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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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Your search for mixing (Keyword) returned 275 results for the whole karstbase:
Showing 1 to 15 of 275
The role of tributary mixing in chemical variations at a karst spring, Milandre, Switzerland, , Perrin J. , Jeannin P. Y. , Cornaton F. ,
SummarySolute concentration variations during flood events were investigated in a karst aquifer of the Swiss Jura. Observations were made at the spring, and at the three main subterraneous tributaries feeding the spring. A simple transient flow and transport numerical model was able to reproduce chemographs and hydrographs observed at the spring, as a result of a mixing of the concentration and discharge of the respective tributaries. Sensitivity analysis carried out with the model showed that it is possible to produce chemical variations at the spring even if all tributaries have constant (but different for each of them) solute concentrations. This process is called tributary mixing. The good match between observed and modelled curves indicate that, in the phreatic zone, tributary mixing is probably an important process that shapes spring chemographs. Chemical reactions and other mixing components (e.g. from low permeability volumes) have a limited influence.Dissolution-related (calcium, bicarbonate, specific conductance) and pollution-related parameters (nitrate, chloride, potassium) displayed slightly different behaviours: during moderate flood events, the former showed limited variations compared to the latter. During large flood events, both presented chemographs with significant changes. No significant event water participates in moderate flood events and tributary mixing will be the major process shaping chemographs. Variations are greater for parameters with higher spatial variability (e.g. pollution-related). Whereas for large flood events, the contribution of event water becomes significant and influences the chemographs of all the parameters. As a result, spring water vulnerability to an accidental pollution is low during moderate flood events and under base flow conditions. It strongly increases during large flood events, because event water contributes to the spring discharge

Corrosion by mixing of waters., 1964, Bogli Alfred
Karst caves are prior to all due to corrosion. According to the well-known formula a CO2 supply is always needed. This type of dissolution explains only the corrosion in free circulation and, under reserve, the one in pressure conducts in the vadose zone. All corrosion in the phreatic domain is excluded, except for some rare cases in the upper levels. The corrosion by mixing of waters of different content in bicarbonates is effective in the entire karst, from the lowermost to the uppermost parts. Also the corrosion due to the lowering of temperature and by mixing of waters at different temperature has to be take into account. Excpet for some exceptional cases (e.g. thermal waters), this effect is very reduced.

Symposium on Cave Origin - Corrosion by Mixing of Karst Waters, 1971, Bogli A.

Hydrogeological investigations into discharge of salt-containing water from a stream into an aquifer., 1976, Neuss Matthias
An aquifer in a horseshoe bend of the Weser river was investigated regarding the processes of the river water infiltration. The geology and geometry of the aquifer was ascertained by means of numerous borings. The hydraulic situation before and after infiltration was determined by water table maps. The intrusion of a salt-freshwater lens could be reconstructed from the beginning of infiltration until ten years later by means of previous results of chemical analysis. By new chemical analysis it was proved that river water infiltrates into the aquifer. Additionally it was established that the relatively high concentration of chloride is reduced during the passage of the groundwater both by mixing with recharged groundwater and by adsorption of the ground. Furthermore temperature measurements in the groundwater at selected stations confirm qualitatively the river water infiltration into the polder.

Karst Hydrogeology and Geomorphology of the Sierra de El Abra and the Valles-San Luis Potosí Region, México, PhD Thesis, 1977, Fish, Johnnie Edward

