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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 mexican onyx is see onyx marble.?

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 scenario (Keyword) returned 76 results for the whole karstbase:
Showing 16 to 30 of 76
Constraints on Black Sea outflow to the Sea of Marmara during the last glacial-interglacial transition, 2002,
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Major Candace, Ryan William, Lericolais Gilles, Hajdas Irka,
New cores from the upper continental slope off Romania in the western Black Sea provide a continuous, high-resolution record of sedimentation rates, clay mineralogy, calcium carbonate content, and stable isotopes of oxygen and carbon over the last 20[punctuation space]000 yr in the western Black Sea. These records all indicate major changes occurring at 15[punctuation space]000, 12[punctuation space]800, 8400, and 7100 yr before present. These results are interpreted to reflect an evolving balance between water supplied by melting glacial ice and other river runoff and water removed by evaporation and outflow. The marked retreat of the Fennoscandian and Alpine ice between 15[punctuation space]000 and 14[punctuation space]000 yr is recorded by an increase in clays indicative of northern provenance in Black Sea sediments. A short return toward glacial values in all the measured series occurs during the Younger Dryas cold period. The timing of the first marine inflow to the Black Sea is dependent on the sill depths of the Bosporus and Dardanelles channels. The depth of the latter is known to be -805 m, which is consistent with first evidence of marine inundation in the Sea of Marmara around 12[punctuation space]000 yr. The bedrock gorge of the Bosporus reaches depths in excess of -100 m (relative to present sea level), though it is now filled with sediments to depths as shallow as -32 m. Two scenarios are developed for the connection of the Black Sea with the Sea of Marmara. One is based on a deep Bosporus sill depth (effectively equivalent to the Dardanelles), and the other is based on a shallow Bosporus sill (less than -35 m). In the deep sill scenario the Black Sea's surface rises in tandem with the Sea of Marmara once the latter connected with the Aegean Sea, and Black Sea outflow remains continuous with inflowing marine water gradually displacing the freshwater in the deep basin. The increase in the [delta]18O of mollusk shells at 12[punctuation space]800 yr and the simultaneous appearance of inorganic calcite with low [delta]18O is compatible with such an early marine water influx causing periodic weak stratification of the water column. In the shallow sill scenario the Black Sea level is decoupled from world sea level and experiences rise and fall depending on the regional water budget until water from the rising Sea of Marmara breaches the shallow sill. In this case the oxygen isotope trend and the inorganic calcite precipitation is caused by increased evaporation in the basin, and the other changes in sediment properties reflect climate-driven river runoff variations within the Black Sea watershed. The presence of saline ponds on the Black Sea shelf circa 9600 yr support such evaporative draw-down, but a sensitive geochemical indicator of marine water, one that is not subject to temperature, salinity, or biological fractionation, is required to resolve whether the sill was deep or shallow

