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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 chamber is (american.) 1. an enlargement in a cave passage or system, commonly formed at a junction of passages, or locally in a single passage, where erosion has been enhanced by collapse exposing more rock to dissolution. maximum chamber size is controlled by the strength and shape of the limestone ceiling. the largest chamber currently known, sarawak chamber in lubang nasib bagus, at mulu, sarawak, is over 700m long, up to 400m wide and nowhere less than 70m high. it has formed where a large stream eroded sideways as it cut obliquely across the included bedding in unusually massive limestone. it is doubtful whether a much larger chamber could exist without collapse of its roof [9]. 2. the largest order of cavity in a cave or cave system; it has considerable length and breadth but not necessarily great height. 3. (british.) a room in a cave [10]. synonyms: (french.) salle; (german.) halle, kammer, dom; (greek.) ypoyios aethousa; (italian.) sala; (russian.) zal; (spanish.) sala, salon; (turkish.) oda; (yugoslavian.) dvorana. see also room; passage.?

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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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;
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Your search for diffraction (Keyword) returned 44 results for the whole karstbase:
Showing 16 to 30 of 44
Authigenic halloysite from El-Gideda iron ore, Bahria Oasis, Egypt: characterization and origin, 2004,
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Baioumy Hm, Hassan Ms,
Halloysite in El-Gideda iron mine occurs as very soft, light and white-to-pinkish white pockets and lenses ranging in diameter from 50 cm to 1 m within the iron ore. Highly hydrated halloysite is the main constituent of these pockets beside some kaolinite and alunite. The diffraction pattern of the clay fraction (<2 {micro}m) shows a rather broad and diffuse 001 reflection spread between 10.3 and 13.6{degrees}2{theta}. Upon treatment, the 001 reflection of halloysite expands up to 10.94 A and 11.9 A corresponding to ethylene glycol and dimethyl formamide treatment, respectively. After these treatments, kaolinite appeared with its characteristic basal spacing (~7 A ). The percentage of halloysite in halloysite-intercalated kaolinite ranged between 80 and 90%. Heating to 350{degrees}C, produces a kaolinite-like structure (~7.1 A ) that developed to a metakaolinite-structure when heated to 550{degrees}C. Morphologically, halloysite appears as well developed tubes composed entirely of SiO2 and Al2O3, while kaolinite is characterized by very fine platelets arranged in book-like or rosette-like shapes. A differential thermal analysis curve of the studied halloysite showed an endothermic peak at ~138{degrees}C due to the dehydration of interlayer water of halloysite. The small shoulder at ~540{degrees}C and the endothermic peak at ~593{degrees}C is attributed to the dehydroxylation of halloysite, kaolinite and alunite. On the other hand the exothermic peak that appeared at 995{degrees}C is due to the formation of new phases such as mullite and/or spinel. The infrared vibrational spectrum is typical of highly disordered halloysite and kaolinite. Halloysite was formed as a result of alteration of the overlying glauconite suggesting intensive chemical alteration during a humid wet period that prevailed in the Bahria Oasis during the late Eocene. Glauconite alteration releases K, Fe, silica and alumina. Iron forms at least part of the iron ore in the El-Gideda mine while alumina forms halloysite as well as alunite when interacted with silica in an acidic environment

Constraints on the geological history of the karst system in southern Missouri, U.S.A. provided by radiogenic, cosmogenic and physical/chemical characteristics of doline fill, 2004,
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Weary David J. , Harrison Richard W. , Wright Maria P. , Jacobson Robert B. , Pavich Milan J. , Mahan Shannon A. , Wronkiewicz David J.

The Ozark Plateaus region of southern Missouri is underlain by dominantly carbonate marine platform rocks of Paleozoic age. The region has been sub-aerially exposed since the late Paleozoic and is characterized by extensive karst. To better understand the geologic history of this regional karst system, we examined the stratigraphic record preserved in the fill of a large doline near the largest spring in the region. Samples of fill from natural exposures and drill core were analyzed using thermoluminescence (TL) and 10Be cosmogenic techniques, and the physical/chemical characteristics of the fill material were determined by visual inspection, X-ray analyses, and grain-size measurements. Drill-hole data indicate that the allochthonous doline fill is 36.3 m thick and rests on at least 15.6 m of cave breakdown and sediment. The doline fill is divisible into 7 zones. Analysis of 10Be concentrations suggest that the entire doline fill was derived from local residuum during the middle (Illinoian) to late Pleistocene (Wisconsinan). X-ray diffraction analyses of clays throughout the doline fill indicate that they consist of nearly equal amounts of kaolinite and illite, consistent with terrestrial weathering.


