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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 Reynolds number is a numerical quantity used as an index to characterize the type of flow in a hydraulic structure in which resistance to motion depends on the viscosity of the liquid in conjunction with the resisting force of inertia. it is the ratio of inertia forces to viscous forces, and is equal to the product of a characteristic velocity of the system (e.g. the mean, surface, or maximum velocity) and a characteristic linear dimension, such as diameter or depth, divided by the kinematic viscosity of the liquid; all expressed in consistent units in order that the combinations will be dimensionless. the number is chiefly applicable to closed systems of flow, such as pipes or conduits where there is a free water surface, or to bodies fully immersed in the fluid so the free surface need not be considered [1]. see also chezy equation; froude number; manning equation.?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for signal (Keyword) returned 95 results for the whole karstbase:
Showing 31 to 45 of 95
Localization of saturated karst aquifer with magnetic resonance sounding and resistivity imagery, 2003, Vouillamoz J. M. , Legchenko A. , Albouy Y. , Bakalowicz M. , Baltassat J. M. , Alfares W. ,
To answer one of the main questions of hydrogeologists implementing boreholes or working on pollution questions in a karst environment-i.e., where is the ground water?-numerous tools including geophysics are used. However, the contribution of geophysics differs from one method to the other. The magnetic resonance sounding (MRS) method has the advantage of direct detection of ground water over other geophysical methods. Eight MRSs were implemented over a known karst conduit explored and mapped by speleologists to estimate the MRS ability to localize ground water. Two direct current resistivity imageries (DC-2D imagery) were also implemented to check their capability to map a known cave. We found that the MRS is a useful tool to locate ground water in karst as soon as the quantity of water is enough to be detected. The threshold quantity is a function of depth and it was estimated by forward modeling to propose a support graph to hydrogeologists. The measured MRS's signals could be used to calculate transmissivity and permeability estimators. These estimators were used to map and to draw a cross section of the case study site, which underline accurately the known karst conduit location and depth. We also found that the DC-2D imagery could underline the karst structures: It was able to detect the known cave through its associated faults. We prepared a computer simulation to check the depth of such a cave to induce resistivity anomaly which could be measured in similar conditions

'Canons' revisited and reviewed: Lester King's views of landscape evolution considered 50 years later, 2003, Twidale C. R. ,
Fifty years after its publication, Lester King's Canons of Landscape Evolution is reviewed and is considered in light of subsequent trends and actual developments. Some of his ideas, such as the role of scarp recession and the antiquity of some surfaces, remain current. His broad view of the world and his interest in major relief anticipated trends that are now fashionable. Some of his interpretations, however, and in particular his downgrading of the importance of structural factors and his linking of scarp retreat and pedimentation, have not stood the test of time. Other concepts, such as the etch or two-stage origin of forms, which were mooted but not fully appreciated in King's day, have come to the forefront, and technological advances in dating and survey, particularly of the ocean floors, have signaled new perspectives in landscape interpretation. Nevertheless, King's was a courageous attempt to provide guidelines for landscape study

Assessment of direct transfer and resuspension of particles during turbid floods at a karstic spring, 2003, Massei N. , Wang H. Q. , Dupont J. P. , Rodet J. , Laignel B. ,
Turbid water can be the source of important sanitary problems in karstic regions. It is the case of the Pays de Caux, in Haute Normandie, where the main resource in drinking water is provided by the chalk aquifer. In the case of the typical binary karst of the Pays de Caux, turbidity results from the input in sinkholes of turbid surface water induced by erosion on the plateaus. At some spring tappings, water may be very turbid in period of intense rainfall. The turbidity observed at a karstic spring is a complex signal which contains a part of direct transfer and a part of resuspension of the particles being transported. The aim of this study is turbidigraph separation, which would permit to distinguish the direct transfer and resuspension components of the turbidigraph. These two components are separated by comparing the elementary surface storm-derived water fluxes and elementary turbidity signals at the spring. The procedure takes place in three phases: (i) spring hydrograph separation by means of a two components mixing model (surface water and karstic groundwater) using specific electrical conductivity, (ii) decomposition of storm-derived water flux and turbidity thanks to the second-derivative method, (iii) comparison of the transfer times (approximate tomodal times) of the elementary turbidity and surface water flux signals, respectively. The mass corresponding to direct transfer, computed after signal decomposition, is then used to re-calculate a particle recovery rate, which passes so from 514 to 373%. Relations between particle flux and hydrodynamics show that resuspension can be either the fact of the dynamics of the introduction system, or that of the chalk karstic aquifer in general (case of resuspension not associated to surface water flux). In this sense, evolution of particle flux (and consequently of turbidity) can be also a marker of the karst structure. (C) 2003 Elsevier Science B.V. All rights reserved

