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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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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. ...

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That superimposed valley is a valley established on the land surface with a pattern that is independent of the underlying rock structure.?

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Your search for turbidity (Keyword) returned 21 results for the whole karstbase:
Showing 1 to 15 of 21
Using turbidity dynamics and geochemical variability as a tool for understanding the behavior and vulnerability of a karst aquifer, , Fournier M, Massei N, Bakalowicz M, Dussartbaptista L, Rodet J, Dupont Jp,

Shallow-marine carbonate facies and facies models, 1985, Tucker M. E. ,
Shallow-marine carbonate sediments occur in three settings: platforms, shelves and ramps. The facies patterns and sequences in these settings are distinctive. However, one type of setting can develop into another through sedimentational or tectonic processes and, in the geologic record, intermediate cases are common. Five major depositional mechanisms affect carbonate sediments, giving predictable facies sequences: (1) tidal flat progradation, (2) shelf-marginal reef progradation, (3) vertical accretion of subtidal carbonates, (4) migration of carbonate sand bodies and (5) resedimentation processes, especially shoreface sands to deeper subtidal environments by storms and off-shelf transport by slumps, debris flows and turbidity currents. Carbonate platforms are regionally extensive environments of shallow subtidal and intertidal sedimentation. Storms are the most important source of energy, moving sediment on to shoreline tidal flats, reworking shoreface sands and transporting them into areas of deeper water. Progradation of tidal flats, producing shallowing upward sequences is the dominant depositional process on platforms. Two basic types of tidal flat are distinguished: an active type, typical of shorelines of low sediment production rates and high meteorologic tidal range, characterized by tidal channels which rework the flats producing grainstone lenses and beds and shell lags, and prominent storm layers; and a passive type in areas of lower meteorologic tidal range and higher sediment production rates, characterized by an absence of channel deposits, much fenestral and cryptalgal peloidal micrite, few storm layers and possibly extensive mixing-zone dolomite. Fluctuations in sea-level strongly affect platform sedimentation. Shelves are relatively narrow depositional environments, characterized by a distinct break of slope at the shelf margin. Reefs and carbonate sand bodies typify the turbulent shelf margin and give way to a shelf lagoon, bordered by tidal flats and/or a beach-barrier system along the shoreline. Marginal reef complexes show a fore-reef--reef core--back reef facies arrangement, where there were organisms capable of producing a solid framework. There have been seven such phases through the Phanerozoic. Reef mounds, equivalent to modern patch reefs, are very variable in faunal composition, size and shape. They occur at shelf margins, but also within shelf lagoons and on platforms and ramps. Four stages of development can be distinguished, from little-solid reef with much skeletal debris through to an evolved reef-lagoon-debris halo system. Shelf-marginal carbonate sand bodies consist of skeletal and oolite grainstones. Windward, leeward and tide-dominated shelf margins have different types of carbonate sand body, giving distinctive facies models. Ramps slope gently from intertidal to basinal depths, with no major change in gradient. Nearshore, inner ramp carbonate sands of beach-barrier-tidal delta complexes and subtidal shoals give way to muddy sands and sandy muds of the outer ramp. The major depositional processes are seaward progradation of the inner sand belt and storm transport of shoreface sand out to the deep ramp. Most shallow-marine carbonate facies are represented throughout the geologic record. However, variations do occur and these are most clearly seen in shelf-margin facies, through the evolutionary pattern of frame-building organisms causing the erratic development of barrier reef complexes. There have been significant variations in the mineralogy of carbonate skeletons, ooids and syn-sedimentary cements through time, reflecting fluctuations in seawater chemistry, but the effect of these is largely in terms of diagenesis rather than facies

