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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 measuring weir is a device used to measure flow rates indirectly through a weir head.?

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

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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

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Your search for ratios (Keyword) returned 116 results for the whole karstbase:
Showing 31 to 45 of 116
Coral Record of Equatorial Sea-Surface Temperatures During the Penultimate Deglaciation at Huon Peninsula, 1999,
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Mcculloch Malcolm T. , Tudhope Alexander W. , Esat Tezer M. , Mortimer Graham E. , Chappell John, Pillans Bradley, Chivas Allan R. , Omura Akio,
Uplifted coral terraces at Huon Peninsula, Papua New Guinea, preserve a record of sea level, sea-surface temperature, and salinity from the penultimate deglaciation. Remnants have been found of a shallow-water reef that formed during a pause, similar to the Younger Dryas, in the penultimate deglaciation at 130,000 2000 years ago, when sea level was 60 to 80 meters lower than it is today. Porites coral, which grew during this period, has oxygen isotopic values and strontium/calcium ratios that indicate that sea-surface temperatures were much cooler (22 degrees 2 degrees C) than either Last Interglacial or present-day tropical temperatures (29 degrees 1 degrees C). These observations provide further evidence for a major cooling of the equatorial western Pacific followed by an extremely rapid rise in sea level during the latter stages of Termination II

Speleothem organic acid luminescence intensity ratios: A new palaeoenvironmental proxy, 2000,
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Baker A. , Bolton Lucy

Lechuguilla Cave Pool Chemistry, 1986-1999, 2000,
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Turin, H. J. , Plummer, M. A.
In May 1986, cavers dug into Lechuguilla Cave, in southeastern New Mexico, USA. Subsequent exploration and research have demonstrated that Lechuguilla is a world-class cave, both in size and in speleological importance. Of particular interest to hydrologists and geochemists are the numerous isolated pools throughout much of the cave. Since 1986, close to 200 water samples have been collected and subjected to over 2000 individual analyses. Results of these analyses are collected and published here for the first time. Dominant cations in the pool waters are calcium and magnesium; dominant anions are bicarbonate and sulfate. These characteristics reflect the limestone/dolomite host bedrock of the cave, modified to varying degrees by the caves massive gypsum deposits, associated with the caves early development. The overall chemistry of the water can be explained by a small number of geochemical processes, starting with evaporation and concentration of local rainfall, and dissolution of soil CO2 and local bedrock. Within the cave, excess CO2 is degassed, leading to precipitation of CaCO3 and increased Mg2+:Ca2+ ratios. In some areas of the cave, infiltrating water encounters and dissolves gypsum, leading to increased CaCO3 precipitation and increased SO42-:HCO3- ratios. In at least one location, massive evaporation has created a magnesium sulfate brine. Geochemical characteristics seem to confirm that the pool located at Lechuguillas current deep point is actually the regional aquifer, suggesting that the caves maximum air-filled depth has been reached.