Dam sites in soluble rocks: a model of increasing leakage by dissolutional widening of fractures beneath a dam, 2003,
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Romanov D. , Gabrovsek F. , Dreybrodt W. ,
Water flowing through narrow fissures and fractures in soluble rock, e.g. limestone and gypsum, widens these by chemical dissolution. This process, called karstification, sculptures subterranean river systems which drain most of their catchment. Close to dam sites, unnaturally high hydraulic gradients are present to drive the water impounded in the reservoir downstream through fractures reaching below the dam. Under such conditions, the natural process of karstification is accelerated to such an extent that high leakage rates may arise, which endanger the operation of the hydraulic structure. Model simulations of karstification below dams by coupling equations of dissolutional widening to hydrodynamic flow are presented. The model scenario is a dam 100 in wide in limestone or gypsum. The modelling domain is a two-dimensional slice 1 m wide directed perpendicular to the dam. It extends 375 in vertically and 750 in horizontally. The dam is located in its center. This domain is divided by fractures and fissures into blocks of 7.5 x 7.5 x 1 m. The average aperture width of the fractures is 0.02 cm. We performed model runs on standard scenarios for a dam site in limestone with the height H of impounded water 150 in, a horizontal impermeable apron of width W=262 m and a grouting curtain reaching down to a depth of G=97 m. In a second scenario, we changed these construction features to G=187 m and W=82 m. To calculate widening of the fractures, well-established experimental data on the dissolution of limestone and gypsum have been used as they occur in such geochemical settings. All model runs show similar characteristic behaviour. Shortly after filling, the reservoir exhibits a small leakage of about 0.01 m(-3) s(-1), which increases steadily until a breakthrough event occurs after several decades with an abrupt increase of leakage to about 1 m(3) s(-1) within the short time of a few years. Then, flow in the fractures becomes turbulent and the leakage increases to 10 m(3) s(-1) in a further time span of about 10 years. The widths of the fractures are visualized in various time steps. Small channels propagate downstream and leakage rises slowly until the first channel reaches the surface downstream. Then breakthrough occurs, the laminar flow changes to turbulent and a dense net of fractures which carry flow is established. We performed a sensitivity analysis on the dependence of breakthrough times on various parameters, determining breakthrough. These are the height of impounded water H, the depth G of grouting, the average aperture width a(0) of the fractures and the chemical parameters, which are c(eq) the equilibrium concentration of Ca with respect to calcite and the Ca-concentration c(in) of the inflowing water. The results show that the most critical parameter is a(0). At fracture aperture widths of 0.01 cm, breakthrough times are above 500 years. For values of a(0)>0.02 cm, however, breakthrough times are within the lifetime of the structure. We have also modelled dam sites in gypsum, which exhibit similar breakthrough times. However, after breakthrough, owing to the much larger dissolution rates of gypsum, the time until unbearable leakage is obtained, is only a few years. The modelling can be applied to complex geological settings, as phreatic cave conduits below the dam, or a complex stratigraphy with varying properties of the rock with respect to hydraulic conductivity and solubility. A few examples are given. In conclusion, our results support the assumption that increasing leakage of dam sites may be caused by dissolutional widening of fractures. (C) 2003 Elsevier Science B.V. All rights reserved

A deterministic approach to the coupled analysis of karst springs' hydrographs and chemographs, 2003,
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Grasso D. A. , Jeannin P. Y. , Zwahlen F. ,
During the chemically based recession flow phase of karstic springs the carbonate (dissolved limestone) concentration can be expressed as negative power of the flow rate. The empirically determined Conc/Q relationship allows two parameters (alpha and A) to be defined, of which one (alpha) depends on the geometric dimensions of the saturated (submerged) karstic network. In this paper we present a deterministic model which simulates the concentration of carbonate at the outlet of a network of circular rectilinear conduits as a function of flow rate. This model, based on hydraulic principles and the calcite dissolution kinetics, allows the sensitivity of the alpha and A parameters to be studied under different chemical, physical and geometric scenarios. Simulation results show that A is a function of the calcite saturation concentration, whereas alpha depends on the spatial dimensions of the karstic network (void length and aperture). The deterministic model results were applied to real karstic systems to evaluate the geometric dimensions of submerged karstic networks. (C) 2002 Elsevier Science B.V. All rights reserved

Hydraulic calculations of postglacial connections between the Mediterranean and the Black Sea, 2003,
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Myers Paul G. , Wielki Chris, Goldstein Shoshana B. , Rohling Eelco J. ,
A series of simple hydraulic calculations has been performed to examine some of the questions associated with the reconnection of the Black Sea to the Mediterranean through the Turkish Strait System during the Holocene. Ryan et al.'s catastrophic flood scenario, whereby the erosive power of the marine in-fluxes, initiated after eustatic sea level reached the sill depth, opened up the Bosphorus, allowing saline water to pour into the Black Sea and filling it on a short time scale, is examined. The calculations show that although it might be possible to fill the palaeo-Black Sea within the order of a decade, a 1-2 year filling time scale is not physically possible. A hydraulic model is also used to examine the more traditional connection hypothesis of (near-)continuous freshwater outflow from the Black Sea, with a slowly increasing saline inflow from the Mediterranean beginning around 8-9 kyr BP. The model considers two forms for the structure of the Bosphorus: a shallow sill as seen today and a deep sill associated with no sediments filling the 100 m gorge above the bedrock in the strait. Sensitivity experiments with the hydraulic model show what possible strait geometric configurations may lead to the Black Sea reaching its present-day salinity of 18 psu. Salinity transients within the Black Sea are shown as a function of time, providing for values that can be validated against estimates from cores. To consider a deep, non-sediment-filled Bosphorus (100 m deep), the entry of Mediterranean water into the Sea of Marmara after 12.0 kyr BP is examined. A rapid entry of marine water into the Sea of Marmara is only consistent with small freshwater fluxes flowing through the Turkish Strait System, smaller than those of the present day by a factor of at least 4. Such a small freshwater flux would lead to the salinification of the Black Sea being complete by an early date of 10.2-9.6 kyr BP. Thus the possibility of a deep Bosphorus sill should be discounted