Turbidity and microorganisms in a karst spring, 1997, Nebbache S. , Loquet M. , Vinceslasakpa M. , Feeny V. ,
This study was focused mainly on relations between turbidity and bacterial contamination of a karst spring. The data from the resurgence site show that for a turbidity <1,2 NTU, the spring is benefits of good sanitary conditions. The highest degree of bacterial contamination generally coincides with increased rainfall (automn and winter). This turbidity is also a factor of enhancing survival in particular-for fecal bacteria. correlations are established between turbidity and fecal bacteria, Those data show different origins of suspended particulate matters. The latter are transfered with superficial waters and rapid throughflow, or with water stored in 'systemes annexes karstifies' (storage units) then flushed out. Following the study of the first peak of turbidity, after recession, we find that turbidity is essentially due to the P3 class of particles (4.3 to 11 mu m) and that some microorganisms are carried by the following classes of articles: ammonifiers by class P1 (<1.7 mu m), mesophilic microflora by P2 (1.7 to 4.3 mu m), fecal streptbcocci by P3 (4.3 to 11 mu m), fecal coliforms and denitrifiers by P4 (11 to 27 mu m). A knowledge of turbidity and bacterial contamination relationships suppose to take into account the stational ecological events and the hydrodynamic of the karst but also the adhesion laws between bacteria and particles

Role of cave information in environmental site characterization,, 1999, Jancin M.
For consultants concerned with developing site-specific conceptual models for flow and transport in karst, cave information can be worth accessingAt the scale of the basin, caves often display patterns that correlate with both the flow and recharge characteristics of their aquifersCharacterization of overall basin hydrology bolsters predictions and monitoring recommendations which address the siteAlthough the presence of caves beneath or near sites is rare, site-based information such as water-table maps (under both natural and pumping conditions), well water-level fluctuations, well turbidity observations, borehole-void yields during drilling, and dye-trace results, are potentially useful in defining conduit-flow boundaries to diffuse-flow blocksThe appropriate choice of dye-tracer methods should acknowledge whether most site conduits (or borehole voids, or even caves) are within the epikarst, the vadose zone, the phreatic zone, or the oscillation zoneFor inferences on site flow directions, it is useful to compare the directional frequencies of cave passages and joints, faults, and photolinears in the areaThere is evidence that where caves are well developed, there tends to be a low correlation between photolinear locations and relatively high well yieldsLNAPL migration will be retarded where main conduits are well beneath the water table, but an extensive overlying system of saturated epikarstic pores serve as trapsKarst with high seasonal or storm variations in water level will tend to repeatedly remobilize LNAPLsGiven sufficient volume, DNAPLs can penetrate vertically integrated networks of pores, fractures, or solution conduits to great depthHowever, where such pathway networks are lie above relatively tight lithologies at shallow depth, and are not sediment filled, lateral movement can greatly exceed vertical movementCharacterization of the 3-D nature of pores and pathways is an important element in understanding the migration of free product, and therefore in understanding the evolution of associated aqueous plumes

Le karst des Arbailles (Pyrnes-Atlantiques, France), 2000, Vanara, Nathalie
The Arbailles massif (200 - 1200 m) is located in the french north face of Pyrnes, Atlantic side. It forms a folded 165 square-kilometres unit of jurassic and cretaceous limestones under an oceanic climate of altitude (2000 mm/year). Observations jointly made on the surface and in the numerous underground galleries allow an occurate correlation of alternate surrective and karstic periods. The dismantled cavities and deposits pockets of the upper surface show two series of minerals, those from weathered marly-albian limestones and others supplied from the conglomerates pudding-stones of Mendibelza. During the Miocene, the Arbailles massif is a low area of tropical erosion on the side of the main mounts. Its surrection caused the scouring of the alterites cover, the formation of fields of karstic butts and a definitive drying of the fluviatile paleosystem. The different levels of dried valleys and the karstic hydrographic systems are successive stations of the karstic levels of origine. Paleomagnetic datations in Etxanko Zola and U/Th datations in Nbl show that the surrection has been of about 500 m since lower Pleistocene. At the present time, water collection is made through drainage systems without any connection to the fossil topography. Three aquifers can be distinguished: in lower cretaceous, in jurassic and in north and south limits. They are water-repellent because of more or less impermeable screens. Waters are aggressive in summer and at equilibrium or lightly undersaturated the rest of the year. The modern human activities create a recent destabilisation of the environment with local erosions of grounds and an increasing turbidity of springs. An occurate study in the fail of Istaurdy allows a mesure of the effect of deforestation for the whole massif.