Controls on trace element (Sr-Mg) compositions of carbonate cave waters: implications for speleothem climatic records, 2000,
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Fairchild Ij, Borsato A, Tooth Af, Frisia S, Hawkesworth Cj, Huang Ym, Mcdermott F, Spiro B,
At two caves (Clamouse, S France and Ernesto, NE Italy), cave drip and pool waters were collected and sampled at intervals over a 2-3 year period. Mg/Ca and Sr/Ca concentration ratios, corrected for marine aerosols, are compared with those of bedrocks and, in some cases, aqueous leachates of soils and weathered bedrocks. Cave waters do not lie along mixing lines between calcite and dolomite of bedrock carbonate, but typically show enhanced and covarying Mg/Ca and Sr/Ca. Four factors are considered as controlling processes. (1) The much faster dissolution rate of calcite than dolomite allows for the possibility of increase of Mg/Ca if water-rock contact times are increased during drier conditions. A theoretical model is shown to be comparable to experimental leachates. (2) Prior calcite precipitation along a flow path is a powerful mechanism for generating enhanced and covarying Mg/Ca and Sr/Ca ratios. This mechanism requires the solution to lose CO, into pores or caverns. (3) Incongruent dolomite dissolution has only limited potential and is best regarded as two separate processes of dolomite dissolution and calcite precipitation. (4) selective leaching of Mg and Sr with respect to Ca is shown to be important in leachates from Ernesto where it appears to be a phenomenon of calcite dissolution. In general selective leaching can occur whenever Ca is sequestered into precipitates due to freezing or drying of soils, or if there is derivation of excess Sr and Mg from non-carbonate species. The Ernesto cave has abundant water supply which in the main chamber is derived from a reservoir with year-round constant P-CO2 of around 10(-2.4) and no evidence of calcite precipitation in the karst above the cave. Two distinct, bur overlying trends of enhanced and covarying Mg/Ca and Sr/Ca away from the locus of bedrock compositions are due to calcite precipitation within the cave and, at a variable drip site, due to enhanced selective leaching at slow drip rates. Mg-enhancement in the first chamber is due to a more dolomitic bedrock and longer residence times. The Clamouse site has a less abundant water supply and presents geochemical evidence of prior calcite precipitation. both in the cave and in overlying porous dolomite/dedolomitized limestone bedrock. Initial P-CO2 values as high as 10(-1) are inferred. Experimental incubations of Clamouse soils which generated enhanced P-CO2 and precipitated CaCO3 had compositions similar to the karst waters. Calcite precipitation is inferred to he enhanced in drier conditions. Hydrological controls on cave water chemistry imply that the trace element chemistry of speleothems may be interpretable in palaeohydrological terms. Drier conditions tends to promote not only longer mean residence times (enhancing dolomite dissolution and hence Mg/Ca), but also enhances degassing and calcite precipitation leading to increased Mg/Ca and Sr/Ca. (C) 2000 Elsevier Science B.V. All rights reserved

Vein and Karst Barite Deposits in the Western Jebilet of Morocco: Fluid Inclusion and Isotope (S, O, Sr) Evidence for Regional Fluid Mixing Related to Central Atlantic Rifting, 2000,
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Valenza Katia, Moritz Robert, Mouttaqi Abdellah, Fontignie Denis, Sharp Zachary,
Numerous vein and karst barite deposits are hosted by Hercynian basement and Triassic rocks of the western Jebilet in Morocco. Sulfur, oxygen, and strontium isotope analyses of barite, combined with fluid inclusion microthermometry on barite, quartz, and calcite were used to reveal the nature and source of the ore-forming fluids and constrain the age of mineralization. The{delta} 34S values of barite between 8.9 and 14.7 per mil are intermediate between the sulfur isotope signatures of Triassic evaporites and Triassic-Jurassic seawater and lighter [IMG]f1.gif' BORDER='0'>, probably derived from the oxidation of dissolved H2S and leaching of sulfides in the Hercynian basement. The 87Sr/86Sr ratios of barite between 0.7093 and 0.7130 range between the radiogenic strontium isotope compositions of micaceous shale and sandstone and the nonradiogenic isotopic signature of Triassic to Jurassic seawater and Cambrian limestone. The{delta} 18O values of barite between 11 and 15 per mil (SMOW) support mixing between two or more fluids, including Late Triassic to Jurassic seawater or a water dissolving Triassic evaporites along its flow path, hot basinal, or metamorphic fluids with{delta} 18O values higher than 0 per mil and/or meteoric fluids with{delta} 18O values lower than 0 per mil. The general trend of decreasing homogenization temperatures and initial ice melting temperatures with increasing salinities of H2O-NaCl {} CaCl2 fluid inclusions trapped in barite, quartz, and calcite indicates that a deep and hot basinal fluid with salinities lower than 6 wt percent NaCl equiv might have mixed with a cooler surficial solution with a mean salinity of 20 wt percent NaCl equiv. Calcium was leached from the Cambrian limestone and the clastic and mafic volcanic rocks of the Hercynian basement. Alkali feldspars and micas contained in the Cambrain sandstones provided most of the Ba to the hydrothermal system. Vein and karst deposits are modeled as a two-component mixing process in which the temperature and the S and Sr isotope composition of the end members changed during the 220 to 155 Ma interval. The hot basinal fluid remained volumetrically dominant during the entire mineralization process. Differences in mean S, O, and Sr isotope compositions among the barite families are interpreted as reflecting differences in mineralization age. Most barite deposits formed before the Kimmeridgian, except for north-south-oriented vein barite, karst barite, and barite cement in the conglomeratic Upper Jurassic, which were deposited later, possibly around 155 Ma. Similar genetic processes have been described for late Paleozoic to Mesozoic F-Ba vein deposits in western Europe. The vein and karst barite in the western Jebilet of Morocco reveals a wide-scale regional mineralization event related to Central Atlantic rifting