A nonlinear rainfall-runoff model using neural network technique: Example in fractured porous media, 2003,
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Lallahem S. , Mania J. ,
One of the more advanced approaches for simulating groundwater flow in karstic and fractured porous media is the combination of a linear and a nonlinear model. The paper presents an attempt to determine outflow influencing parameters in order to simulate aquifer outflow. Our approach in this study is to create a productive interaction system between expert, mathematical model, MERO,. and artificial neural networks (ANNs). The proposed method is especially suitable for the problem of large-scale and long-term simulation. In the present project, the first objective is to determine aquifer outflow influencing parameters by the use of MERO model, which gave a good results in a fissured and chalky media, and then introduce these parameters in neural network (NN). To determine outflow influencing parameters, we propose to test the NN under fourth different external input scenarios. The second objective is to investigate the effect of temporal information by taking current and past data sets. The good found results reveal the merit of ANNs-MERO combination and specifically multilayer perceptron (MLP) models. This methodology provided that the network with lower, lag and number hidden layer, consistently produced better performance. (C) 2003 Elsevier Science Ltd. All rights reserved

Modeling of karst aquifer genesis: Influence of exchange flow, 2003,
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Bauer S, Liedl R, Sauter M,
[1] This paper presents a numerical model study simulating the early karstification of a single conduit embedded in a fissured system. A hybrid continuum-discrete pipe flow model (CAVE) is used for the modeling. The effects of coupling of the two flow systems on type and duration of early karstification are studied for different boundary conditions. Assuming fixed head boundaries at both ends of the conduit, coupling of the two flow systems via exchange flow between the conduit and the fissured system leads to an enhanced evolution of the conduit. This effect is valid over a wide range of initial conduit diameters, and karstification is accelerated by a factor of about 100 as compared to the case of no exchange flow. Parameter studies reveal the influence of the exchange coefficient and of the hydraulic conductivity of the fissured system on the development time for the conduit. In a second scenario the upstream fixed head boundary is switched to a fixed flow boundary at a specified flow rate during the evolution, limiting the amount of water draining toward the evolving conduit. Depending on the flow rate specified, conduit evolution may be slowed down or greatly impaired if exchange flow is considered

Simulation of the development of karst aquifers using a coupled continuum pipe flow model - art. no. 1057, 2003,
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Liedl R. , Sauter M. , Huckinghaus D. , Clemens T. , Teutsch G. ,
[1] This paper is intended to provide insight into the controlling mechanisms of karst genesis based on an advanced modeling approach covering the characteristic hydraulics in karst systems, the dissolution kinetics, and the associated temporal decrease in flow resistance. Karst water hydraulics is strongly governed by the interaction between a highly conductive low storage conduit network and a low-conductive high-storage rock matrix under variable boundary conditions. Only if this coupling of flow mechanisms is considered can an appropriate representation of other relevant processes be achieved, e.g., carbonate dissolution, transport of dissolved solids, and limited groundwater recharge. Here a parameter study performed with the numerical model Carbonate Aquifer Void Evolution (CAVE) is presented, which allows the simulation of the genesis of karst aquifers during geologic time periods. CAVE integrates several important features relevant for different scenarios of karst evolution: (1) the complex hydraulic interplay between flow in the karst conduits and in the small fissures of the rock matrix, (2) laminar as well as turbulent flow conditions, (3) time-dependent and nonuniform recharge to both flow systems, (4) the widening of the conduits accounting for appropriate physicochemical relationships governing calcite dissolution kinetics. This is achieved by predefining an initial network of karst conduits ('protoconduits'') which are allowed to grow according to the amount of aggressive water available due to hydraulic boundary conditions. The increase in conduit transmissivity is associated with an increase in conduit diameters while the conductivity of the fissured system is assumed to be constant in time. The importance of various parameters controlling karst genesis is demonstrated in a parameter study covering the recharge distribution, the upgradient boundary conditions for the conduit system, and the hydraulic coupling between the conduit network and the rock matrix. In particular, it is shown that conduit diameters increase in downgradient or upgradient direction depending on the spatial distribution (local versus uniform) of the recharge component which directly enters the conduit system