Vashegyite from Gaura cu Musc? Cave., 2006,
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Onac Bogdan P. , Zaharia Lumini?a, Kearns Joe, Veres Daniel
This study investigated the occurrence of vashegyite from a guano-rich deposit located in the Gaura cu Musc? Cave, Romania. Analytical methods used include optical microscopy, X-ray powder diffraction (XRD), scanning electron-microscopy (SEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermal investigations and Fourier-transform infrared (FT-IR) analyses. Vashegyite occurs as friable, chalky white, irregular nodules of up to 2.5 cm in diameter, within a 15 cm thick sequence of organic and minerogenic sediments. The chemical structural formula is: (Al10.91Fe3+ 0.06Na0.1Ca0.02Mg0.08)?=11.17[(PO4)8.78(SiO4)0.056]?=8.83(OH)6.1743.79H2O. Electron microscope images show vashegyite crystals to be flattened on (001). The orthorhombic lattice constants of vashegyite determined by XRD are a = 10.766(2) , b = 15.00(4) , c = 22.661(1) , and V = 3660.62 3 (Z = 4). The major weight loss, reflected in 3 endothermic peaks, was observed between 40 and 200C, corresponding to the removal of water molecules. Vashegyite FT-IR absorption bands are comparable in position and relative intensity to other Al-phosphates. Water percolating through guano becomes strongly acidic and reacts with the clay-rich sediment laid down by the underground stream to form vashegyite. In the lower part of the investigated profile, crandallite and ardealite were also found.

Identification of cave minerals by Raman spectroscopy: New technology for non-destructive analysis., 2006,
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White William B.
The identification of minerals from caves generally requires that samples be removed from the cave for analysis in the laboratory. The usual tools are X-ray powder diffraction, the optical microscope, and the scanning electron microscope. X-ray diffraction gives a definitive fingerprint by which the mineral can be identified by comparison with a catalog of reference patterns. However, samples must be ground to powder and unstable hydrated minerals may decompose before analysis is complete. Raman spectroscopy also provides a fingerprint useful for mineral identification but with the additional advantage that some a-priori interpretation of the spectra is possible (distinguishing carbonates from sulfates, for example). Because excitation of the spectra is by means of a laser beam, it is possible to measure the spectra of samples in sealed glass containers, thus preserving unstable samples. Because laser beams can be focused, spectra can be obtained from individual grains. New technology has reduced the size of the instrument and also the sensitivity of the optical system to vibration and transport so that a portable instrument has become possible. The sampling probe is linked to the spectrometer by optical fibers so that large specimens can be examined without damage. Comparative spectra of common cave minerals demonstrate the value of Raman spectra as an identification technique.

Application of x-ray microanalytical techniques to preliminary geomorphological studies in the Jiang Zhou cave system, China, 2007,
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Dale, John And Tony Harrison.
The increasing availability of microanalytical techniques for the compositional analysis of rock and mineral samples provides an attractive supplement or alternative to traditional water chemistry for geomorphological studies by small caving expeditions overseas. The paper describes how x-ray diffraction (XRD) and energy dispersive x-ray (EDX) spectrometry were used to throw light on queries raised about the speleogenesis of the vast Jiang Zhou cave system, which was recently discovered and explored by three China Caves Project expeditions to Guangxi Province in southern China.

Biotic versus abiotic calcite formation on prehistoric cave paintings: the Arcy-sur-Cure 'Grande Grotte' (Yonne, France) case, 2007,
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Chalmin E, D'orlye F, Zinger L, Charlet L, Geremia Ra, Orial G, Menu M, Baffier D, Reiche I,
The Grande Grotte' cave at Arcy-sur-Cure (Yonne, France) with its prehistoric paintings shows important calcite concretions. Two types of calcite have been observed on the wall: translucent yellowish layers and opaque white or grey layers that completely obstruct the paintings. Other calcite types are present in the lakes of the cave (floating calcite rafts at the surface of the lake and soft calcite at the bottom of the lake). The morphology of the different calcites was observed at different scales by optical microscopy with normal and polarized light, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The elemental composition was measured by using particle-induced X-ray emission (micro-PIXE) and the structure by X-ray diffraction (XRD), infrared (FT-IR) and Raman spectroscopy. The bacterial diversity and its role in calcite formation were assessed by culture and 16S-SSCP in order to distinguish and to assess various abiotic and biotic formation mechanisms. The investigation of calcite characteristics enables conclusions on the formation mechanism and on a biotic or abiotic origin of the calcites. The change of calcite types on the walls reveals changes of the environmental cave parameters. In addition, interactions of calcites with the prehistoric paint layer could be evaluated

