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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 hydrogeologic is those factors that deal with subsurface waters and related geologic aspects of surface waters.?

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;
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Your search for fluxes (Keyword) returned 56 results for the whole karstbase:
Showing 31 to 45 of 56
Geomorphic history of Crystal Cave, Southern Sierra Nevada, California., 2005,
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Despain J. D. , Stock G. M.
Cave development in mountainous regions is influenced by a number of factors, including steep catchments, highly variable allogenic recharge, large sediment fluxes, and rapid rates of canyon downcutting. Caves can help to quantify this latter process, provided their ages are determined. Here we investigate the history of 4.8 km long Crystal Cave, a complex, multiple level cave in the Sierra Nevada, through detailed geomorphic and geochronologic investigations. Crystal Cave is composed of six major levels spanning 64 m in elevation. The levels are comprised of large, low gradient conduit tubes, and are connected by numerous narrow, steeply descending canyon passages. Passages in the upstream end of the cave are significantly modified by collapse, while in the downstream section they are intact with an anastomotic maze overprinting. Dye tracing confirms that the cave stream originates from partial sinking of Yucca Creek to the north. Passage gradients, wall scallops, and sediment imbrication indicate that groundwater flowed consistently southeast through time, forming cave levels as bedrock incision of Cascade Creek lowered local base level. Although modern cave stream discharges are restricted to ~0.03 m3 s?1, likely due to passage collapse near the sink point ca. 0.5 million years ago (Ma), bedrock scallops and coarse clastic sediment in upper levels indicate paleodischarges as much as three orders of magnitude greater prior to that time. Infrequent high discharge flood events played an important role in passage development and sediment transport. Cosmogenic 26Al/10Be burial dating of sediment suggest that the majority of Crystal Cave formed rapidly between ca. 1.2 and 0.5 Ma; rates of cave development approach theoretical maximums, presumably due to a combination of allogenic recharge highly under-saturated with respect to calcite, and physical erosion by transported sediment.

Groundwater fluxes into a submerged sinkhole area, Central Italy, using radon and water chemistry, 2005,
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Tuccimei P. , Salvati R. , Capelli G. , Delitala M. C. , Primavera P. ,
The groundwater contribution into Green Lake and Black Lake (Vescovo Lakes Group), two cover collapse sinkholes in Pontina Plain (Central Italy), was estimated using water chemistry and a Rn-222 budget. These data can constrain the interactions between sinkholes and deep seated fluid circulation, with a special focus on the possibility of the bedrock karst aquifer feeding the lake. The Rn budget accounted for all quantifiable surface and subsurface input and output fluxes including the flux across the sediment-water interface. The total value of groundwater discharge into Green Lake and Black Lake (similar to 540 160 L s(-1)) obtained from the Rn budget is lower than, but comparable with historical data on the springs group discharge estimated in the same period of the year (800 90 L s(-1)). Besides being an indirect test for the reliability of the Rn-budget 'tool', it confirms that both Green and Black Lake are effectively springs and not simply 'water filled' sinkholes. New data on the water chemistry and the groundwater fluxes into the sinkhole area of Vescovo Lakes allows the assessment of the mechanism responsible for sinkhole formation in Pontina Plain and suggests the necessity of monitoring the changes of physical and chemical parameters of groundwater below the plain in order to mitigate the associated risk. (c) 2005 Elsevier Ltd. All rights reserved

The transition of a freshwater karst aquifer to an anoxic marine system, 2005,
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Garman Km, Garey Jr,
Jewfish Sink is located in the shallow seagrass flats of the Gulf of Mexico in west central Florida. Jewfish Sink was a submarine spring until the drought of 1961-1962 when it ceased flowing. Today, the sink is an anaerobic marine basin and provides the opportunity to study the implications of saltwater intrusion in coastal karstic areas. The biogeochemistry of Jewfish Sink was studied from summer 2001 through spring 2004. A distinct feature of the sink is the uniform cold temperature (16-17 degrees C) of the deeper anoxic water that does not match groundwater found nearshore or onshore (22-24 degrees C). There are four zones within the sink: oxic zone, transition zone, upper anoxic zone, and anoxic bottom water. The anoxic bottom water does not mix with water from above but may be linked to deep Gulf shelf water through ancient aquifer conduits. The other three zones vary seasonally in oxygen, salinity, and temperature because of limited mixing in the winter due to cooling and sinking of surface water. The walls of the anoxic zones have characteristic microbial mats that are found in other sulfidic karstic features in the area. Bacterial activity appears to be carbon limited in the anoxic zones where sulfate reduction appears to be the major metabolic process. The reduction of sulfate to sulfide appears to be driven by irregular influxes of organic matter including macroalgae, horseshoe crabs, and stingrays that become entrapped within the sink. Bacterial activity in the oxic zones appears to be phosphate limited. Although the system is partially isolated from the overlying marine ecosystem, organic input from above drives the bacterial anaerobic ecosystem, resulting in a sulfide pump. In this model, sulfide percolates up through the karst and removes oxygen from the overlying sediment, which has likely caused changes in the shallow benthic ecosystem. Jewfish Sink appears to be part of an extensive anoxic subterranean estuary that extends under parts of at least three coastal counties in Florida and can serve as a model for the effects of rising sea levels or aquifer mining