Forecasting of turbid floods in a coastal, chalk karstic drain using an artificial neural network, 2001, Beaudeau P, Leboulanger T, Lacroix M, Hanneton S, Wang Hq,
Water collected at the Yport (eastern Normandy, France) Drinking Water Supply well, situated on a karst cavity, is affected by surface runoff-related turbidity spikes that occur mainly in winter, In order to forecast turbidity, precipitation was measured at the center of the catchment basin over two years, while water level and turbidity were monitored at the web site. Application of the approach of Box and Jenkins (1976) leads to a linear model that can accurately predict major floods about eight hours in advance, providing an estimate of turbidity variation on the basis of precipitation and mater level variation over the previous 24 hours. However, this model is intrinsically unable to deal with (1) nonstationary changes in the time process caused by seasonal variations of in ground surface characteristics or tidal influence within the downstream past of the aquifer, and (2) nonlinear phenomena such as the threshold for the onset of runoff. This results in many false-positive signals of turbidity in summer. Here we present an alternative composite model combining a conceptual runoff submodel with a feedforward artificial neural network (ANN), This composite model allows us to deal with meaningful variables, the actioneffect of which on turbidity is complex, nonlinear, temporally variable and often poorly described. Predictions are markedly improved, i.e,, the variance of the target variable explained by 12-hour forward predictions increases from 28% to 74% and summer inaccuracies are considerably lowered. The ANN can adjust itself to new hydrological conditions, provided that on-line learning is maintained

Late Archaean foreland basin deposits, Belingwe greenstone belt, Zimbabwe, 2001, Hofmann A. , Dirks P. H. G. M. , Jelsma H. A. ,
The c. 2.65 Ga old sedimentary Cheshire Formation of the Belingwe greenstone belt (BDB), central Zimbabwe, has been studied in detail for the first time to shed some light on the much debated evolution of this classical belt. The Cheshire Formation rests sharply on a mafic volcanic unit (Zeederbergs Formation) and comprises a basal, eastward-sloping carbonate ramp sequence built of shallowing-upward, metre-scale sedimentary cycles. The cycles strongly resemble Proterozoic and Phanerozoic carbonate cycles and might have formed by small-scale eustatic sea level changes. The top of the carbonate ramp is represented by a karst surface. The carbonates are overlain by and grade laterally to the east into deeper water (sub-wave base) siliciclastic facies. Conglomerate, shale and minor sandstone were deposited by high- to low-density turbidity currents and were derived from the erosion of Zeederbergs-like volcanic rocks from the east. Shortly after deposition, the Cheshire Formation and underlying volcanics were affected by a northwest-directed thrusting event. Thrusting gave rise to the deformation of semi-consolidated sediments and resulted in the juxtaposition of a thrust slice of Zeederbergs basalts onto Cheshire sediments. The stratigraphy, asymmetric facies and sediment thickness distribution, palaeogeographic constraints and evidence for an early horizontal tectonic event suggest that the Cheshire Formation formed in a foreland-type sedimentary basin. (C) 2001 Elsevier Science B.V. All rights reserved