The impact of host rock geochemistry on bacterial community structure in oligotrophic cave environments, 2007,
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Barton Hazel A. , Taylor Nicholas M. , Kreate Michael P. , Springer Austin C. , Oehrle Stuart A. And Bertog Janet L.
Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In order to assess whether microbial activity was leading to changes in the bedrock at each location, the samples were also examined by petrology, X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Our results suggest that on the chemically complex Yates Formation (sF88), the microbial community was significantly more diverse than on the limestone surfaces of the Capitan (WF1), despite a higher total number of cells on the latter. Further, the broader diversity of bacterial species at sF88 reflected a larger range of potential metabolic capabilities, presumably due to opportunities to use ions within the rock as nutrients and for chemolithotrophic energy production. The use of these ions at sF88 is supported by the formation of a corrosion residue, presumably through microbial scavenging activities. Our results suggest that rock fabric and mineralogy may be an important driver of ecosystem function and should be carefully reviewed when carrying out microbial community analysis in cave environments.

The impact of host rock geochemistry on bacterial community structure in oligotrophic cave environments., 2007,
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Barton Hazel A. , Taylor Nicholas M. , Kreate Michael P. , Springer Austin C. , Oehrle Stuart A, Bertog Janet L.
Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In order to assess whether microbial activity was leading to changes in the bedrock at each location, the samples were also examined by petrology, X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Our results suggest that on the chemically complex Yates Formation (sF88), the microbial community was significantly more diverse than on the limestone surfaces of the Capitan (WF1), despite a higher total number of cells on the latter. Further, the broader diversity of bacterial species at sF88 reflected a larger range of potential metabolic capabilities, presumably due to opportunities to use ions within the rock as nutrients and for chemolithotrophic energy production. The use of these ions at sF88 is supported by the formation of a corrosion residue, presumably through microbial scavenging activities. Our results suggest that rock fabric and mineralogy may be an important driver of ecosystem function and should be carefully reviewed when carrying out microbial community analysis in cave environments.

The impact of host rock geochemistry on bacterial community structure in oligotrophic cave environments, 2007,
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Barton H. A. , Taylor N. M. , Kreate M. P. , Springer A. C. , Oehrle S. A. , Bertog J. L.

Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In order to assess whether microbial activity was leading to changes in the bedrock at each location, the samples were also examined by petrology, X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Our results suggest that on the chemically complex Yates Formation (sF88), the microbial community was significantly more diverse than on the limestone surfaces of the Capitan (WF1), despite a higher total number of cells on the latter. Further, the broader diversity of bacterial species at sF88
reflected a larger range of potential metabolic capabilities, presumably due to opportunities to use ions within the rock as nutrients and for chemolithotrophic energy production. The use of these ions at sF88 is supported by the formation of a corrosion residue, presumably through microbial scavenging activities. Our results suggest that rock fabric and mineralogy may be an important driver of ecosystem function and should be carefully reviewed when carrying out microbial community analysis in cave environments.


Wurmfrmige Excentriques mit ungewhnlichem Calcitgefge - Untersuchungen mit der Elektronen-Rckstreu-Beugungs-Methode, 2007,
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Richter D. K. , Neuser R. D.
Vermiform helictites (excentriques) from a former side branch of the Breitscheid-Erdbach cave are frequently polycrystalline and not composed of a single calcite crystal. The electron backscatter diffraction (EBSD)-technique reveals a lath-shaped calcite structure with c-axes oriented nearly parallel to the elongation of the helictites. The resulting structure of the helictites is a calcite fibre bundle diverging along the growth direction. Three equivalent symmetrical sectors can be distinguished. The maximum deviation from the elongation is 18 and occurs at the exterior in the centre of the segments of the excentriques. The complex internal structure and the conical shape of the tip of the excentriques suggest a special kind of calcite precipitation, whereby biofilms seem to have played a significant role.