Late Quaternary intensified monsoon phases control landscape evolution in the northwest Himalaya, 2005,
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Bookhagen B, Thiede Rc, Strecker Mr,
The intensity of the Asian summer-monsoon circulation varies over decadal to millennial time scales and is reflected in changes in surface processes, terrestrial environments, and marine sediment records. However, the mechanisms of long-lived (2-5 k.y.) intensified monsoon phases, the related changes in precipitation distribution, and their effect on landscape evolution and sedimentation rates are not yet well understood. The arid high-elevation sectors of the orogen correspond to a climatically sensitive zone that currently receives rain only during abnormal (i.e., strengthened) monsoon seasons. Analogous to present-day rainfall anomalies, enhanced precipitation during an intensified monsoon phase is expected to have penetrated far into these geomorphic threshold regions where hillslopes are close to the angle of failure. We associate landslide triggering during intensified monsoon phases with enhanced precipitation, discharge, and sediment flux leading to an increase in pore-water pressure, lateral scouring of rivers, and oversteepening of hillslopes, eventually resulting in failure of slopes and exceptionally large mass movements. Here we use lacustrine deposits related to spatially and temporally clustered large landslides (>0.5 km3) in the Sutlej Valley region of the northwest Himalaya to calculate sedimentation rates and to infer rainfall patterns during late Pleistocene (29-24 ka) and Holocene (10-4 ka) intensified monsoon phases. Compared to present-day sediment-flux measurements, a fivefold increase in sediment-transport rates recorded by sediments in landslide-dammed lakes characterized these episodes of high climatic variability. These changes thus emphasize the pronounced imprint of millennial-scale climate change on surface processes and landscape evolution

Weathering, geomorphic work, and karst landscape evolution in the Cave City groundwater basin, Mammoth Cave, Kentucky, 2005,
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Groves C. , Meiman J. ,
Following the pioneering work of Wolman and Miller [Wolman, M.G., Miller, J.P., 1960. Magnitude and frequency of forces in geomorphic processes. J. Geol., 68, 54-74.] in evaluation of geomorphic work and the frequencies and magnitudes of forces that drive it, a large number of quantitative studies have focused on the evolution of fluvial systems and transport of elastic sediment. Less attention has been given to understanding frequencies and magnitudes of processes in rock weathering, including investigation of rates at which solutes are removed from landscapes under various flow distributions as an analog to Wolman and Miller's [Wolman, M.G., Miller, J.P., 1960. Magnitude and frequency of forces in geomorphic processes. J. Geol., 68, 54-74.] concept of geomorphic work. In this work, we use I year of high-resolution flow and chemical data to examine the work done in landscape evolution within and at the outlet of Kentucky's Cave City Basin, a well-developed karst landscape/aquifer system that drains about 25 km(2). We consider both removal of solutes contributing to landscape denudation based on calcium mass flux as well as predicted dissolution rates of the conduit walls at the outlet of this basin based on limestone dissolution kinetics. Intense, short-duration events dominate. Storms that filled the Logsdon River conduit occurred < 5% of the year but were responsible for 38% of the dissolved load leaving the system and from 63% to 100% of conduit growth for various scenarios of sediment influence. Landscape denudation is a linear function of the amount of water moving through the system, but conduit growth rates, and thus rates of recharge area evolution from fluvial to karst surface landscapes, depend both on the amount of water available and the distribution of precipitation. © 2004 Published by Elsevier B.V

