

The purpose of this study was to provide new insights into the interpretation of speleothem (cave calcite deposit) δ13C values. We studied two caves in central Texas, which have been actively monitored for over 12 years. We compared δ13C values of soil CO2 (δ13Cs), cave drip water (δ13CDIC), and modern cave calcite (δ13Ccc). Measured average δ13C values of soil CO2 were -13.9 ± 1.4‰ under mixed, shallowly-rooted C3-C4 grasses and were -18.3 ± 0.7‰ under deeply-rooted ashe juniper trees (C3). The δ13CDIC value of minimally-degassed drip water in Natural Bridge Caverns was -10.7 ± 0.3‰. The carbon isotope composition of CO2 in equilibrium with this measured drip water is -18.1 ± 0.3‰. The agreement between juniper soil CO2 and drip water (within ~0.2‰) suggests that the δ13C value of drip water (δ13CDIC) that initially enters the cave is controlled by deeply-rooted plants and may be minimally influenced by host-rock dissolution and/or prior calcite precipitation (PCP). At Inner Space Caverns, δ13CDIC values varied with vegetation above the drip site, distance from the cave entrance, and distance along in-cave flow paths. Whereas CO2 derived from deeply-rooted plants defines the baseline for drip water δ13CDIC entering the caves, kinetic effects associated with the degassing of CO2 and simultaneous precipitation of calcite account for seasonal variability in δ13CDIC and δ13Ccc. We documented increases in δ13CDIC at a rate of up to 0.47‰/hour during the season of peak degassing (winter), suggesting that δ13CDIC variations may be controlled by total elapsed time of CO2 degassing from drip water (Ttotal). We also observed seasonal shifts in the δ13C values of modern calcite grown on glass substrates that are correlated with shifts in drip water δ13CDIC values and drip-rate. Therefore, we suggest that increased aridity at the surface above a given cave results in, slower drip-rates, higher Ttotal, and therefore higher δ13CDIC values. We propose that large variability (>2‰) in speleothem δ13Ccc values dominantly reflect major vegetation changes, and/or increasing Ttotal by slowing drip-rates. Based on these findings, variability in speleothem carbon isotope records may serve as a proxy for paleoaridity and/or paleovegetation change.


New insights into the carbon isotope composition of speleothem calcite : an assessment from surface to subsurface, 2012,
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Meyer, Kyle William

The purpose of this study was to provide new insights into the interpretation of speleothem (cave calcite deposit) δ13C values. We studied two caves in central Texas, which have been actively monitored for over 12 years. We compared δ13C values of soil CO2 (δ13Cs), cave drip water (δ13CDIC), and modern cave calcite (δ13Ccc). Measured average δ13C values of soil CO2 were -13.9 ± 1.4‰ under mixed, shallowly-rooted C3-C4 grasses and were -18.3 ± 0.7‰ under deeply-rooted ashe juniper trees (C3). The δ13CDIC value of minimally-degassed drip water in Natural Bridge Caverns was -10.7 ± 0.3‰. The carbon isotope composition of CO2 in equilibrium with this measured drip water is -18.1 ± 0.3‰. The agreement between juniper soil CO2 and drip water (within ~0.2‰) suggests that the δ13C value of drip water (δ13CDIC) that initially enters the cave is controlled by deeply-rooted plants and may be minimally influenced by host-rock dissolution and/or prior calcite precipitation (PCP). At Inner Space Caverns, δ13CDIC values varied with vegetation above the drip site, distance from the cave entrance, and distance along in-cave flow paths. Whereas CO2 derived from deeply-rooted plants defines the baseline for drip water δ13CDIC entering the caves, kinetic effects associated with the degassing of CO2 and simultaneous precipitation of calcite account for seasonal variability in δ13CDIC and δ13Ccc. We documented increases in δ13CDIC at a rate of up to 0.47‰/hour during the season of peak degassing (winter), suggesting that δ13CDIC variations may be controlled by total elapsed time of CO2 degassing from drip water (Ttotal). We also observed seasonal shifts in the δ13C values of modern calcite grown on glass substrates that are correlated with shifts in drip water δ13CDIC values and drip-rate. Therefore, we suggest that increased aridity at the surface above a given cave results in, slower drip-rates, higher Ttotal, and therefore higher δ13CDIC values. We propose that large variability (>2‰) in speleothem δ13Ccc values dominantly reflect major vegetation changes, and/or increasing Ttotal by slowing drip-rates. Based on these findings, variability in speleothem carbon isotope records may serve as a proxy for paleoaridity and/or paleovegetation change.


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