The general objective of this work was to develop a basic understanding of the karst hydrology, the nature and origin of the caves, the water chemistry, the surface geomorphology, and relationships among these aspects for a high relief tropical karst region having a thick section of limestone. The Valles-San Luis Potosí region of northeastern México, and in particular, the Sierra de El Abra, was selected for the study. A Cretaceous Platform approximately 200 km wide and 300 km long (N-S) delimits the region of interest. A thick Lower Cretaceous deposit of gypsum and anydrite, and probably surrounded by Lower Cretaceous limestone facies, is overlain by more than 1000 m of the thick-bedded middle Cretaceous El Abra limestone, which has a thick platform-margin reef. The Sierra de El Abra is a greatly elongated range along the eastern margin of the Platform. During the late Cretaceous, the region was covered by thick deposits of impermeable rocks. During the early Tertiary, the area was folded, uplifted, and subjected to erosion. A high relief karst having a wide variety of geomorphic forms controlled by climate and structure has developed. Rainfall in the region varies from 250-2500 mm and is strongly concentrated in the months June-October, when very large rainfalls often occur.
A number of specific investigations were made to meet the general objective given above, with special emphasis on those that provide information concerning the nature of ground-water flow systems in the region. Most of the runoff from the region passes through the karstic subsurface. Large portions of the region have no surface runoff whatsoever. The El Abra Formation is continuous over nearly the whole Platform, and it defines a region of very active ground-water circulation. Discharge from the aquifer occurs at a number of large and many small springs. Two of them, the Coy and the Frío springs group, are among the largest springs in the world with average discharges of approximately 24 m³/sec and 28 m³/sec respectively. Most of the dry season regional discharge is from a few large springs at low elevations along the eastern margin of the Platform. The flow systems give extremely dynamic responses to large precipitation events; floods at springs usually crest roughly one day after the causal rainfall and most springs have discharge variations (0max/0min) of 25-100 times. These facts indicate well-developed conduit flow systems.
The hydrochemical and hydrologic evidence in combination with the hydrogeologic setting demonstrate the existence of regional ground-water flow to several of the large eastern springs. Hydrochemical mixing-model calculations show that the amount of regional flow is at least 12 m³/sec, that it has an approximately constant flux, and that the local flow systems provide the extremely variable component of spring discharge. The chemical and physical properties of the springs are explained in terms of local and regional flow systems.
Local studies carried out in the Sierra de El Abra show that large conduits have developed, and that large fluctuations of the water table occur. The large fossil caves in the range were part of great deep phreatic flow systems which circulated at least 300 m below ancient water tables and which discharged onto ancient coastal plains much higher than the present one. The western margin swallet caves are of the floodwater type. The cave are structurally controlled.
Knowledge gained in this study should provide a basis for planning future research, and in particular for water resource development. The aquifer has great potential for water supply, but little of that potential is presently used.

Phreatische Fauna in Ljubljansko polje (Ljubljana-Ebene, Jugoslavien); ihre oekologische Verteilung und zoogeographische Beziehungen., 1981, Sket Boris, Velkovrh Franci
The phreatic basin of Ljubljansko polje (polje = plain, field) recharges its water supply mainly from the Sava river-bed and at a few other locations where connections with karstic subterranean waters might exist and only up to 15% from precipitation. An important zone of infiltration in the river-bed is the bottom and not the bank which is to a large extent watertight due to organic debris (rests of Sphaerotilus e.g.). The main water-body moves about 10 m/day, there are however some local jets with far higher speeds. Yearly amplitudes of water temperatures are high near the river but in the centre of the plain only a couple of centigrades. Oxygen saturation is in the open river-water 100%, dropping to 40-60% just 1 m into the phreatic. True stygopsammal animals are represented here only by a few species and specimen in spite of the fact, that the interstices in the gravel are mostly filled with finer sediments. Remarkable is also the scarcity of Nematodes and the near absence of Acarina (compare with Danielopol 1976). Only a few specimen of the river benthos (Chironomidae, Tipulidae, Leuctra supp., Baets spp.) penetrate the interstitial water (compare with Ruffo 1961, Danielopol 1976) and only Naididae are more frequent there. However, many epigean animals occur in interstitial waters in the periodically flooded gravel-banks; one can explain this with oscillations of the water level. Some epigean animals (creno- and troglophilic) are quite regularly represented in the phreatic near the river, but have not been found in the river-bed. The distribution of phreatic species within the studied water-body seems to be controlled mainly by the presence of food supplies and the consequent competition among species. The same is true for the speed of the water current and some other factors which are less easily defined. The characteristics of the substratum as well as O2-saturation and other characteristics of the water seem to have little influence on the fauna. The energetically (food-) rich neighbourhood of the river is inhabited by a number of species in quite dense populations while the central parts of the phreatic water body exhibit a great poverty of species and of specimen. However, some species live here, which don't occur in the presence of larger food supplies and of greater competition (Niphargus serbicus). The higher current speed seems to prevent settlement of some species (Cyclopoida, Proasellus deminutus) while some are bound to such habitats (Proasellus vulgaris). Some species exhibit a high degree of euryvalency inside the stygopsephale habitats (Niphargus longidactylus e.g.), while some are highly specialized. Some of them form dense populations (comparatively dense even in energetically poor places) while others exhibit even in most favourable conditions very low densities (Niphargus jovanovici multipennatus). The present fauna is zoogeographically very diverse. Some species are distributed throughout Europe; some reach from Central Europe to the borders of Dinaride Karst (Bogidiella albertimagni) and some even penetrate it (Trichodrilus pragensis, Acanthocyclops kiefer). Bogidiella semidenticulata. Niphargus pectinicauda, Hadziella deminuta seem to be limited to the higher reaches of the Sava River. All of the above mentioned animals live regularly in interstitial waters and only sporadically in karstic hypogean waters. Niphargus stygius is here the only animal of a certainly karstic provenience; inside the plain it is limited to a completely special habitat. It is very likely that the entire Proasellus-deminutusgroup has developed in interstitial waters of larger plains which are in contact with karstic areas; some species penetrated from the plains into the karst rather than the reverse. To the contrary (judging from the distribution of the genera) karstic waters seem to be the cradle of Hauffenia and Hadziella. Such a sharp delimitation between cave- and interstitial fauna resp. in this area is very noteworthy. Both faunas live here in abundance and in close contact. It is very probable that particularly high competition and specialization of both faunas, caused by their richness and diversity, prevent mixing of species.