Land use change and soil nutrient transformations in the Los Haitises region of the Dominican Republic, 2005,
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Templer P. H. , Groffman P. M. , Flecker A. S. , Power A. G. ,
We characterized soil cation, carbon (C) and nitrogen (N) transformations within a variety of land use types in the karst region of the northeastern Dominican Republic. We examined a range of soil pools and fluxes during the wet and dry seasons in undisturbed forest, regenerating forest and active agricultural sites within and directly adjacent to Los Haitises National Park. Soil moisture, soil organic matter (SOM), soil cations, leaf litter C and pH were significantly greater in regenerating forest sites than agricultural sites, while bulk density was greater in active agricultural sites. Potential denitrification, microbial biomass C and N, and microbial respiration g(-1) dry soil were significantly greater in the regenerating forest sites than in the active agricultural sites. However, net mineralization, net nitrification, microbial biomass C, and microbial respiration were all significantly greater in the agricultural sites on g(-1) SOM basis. These results suggest that land use is indirectly affecting microbial activity and C storage through its effect on SOM quality and quantity. While agriculture can significantly decrease soil fertility, it appears that the trend can begin to rapidly reverse with the abandonment of agriculture and the subsequent regeneration of forest. The regenerating forest soils were taken out of agricultural use only 5-7 years before our study and already have soil properties and processes similar to an undisturbed old forest site. Compared to undisturbed mogote forest sites, regenerating sites had smaller amounts of SOM and microbial biomass N, as well as lower rates of microbial respiration, mineralization and nitrification g(-1) SOM. Initial recovery of soil pools and processes appeared to be rapid, but additional research must be done to address the long-term rate of recovery in these forest stands. (C) 2004, Elsevier Ltd. All rights reserved

Reactive transport modeling and hydrothermal karst genesis: The example of the Rocabruna barite deposit (Eastern Pyrenees), 2006,
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Corbella M, Ayora C, Cardellach E, Soler A,
In western Europe and North Africa, many sulfide and barite deposits appear to be related to the pre-Triassic paleosurface. Some of these mineralizations have traditionally been interpreted as the result of mineral fillings of previously formed karstic cavities. However, reactive transport modeling suggests that those minerals may have originated at depth and simultaneous with the cavity in the carbonate rocks. Numerical simulations using the Rocabruna deposit as an example recreate the genesis of such cavities and their filling by new minerals in a hydrothermal environment. Two warm (T = 150 [deg]C) fluids with different compositions but both saturated with dolomite were allowed to mix at a fracture intersection; the resulting solution strongly corroded the dolomite host rock and was able to create large voids in a hundred thousand year time scale. Our results show that equidimensional cavities originate from mixtures with equal fluxes of the contributing fluids, but elongated dissolution zones appear when the flux ratios were different from unity and the slowest flow direction coincided with the longest dimension of the void. Moreover, when the fluid mixture was dominated by a diluted and slightly alkaline groundwater instead of a 50-50 mixture with an acidic brine, dolomite dissolution or corrosion was more effective. Sulfide minerals precipitate around cavity walls replacing the host dolostone as the dolomite dissolution reaction couples with that of sulfide precipitation. This coupling produces some porosity, which is negligible compared to that caused by the mixing itself. Barite may also precipitate inside the forming cavity, but as the sulfate mineral precipitation reaction is not coupled with that of dolomite dissolution, barite grows in open space

Methane discharge into the Black Sea and the global ocean via fluid flow through submarine mud volcanoes, 2006,
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Wallmann Klaus, Drews Manuela, Aloisi Giovanni, Bohrmann Gerhard,
During the MARGASCH cruise M52/1 in 2001 with RV Meteor we sampled surface sediments from three stations in the crater of the Dvurechenskii mud volcano (DMV, located in the Sorokin Trough of the Black Sea) and one reference station situated 15[no-break space]km to the northeast of the DMV. We analysed the pore water for sulphide, methane, alkalinity, sulphate, and chloride concentrations and determined the concentrations of particulate organic carbon, carbonate and sulphur in surface sediments. Rates of anaerobic oxidation of methane (AOM) were determined using a radiotracer (14CH4) incubation method. Numerical transport-reaction models were applied to derive the velocity of upward fluid flow through the quiescently dewatering DMV, to calculate rates of AOM in surface sediments, and to determine methane fluxes into the overlying water column. According to the model, AOM consumes 79% of the average methane flux from depth (8.9 [middle dot] 10 6[no-break space]mol a- 1), such that the resulting dissolved methane emission from the volcano into the overlying bottom water can be determined as 1.9 [middle dot] 10 6[no-break space]mol a- 1. If it is assumed that all submarine mud volcanoes (SMVs) in the Black Sea are at an activity level like the DMV, the resulting seepage represents less than 0.1% of the total methane flux into this anoxic marginal sea. The new data from the DMV and previously published studies indicate that an average SMV emits about 2.0 [middle dot] 10 6[no-break space]mol a- 1 into the ocean via quiescent dewatering. The global flux of dissolved methane from SMVs into the ocean is estimated to fall into the order of 10 10[no-break space]mol a- 1. Additional methane fluxes arise during periods of active mud expulsion and gas bubbling occurring episodically at the DMV and other SMVs

