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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 food chain is a series of plants and animals linked by their food relationships; the passage of energy and materials from producer through a succession of consumers. green plants, plant- eating insects, and an insect-eating bat would form a simple food chain [23]. see also food web.?

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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 trace elements (Keyword) returned 32 results for the whole karstbase:
Showing 1 to 15 of 32
Origin of the sedimentary deposits of the Naracoorte Caves, South Australia, , Forbes Ms, Bestland Ea,
The origin of the sediments located in the Naracoorte Caves (South Australia) was investigated via the analysis of strontium isotope ratios (87Sr/86Sr), elemental geochemistry, and mineralogy. Sedimentary deposits located in Robertson, Wet, Blanche and several other chambers in Victoria Cave are all variable mixes of fine sand and coarse silts, which display similar and consistent strontium isotope ratios (0.717-0.725). This suggests that over the 400[no-break space]ka time frame that these deposits span there has been minimal variation in the source of the clastic sediments. Increased strontium concentrations for these cave sediments correspond with increasing silt content, yet there is no correlation between 87Sr/86Sr ratios and silt content. This implies that the silt-sized component of the sediments is the main contributor of strontium to the cave sediments. Comparisons of 87Sr/86Sr with regional surficial deposits show a significant correlation between the cave sediments (avg: 0.7228; n = 27), the fine silt lunettes of the Bool Lagoon area (avg: 0.7224; n = 4), the sandy A horizons of the Coonawarra Red Brown Earths (RBEs; avg: 0.726; n = 5), and Holocene age podsolic sand deposits (0.723). These data suggest that there has been substantial flux from this group of deposits to the caves, as would be expected considering prevailing winds. This relationship is further supported by a strong correlation between many trace elements, including Ti, Zr, Ce, and Y; however, variations in clay mineralogy suggest that the fine silt-dominated lunettes and Padthaway RBEs were not significant contributors to the cave deposits. Hence, the detritus entering the caves was more than likely from areas proximal to the cave entrance and was dominated by medium grain-sized materials. Major regional deposits, including the coarser-grained, calcite-rich Bridgewater Formation sands, basalts from the lower SE, Padthaway Horst granites, Gambier limestone, and metamorphics from the Adelaide geosyncline show minimal correlation in 87Sr/86Sr ratios, elemental geochemistry, and mineralogy with the cave sediments, and are discounted as significant sources. In comparison, 87Sr/86Sr ratios for the Coorong silty sands (0.717-0.724), Lower Murray sands (0.727-0.730), and the medium size silt component of the Murray-Darling River system (0.71-0.72), compare favourably with the cave sediments. This relationship is further supported by similarities in elemental chemistry and mineralogy. Thus, much of the strontium-rich silt that is now located in the Naracoorte Cave sediments likely originated from the Murray-Darling basin. Over time, this material has been transported to the SE of South Australia, where it mixed with the medium sand component of the regressive dune ridge sequence, locally derived organic matter, limestone fragments, and fossil material to produce the unique deposits that we see evident in many of the chambers of the Naracoorte Cave system today

Trace-element partition coefficients in the calcite-water system and their paleoclimatic significance in cave studies, 1983, Gascoyne M,
Speleothems (stalactites, stalagmites) formed in limestone caves have been found to contain much information on the timing and intensity of past climates, from analysis of their U, Th, 13C and 18O contents. Because the incorporation of certain trace elements (e.g., Mg, Mn and Zn) in calcite is known to be temperature-dependent, it may be possible to use variations in trace-metal content of fossil speleothems as an alternative paleotem-perature indicator. Using specially developed ion-exchange sampling techniques, analysis of trace-metal content of seepage water and associated fresh calcite deposits in caves in Vancouver Island and Jamaica shows that Mg is distributed between phases in a consistent manner within the temperature regimes of the caves (7[deg] and 23[deg]C, respectively). Average values of the distribution coefficient for Mg are respectively 0.017 and 0.045 at these temperatures. These results indicate that the Mg content of calcite varies directly with temperature and in a sufficiently pronounced manner that a 1[deg]C rise in depositional temperature of a speleothem containing 500 ppm Mg, at ~10[deg]C, would be seen as an increase of ~35ppm Mg -- a readily determinable shift. Other factors affecting Mg content of a speleothem are considered