Epikarst storage in a karst aquifer: a conceptual model based on isotopic data, Milandre test site, Switzerland, 2003, Perrin K. , Jeannin P. Y. , Zwahlen F. ,
The Milandre test site is a karst aquifer characterized by diffuse infiltration, a well developed conduit network, and several tributaries feeding an underground river. Field data include discharge rate measurements, stable isotopes, weekly rainfall and spring-water isotope sampling, and detailed isotope sampling during three flood events. Flood sampling was carried out at several tributaries corresponding to conduit flow, vadose flow and seepage flow. Weekly sampling showed a strong buffering of the rainfall isotopic signal at the spring. This attenuation suggests an important mixing reservoir in the system. Flood events showed highly peaking hydraulic responses but buffered rain isotope responses. These results indicate that the soil and epikarst sub-systems have an important storage capacity. A conceptual model of flow and transport in the soil and epikarst zone is proposed: Soil plays an important role in mixing due to the presence of capillary water storage. Consequently dampened concentrations reach the epikarst despite a rapid hydraulic response. The epikarst acts as the storage element and distributes water as either a base flow component or a quick flow component. When recharge exceeds a given threshold, excess infiltrated water bypasses the soil and epikarst and reaches the saturated zone as fresh flow. Based on this model, the significance of phreatic storage is thought to be limited, at least in Milandre test site. Hence the saturated zone is seen mainly as a transmissive zone through its well developed conduit network. (C) 2003 Elsevier B.V. All rights reserved

Soil and karst aquifer hydrological controls on the geochemical evolution of speleothem-forming drip waters, Crag Cave, southwest Ireland, 2003, Tooth Anna F. , Fairchild Ian J. ,
In recent years there has been increased interest in cave speleothems as archives of palaeoclimate. Monitoring of rainfall and soil and karst water chemistries was performed at Crag Cave, Castleisland, Co. Kerry, southwest Ireland, in August 1997 and January 1998 in order to understand temporal and spatial variations in karst water hydrology and chemistry and their implications for interpreting the potential palaeohydrological signal preserved by speleothems at this site. Temporal variations in karst water drip rates and geochemistry allow drips to be classified by hydrological response to rainfall and the associated processes of dilution, piston flow, source change and prior calcite precipitation during aquifer throughflow. Evolution from soil matrix and preferential flow solutions has also been determined to exert an important control on karst water chemistries. As a result of these findings we present hydrogeochemical models and plumbing diagrams that delineate the controls on karst water evolution at a number of sampling locations within the cave at this site. We propose that a palaeohydrological signal may be recorded by Crag Cave speleothems that may be interpreted via the study of Mg/Ca ratios in speleothems linked to monitoring of modern drip water chemistry