Dolomitization and Dolomite Neomorphism: Trenton and Black River Limestones (Middle Ordovician) Northern Indiana, U.S.A, 2000,
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Yoo Chan Min, Gregg Jay M. , Shelton Kevin L. ,
The Trenton and Black River Limestones are dolomitized extensively along the axis of the Kankakee Arch in Indiana, with the proportion of dolomite decreasing to the south and southeast of the arch. Planar and nonplanar dolomite replacement textures and rhombic (type 1) and saddle (type 2) void-filling dolomite cements are present. Three stages of dolomitization, involving different fluids, are inferred on the basis of petrographic and geochemical characteristics of the dolomites. Nonferroan planar dolomite has relatively high {delta}18O values (-1.8 to -6.1{per thousand} PDB) and has 87Sr/86Sr ratios (0.70833 to 0.70856) that overlap those of Middle Ordovician seawater. Petrography, geochemistry, and the geometry of the dolomitized body suggest that the planar dolomite was formed in Middle and Late Ordovician seawater during the deposition of the overlying Maquoketa Shale. Ferroan planar and nonplanar dolomite occurs in the upper few meters of the Trenton Limestone, confined to areas underlain by planar dolomite. This dolomite contains patches of nonferroan dolomite with cathodoluminescence (CL) characteristics similar to underlying planar dolomite. Ferroan dolomite has relatively low {delta}18O values (-5.1 to -7.3{per thousand} PDB) and has slightly radiogenic 87Sr/86Sr ratios (0.70915 to 0.70969) similar to those obtained for the overlying Maquoketa Shale. These data indicate that ferroan dolomite formed by neomorphism of nonferroan planar dolomite as fluids were expelled from the overlying Maquoketa Shale during burial. The absence of ferroan dolomite at the Trenton-Maquoketa contact, in areas where the earlier-formed nonferroan planar dolomite also is absent, indicates that the fluid expelled from the overlying shale did not contain enough Mg2 to dolomitize limestone. Type 1 dolomite cement has isotopic compositions similar to those of the ferroan dolomite, suggesting that it also formed from shale-derived burial fluids. CL growth zoning patterns in these cements suggest that diagenetic fluids moved stratigraphically downward and toward the southeast along the axis of the Kankakee Arch. Type 2 saddle dolomite cements precipitated late; their low {delta}18O values (-6.0 to -7.0{per thousand} PDB) are similar to those of the type 1 dolomite cement. However, fluid-inclusion data indicate that the saddle dolomite was precipitated from more saline, basinal fluids and at higher temperatures (94{degrees} to 143{degrees}C) than the type 1 cements (80{degrees} to 104{degrees}C). A trend of decreasing fluid-inclusion homogenization temperatures and salinities from the Michigan Basin to the axis of Kankakee Arch suggests that these fluids emerged from the Michigan Basin after precipitation of type 1 cement

Controls on the geochemistry of speleothem-forming karstic drip waters, PhD thesis, 2000,
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Tooth, A.