Evolution of Karst Aquifers in Natural and Man Made Environments: A Modeling Approach. Ph.D. thesis, 2003,
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Romanov, Douchko

The evolution of karst aquifers under various hydrological and chemical boundary conditions is studied.
In the first part the influence of exchange flow from a prominent fracture into a two-dimensional network of fissures is compared to the evolution of a fracture isolated from this net. The modeling domain is 742.5 m long and 375 m wide dissected by fractures into 100 by 51 blocks. The wide prominent fracture extends along its center, thus constituting a part of the network. Under constant head conditions between the left and the right hand side of the domain it looses flow into the network. We have studied the influence of the fracture widths of the fine net to the breakthrough time (BT) of the system. Because of loss of flow from the central fracture to the net, aggressive solution from the input enhances dissolution and breakthrough times are reduced. This effect is most effective, when the aperture width of the fine net is only smaller by about 1% than the widths of the prominent fracture, such that a large amount of water can flow into the net. To obtain further information on the processes involved, an isolated one-dimensional fracture with an additional single point of outflow from it, is investigated.
As an application of the results above, the evolution of a karst aquifer below dam sites is studied. The modeling domain is a 2D, 1 m wide vertical section of soluble rock (gypsum and limestone), perpendicular to the dam. The block extends 750 m horizontally and 375 m vertically. It is divided by fractures and fissures into blocks of 7.5 m x 7.5 m x 1m. The chemical composition of the inflowing water is equal at all input points. Because of dissolution along the fractures, a large zone of increasing permeability is created below the structure, causing high unbearable water losses from the dam site and also endangering the mechanical stability of the dam. The dependence of BT on the basic parameters - the height of the impounded water, the depth of the grouting curtain, the initial aperture widths of the fractures and the fissures, and the chemical parameters of the inflowing water (equilibrium concentration with respect to calcite and input concentration) is investigated. For fracture aperture widths larger than 0.02 cm breakthrough occurs within the lifetime of the structure.
In the second part the effect of chemical boundary conditions on the evolution of a karst aquifer is studied. The model domain is 500 m x 225 m, divided into blocks of 5 m x 5 m x 1 m by fracture network. There are two input points at constant head (25 m) at the inflow side of the block. The outflow side is open at constant head – 0 m. The hydrological boundaries are equal for all simulated scenarios. The chemical composition of the inflowing water at both inputs is varied, and the reaction of the aquifer is studied. Mixing corrosion is the reason for zones of increased permeability deep inside the aquifer along the boundary, where the solutions mix. The influence of mixing corrosion for various values of the input Ca concentration is studied. The results show two types of evolution. Breakthrough (BT) governed evolution – for values of cin<0.96?ceq, and mixing corrosion (MC) - governed evolution for values of cin>0.96?ceq. The BT - type is characterized by enlarged pathways connecting an inflow point with the outflow boundary. For increasing values of the input concentrations the effect of MC becomes stronger. For high Ca concentrations, MC is dominating. There is no considerably widened connection between the inflow points and the out flow boundary. but an enlarged channel along the mixing zone is observed. The timescale for this type of evolution is considerably longer. For solutions saturated with respect to calcite, the mixing zone is the only area of widening inside the aquifer.