Comparison of immunofluorescence assay and immunomagnetic electrochemiluminescence in detection of Cryptosporidium parvum oocysts in karst water samples, 2003, Kuczynska E. , Boyer D. G. , Shelton D. R. ,
Immunofluorescence assay (IFA) and immunomagneticelectrochemiluminescence (IM-ECL) were used for comparison of the percent recovery of Cryptosporidium parvum in environmental water samples obtained from a spring draining a karst basin. The monoclonal antibodies to C. parvum, isotype IgG3 were used for optimization of the IM-ECL protocol. The combination of biotinylated and TAG-labeled anti-C. parvum antibodies with the streptavidin beads gave a linear regression slope for log ECL vs. log fresh oocysts of 0.79 (from 5 to 5000 oocysts), which indicates a constant ECL signal per oocyst. Standard curves gave a dynamic range of 5 to 5000 oocysts/ml (fresh) and 10 to 100,000 cells/ml (4-month-old oocysts) with the maximum limit of linear detection higher than 100,000. The linear slope of 4-month-old oocysts decreased to 0.62, which indicates that ECL signal is a function of oocyst age. The experiment associated with bead storage time shows that even after 4 months of storage of the biotinylated antibodies, the complex retains the ability for binding the oocysts and generating the ECL signal. Based on the IFA results in the experiment evaluating different protocols for oocysts recovery from karst water samples, the most efficient protocol involved dispersion, followed by flotation and immunomagnetic separation (IMS) (24% recovery). The ECL results obtained in that experiment were very similar to the results obtained in the IFA method, which indicates that the IM-ECL method is accurate. Results of the IFA in the study of the prevalence of C. parvum in the groundwater showed that oocysts were present in 78% of 1 L water samples with average number of oocysts of 6.4 5.5 and ranged from 0 (13 samples) to 23.3 (2 samples). The ECL signal generated from these water samples ranged from 3771 to 622 (average 1620 465). However, the background value estimated in groundwater samples with low number of oocysts detected by IFA was highly variable and elevated (from 3702 to 272, average 1503 475). The background value as a result of nonspecific binding to beads by unidentified organic components in the water can inhibit or even completely mask the signal generated by oocysts. Our investigations showed that the IM-ECL method appears to be promising for the qualitative and quantitative detection of C parvum from the environmental water; however, the method requires further development to improve sensitivity and account for background signals. Published by Elsevier Science B.V

Unraveling the Origin of Carbonate Platform Cyclothems in the Upper Triassic Durrenstein Formation (Dolomites, Italy), 2003, Preto Nereo, Hinnov Linda A. ,
Facies analysis of the Durrenstein Formation, central-eastern Dolomites, northern Italy, indicates that this unit was deposited on a carbonate ramp, as evidenced by the lack of a shelf break, slope facies, or a reef margin, together with the occurrence of a 'molechfor' biological association. Its deposition following the accumulation of rimmed carbonate platforms during the Ladinian and Early Carnian marks a major shift in growth mode of the Triassic shallow marine carbonates in the Dolomites. The Durrenstein Formation is characterized by a hierarchical cyclicity, with elements strongly suggestive of an allocyclic origin, including (a) subaerial exposure features directly above subtidal facies within meter-scale cyclothems, (b) purely subtidal carbonate cyclothems, (c) symmetric peritidal carbonate cyclothems, and (d) continuity of cyclothems of different orders through facies boundaries. The Durrenstein cyclothems are usually defined by transgressive and regressive successions, and so most of them probably originated from sea-level oscillations. Their allocyclic origin allows their use for high-resolution correlations over distances up to 30 km. A stratigraphic section in the Tre Cime di Lavaredo area, encompassing the upper part of the Durrenstein Formation and the lower part of the overlying Raibl Formation (Upper Carnian) was studied using time-frequency analysis. A strong Milankovitch signal appeared when interference arising from a variable sedimentation rate was estimated and removed by tuning the short precession line in a spectrogram. All of the principal periodicities related to the precession index and eccentricity, calculated for 220 Ma, are present: P1 (21.9 ky); P2 (17.8 ky); E1 (400 ky), E2 (95 ky), and E3 (125 ky), along with a peak at a frequency double that of the precession, which is a predicted feature of orbitally forced insolation at the equator. Components possibly related to Earth's obliquity at ca. 35 ky and ca. 46 ky are present as well. The recovery of Milankovitch periodicities allows reconstruction of a high-resolution timescale that is in good agreement with published durations of the Carnian based on radiometric ages. The recognition of a Milankovitch signal in the Durrenstein and lower Raibl formations, as well as in other Mesozoic carbonate platforms, strongly supports a deterministic and predictable--rather than stochastic--control on the formation of carbonate platforms. Carbonate platforms might thus be used in the future for the construction of an astronomical time scale for the Mesozoic