Research was performed at Crag Cave, Castleisland, southwest Ireland, and P8 Cave, Castleton, Derbyshire, in order to determine the main factors responsible for modifying rainwater geochemistry during flow through soil and karstic aquifer zones. Monitoring was performed on a daily basis in summer and winter at Crag Cave, and on a monthly basis over one year at P8 Cave. At both sites, biannual peaks in karst system Ca2+ concentrations occurred due to: (i) promotion of microbial CO2 production by increased summer temperatures, and (ii) retardation of gaseous exchange by ponding of elevated winter rainfall input leading to an unseasonable build up in soil zone CO2. Therefore, speleothems at both sites may form biannual bands in hydrological years subject to elevated winter rainfall input.

In addition to variations in carbonate weathering due to fluctuations in CO2 levels, cation yields in Crag Cave matrix soil water were controlled by dolomite dissolution (Mg2+), plant uptake (K+), and evapotranspiration balanced by enhanced winter marine aerosol input (Na+). Strontium isotope analysis indicates that Sr2+ was derived from a 50:50 silicate/carbonate mixture, whereas the relatively light ?13C signal was related to direct evolution of CO2 into the aqueous phase in water-logged pores.

Within the Crag Cave aquifer variations in karst water geochemistry were controlled by dilution, flow switching, prior precipitation of calcite, and dolomite dissolution along the flow path. Strontium isotope analysis indicates that dissolution in the aquifer dominated, with Sr2+ being sourced from a 25:75 silicate/carbonate mixture. Light karst water 13C values were constrained by the supply of light soil gas to the aquifer.

Elevation in the Mg/Ca and Sr/Ca ratios in the Crag Cave speleothem record compared to present day analogues indicates that the former Holocene climate was drier, whereas heavier 87Sr/86Sr ratios and 13C values suggest variation in soil hydrology over time.

Seasonal variations in Sr, Mg and P in modern speleothems (Grotta di Ernesto, Italy), 2001,
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Huang Yiming, Fairchild Ian J. , Borsato Andrea, Frisia Silvia, Cassidy Nigel J. , Mcdermott Frank, Hawkesworth Chris J. ,
Sub-annual variations in trace element chemistry and luminescence have recently been demonstrated from speleothems and offer the potential of high-resolution palaeoclimatic proxies. However, no studies have yet examined microscopic trace element variations in relation to modern cave conditions. In this study, the spatial variations in trace element (Sr, Mg and P) concentrations in speleothems (a stalagmite and a soda straw stalactite) from the alpine Ernesto cave (temperature 6.60.1[deg]C) in a forested catchment in NE Italy have been studied using secondary ion mass spectrometry (SIMS) and compared with environmental parameters and waters in the modern cave. An annual lamination exists in the stalagmite and soda straw stalactite in the form of clear calcite with narrow visible layers, which are UV-fluorescent and interpreted to contain soil-derived humic/fulvic acids washed into the cave during autumn rains. Microanalyses were undertaken of seven annual laminae, probably deposited during the 1960s in the stalagmite, and seven laminae in the 1990s for the stalactite.The analysis results show that Sr consistently has a trough and P, a peak centred on the inclusion-rich layer. Mg shows mainly a negative covariation with Sr in laminae formed in the 1990s, but a positive covariation in the stalagmite formed in 1960s. The spatial scale of the main geochemical variations is the same as that of annual laminae of inclusion-poor and inclusion-rich couplets. Mass balance arguments are used to show that the P is inorganic in form and presumably occurs as individual phosphate ions within the calcite.Most drip waters show limited chemical variations, but a summer peak in trace elements in 1995 and a decrease in Mg/Ca in the following winter are notable. More pronounced covariations in Mg/Ca and Sr/Ca are shown by a site with highly variable drip rates where ratios increase at slow drip rates. The strongest seasonal variations are found in pool waters, where ratios increase reflecting significant Ca removal from the water into the calcite during the winter in response to seasonal PCO2 variations in cave air. Thus, the cave waters' compositions tend to reflect climate conditions, such that Mg/Ca and Sr/Ca are tentatively interpreted to be higher when climate conditions are dry.Combining results from the speleothems and cave water along with the behaviour of each trace species, Mg/Ca variations in the speleothems are considered to reflect their variation in the cave waters, whereas, Sr incorporation is also dependent on precipitation rate, in this case, mainly controlled by temporal variations in PCO2 in the cave (and conceivably, also by inhibitors such as phosphate). P adsorption (a fraction of which is subsequently incorporated within calcite) depends on aqueous phosphate concentration and water flux, both of which should increase during the autumn. Therefore, multiple trace element profiles in speleothems reflect multiple aspects of environment seasonality and conditions, and hence, a calibration against weather records is desirable to establish their palaeoclimatological meaning. The strong annual variation of trace elements, and particularly P, can provide chronological markers for high-resolution studies of other climate proxies, such as stable isotopes