Geomorphic constraints on surface uplift, exhumation, and plateau growth in the Red River region, Yunnan Province, China, 2004,
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Schoenbohm L. M. , Whipple K. X. , Burchfiel B. C. , Chen L. ,
Field observations, digital elevation model (DEM) data, and longitudinal profile analysis reveal a perched low-relief upland landscape in the Red River region, Yunnan Province, China, which correlates to an uplifted, regional low-relief landscape preserved over the eastern margin of the Tibetan Plateau. As with other major rivers of the plateau margin, the Red River has deeply incised the low-relief upland landscape, which we interpret to be the remnants of a pre-uplift or relict landscape. We examine longitudinal river profiles for 97 tributaries of the Red River. Most profiles consist of three segments separated by sharp knickpoints: an upper, low-gradient channel segment, a steeper middle channel segment, and a very steep lower channel segment. Upper channel segments correspond to the relict landscape and have not yet experienced river incision. Steeper middle and lower segments indicate onset of rapid, two-phase river incision, on the basis of which changes in external forcings, such as climate or uplift, can be inferred. In terms of two end-member scenarios, two-phase incision could be the result of pulsed plateau growth, in which relatively slow uplift during the first phase is followed by rapid uplift during the second phase, or it could reflect adjustments of the main channel to changing climate conditions against the backdrop of steady plateau growth. Reconstruction of the paleo-Red River indicates [~]1400 m river incision, 1400-1500 m surface uplift, and a maximum of 750 m vertical displacement across the northern Red River fault, elevating the northern Ailao Shan range above the surrounding relict landscape. On the basis of stratigraphic constraints, incision along the Red River likely began in Pliocene time

Forecasting Versus Predicting Solute Transport in Solution Conduits for Estimating Drinking-Water Risks, 2004,
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Field, Malcolm S.

Contaminant releases in karstic terranes can cause rapid and devastating affects on drinking-water supplies. Because future contaminant releases are likely it is necessary that local water managers develop release scenarios so as to be prepared prior to an actual contaminant release occurring. Release scenarios may be forecasted using appropriate historical data or they may be predicted using selected measured parameters. Forecasting contaminant releases to drinking-water supplies in karstic terranes is best accomplished by conducting numerous tracer tests from each potential source location to each exposure point so that acceptable solute-transport parameters for each solution conduit may be estimated from analyses of the breakthrough curves. Compositing the numerous breakthrough curves and fitting a quintic spline allows development of a single representative breakthrough curve that may then be used to forecast the effects of a release. Predicting contaminant releases is accomplished by combining basic measured field parameters for selected solution conduits in functional relationships for application in solute-transport models. The resulting breakthrough curve and solute-transport parameters can be used to predict the effects of a release. The forecasting and prediction methodologies were tested using a hypothetical release into a solution conduit developed in a karstic aquifer. Both methods were shown to produce reasonably acceptable results. The prediction methodology produced better time-of-travel results and better mass recovery and exposure concentration results than did the forecasting methodology.

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

Modeling the influence of epikarst evolution on karst aquifer genesis: A time-variant recharge boundary condition for joint karst-epikarst development, 2005,
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Bauer S, Liedl R, Sauter M,
The epikarst, a zone of increased weathering near the land surface, determines the distribution of recharge to a karst aquifer in both space and time. It links climatic and near-surface geological conditions with the karstification of a limestone aquifer, defining both the hydraulic and the chemical boundary conditions for the development of the karst system. Realistic modeling of the epikarst is therefore a prerequisite for the simulation of karst aquifer genesis. A conceptual model of the joint karst-epikarst evolution is presented in this paper. An epikarst module is developed and implemented in a numerical continuum-discrete conduit flow model for karst genesis, which accounts for the joint evolution of the epikarst and the main karstic conduit network under unconfined conditions. The influence of epikarst genesis on the evolution of the underlying karst aquifer is investigated in four scenarios. It is found that only the interaction of epikarst and initial heterogeneity in the underlying carbonate rock leads to the development of a dendritic cave system. If no heterogeneity in the initial conduit network or in the recharge distribution is included, maze-type caves develop

Stable isotope investigations on speleothems from different cave systems in Germany, 2005,
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Nordhoff, P.