Carbonate chemistry of surface waters in a temperate karst region: the southern Yorkshire Dales, UK, 1992, Pentecost Allan,
A detailed study of surface water chemistry is described from an important limestone region in northern England. Major ions and pH were determined for 485 sites (springs, seeps, streams, rivers and lakes) during summertime. The saturation state of the waters with respect to calcite was determined as the calcite saturation ratio ([Omega]). An unexpectedly large number of samples were found to be supersaturated (65.5% of the 268 km of watercourses surveyed). As a consequence, several streams entering major cave systems were incapable of further limestone solution, at least during periods of low flow. Many waters were supersaturated from their source and some deposited travertine. A significant negative correlation was found between spring discharge and both ([Omega]) and pH. Supersaturation was caused primarily by atmospheric degassing, with some contribution from aquatic plant photosynthesis.The median total dissolved inorganic carbon and Ca concentrations were 2.49 and 1.35 millimoles 1-1 respectively. Calcium originated exclusively from limestone, and carbon dioxide mainly from the soil and dissolved limestone. South facing catchments provided springwaters with significantly higher levels of TDIC and Ca when compared with north facing catchments. The study suggests that acid rain made a measurable contribution to limestone dissolution.Carboniferous limestone denudation rates were estimated as 54 to 63 m3 km-2 a-1 (54 to 63 mm 1000 years-1). About 50% of the Mg came from limestone and the remainder, together with most K, Na, SO4 and Cl from precipitation.Concentrations of dissolved nutrients were low, medians for NO3, NH4, total PO4 and SiO3 were 24 [mu]mol, 1.4 [mu]mol, 0.64 [mu]mol and 15.5 [mu]mol 1-1 respectively. The concentration of a further 23 trace elements was determined

Geochemistry and water dynamics: Application to short time-scale flood phenomena in a small Mediterranean catchment .1. Alkalis, alkali-earths and Sr isotopes, 1997, Benothman D, Luck Jm, Tournoud Mg,
We report major, trace elements and Sr isotope data for water samples taken regularly during a four-day-long September flood of a Mediterranean river, the Vene (Herault, S. France). The objective is to combine all these data into a dynamic model that describes the origin(s) and movements of waters and their loads. This river drains the runoff from a small, mainly carbonate, partly karstified watershed with Miocene and Jurassic lithologies. The watershed is also impacted by both agricultural and urban activities. Both the dissolved and the particulate loads were analyzed. Concentrations of the dissolved components show major remobilization of almost all elements during the first few hours of the flood (water treatment plants and aerosol scavenging), followed by a sharp concentration decrease. Some major species return to their previous summer values (Ca, HCO3) while others reach low 'background' levels (Na, K, Cl, SO4). Some trace elements (Rb, Sr, Cs) show similar behaviour but (Ba) appears somewhat unaffected. Trace element concentrations and ratios define two main periods (three in the suspended particulate matter). Ratios do not allow distinguishing between the three main sources for the dissolved load in the first period (Miocene, Jurassic, water treatment plants), but clearly show the Jurassic karst influence later on. The Sr-87/Sr-86 Of the suspended particulate matter is more variable and more radiogenic than in the dissolved phase. Variations in concentration ratios and Sr isotope composition in particulates indicate the large and variable contribution of Miocene silicates with some carbonate. However, there is a need for another component with [Rb]/[Sr] higher than bedrocks, internal or external to the watershed, possibly due to differential erosion. Dissolved Ca and Mg fluxes during the flood were calculated at 0.26 ton and 0.029 ton/km(2), respectively. Even though the carbonate nature of the watershed restricts variability in Sr isotope composition in the dissolved load, we distinguish several endmembers: seawater(approximate to marine rain), Miocene marls, Jurassic limestones, water treatment plants (and possibly another attributable to fertilizers). Combined with major and trace element variational Sr isotope fluctuations indicate time-varying proportions of different water endmembers at the outflow and suggest a general dynamic model. Based on PCA (principal component analysis), a 3D representation allows to visualize the geochemical evolution of the Vene waters. In particular, Sr isotopes clearly indicate that the inflow of karstic waters during the flood was not continuous but occurred as a series of marked oscillations between flowing waters with chemical signature of Miocene lithologies and increasing flushes of deeper waters that interacted with Jurassic lithologies. (C) 1997 Elsevier Science B.V