Timescales for nitrate contamination of spring waters, northern Florida, USA, 2001,
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Katz B. G. , Bohlke J. K. , Hornsby H. D. ,
Residence times of groundwater, discharging from springs in the middle Suwannee River Basin, were estimated using chlorofluorocarbons (CFCs), tritium ((3) H), and tritium/helium-3 (H-3/He-3) age-dating methods to assess the chronology of nitrate contamination of spring waters in northern Florida. During base-flow conditions for the Suwannee River in 1997-1999, 17 water samples were collected from 12 first, second, and third magnitude springs discharging groundwater from the Upper Floridan aquifer. Extending age-dating techniques, using transient tracers to spring waters in complex karst systems, required an assessment of several models [piston-flow (PFM), exponential mixing (EMM), and binary-mixing (BMM)] to account for different distributions of groundwater age. Multi-tracer analyses of four springs yielded generally concordant PFM ages of around 20 2 years from CFC- 12, CFC- 113, H-3, and He-3. with evidence of partial CFC- 11 degradation. The EMM gave a reasonable fit to CFC- 113, CFC- 12. and H-3 data, but did not reproduce the observed He-3 concentrations or H-3/He-3 ratios, nor did a combination PFM-EMM. The BMM could reproduce most of the multi-tracer data set only if both endmembers had H-3 concentrations not much different front modern values. CFC analyses of 14 additional springs yielded apparent PFM ages from about 10 to 20 years from CFC- 113, with evidence of partial CFC- 11 degradation and variable CFC-12 contamination. While it is not conclusive, with respect to the age distribution within each spring, the data indicate that the average residence times were in the order of 10-20 years and were roughly proportional to spring magnitude. Applying similar models to recharge and discharge of nitrate based on historical nitrogen loading data yielded contrasting trends for Suwanee County and Lafayette County. In Suwance County, spring nitrate trends and nitrogen isotope data were consistent with a peak in fertilizer input in the 1970s and a relatively high overall ratio of artificial fertilizer/manure whereas in Lafayette County, spring nitrate trends and nitrogen isotope data were consistent with a more monotonic increase in fertilizer input and relatively low overall ratio of artificial fertilizer/manure. The combined results of this study indicate that the nitrate concentrations of springs in the Suwannee River basin have responded to increased nitrogen loads from various sources in the watersheds over the last few decades, however, the responses have been subdued and delayed because the average residence time of groundwater discharging from springs are in the order of decades. (C) 2001 Published by Elsevier Science B.V