Sedimentary manganese metallogenesis in response to the evolution of the Earth system, 2006,
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Roy Supriya,
The concentration of manganese in solution and its precipitation in inorganic systems are primarily redox-controlled, guided by several Earth processes most of which were tectonically induced. The Early Archean atmosphere-hydrosphere system was extremely O2-deficient. Thus, the very high mantle heat flux producing superplumes, severe outgassing and high-temperature hydrothermal activity introduced substantial Mn2 in anoxic oceans but prevented its precipitation. During the Late Archean, centered at ca. 2.75[no-break space]Ga, the introduction of Photosystem II and decrease of the oxygen sinks led to a limited buildup of surface O2-content locally, initiating modest deposition of manganese in shallow basin-margin oxygenated niches (e.g., deposits in India and Brazil). Rapid burial of organic matter, decline of reduced gases from a progressively oxygenated mantle and a net increase in photosynthetic oxygen marked the Archean-Proterozoic transition. Concurrently, a massive drawdown of atmospheric CO2 owing to increased weathering rates on the tectonically expanded freeboard of the assembled supercontinents caused Paleoproterozoic glaciations (2.45-2.22[no-break space]Ga). The spectacular sedimentary manganese deposits (at ca. 2.4[no-break space]Ga) of Transvaal Supergroup, South Africa, were formed by oxidation of hydrothermally derived Mn2 transferred from a stratified ocean to the continental shelf by transgression. Episodes of increased burial rate of organic matter during ca. 2.4 and 2.06[no-break space]Ga are correlatable to ocean stratification and further rise of oxygen in the atmosphere. Black shale-hosted Mn carbonate deposits in the Birimian sequence (ca. 2.3-2.0[no-break space]Ga), West Africa, its equivalents in South America and those in the Francevillian sequence (ca. 2.2-2.1[no-break space]Ga), Gabon are correlatable to this period. Tectonically forced doming-up, attenuation and substantial increase in freeboard areas prompted increased silicate weathering and atmospheric CO2 drawdown causing glaciation on the Neoproterozoic Rodinia supercontinent. Tectonic rifting and mantle outgassing led to deglaciation. Dissolved Mn2 and Fe2 concentrated earlier in highly saline stagnant seawater below the ice cover were exported to shallow shelves by transgression during deglaciation. During the Sturtian glacial-interglacial event (ca. 750-700[no-break space]Ma), interstratified Mn oxide and BIF deposits of Damara sequence, Namibia, was formed. The Varangian ([identical to] Marinoan; ca. 600[no-break space]Ma) cryogenic event produced Mn oxide and BIF deposits at Urucum, Jacadigo Group, Brazil. The Datangpo interglacial sequence, South China (Liantuo-Nantuo [identical to] Varangian event) contains black shale-hosted Mn carbonate deposits. The Early Paleozoic witnessed several glacioeustatic sea level changes producing small Mn carbonate deposits of Tiantaishan (Early Cambrian) and Taojiang (Mid-Ordovician) in black shale sequences, China, and the major Mn oxide-carbonate deposits of Karadzhal-type, Central Kazakhstan (Late Devonian). The Mesozoic period of intense plate movements and volcanism produced greenhouse climate and stratified oceans. During the Early Jurassic OAE, organic-rich sediments host many Mn carbonate deposits in Europe (e.g., Urkut, Hungary) in black shale sequences. The Late Jurassic giant Mn Carbonate deposit at Molango, Mexico, was also genetically related to sea level change. Mn carbonates were always derived from Mn oxyhydroxides during early diagenesis. Large Mn oxide deposits of Cretaceous age at Groote Eylandt, Australia and Imini-Tasdremt, Morocco, were also formed during transgression-regression in greenhouse climate. The Early Oligocene giant Mn oxide-carbonate deposit of Chiatura (Georgia) and Nikopol (Ukraine) were developed in a similar situation. Thereafter, manganese sedimentation was entirely shifted to the deep seafloor and since ca. 15[no-break space]Ma B.P. was climatically controlled (glaciation-deglaciation) assisted by oxygenated polar bottom currents (AABW, NADW). The changes in climate and the sea level were mainly tectonically forced