Mixing corrosion in CaCO3/1bCO2/1bH2O systems and its role in the karstification of limestone areas, 1981, Dreybrodt W,
Mixtures of two saturated H2O/1bCO2/1bCaCO3 solutions of different chemical composition gain renewed capability of dissolving calcite. This is an important mechanism in the solution processes of limestone during karstification. Using recent data on the kinetics of calcite dissolution, dissolution rates in mixture corrosion are calculated. In the region of the chemical composition of natural karst waters the solution rate is approximated by:R=-[alpha]([Ca2] - [Ca2]s where [Ca2], [Ca2]s are the concentrations of the Ca2 ion in the solution and at saturation, respectively. [alpha] ranges from 10-4 to 3[middle dot]10-4 cm s-1.This result is applied to the solution of limestone in karst water mixtures flowing in cylindrical conduits. The saturation length, i.e. the length xs which the solution has to travel to drop to 37% of its renewed dissolving capability, is calculated in the region of turbulent flow. This region starts at conduit radii R of several millimeters. At the onset of turbulent flow the saturation length is 260 m, increasing with R1.665. The increase of conduit radii is calculated from the dissolution rates of calcite solution to be on the order of 10-3 cm yr.-1.The results are discussed for a comprehensive model of karstification and cave development, which for the first time gives a realistic theoretical time region for cave development, in agreement to experience

Hydrology and hydrochemistry of the Caves Branch karst, Belize, 1983, Miller T. ,
A large conduit spring issuing from Cretaceous limestones in Belize, Central America, displays a positive relation of discharge to solute concentration. Beneath a maturely-dissected cockpit karst, the hydrologic system combines allogenic surface water from an invasion polje with authigenic karst water. Dynamic mixing produces three climatically-induced discharge phases: baseflow, normal, and high-stage flow. Each has an associated hydrochemical regime, predominantly diffuse-flow karst water. An areal solute concentration of ~80 mg l-1 Ca2 is estimated, with a “denudation rate” of 100 mm per 1000 yr

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

Regional dolomitization of subtidal shelf carbonates: Burlington and Keokuk Formations (Mississippian), Iowa and Illinois, 1987, Harris David C. , Meyers William J. ,
Cathodoluminescent petrography of crinoidal limestones and dolomites from the Mississippian (Osagean) Burlington and Keokuk Formations in Iowa and Illinois has revealed a complex diagenetic history of calcite cementation, dolomitization, chertification and compaction. Dolomite occurs abundantly in subtidal, open-marine facies throughout the study area. Three luminescently and chemically distinct generations of dolomite can be recognized regionally. Dolomite I, the oldest generation, is luminescent, thinly zoned, and occurs mainly as a replacement of lime mud. Dolomite II has dull red unzoned luminescence, and occurs mainly as a replacement of dolomite I rhombs. Dolomite III is non-luminescent, and occurs as a syntaxial cement on, and replacement of, older dolomite I and II rhombs. Petrography of these dolomite generations, integrating calcite cement stratigraphy, chertification and compaction histories has established the diagenetic sequence. Dolomites I and II pre-date all calcite cements, most chert, intergranular compaction and styloites. Dolomite III precipitation occurred within the calcite cement sequence, after all chert, and after at least some stylolitization. The stratigraphic limit of these dolomites to rocks older than the St Louis Limestone (Meramecian) suggests that dolomitization took place before or during a regional mid-Meramecian subaerial unconformity. A single dolomitization model cannot reasonably explain all three generations of dolomite in the Burlington and Keokuk limestones. Petrographic and geochemical characteristics coupled with timing constraints suggest that dolomite I formed in a sea water-fresh water mixing zone associated with a meteoric groundwater system established beneath the pre-St Louis unconformity. Dolomite II and III may have formed from externally sourced warm brines that replaced precursor dolomite at shallow burial depths. These models therefore suggest that the required Mg for dolomite I was derived mainly from sea water, whereas that for dolomites II and III was derived mainly from precursor Burlington--Keokuk dolomites through replacement or pressure solution

Carbonate dissolution in a modern mixing zone, 1988, Smart P. L. , Dawans J. M. , Whitaker F. ,