Turbidit, indicateur du fonctionnement perturb du gosystme karstique de lAtlas de Beni Mellal (Moyen Atlas mridional, Maroc), 2002, Elkhalki Yahia, Hafid Abdellatif
Turbidity, as an indicator of perturbed functioning of karst geosystem of Beni Mellal Atlas (Southern Middle Atlas, Morocco) - The turbidity of karst springs is a general phenomenon of anthropized Mediterranean limestone mountains. But actually we note that it has been somewhat neglected by karstologists. In other respects, it represents a pertinent indicator of the dysfunctioning of karst geosystems which have undergone a strong impact of human action. Cloudy waters distinguish Asserdoune spring, as the main outlet of Liassic aquifer. After dry periods, followed by brutal storms, water turbidity can exceed 2000 JTU (Jackson Turbidity Unit). Three factors are united to favour the turbidity water: 1) The climate: autumn rain storms which follow a long dry season, fall on soils that are dry and badly protected by vegetation. They cause an important mobilisation of fine particles, which infiltrate the epikarst.2) Inner karst structure: the advance of cloudy water toward An Asserdoune spring is made easier by developed drains. Dye tracings have shown that the time of transit waters is comprised between 24 and 72 hours.3) Human impact: the agriculture modernisation of Tadla plain (140 000 ha irrigated) was accompanied with a violent action on forest resources of Beni Mellal Atlas. Clearings induced a large stripping of soils, which caused the excavation of covered karrens. Furthermore, the dysfunctioning of the karst geosystem of Beni Mellal Atlas is translated by the hindrance of present travertinisation at the downstream of springs.

Turbidity mechanism of water from a karstic spring: example of the Ain Asserdoune spring (Beni Mellal Atlas, Morocco)., 2002, Bouchaou L. , Mangin A. , Chauve P.

Transport of suspended solids from a karstic to an alluvial aquifer: the role of the karst/alluvium interface, 2002, Massei N. , Lacroix M. , Wang H. Q. , Mahler B. J. , Dupont J. P. ,
This study focuses on the coupled transport of dissolved constituents and particulates, from their infiltration on a Karst plateau to their discharge from a karst spring and their arrival at a well in an alluvial plain, Particulate markers were identified and the transport of solids was characterised in situ in porous and karstic media, based on particle size analyses, SEM, and traces. Transport from the sinkhole to the spring appeared to be dominated by flow through karst: particulate transport was apparently conservative between the two sites, and there was little difference in the overall character of the particle size distribution of the particulates infiltrating the sinkhole and of those discharging from the spring. Qualitatively, the mineralogy of the infiltrating and discharging material was similar, although at the spring an autochthonous contribution from die aquifer was noted (chalk particles eroded from the parent rock by weathering). In contrast, transport between the spring and the well appears to be affected by the overlying alluvium: particles in the water from the well, showed evidence of considerable size-sorting. Additionally, SEM images of the well samples showed the presence of particles originating from the overlying alluvial system; these particles were not found in samples from the sinkhole or the spring. The differences between the particulates discharging from the spring and the well indicate that the water pumped from the alluvial plain is coming from the Karst aquifer via the very transmissive, complex geologic interface between the underlying chalk formation and the gravel at the base of the overlying alluvial system. (C) 2002 Elsevier Science B.V. All rights reserved

Effects of precipitation events on colloids in a karst aquifer, 2002, Shevenell L. , Mccarthy J. F. ,
The effects of precipitation events on colloid mobilization were evaluated during several storms from six wells in a karstic aquifer at the Oak Ridge Y-12 Plant in eastern Tennessee (USA). Turbidity increases and rapidly recedes following rain events. Although the magnitude of the turbidity increases are relatively small (less than or equal to4.78 NTU), the increased turbidity suggests transient increases in colloid abundance during storm versus non-storm periods. During the larger storms (> 19 mm), the increased turbidity is associated with increases in pH, total organic carbon (TOC) and temperature, and with decreases in dissolved oxygen (DO). These larger storms result in flushing of a greater proportion of higher pH, TOC (and lower DO) soil or matrix waters into the fractures and conduits than occurs during smaller storms. Smaller storms also result in increases in turbidity, but show increases in DO and decreases in pH reflecting less influence on the water chemistry from the longer residence time epikarst or and matrix waters, and greater impact from the more dilute, newly recharged waters. Due to the complexity of karst flow and temporal variations in flow and chemistry, controls on turbidity are not consistent through time and space at the wells. During smaller storms. recharge by lower ionic strength waters may promote colloid release and thus contribute to observed increases in turbidity. During larger storms, elevated turbidity may be more related to pH increases resulting from greater influx of matrix and soil waters into fractures and conduits. Chemical factors alone cannot account for the changes in turbidity observed during the various storms. Because of the complicated nature of flow and particle transport in karst aquifers, the presence of colloids during precipitation events is dictated by a complex interplay of chemical reactions and the effects of physical perturbations due to increased flow through the conduits and fractures. Simple trends in water quality parameters could not be identified, and broad generalizations cannot easily be made in karst settings, and some of the expected correlations between chemical parameters during the storms were not observed in this work. (C) 2002 Elsevier Science B.V. All rights reserved