Kryogene Karbonate im Hhleneis der Eisriesenwelt, 2008,
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Sptl, C.
Progressive freezing of calcium- and bicarbonate- bearing cave waters can give rise to high supersaturation and the subsequent precipitation of microscopic calcite crystals and aggregates thereof. These particles are disseminated in the ice of ice caves and may later be concentrated by sublimation or melting of ice to form thin carbonate beds in layered ice (cryogenic carbonates). Such white to light brown, silty to fine sandy layers occur in the rear of the ice-bearing part of the Eisriesenwelt cave (Werfen, Salzburg) and were previously regarded as finely disintegrated limestone powder derived from the cave ceiling. Studies using scanning electron microscopy show that this material consists of 30-200 ?m aggregates of euhedral crystals, which, according to powder Xray diffraction analyses, are near-stoichiometric low-Mg calcite. The crystal aggregates commonly show a conspicuous flat top and resemble larger floating calcite rafts known from calcite-precipitating pools in ice-free caves. There are gradual transitions between these aggregates and skeletal crystal aggregates and (hemi)spherulitic forms, respectively. The small particle size and the skeletal crystal habit strongly argue in favour of rapid crystal growth during freezing of shallow puddles of icy water. This interpretation is corroborated by the highly positive C isotope values, which, in conjunction with the O isotope data, prove the cryogenic origin of these carbonates. The proportion of detrital contamination is very low. This study is the first report of fine-grained cryogenic speleothems in an eastalpine cave. It is supposed that such sediments are more wide spread and thicker layers may represent important paleoenvironmental marker horizons.

THE RELATIONSHIP BETWEEN CAVE MINERALS AND H2S RICH THERMAL WATERS ALONG THE CERNA VALLEY (SW ROMANIA), 2009,
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Onac Bogdan P. , Sumrall Jonathan, Tamas Tudor, Povara Ioan, Kearns Joe, Drmiceanu Veronica, Veres Daniel & Lascu Cristian
Within the Cerna Valley in southwestern Romania, over a 100 caves were formed in the Jurassic and Cretaceous limestone that outcrops on the valley walls. Three aspects are prominent when entering most of the caves in this region: the presence of considerable gypsum deposits, the amount of guano, and the cave temperature. High temperature anomalies are uncommon in the cave environment. In certain caves in the lower part of Cerna Valley, however, one can measure air temperatures as high as 40C. This situation is due to the presence of thermal water pooling or =owing through the caves or to the hot steam that rises along fractures from deeper thermal water pools. As a result, these caves provide a unique set of conditions that allowed for the deposition of a suite of unusual minerals. This study presents the results of fiftyy-seven mineral samples that were investigated by means of X-ray diffraction, geochemical, Fourier-transformed infrared spectroscopy, and scanning electron microscope analyses with the scope of linking the cave minerals with likely hypo- gene speleogenetic processes. Here we document the occurrence of twenty-two secondary cave minerals, among which, apjonite and tamarugite are the first recorded occurrences in a limestone cave environment. The minerals fall into three distinct associations: sulfate-dominated (Diana Cave), phosphate-dominated (Adam Shaft), and sulfate-phosphate-nitrate-rich assemblage (Great Salitrari Cave). Additional isotopic measurements performed on sulfate speleothems contribute valuable information on both minerals and cave origins.

The mineralogy and trace element chemistry of black manganese oxide deposits from caves, 2009,
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White W. B. , Vito C. , And Scheetz B. E.

Free surface streams in caves and their surface infeeders often contain pebbles and cobbles coated with black manganese oxide minerals. Coating thicknesses vary from fractions of a millimeter to a few millimeters. In addition, a few caves contain loose masses of black oxide material. The results reported here are based on examination of 39 specimens and detailed chemical analyses of 18 of them. Most of the coatings are amorphous to x-rays, with at best, only a few broad diffraction lines. Infrared spectroscopy shows that most of the specimens are birnessite, with evidence for romanechite, ranceite, and pyrolusite in a few specimens. All specimens contain both iron and manganese, but the Mn/Fe ratio varies widely. Many specimens are enriched in Ba but depleted in Sr. The manganese and iron oxides contain the transition metals Co, Cu, Ni, V, and Zn in concentrations greater than 0.5 wt% in some specimens. Minor Cr and Mo also occur. Given the extremely low concentrations of these elements expected in freshwater streams in carbonate terrains, the manganese oxides exert a dramatic amplifying effect over the expected background. Manganese oxides appear to act as a dosimeter for heavy metals in karst waters.


The relationship between cave minerals and H2S rich thermal waters along the Cerna Valley (SW Romania), 2009,
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Onac Bogdan P. , Sumbrall Jonathan, Tamas Tudor, Povara Ioan, Kearns Joe, Darmiceanu Veronica, Veres Daniel, Lascu Cristian