Quantifying submarine groundwater discharge in the coastal zone via multiple methods, 2006,
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Burnett Wc, Aggarwal Pk, Aureli A, Bokuniewicz H, Cable Je, Charette Ma, Kontar E, Krupa S, Kulkarni Km, Loveless A,
Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of near-shore waters. These discharges typically display significant spatial and temporal variability making assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise.A joint project of UNESCO and the International Atomic Energy Agency (IAEA) has examined several methods of SGD assessment and carried out a series of five intercomparison experiments in different hydrogeologic environments (coastal plain, karst, glacial till, fractured crystalline rock, and volcanic terrains). This report reviews the scientific and management significance of SGD, measurement approaches, and the results of the intercomparison experiments. We conclude that while the process is essentially ubiquitous in coastal areas, the assessment of its magnitude at any one location is subject to enough variability that measurements should be made by a variety of techniques and over large enough spatial and temporal scales to capture the majority of these changing conditions.We feel that all the measurement techniques described here are valid although they each have their own advantages and disadvantages. It is recommended that multiple approaches be applied whenever possible. In addition, a continuing effort is required in order to capture long-period tidal fluctuations, storm effects, and seasonal variations

Anthropogenic CO2-flux into cave atmosphere and its environmental impact: A case study in the Cisarska Cave (Moravian Karst, Czech Republic), 2006,
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Faimon J, Stelcl J, Sas D,
The evolution of CO2 levels was studied in the ventilated and unventilated Nagel Dome chamber (the Cisarska Cave) with- and without human presence. Based on a simplified dynamic model and CO2/Rn data (222Rn considered as a conservative tracer), two types of CO2-fluxes into the chamber were distinguished: (1) the natural input of (2-4) x 10- 6[no-break space]m3 s- 1, corresponding to a flux of (8.5-17) x 10- 10[no-break space]m3 m- 2 s- 1 and (2) an anthropogenic input of (0.6-2.5) x 10- 4[no-break space]m3 s- 1, corresponding to an average partial flux of (4.8-7.7) x 10- 6[no-break space]m3 s- 1 person- 1. The chamber ventilation rates were calculated in the range from 0.033 to 0.155[no-break space]h- 1. Comparison of the chamber CO2-levels with chamber dripwater chemistry indicates that the peak CO2-concentrations during stay of persons (log pCO2 ~ - 2.97, - 2.89, and - 2.83) do not reach the theoretical values at which dripwater carbonate species and air CO2 are at equilibrium (log pCO2[DW] ~ - 2.76 to - 2.79). This means that CO2-degassing of the dripwaters will continue, increasing supersaturation with respect to calcite (dripwater saturation index defined as SIcalcite = aCa2? / 10- 8.4 varied in the range from 0.76 to 0.86). The pCO2[DW] values, however, would easily be exceeded if the period of person stay in the chamber had been slightly extended (from 2.85 to 4[no-break space]h under given conditions). In such case, the dripwater CO2-degassing would be inverted into CO2-dissolution and dripwater supersaturation would decrease. Achieving the threshold values at which water become aggressive to calcite (log pCO2[EK] ~ - 1.99, - 2.02, and - 1.84) would require extreme conditions, e.g., simultaneous presence of 100 persons in the cave chamber for 14[no-break space]h. The study should contribute to a better preservation of cave environment