Dosimetric and radiocarbon chronology of a pre-Wisconsinan mastodon fossil locality at East Milford, Nova Scotia, Canada, 2003, Godfreysmith D. I. , Grist A. M. , Stea R. R. ,
We report the final results of a multidisciplinary geochronological study of two subfossil mastodon remains and the sediments associated with them. from the East Milford, N.S. mastodon locality discovered in 1991. The mastodons, which were found in a karstic sinkhole system, are the latest and the most complete of several mastodon remains discovered in Nova Scotia, New Brunswick and Maine over the last 170 years. The unconsolidated sediments containing the adult specimen were dated using optical dating (IRSL); the mastodon dental enamel was dated using electron spin resonance (ESR); and bone collagen from both individuals plus associated wood were dated using radiocarbon (C-14) dating. Two samples of sediment adhering to the walls of the karstic cavity at the elevation corresponding to the location of the adult specimen yielded statistically indistinguishable IRSL ages of 127 13 (EMM1) and 143 16 ka (EMM2), with a weighted mean of 133 6 ka. This is consistent with pollen data which indicate an interglacial climate. On the basis of its stratigraphic position with respect to overlying till units, the locality is attributed to oxygen isotope stage 5. Three ESR dates on dental enamel (natural prompt, deproteinated prompt, and deproteinated delayed) yielded statistically indistinguishable ages whose weighted mean is 74.9 5.0 ka. This indicates consignment to the geologic record of the mastodon tooth during terminal oxygen isotope stage 5a, when the climatic cooling leading to the Wisconsinan glacial period had already begun. Fission-track analysis of the enamel and dentine cross sections showed minimal U uptake, resulting in no need for early, linear, or late uptake modelling. The direct ESR age indicates that the specimen either became mired in a cavity that was already at least partly infilled with older, probably waterlogged, sediments, or that the sediment's IRSL signal was not completely erased during deposition. The dosimetric ages are consistent with limiting radiocarbon ages on bone collagen (juvenile > 45,760 years BP; adult greater than or equal to 37,040 1730 BP) and wood (near the adult mastodon > 51,000 BP; organic-rich horizon above the karst surface > 50,000 BP). These results provide the first direct age on a mastodon fossil from Atlantic Canada, and the first numeric estimate to demonstrate that mammoths were present in this region during pre-Wisconsinan times, specifically during late oxygen isotope stage 5a. (C) 2003 Elsevier Science Ltd. All rights reserved

Annual resolution analysis of a SW-France stalagmite by X-ray synchrotron microprobe analysis, 2003, Kuczumow A. , Genty D. , Chevallier P. , Nowak J. , Ro C. U. ,
A sample of stalagmite from Grotte de Villars, Dordogne, France was analyzed by the use of X-ray synchrotron microprobe in LURE, Orsay, France. Together with the signal of Ca, the main element, much weaker but clear signals of Sr, Fe, Zn and Pb were registered. The X-ray scattered radiation was applied for recognition of the annual zones in the stalagmite structure in parallel with the gray scale morphology from the optical microscope. The elemental scans were superimposed on the optical image of the sample. It was established that places corresponding to dark locations on the annual rings were narrower, composed of less porous matter and had much greater contents of iron and zinc and elevated ratio of Sr/Ca. In the supplementary electron microprobe measurements, the elevated amounts of lighter elements, Si and Mg were found in the same locations. These results will allow a very accurate study of stalagmite elemental composition which is of first importance for paleoclimatic studies from speleothems. (C) 2003 Elsevier Science B.V. All rights reserved

Geophysical evidence for karst formation associated with offshore groundwater transport: An example from North Carolina, 2003, Evans Rob L. , Lizarralde Dan