Within the Cerna Valley in southwestern Romania, over a 100 caves were formed in the Jurassic and Cretaceous limestone that outcrops on the valley walls. Three aspects are prominent when entering most of the caves in this region: the presence of considerable gypsum deposits, the amount of guano, and the cave temperature. High temperature anomalies are uncommon in the cave environment. In certain caves in the lower part of Cerna Valley, however, one can measure air temperatures as high as 40°C. This situation is due to the presence of thermal water pooling or =owing through the caves or to the hot steam that rises along fractures from deeper thermal water pools. As a result, these caves provide a unique set of conditions that allowed for the deposition of a suite of unusual minerals. This study presents the results of fiftyy-seven mineral samples that were investigated by means of X-ray diffraction, geochemical, Fourier-transformed infrared spectroscopy, and scanning electron microscope analyses with the scope of linking the cave minerals with likely hypo- gene speleogenetic processes. Here we document the occurrence of twenty-two secondary cave minerals, among which, apjonite and tamarugite are the first recorded occurrences in a limestone cave environment. The minerals fall into three distinct associations: sulfate-dominated (Diana Cave), phosphate-dominated (Adam Shaft), and sulfate-phosphate-nitrate-rich assemblage (Great Salitrari Cave). Additional isotopic measurements performed on sulfate speleothems contribute valuable information on both minerals and cave origins.


EVIDENCE FROM CERNA VALLEY CAVES (SW ROMANIA) FOR SULFURIC ACID SPELEOGENESIS: A MINERALOGICAL AND STABLE ISOTOPE STUDY, 2009,
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Onac B. , Sumrall J. , Wynn J. , Tamas T. , Dormiceanu V. , Cizma? C.

Over 30 caves are known to develop in the Jurassic and Cretaceous limestone that outcrops along the lower part of the Cerna Valley and its tributaries in southwestern Romania. There are three features that strike observers when entering most of these caves: a variety of sulfate speleothems, large amounts of bat guano (both fossil and fresh), and unusually high cave temperatures. Such thermal anomalies are rather uncommon in the ordinary cave environment. Along Cerna Valley, however, one can measure temperatures (in some cavities) as high as 40ºC. This situation is due to (i) presence of thermal water pools, (ii) hot water flowing along cave passages, (iii) hot steam rising up fractures from depth.
Seventy-four mineral samples were collected from eight caves in the Cerna Valley. These were investigated by means of X-ray diffraction, scanning electron microscope, and electron microprobe analyses. The minerals identified so far in Sălitrari, Ion Barzoni, Sălitrari 2, Diana, Adam, Despicătura, and Grota cu Aburi caves, are: calcite [CaCO3], aragonite [CaCO3], gypsum [CaSO4•2H2O], anhydrite [CaSO4], pickeringite [MgAl2(SO4)4•22H2O], halotrichite [Fe2+Al2(SO4)4•22H2O], kalinite [KAl(SO4)2•11H2O], melanterite [FeSO4•7H2O], apatite- (Ca(OH) [Ca5(PO4)3(OH)], brushite [CaHPO4•2H2O], darapskite [Na3(SO4)(NO3)•H2O], and nitratine [NaNO3]. The phosphates and nitrates (except for darapskite) were precipitated in a typical vadose environment from reactions between phosphoric solutions supplied by bat guano and limestone bedrock. Most of the sulfates and darapskite are the result of sulfuric acid speleogenesis.
In addition, sulfur isotope measurements (δ34S) on sulfate speleothems and spring waters were undertaken to determine the origin of cave sulfates (i.e., vadose, hypogene, bacteriogenic, etc.). The isotope measurements in the springs show sulfide δ34S ranges from -21.9‰ to 24.0‰ with a mean value of 6.6‰ (n=9), whereas the sulfate δ34S ranges from 16.6‰ to 71.3‰ with a mean value of 30.1‰ (n=10).
Three populations of sulfur isotope values (negative, near zero, and positive) were found in the caves. Samples from Barzoni Cave (the most distant cave from any modern thermal spring) are extremely depleted (-23 to -28‰). Sulfide values of the nearest springs are approximately -20‰. In Sălitrari Cave, the range of values was from -19.8 to +6.5‰. It is more than likely a reflection of the increase in completeness of the reduction of sulfate. The δ34S value of gypsum in Grota cu Aburi (active H2S hot steam cave) was 6.5‰. This value is similar to the sulfur isotopic composition measured in darapskite from Sălitrari Cave; thus, probably documenting earlier sulfuric acid activity in the latter cave.
The final population of caves, especially Despicătura and Diana caves, has enriched sulfur isotope values, which correspond well to the sulfide values of nearby springs. Diana Cave from which Diana 3 spring originates has a sulfide isotopic composition of +19‰, which is approximately the value of the mean of the cave sulfates from Diana Cave. This shows that the cave sulfate isotopic value is controlled by the sulfide, which (after being oxidized) reacts with limestone/marls to produce gypsum or other sulfate minerals.


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