Partitioning of Sr2 and Mg2 into calcite under karst-analogue experimental conditions, 2001,
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Huang Yiming, Fairchild Ian J. ,
There is a paucity of experimental data on calcite precipitation from waters at low ionic strength and low ratios of Mg/Ca and Sr/Ca, using controlled and constant precipitation rates. Such data are particularly needed for studies of speleothem geochemistry in relation to palaeoclimates.We carried out a series of experiments using a karst-analogue set-up in a chamber of constant temperature and 100% humidity. A steady flow of NaHCO3 and CaCl2 solutions at PCO2 around 10-3.2 were mixed just before passage through a tube (analogous to a soda-straw stalactite) and allowed to drip onto a surface, analogous to a stalagmite. Growth rates were comparable with linear extension rates of natural speleothems.Analytical spots gave reproducible analyses in later analytical cycles after ablation of surface calcite with Na and Mg contamination. Different crystals from the same experiment tended to show positive covariation of Na and Mg with negative covariation with Sr. This may be due to the presence of growth hillocks with vicinal faces with differential partitioning behaviour.The result for the partition coefficient for Mg (DMg) at 25[deg]C is 0.031 0.004, which is quantitatively in good agreement with the trends of previous workers. At 15[deg]C, the result is 0.019 0.003. The temperature dependency is higher than experimental data on seawater-analogue solutions, but lower than a previous estimate based on a comparison of speleothem chemistry with single water analyses.Data for DSr are mainly in the range of 0.057 to 0.078, with a possible weak dependency on growth rate, consistent with previous experimental work. Absolute values are higher than studies in Mg-free saline solutions, which is attributed mainly to salinity effects. Values of DSr are nevertheless somewhat lower than in natural caves, which may relate to crystal growth factors.Mg partition coefficient values should allow robust determination of solution Mg/Ca compositions in enclosed caves, which are at constant temperature on the decadal timescale. The inferred sensitivity of DSr to growth rate factors implies that Sr values should be interpreted more cautiously. Muted changes could relate entirely to growth rate variations, whereas changes of large magnitude imply a control by solution composition. The absence of local (tens of micron scale) antipathetic variations in Sr and Mg in studied natural speleothems, implies that intracrystalline zoning phenomena, if present, are on a finer scale in those natural materials compared with experimental products

Ecological assessment and geological significance of microbial communities from Cesspool Cave, Virginia, 2001,
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Engel As, Porter Ml, Kinkle Bk, Kane Tc,
Microbial mats from hydrogen sulfide-rich waters and cave-wall biofilms were investigated from Cesspool Cave, Virginia, to determine community composition and potential geomicrobiological functioning of acid-producing bacteria. Rates of microbial mat chemoautotrophic productivity were estimated using [C-14]-bicarbonate incorporations and microbial heterotrophy was determined using [C-14]-leucine incubations. Chemoautotrophic fixation was measured at 30.4 12.0 ng C mg dry wt(1) h(1), whereas heterotrophic productivity was significantly less at 0.17 0.02 ng C mg dry wt(1) h(1). The carbon to nitrogen ratios of the microbial mats averaged 13.5, indicating that the mats are not a high quality food source for higher trophic levels. Ribosomal RNA-based methods were used to examine bacterial diversity in the microbial mats, revealing the presence of at least five strains of bacteria. The identity of some of the strains could be resolved to the genus Thiothrix and the Flexibacter-Cytophaga-Bacteriodes phylum, and the identity of the remaining strains was to either the Helicobacter or Thiovulum group. Two of 10 sulfur-oxidizing, chemoautotrophic pure cultures of Thiobacillus spp. (syn. Thiomonas gen. nov.) demonstrated the ability to corrode calcium carbonate, suggesting that the colonization and metabolic activity of these bacteria may be enhancing cave enlargement