Chemical hydrogeology in natural and contaminated environments, 1989, Back W, Baedecker Mj,
Chemical hydrogeology, including organic and inorganic aspects, has contributed to an increased understanding of groundwater flow systems, geologic processes, and stressed environments. Most of the basic principles of inorganic-chemical hydrogeology were first established by investigations of organic-free, regional-scale systems for which simplifying assumptions could be made. The problems of groundwater contamination are causing a shift of emphasis to microscale systems that are dominated by organic-chemical reactions and that are providing an impetus for the study of naturally occurring and manmade organic material. Along with the decrease in scale, physical and chemical heterogeneity become major controls.Current investigations and those selected from the literature demonstrate that heterogeneity increases in importance as the study site decreases from regional-scale to macroscale to microscale. Increased understanding of regional-scale flow systems is demonstrated by selection of investigations of carbonate and volcanic aquifers to show how application of present-day concepts and techniques can identify controlling chemical reactions and determine their rates; identify groundwater flow paths and determine flow velocity; and determine aquifer characteristics. The role of chemical hydrogeology in understanding geologic processes of macroscale systems is exemplified by selection of investigations in coastal aquifers. Phenomena associated with the mixing zone generated by encroaching sea water include an increase in heterogeneity of permeability, diagenesis of minerals, and formation of geomorphic features, such as caves, lagoons, and bays. Ore deposits of manganese and uranium, along with a simulation model of ore-forming fluids, demonstrate the influence of heterogeneity and of organic compounds on geochemical reactions associated with genesis of mineral deposits. In microscale environments, importance of heterogeneity and consequences of organic reactions in determining the distributions and concentrations cf. constituents are provided by several studies, including infiltration of sewage effluent and migration of creosote in coastal plain aquifers. These studies show that heterogeneity and the dominance of organically controlled reactions greatly increase the complexity of investigations

Glaciation and saline-freshwater mixing as a possible cause of cave formation in the eastern Midcontinent region of the United States; a conceptual model, 1990, Panno Samuel V. , Bourcier William L. ,

Limestone caves form along ground-water paths of greatest discharge and solutional aggressiveness. Flow routes that acquire increasing discharge accelerate in growth, while others languish with negligible growth. As discharge increases, a maximum rate of wall retreat is approached, typically about 0.01-0.1 cm/yr, determined by chemical kinetics but nearly unaffected by further increase in discharge. The time required to reach the maximum rate is nearly independent of kinetics and varies directly with flow distance and temperature and inversely with initial fracture width, discharge, gradient, and P(CO2). Most caves require 10(4) - 10(5) yr to reach traversable size. Their patterns depend on the mode of ground-water recharge. Sinkhole recharge forms branching caves with tributaries that join downstream as higher-order passages. Maze caves form where (1) steep gradients and great undersaturation allow many alternate paths to enlarge at similar rates or (2) discharge or renewal of undersaturation is uniform along many alternate routes. Flood water can form angular networks in fractured rock, anastomotic mazes along low-angle partings, or spongework where intergranular pores are dominant. Diffuse recharge also forms networks and spongework, often aided by mixing of chemically different waters. Ramiform caves, with sequential outward branches, are formed mainly by rising thermal or H2S-rich water. Dissolution rates in cooling water increase with discharge, CO2 content, temperature, and thermal gradient, but only at thermal gradients of more than 0.01-degrees-C/m can normal ground-water CO2 form caves without the aid of hypogenic acids or mixing. Artesian flow has no inherent tendency to form maze caves. Geologic structure and stratigraphy influence cave orientation and extent, but alone they do not determine branch-work versus maze character

Dissolution of carbonate minerals in the coastal halocline is taking place in the karst terrain along the northeastern coast of the Yucatan Peninsula. The dissolution is being accelerated in cenotes (sinkholes) where sulfate reduction and oxidation of the produced sulfide is occurring. Hydrogen-sulfide concentrations ranged from 0.06 to 4 mmolal within the halocline in two sinkholes. Relative to concentrations expected by conservative mixing, fluids with high hydrogen-sulfide concentrations were correlated with low sulfate concentrations, high alkalinities, low pH values, and heavy sulfur isotope values for sulfate. Hydrogen-sulfide concentrations were less than those predicted from sulfate reduction, calculated from deficiencies in measured sulfate concentrations, indicating mobility and loss of aqueous sulfide. Fluids with low hydrogen-sulfide concentrations were correlated with very high calcium concentrations, high strontium and sulfate concentrations, slightly elevated alkalinities, low pH values, and sea-water sulfur isotope values for sulfate. Gypsum dissolution is supported by the sulfur isotopes as the major process producing high sulfate concentrations. However, oxidation of aqueous sulfide to sulfuric acid, resulting in carbonate-mineral dissolution is needed to explain the calcium concentrations, low pH values, and only slightly elevated alkalinities. The halocline may trap hydrogen sulfide that has been stripped from the underlying anoxic salt water. The halocline can act as a stable, physical boundary, holding some of the hydrogen sulfide until it is oxidized back to sulfuric acid through interaction with the overlying, oxygenated fresh water or through the activity of sulfide-oxidizing bacteria

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