Interactions between ground water and surface water in the Suwannee River Basin, Florida, 1997, Katz B. G. , Dehan R. S. , Hirten J. J. , Catches J. S. ,
Ground water and surface water constitute a single dynamic system in most parts of the Suwannee River basin due to the presence of karst features that facilitate the interaction between the surface and subsurface. Low radon-222 concentrations (below background levels) and enriched amounts of oxygen-18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where around water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low-flow and high-flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River

Petrography, strontium, barium and uranium concentrations, and strontium and uranium isotope ratios in speleothems as palaeoclimatic proxies: Soreq Cave, Israel, 1999, Ayalon A, Barmatthews M, Kaufman A,
The reconstruction of the palaeoclimate of the eastern Mediterranean region for the last 60 ka BP is based on the delta(18)O and delta(13)C variations of speleothems from Soreq Cave, Israel. Climatic conditions during most of the rime interval between 60 and 17 ka BP (the period equivalent to the last glacial) were relatively cold and dry, while they were warmer and wetter from 17 ka BP to the present. At similar to 17 ka BP, there was a major climatic change with a sharp increase in annual rainfall and temperature and a very wet period occurring between 8.5 and 7.0 ka BP. During the colder and drier period, large, detritus-free, preferentially oriented calcite crystals were deposited from slow-moving water. As a result of a sharp change in the hydrological regime at similar to 17 ka BP, fast-moving water started entrainment of the soil and carrying detrital material into the cave, and the calcite crystals deposited became small and anhedral. Coinciding with the petrographic and isotopic changes, a sharp drop occurred in the concentrations of strontium, barium and uranium, and in the ratios Sr-87/Sr-86 and (U-234/U-238)(0), which reached mini mum values during the wettest period. This drop reflects enhanced weathering of the soil dolomite host rock. During colder and drier periods, higher trace-element concentrations and higher isotopic ratios reflect an increase in the contribution of salts derived from exogenic sources (sea spray and aeolian dust), and a reduced contribution of weathering from the host dolomites

Tertiary weathered sediments located immediately to the west of the harbor at Newhaven, Sussex, UK, were investigated by examination of major and trace elements by scanning electron microscope (SEM), microprobe, and inductively coupled plasma mass spectrometer (ICP-MS), and the mineralogy was studied by optical petrography, X-ray diffraction (XRD), transmission electron microscope (TEM), selective leaching, and thermodynamic modeling. Studied outcrops experienced acid leaching by sulfuric acid percolating downward through Tertiary sediments overlying Cretaceous chalk. The progressive neutralization of the percolating acid fluids resulted in 'sequentially' layered neoformation of minerals: jarosite, iron oxides, aluminous minerals (sulfates, oxyhydroxides), gypsum, and Fe-Mn oxides. Substantial agreement was found between field observations and mineral assemblages obtained by modeling with the program CHILLER. These results suggest that the initial assumptions on the weathering process and mechanisms are correct. The relevance and implications of this study in the modeling of future denudation and weathering processes of radioactive waste-disposal sites (both deeply buried sites for high-level waste and surface sites for low-level waste) are discussed. Neoformed phases, such as jarosite, aluminous minerals, and silico-aluminous gels may play a significant role in the efficient trapping of mobilized pollutant radionuclides