Identifying Late Miocene episodes of connection and isolation in the Mediterranean-Paratethyan realm using Sr isotopes, 2006,
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Flecker R, Ellam Rm,
After decades of research, the timing and nature of Late Miocene connections between the Mediterranean, Paratethys and the global ocean are still speculative. The hydrologic flux implications of exchange or isolation are central to all hypotheses for generating the major lithological changes that represent the Messinian Salinity Crisis. Moreover, differences in the hydrologic fluxes envisaged are the primary distinction between models. Despite this, these fluxes remain largely unconstrained. This paper describes the basis for using Sr isotope data innovatively combined with salinity data through hydrologic budget modelling to determine the timing and nature of Mediterranean hydrologic connectivity. We examine the hypotheses for three Late Miocene events to illustrate how this approach allows us to test implied hydrologic scenarios and exclude incompatible models. 1) Pre-evaporite restriction of the Mediterranean; 2) the initiation of salt precipitation; 3) connection between the Sea of Marmara and both Paratethys and the Mediterranean during the Messinian. This process suggests that the Atlantic-Mediterranean exchange was significantly reduced up to three million years before evaporite precipitation. It also indicates that end-member hypotheses for initiating salt precipitation in the Mediterranean (desiccation and connected basin models) are inconsistent with Sr isotope data. A contrasting model where evaporite formation was triggered by Atlantic transgression into a strongly evaporation-dominated Mediterranean is shown to be more compatible with available datasets. The application to Sea of Marmara samples indicates that salinity changes in the basin were not caused by changes to the amount of inflow from either Paratethys or the Mediterranean. Other possible as yet untested applications important for constraining different aspects of the Messinian Salinity Crisis are highlighted

A conceptual model of the flow and distribution of organic carbon in caves, 2007,
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Simon K. S. , Pipan T. , And Culver D. C.
We present a conceptual model for the movement of organic carbon in karst. We argue that the drainage basin is the most appropriate unit for analyzing energy flux in karst. There are two main inputs in karst basins: 1) localized flow of particulate organic carbon (POC) and dissolved organic carbon (DOC) through sinks and shafts and 2) diffuse flow of POC and DOC from soils and epikarst. After entry, this organic matter is processed and transported before eventual loss through respiration or export from the basin. To begin parameterizing our conceptual model, we estimated carbon fluxes for the first two inputs for two karst basins (Organ Cave in West Virginia and Postojna-Planina Cave System (PPCS) in Slovenia) that have sinking streams and many active epikarst drips. We made a series of measurements of organic carbon, especially DOC in epikarst drip water, cave streams, surface streams sinking into the cave, and at resurgences, which we combined with other published data. In both caves, most of the organic carbon entering through the epikarst was DOC, at concentrations averaging around 1 mg C L21. In both basins, sinking streams accounted for the large majority of DOC input. It is likely that considerable processing of organic carbon occurs within both caves, but more detailed measurements of organic carbon flux at both the basin and stream scale are needed.

Time scales in the evolution of solution porosity in porous coastal carbonate aquifers by mixing corrosion in the saltwater-freshwater transition zone, 2007,
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Dreybrodt W. , Romanov D.

Dissolution of calcium carbonate in the saltwater-freshwater mixing zone of coastal carbonate aquifers up to now has been treated by coupling geochemical equilibrium codes to a reactive- transport model. The result is a complex nonlinear coupled set of differential transport-advection equations, which need high computational efforts. However, if dissolution rates of calcite are sufficiently fast, such that one can assume the solution to be in equilibrium with respect to calcite a highly simplified modelling approach can be used. To calculate initial changes of porosity in the rock matrix one only needs to solve the advection-transport equation for salinity s in the freshwater lens and its transition zone below the island. Current codes on density driven flow such as SEAWAT can be used. To obtain the dissolution capacity of the mixed saltwater-freshwater solutions the calcium equilibrium concentration ceq(s) is obtained as a function of salinity by PHREEQC-2. Initial porosity changes can then be calculated by a simple analytical expression of the gradient of the spatial distribution s(x, y) of salinity, the distribution of flow fluxes q(x,y) and the second derivative of the calcium equilibrium concentration ceq(s) with respect to salinity s. This modelling approach is employed to porosity evolution in homogeneous and heterogeneous carbonate islands and coastal aquifers. The geometrical patterns of porosity changes and the reasons of their origin will be discussed in detail. The results reveal initial changes of porosity in the order of several 10-6 per year. This places the time scale of cavern evolution to orders from several tens of thousands to a hundred thousand years.


Hydrogeologic Characterization and Methods Used in the Investigation of Karst Hydrology, 2008,
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Taylor Ch. J. , Greene E. A.


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