Water quality impacts and palaeohydrogeology in the Yorkshire Chalk aquifer, UK, 2001,
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Elliot T, Chadha Ds, Younger Pl,
A large hydrochemical data-set for the East Yorkshire Chalk aquifer has been assessed. Controls on the distribution of water qualities reflect: water-rock interactions (affecting especially the carbonate system and associated geochemistry); effects of land-use change (especially where the aquifer is unconfined); saline intrusion and aquifer refreshening (including ion exchange effects); and overexploitation (in the semi-confined and confined zones of the aquifer). Both Sr and I prove useful indicators of groundwater esidence times, and I/Cl ratios characterize two sources of saline waters. The hydrochemical evidence clearly reveals the importance both of recent management decisions and palaeohydrogeology in determining the evolution and distribution of groundwater salinity within the artesian and confined zones of the aquifer. Waters encountered in the aquifer are identified as complex (and potentially dynamic) mixtures between recent recharge waters, modern seawater, and ancient seawater which entered the aquifer many millennia ago

Isotopic compositions of strontium in river water of Guizhou karst areas, China, 2001,
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Han G. L. , Liu C. Q. ,
We have carried out a study on the variation of strontium isotope composition of river waters, Wujiang and Yuangjiang River, in karst areas of Guizhou Province, China. The results obtained permit us to characterize the geochemistry of the river draining karst terrain and obtain a better understanding of main controls of catchment geology, chemical weathering of different rocks, and evaluate impact of human activities on the environment. The isotopic ratios of dissolved Sr in all rivers are between Sr-87/Sr-86 = 0.7077 and 0.7110, totally lower than the weighted average of Sr-87/Sr-86 = 0.7119 for the world large rivers. The Wujiang River waters have Sr concentrations from 1.0 to 6.1 mu mol/L, while the Yuanjiang River waters have much lower Sr concentrations ranging from 0.28 to 1.3 mu mol/L. Most of the river waters from the Wujiang river are characterized by low Ca/Sr and Mg/Sr, and Sr-87/Sr-86 ratios, in which a majority of river waters are of Sr-87/Sr-86 ratios lower than the average Sr isotope ratio (Sr-87/Sr-86 = 0.709) of present seawater. The higher Sr-87/Sr-86 ratios are observed in the river waters in the lower reach of the Wujiang River, where the lithology is dominated by detrital rocks and dolomite. The water from Yuanjiang River show higher Ca/Sr, Mg/Sr and Sr-87/Sr-86 ratios due to weathering of silicates, as compared to the river waters from Wujiang river

Derivation of effective hydraulic parameters of a karst aquifer from discharge hydrograph analysis, 2001,
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Baedke Sj, Krothe Nc,
In well-developed karst terrains, three or more distinct portions of the karst continuum can be identified from hydrographs of springs issuing from the karat aquifer. Hydrographs from mio karat springs within the same drainage basin at the Crane Naval Surface Warfare Center, Indiana, have been analyzed, and ratios of transmissivity and specific yield (T/S-y) have been established for the conduit and diffuse flow systems. These ratios have been compared with values of T derived from aquifer tests, so that independent values of S-y can be calculated for the diffuse system. Similarly, if the value of S-y is assumed to be 1.0 for a pure conduit, then independent values of T can be calculated for this end-member of the karst continuum. The values of T and S-y derived from this study are similar to values obtained from a dye trace of the conduit-dominated flow system and of values derived from aquifer tests of the diffuse flow system. Values of T for the conduit system of these springs may need to be established at a local scale, while the values for the diffuse flow system may be applicable at a regional scale. A hydrograph separation using isotopic data suggests that the intermediate-flow system represents a mix of water from the conduit and diffuse flow systems. If this portion of the hydrograph is a truly mixing phenomena, ratios of TIS cannot be determined from the hydrograph analysis presented herein. However. if instead, the intermediate-flow system represents water released from a third reservoir (such as small fractures), ratios of T/S, can be established for the intermediate-flow system