Seasonal variations in Sr, Mg and P in modern speleothems (Grotta di Ernesto, Italy), 2001, Huang Yiming, Fairchild Ian J. , Borsato Andrea, Frisia Silvia, Cassidy Nigel J. , Mcdermott Frank, Hawkesworth Chris J. ,
Sub-annual variations in trace element chemistry and luminescence have recently been demonstrated from speleothems and offer the potential of high-resolution palaeoclimatic proxies. However, no studies have yet examined microscopic trace element variations in relation to modern cave conditions. In this study, the spatial variations in trace element (Sr, Mg and P) concentrations in speleothems (a stalagmite and a soda straw stalactite) from the alpine Ernesto cave (temperature 6.60.1[deg]C) in a forested catchment in NE Italy have been studied using secondary ion mass spectrometry (SIMS) and compared with environmental parameters and waters in the modern cave. An annual lamination exists in the stalagmite and soda straw stalactite in the form of clear calcite with narrow visible layers, which are UV-fluorescent and interpreted to contain soil-derived humic/fulvic acids washed into the cave during autumn rains. Microanalyses were undertaken of seven annual laminae, probably deposited during the 1960s in the stalagmite, and seven laminae in the 1990s for the stalactite.The analysis results show that Sr consistently has a trough and P, a peak centred on the inclusion-rich layer. Mg shows mainly a negative covariation with Sr in laminae formed in the 1990s, but a positive covariation in the stalagmite formed in 1960s. The spatial scale of the main geochemical variations is the same as that of annual laminae of inclusion-poor and inclusion-rich couplets. Mass balance arguments are used to show that the P is inorganic in form and presumably occurs as individual phosphate ions within the calcite.Most drip waters show limited chemical variations, but a summer peak in trace elements in 1995 and a decrease in Mg/Ca in the following winter are notable. More pronounced covariations in Mg/Ca and Sr/Ca are shown by a site with highly variable drip rates where ratios increase at slow drip rates. The strongest seasonal variations are found in pool waters, where ratios increase reflecting significant Ca removal from the water into the calcite during the winter in response to seasonal PCO2 variations in cave air. Thus, the cave waters' compositions tend to reflect climate conditions, such that Mg/Ca and Sr/Ca are tentatively interpreted to be higher when climate conditions are dry.Combining results from the speleothems and cave water along with the behaviour of each trace species, Mg/Ca variations in the speleothems are considered to reflect their variation in the cave waters, whereas, Sr incorporation is also dependent on precipitation rate, in this case, mainly controlled by temporal variations in PCO2 in the cave (and conceivably, also by inhibitors such as phosphate). P adsorption (a fraction of which is subsequently incorporated within calcite) depends on aqueous phosphate concentration and water flux, both of which should increase during the autumn. Therefore, multiple trace element profiles in speleothems reflect multiple aspects of environment seasonality and conditions, and hence, a calibration against weather records is desirable to establish their palaeoclimatological meaning. The strong annual variation of trace elements, and particularly P, can provide chronological markers for high-resolution studies of other climate proxies, such as stable isotopes

Mineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, Russia, 2001, Mordberg L. E. , Stanley C. J. , Germann K. ,
Processes of mineral alteration involving the mobilization and deposition of more than 30 chemical elements during bauxite formation and epigenesis have been studied on specimens from the Devonian Schugorsk bauxite deposit, Timan, Russia. Chemical analyses of the minerals were obtained by electron microprobe and element distribution in the minerals was studied by element mapping. Interpretation of these data also utilized high-resolution BSE and SE images. The main rock-forming minerals of the Vendian parent rock are calcite, dolomite, feldspar, aegirine, riebeckite, mica, chlorite and quartz; accessory minerals are pyrite, galena, apatite, ilmenite, monazite, xenotime, zircon, columbite, pyrochlore, chromite, bastnaesite and some others. Typically, the grain-size of the accessory minerals in both parent rock and bauxite is from 1 to 40 {micro}m. However, even within these rather small grains, the processes of crystal growth and alteration during weathering can be determined from the zonal distribution of the elements. The most widespread processes observed are: (1) Decomposition of Ti-bearing minerals such as ilmenite, aegirine and riebeckite with the formation of leucoxene', which is the main concentrator of Nb, Cr, V and W. Crystal growth can be traced from the zonal distribution of Nb (up to 16 wt.%). Vein-like leucoxene' is also observed in association with organics. (2) Weathering of columbite and pyrochlore: the source of Nb in leucoxene' is now strongly weathered columbite, while the alteration of pyrochlore is expressed in the growth of plumbopyrochlore rims around Ca-rich cores. (3) Dissolution of sulphide minerals and apatite and the formation of crandallite group minerals: crandallite' crystals of up to 40 {micro}m size show a very clear zonation. From the core to the rim of a crystal, the following sequence of elements is observed: Ca [->] Ba [->] Ce [->] Pb [->] Sr [->] Nd. Sulphur also shows a zoned but more complicated distribution, while the distribution of Fe is rather variable. A possible source of REE is bastnaesite from the parent rock. More than twelve crandallite type cells can be identified in a single crandallite' grain. (4) Alteration of stoichiometric zircon and xenotime with the formation of metamict solid solution of zircon and xenotime: altered zircon rims also bear large amounts of Sc (up to 3.5 wt.%), Fe, Ca and Al in the form of as yet unidentified inclusions of 1-2 {micro}m. Monazite seems to be the least altered mineral of the profile. In the parent rock, an unknown mineral of the composition (wt.%): ThO2 - 54.8; FeO - 14.6; Y2O5 -2.3; CaO - 2.0; REE - 1.8; SiO2 - 12.2; P2O5 - 2.8; total - 94.2 (average from ten analyses) was determined. In bauxite, another mineral was found, which has the composition (wt.%): ThO2 - 24.9; FeO - 20.5; Y2O5 - 6.7; CaO - 2.0; ZrO - 17.6; SiO2 - 8.8; P2O5 - 5.4; total - 89.3 (F was not analysed; average from nine analyses). Presumably, the second mineral is the result of weathering of the first one. Although the Th content is very high, the mineral is almost free of Pb. However, intergrowths of galena and pyrite are observed around the partially decomposed crystals of the mineral. Another generation of galena is enriched in chalcophile elements such as Cu, Cd, Bi etc., and is related to epigenetic alteration of the profile, as are secondary apatite and muscovite

Blue Bone Analyses as a Contribution to the Study of Bone Taphonomy in San Josecito Cave, Nuevo Leon, Mexico, 2002, Robles, J. , Arroyocabrales, J. , Johnson, E. , Allen, B. L. , Izquierdo, G.
Blue-stained bones, collected along a single stratigraphic level in San Josecito Cave, Nuevo Le?n, M?xico, were analyzed in order to better understand the diagenetic processes that pertained to their formation, and in order to ascertain if those processes could be used in inferring past environmental conditions. Using XRD, two minerals were identified as composing the fossil bone, hydroxylapatite and calcite. INAA, ICPS, XRFS, and colorimetric methods were used to quantify trace elements, including Cu, Sr, Zn, F, and Cl (in descending order). The findings point to the presence of a physical phenomenon produced by transition metal ions impurities, that in turn seems to be associated with physical and chemical processes occurring inside the cave, rather than with outside paleoenvironmental conditions

Origin, evolution and residence time of saline thermal fluids (Balaruc springs, southern France): implications for fluid transfer across the continental shelf, 2002, Aquilina L. Ladouche B. Doerfliger N. , Seidel J. L. , Bakalowicz M. , Dupuy C. , Le Strat P.