Seven speleothems from six independent cave systems in Germany were investigated on their suitability as paleoclimatic archives. The caves are located in the Jurassic Limestones of the Swabian/Franconian Alb (southern Germany) and in a small-scale Devonian (reef) complex of the Harz Mountains (northern Germany). Based on the chronological control using 234U/230Th (TIMS) ages, δ18O/δ13C timeseries of the speleothems were established and related to known paleoclimatic events.
Results of the present-day assessment of the cave systems demonstrated that the cave temperature responses; the stable isotopic abundances of the dripwater, and present-day cave calcites reflect mean annual surface air temperatures as well as established isotopic equilibrium conditions during cave calcite precipitation. However, existing biases have been monitored but most of them may be deduced to anthropogenic influences like mining operations (Zaininger-Cave, Swabian Alb) or showcave business (Hermann’s- and Baumann’s-Cave, Harz Mountains). Although the scenarios leave partially an imprint on present-day spelean calcites, like the indicated non-equilibrium conditions at the Zaininger-Cave, their temporal imprint is restricted very much to the last couple of decennial years and thus assumed not to influence the paleorecords at all. Since the δ18O compositions of present-day calcite precipitates are primarily controlled by temperature, the sites may thus be suitable for paleoclimatic investigations from a today perspective.
Since the paleorecords of the Hermann’s- and Baumann’s-Cave stalagmites (Harz Mountains) display ages, which are not in chronological order, a construction of timeseries was not possible.
Past stable isotopic equilibrium conditions of the remaining paleorecords were verified using the single layer “Hendy-Test” as well as δ18O/δ13C regression analyzes of the subsample profiles. Late Pleistocene growth periods were found in the Paleocave Hunas Stalagmite (79373 ± 8237 to 76872 ± 9686 a. B.P.; Franconian Alb) and the Cave Hintere Kohlhalde Stalagmite (44158 ± 3329 to 2709 ± 303 a B.P.; Swabian Alb). Unexpectedly, the latter displays no macroscopic visible growth hiatuses and was deposited continuously during the “cold” OIS 2 and the LGM. This has been interpreted owing to the special conditions and mode of vadose water circulation of a discontinuous permafrost zone which may have prevailed on the Swabian Alb during that time. Here, just like for the subsequent periods, principal changes in mean δ18O/δ13C and linear extension rates of the timeseries echoed the Boelling/Alleroed Interstadial and Younger Dryas cold phase. The comparison of coeval timeseries between the Cave Hintere Kohlhalde stalagmite, the Zaininger-Cave stalactite (both Swabian Alb) and the Mühlbach-Cave stalagmite (Franconian Alb) reveal some analogy such as the transitions from the Late Glacial to the Early Holocene between 10513 and 10587 cal. a B.P. for the Swabian Alb and 10227 cal. a B.P. for the Franconian Alb; the anomaly around 8.2 ka B.P. recorded in the Zaininger- and Mühlbach-Cave; and a climatic deterioration which leads to an almost simultaneous cessation of speleothem growth on the Swabian/Franconian Alb between 2.5 and 2.8 ka B.P.
Important changes of the stable isotopic composition occur together with changes in growth rate and in the macroscopic aspect of the investigated speleothems. This confirms that general climatic and environmental parameters control the recorded variations and that they are not owing to very local factors.

Sensitivity of ancient Lake Ohrid to local anthropogenic impacts and global warming, 2006,
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Matzinger A. , Spirkovski Z. , Patceva S. , Wuest A. ,
Human impacts on the few ancient lakes of the world must be assessed, as any change can lead to an irreversible loss of endemic communities. In such an assessment, the sensitivity of Lake Ohrid (Macedonia/Albania; surface area A = 358 km(2), volume V = 55 km(3), > 200 endemic species) to three major human impacts-water abstraction, eutrophication, and global warming-is evaluated. It is shown that ongoing eutrophication presents the major threat to this unique lake system, even under the conservative assumption of an increase in phosphorus (P) concentration from the current 4.5 to a potential future 9 mg P m(-3). Eutrophication would lead to a significant reduction in light penetration, which is a prerequisite for endemic, deep living plankton communities. Moreover, a P increase to 9 mg P m(-3) would create deep water anoxia through elevated oxygen consumption and increase in the water column stability due to more mineralization of organic material. Such anoxic conditions would severely threaten the endemic bottom fauna. The trend toward anoxia is further amplified by the predicted global warming of 0.04 degrees C yr(-1), which significantly reduces the frequency of complete seasonal deep convective mixing compared to the current warming of 0.006 degrees C yr(-1). This reduction in deep water exchange is triggered by the warming process rather than by overall higher temperatures in the lake. In contrast, deep convective mixing would be even more frequent than today under a higher temperature equilibrium, as a result of the temperature dependence of the thermal expansivity of water. Although water abstraction may change local habitats, e.g., karst spring areas, its effects on overall lake properties was shown to be of minor importance

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

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