Dachstein-Altflche, Augenstein-Formation und Hhlenentwicklung - die Geschichte der letzten 35 Millionen Jahre in den zentralen Nrdlichen Kalkalpen., 2002,
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Frisch W. , Kuhlemann J. , Dunkl I. , Szekely B. , Vennemann T. , Rettenbacher A.
The landscape of the central Northern Calcareous Alps (NCA) is largely determined by the celebrate elevated karst plateaus, which represent relics of the Dachstein paleosurface and can be followed as far as the eastern margin of the NCA. The Dachstein paleosurface formed in late Eocene to early Oligocene times as a karstic hilly landscape. It was modified by later erosional processes to a limited extent only and is preserved as such in the karst plateaus. In the Oligocene, the paleosurface subsided and was sealed by the Augenstein Formation, a terrestrial sequence of conglomerates and sandstones, which are only preserved in small remnants on the plateaus. The poorly and contradictingly defined terms Rax landscape" and Augenstein landscape" are not used any more. From the overall geological situation, the age of the Augenstein Formation can be inferred as Lower Oligocene to early Lower Miocene. Fission track dating on zircon support the Lower Oligocene age of the basal Augenstein sediments (only these are preserved). Their source area was situated in the south and mainly occupied by weakly metamorphosed Paleozoic sequences (Graywacke Zone and its equivalents) and the latest Carboniferous to Lower Triassic siliciclastic base of the NCA. To the west, the Augenstein Formation interfingered with the Tertiary sediments of the Lower Inn Valley. Thermal modeling of fission track data from apatite, which is contained in pebbles as an accessory phase, suggest that the Augenstein Formation attained thicknesses of locally 1.3 km, possibly even more than 2 km. Augenstein sedimentation probably ended in Early Miocene times with the onset of lateral tectonic extrusion in the Eastern Alps, which caused lowering of the relief in the source area and created a new, fault-bounded river network. In the following period, the Augenstein sediments were eroded and redeposited in the foreland molasse basin. From Pannonian times (ca. 10 Ma) on, the central and eastern NCA, and therefore also the Dachstein paleosurface, experienced uplift in pulses. The paleosurface remained preserved in those areas, where thick limestone sequences enabled subsurface erosion in cave systems and considerably reduced surface erosion. Augenstein sediments became washed into the widespread cave systems of the plateau-topped limestone massifs. The arrangement of the caves in three horizons shows that uplift of the NCA occurred in pulses separated from periods of tectonic quiescence. In our model of the evolution of the NCA since the late Eocene, the highest cave system, the surface-near ruin cave system, was probably formed during formation of the Dachstein paleosurface. The largest system, the giant cave system, formed in Upper Miocene times, i.e., in the early stage of the final uplift period of the NCA. The youngest and lowest system, the source cave system, formed in Pliocene to Quaternary times. We aimed to date material from the giant cave system by radiometric methods. U/Pb dating on speleothems from the Mammut cave (Dachstein) and the Eisriesenwelt (Tennengebirge) gave no formation age because of the low U contents; however, the isotope ratios allow to infer that the speleothems formed in pre-Pleistocene time. Quartz pebbles from the Augenstein Formation, washed into the caves before the formation of the speleothems, were analyzer for cosmogenic beryllium and aluminum isotopes in order to date the time of redeposition. The isotope contents, however, did no yield a sufficiently strong signal. Oxygen and carbon isotope ratios were determined on the Eisriesenwelt speleothem in order to receive information on climatic changes during speleothem growth. A 260 mm long core from the outer zone of the speleothem shower limited variation for the temperatures of the seeping rainwater, which caused the speleothems to form. This indicates moderate climate and thus, again, pre-Pleistocene formation of the speleothems. All these results are in accord with the supposed Upper Miocene formation age of the giant cave system. Displacement of a speleothem along a shear plane and normal faults visible on the plateaus by the offset of the actual surface testify young, partly Quaternary tectonics, which affected the NCA.[ausfhrliche Darstellung, geol. Krtchen, Farbbilder, ganzes Heft.]

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