Marine geophysical data from Long Bay, North Carolina, involving a novel combination of electromagnetic and high-resolution Chirp seismics, show evidence of submarine karst formation associated with what has been inferred to be a site of high-flux submarine groundwater discharge (SGD) a substantial distance offshore. Recently observed temperature and chemical signals from wells in this area provide the basis for the interpretation of the high-flux SGD here, and they also suggest a terrestrial source for the groundwater and thus a potentially important route for nutrient transport to the oceans. Our data indicate that karstification is localized to the high-flux zone, and we suggest that mixing of the chemically distinct (but saline) groundwater with seawater has resulted in the karstification. As karstification increases permeability and flux, a positive feedback would tend to progressively enhance submarine groundwater discharge. Our data reveal a significant local anomaly in apparent porosity: a dense block that may have initiated the local focusing of groundwater flow. Conditions favorable to the formation of similar locally punctuated sites of high-flux SGD are likely to exist along the mid to inner shelf of the southeastern United States, where carbonate aquifers are prevalent


A conceptual model of flow and transport in a karst aquifer based on spatial and temporal variations of natural tracers, 2003, Perrin, Jerome

Karst aquifers represent an important groundwater resource world-wide. They are highly vulnerable to contamination due to fast transport through the system and limited attenuation of contaminants. The two main hydrogeological approaches developed for studying flow and transport are: inference of the
system structure from karst spring hydrographs and chemographs; numerical modelling of flow and transport using a theoretical distribution of flow and transport field parameters. These two approaches lack of validation by detailed field measurements and observations. The main objective of this thesis is to “fill the gap” existing between field and model data. Observations of flow and transport parameters at several locations within the system were used to develop a conceptual model. This model was then compared to the existing models.
The main field test site is the Milandre karst aquifer, located in the Swiss tabular Jura. Natural tracers (major ions, oxygen-18, specific conductance) and discharge were measured on the underground river, its main tributaries, percolation waters, and the main spring. These data were collected on a long-term basis in order to assess the spatial variability of the parameters, and on a short time scale (i.e. flood events) in order to investigate the dynamic processes. Complementary sites (Brandt and Grand Bochat) were used for more observations at the base of the epikarst.
The proposed conceptual model considers four sub-systems: the soil zone, the epikarst, the unsaturated zone, and the phreatic zone. Each has its own specificity with respect to flow and transport. The soil zone controls the actual infiltration into the system. It contributes efficiently to groundwater storage. It mixes quickly stored water with fresh infiltrated water. Its thickness determines land-use: thick soils are generally cultivated whereas thin soils are under forested areas. The solutes concentration of soil waters depends on land-use for pollution-related parameters (nitrate, chloride, sulfate, potassium, sodium). Moreover the soil zone is the main source of CO2 which controls the limestone dissolution-related parameters. The epikarst zone contributes largely to groundwater storage. It distributes groundwater into vadose flow through conduits, and base flow through low permeability volumes (LPV) in the unsaturated zone. It is the sub-system where dissolution-related parameters are mostly acquired.
The unsaturated zone is seen as a transmissive zone connecting the epikarst to the horizontal conduit network of the phreatic zone. In case of flood events, some dissolution still occurs in this sub-system.
The phreatic zone is the partly flooded conduit network draining groundwater to the spring. It collects waters issued from the unsaturated zone, mixes the tributaries, and drain the water towards the discharge area. The role of phreatic storage appears to be limited for both hydraulics and transport.
Tributary mixing is a prominent process that shapes spring chemographs during flood events. In steady-state conditions, base flow is mainly sustained by the epikarst reservoir. Tracer concentrations are stable as the chemical equilibrium is already reached in the epikarst. Waters issued from the different tributaries mix in the conduit network, and the spring chemistry is the result of this mixing.
During flood events, transient flow induces non-linear mixing of the tributaries. The respective contributions of the tributaries change throughout the flood, and the spring chemographs vary accordingly. In case of important recharge, waters issued from other sources than the epikarst participate to the flood. First, soil water reaches the phreatic zone. Its characteristics are a dampened isotopic signal, and ionic concentrations differing from those of the epikarst. Second, fresh water directly issued from rainfall, may reach the phreatic zone. Its characteristics are a varying isotopic signal, and diluted ionic concentrations. The mixing components participating to the flood are controlled by the actual infiltration volume (or height). The limestone dissolution process is effective for the fresh and soil components of flow. However mixing processes play a more important role than dissolution for shaping the spring chemographs.
From a practical point of view, the project confirmed the prominent role of the soil zone and the epikarst on the solute transport in karst systems. This was already integrated in karst vulnerability mapping methods recently developed (EPIK, PI, VULK).

http://doc.rero.ch/record/2604/files/these_PerrinJ.pdf


Symposium Abstract: Transmission and preservation of climatic signals via karstic hydrological systems, 2004, Fairchild I. J.