Particle transport in a karst aquifer: natural and artificial tracer experiments with bacteria, bacteriophages and microspheres, 2002, Auckenthaler A, Raso G, Huggenberger P,
Fast changes in spring water quality in karst areas are a major concern for production of drinking water and require detailed knowledge of the complex interaction between karst aquifer, transport behavior of microorganisms and water treatment We have conducted artificial and natural particle transport experiments at a karst spring with bacteria, bacteriophages, microspheres, and pathogens Transport of the investigated microorganisms, turbid matter and chemical pullutants as well as increase in discharge are strongly related to precipitation and the heterogeneity of the aquifer The indicator bacteria E cob revealed a significant correlation to verotoxin-producing E cob and Cryptosporidium spp We conclude that artificial particle tracers can help identify 'hot spots' for microbial recharge and that system parameters in spring water such as turbidity, UV-extinction and increase in discharge can be key parameters for efficient raw water management

Transfer of bacteria-contaminated particles in a karst aquifer: evolution of contaminated materials from a sinkhole to a spring, 2003, Dussartbaptista L, Massei N, Dupont Jp, Jouenne T,
The transport of particle-associated bacteria during rain events in karst waters has been investigated. In this aim, we studied the correlations between water turbidity and enumerations of sessile (attached) and planktonic (non-attached) bacteria. We monitored physicochemical, i.e. turbidity, electrical conductivity, size and nature of the transported particles, and bacteriological properties of waters since their infiltration on a karst plateau to their discharge at a karstic spring. Results showed a decrease of the concentration of sessile bacteria at the sinkhole for high turbidities. This phenomenon might be explained by the arrival of lower contaminated material. On the other hand, the amount of sessile bacteria at the spring was not influenced by the turbidity values. These data demonstrated that slightly contaminated larger particles were not recovered, whereas small-size particles, which exhibited a higher bacterial contamination, were directly transferred (i.e. not affected by intra-karstic deposition) through the aquifer. Our study highlighted some significant differences between the bacteriological time series at the sinkhole and at the spring, which characterizes the storage/resuspension function of the considered karst system. Moreover, we show a decrease of the concentration of planktonic bacteria after transport through the system whereas no reduction of the sessile population occur-red. The present data confirm that turbidity does not constitute a good indicator for bacterial contamination: if high turbidity corresponds to high bacterial contamination, low turbidity does not systematically exclude a risk of contamination by sessile organisms. (C) 2003 Elsevier B.V. All rights reserved

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

Water quality modelling of Jadro spring, 2004, Margeta J. , Fistanic I. ,
Management of water quality in karst is a specific problem. Water generally moves very fast by infiltration processes but far more by concentrated flows through fissures and openings in karst. This enables the entire surface pollution to be transferred fast and without filtration into groundwater springs. A typical example is the Jadro spring. Changes in water quality at the spring are sudden, but short. Turbidity as a major water quality problem for the karst springs regularly exceeds allowable standards. Former practice in problem solving has been reduced to intensive water disinfection in periods of great turbidity without analyses of disinfection by-products risks for water users. The main prerequisite for water quality control and an optimization of water disinfection is the knowledge of raw water quality and nature of occurrence. The analysis of monitoring data and their functional relationship with hydrological parameters enables establishment of a stochastic model that will help obtain better information on turbidity in different periods of the year. Using the model a great number of average monthly and extreme daily values are generated. By statistical analyses of these data possibility of occurrence of high turbidity in certain months is obtained. This information can be used for designing expert system for water quality management of karst springs. Thus, the time series model becomes a valuable tool in management of drinking water quality of the Jadro spring

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