Stalagmite growth and palaeo-climate: an inverse approach, 2004, Kaufmann G. , Dreybrodt W. ,
The growth of stalagmites is controlled by climatic conditions such as temperature, soil activity, and precipitation. Hence, a stalagmite stratigraphy reflects fluctuations of palaeo-climate conditions on various time scales, from annual variations to ice-age cycles. However, no attempt has been made to infer palaeo-climate fluctuations from the stratigraphy itself We describe the complicated growth of a stalagmite with a simple mathematical model, in which both the growth rate and the equilibrium diameter of stalagmites are functions of palaeo-climate variables. Hence, inverting a given stalagmite stratigraphy in terms of growth rate and equilibrium diameter can in principle recover the palaeo-climate signal. The strongly nonlinear dependence of these two geometrical parameters, however, limits the success of a formal inversion of stratigraphical data. In this paper, we explore the resolving power of both growth rate and equilibrium diameter data for the palaeo-climate signals temperature, carbon-dioxide concentration, and precipitation. We use numerically generated stalagmite stratigraphies as observational data, thus we know beforehand the palaeo-climate signal contained in the stratigraphic record. Our results indicate that both variations in carbon-dioxide concentrations (as a proxy of soil cover) and drip interval (as a proxy of precipitation) can be recovered from the stratigraphy. However, temperature variations are poorly resolved. (C) 2004 Elsevier B.V. All rights reserved

A frequency domain approach to groundwater recharge estimation in karst, 2004, Jukic D. , Icjukic V. ,
This paper presents an alternative method for determining the values of parameters of a groundwater recharge model. The phreatic zone of a karst aquifer is considered as the linear and time-invariant filter that transforms the input signal of groundwater recharge rates into the output signal of spring discharges. Similarities between transfer functions of total rainfall rates and transfer functions of groundwater recharge rates are the basis for developing the parametric periodogram depending on parameters of a groundwater recharge model. The values of parameters are estimated by minimizing the differences between the parametric periodogram and a periodogram of spring discharges. The approximate Whittle log likelihood function is the criterion for determining the optimal values of the parameters. By using this frequency domain approach, groundwater-balance calculations are avoided so the method can be applied on unexplored karst aquifers when groundwater-balance cannot be achieved without extensive geologic and hydrogeologic investigations. The results of the applications on two springs located in the Dinaric karst area in Croatia are discussed. (C) 2003 Elsevier B.V. All rights reserved

Linear model describing three components of flow in karst aquifers using O-18 data, 2004, Long A. J. , Putnam L. D. ,
The stable isotope of oxygen, 180, is used as a naturally occurring ground-water tracer. Time-series data for 5 180 are analyzed to model the distinct responses and relative proportions of the conduit, intermediate, and diffuse flow components in karst aquifers. This analysis also describes mathematically the dynamics of the transient fluid interchange between conduits and diffusive networks. Conduit and intermediate flow are described by linear-systems methods, whereas diffuse flow is described by mass-balance methods. An automated optimization process estimates parameters of lognormal, Pearson type III, and gamma distributions, which are used as transfer functions in linear-systems analysis. Diffuse flow and mixing parameters also are estimated by these optimization methods. Results indicate the relative proximity of a well to a main conduit flowpath and can help to predict the movement and residence times of potential contaminants. The three-component linear model is applied to five wells, which respond to changes in the isotopic composition of point recharge water from a sinking stream in the Madison aquifer in the Black Hills of South Dakota. Flow velocities as much as 540 m/d and system memories of as much as 71 years are estimated by this method. Also, the mean, median, and standard deviation of traveltimes; time to peak response; and the relative fraction of flow for each of the three components are determined for these wells. This analysis infers that flow may branch apart and rejoin as a result of an anastomotic (or channeled) karst network. Published by Elsevier B.V

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