Thermal fluids in the Balaruc-les-Bains peninsula, on the northeastern edge of the Thau lagoon (southern France), supply the third largest spa in France. These thermal fluids interact with karst water in the Upper Jurassic aquifer composed of limestone and dolomite, forming two massifs to the east and north of the lagoon. These calcareous formations extend under the western end of the Thau lagoon. Geochemical and isotope analyses were carried out in 1996 and 1998 on the thermal wells of the Balaruc-les-Bains peninsula to determine the origin of the thermal fluids and their interaction with subsurface karst water. The thermal fluids are a mixture of karst water and water of marine origin. 3H and NO3 concentrations show that the proportion of present-day karst water in certain thermal wells is small ( < 5%), thus enabling us to define a ‘‘pure’’ thermal end-member. The thermal end-member is itself a mixture of seawater and meteoric paleowater. Ca and Sr concentrations indicate a lengthy interaction with the carbonate substratum of the deep reservoir. Sr isotope signatures are very homogeneous and associated mainly with the dissolution of Jurassic carbonate, but also to evaporitic minerals. y13C contents indicate that this dissolution is linked to deep inflow of CO2. 87Sr, trace element and rare earth element (REE) concentrations indicate that there is also a component, with a systematically minor participation, whose origin is deeper than the Jurassic carbonate and attributed to the Triassic and/or to the crystalline basement. 36Cl concentrations are extremely low, indicating a residence time of around a hundred thousand years. The outflow temperature of the thermal fluids reaches 50 jC, and geothermometers indicate a reservoir temperature of around 80–100 jC, locating this aquifer at a depth of between 2000 and 2500 m. The geometry of the geological formations indicates a thrust plane associated with major basement faulting that separates the two calcareous massifs and seems to control the rise of deep thermal fluids from the Jurassic carbonate reservoirs and the participation of a deeper component from the basement and/or the Triassic. The present study shows that seawater can infiltrate at great depths and reside for long periods of time compared to the subsurface groundwater cycle. Compared to other highly saline fluids encountered in basement zones, these waters have a relatively well-preserved marine signature, probably due to the carbonate nature of the aquifer in which the fluids resided and their short residence time.

Analysis of karst tufa from Guangxi, China, 2003, Franciskovicbilinski S, Bilinski H, Barisic D, Horvatincic N, Yuan Dx,
The paper presents an analysis of characteristic karst tufa from Guangxi, China, which has not been studied before. A comparison with tufa from Dinaric Karst of Croatia is discussed in view of the C-type climate. The major mineral is calcite. Minor minerals are quartz and dolomite, depending on location. The content of calcium carbonate varies from 65% to 92%, and that of magnesium carbonate from 0.03% to 1.77%. Among other elements, the most abundant are Fe, from 0.02% to 1.50%, and Ti, from 0.15% to 0.27%. Many other trace elements (V, Cr, Mn, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Hg and Pb) are also present. Specific activity of radionuclides K-40, Th-232, Cs-137, Ra-226 and U-238 varies from sample to sample. Concentration of U in tufa is close to that reported for sedimentary carbonate. Low concentration Of Cs-137 indicates that this part of the world was not exposed to nuclear explosions. The concentration of Ra-226 is the highest in Mashan County. The ratio U-238/Ra-226 (0.21-0.71) in tufa from Mashan County is significantly lower than the theoretical value of 1. In 5 of the 11 studied samples, stable isotopes delta(13)C and delta(18)O were analyzed. They were dated by means of the C-14 method. One tufa sample originated in the Pleistocene and the others in the Holocene. Because all of the tufa samples contain traces of Na and K, and K < Na, the tufa from Guangxi belong to the CO2-outgassing 'N' type according to the classification of Liu and He (1994)

Trace elements in speleothems. A short review of the state of the art., 2004, Verheyden Sophie
A state of the art of the research on trace elements of speleothems is given. First studies focussed on problems such as the colour of speleothems and the aragonite problem. Insitu studies and studies oriented towards a better understanding of vadose hydrology brought new insights in the controls on trace elemental composition of speleothems. Recent studies deal with microscale analyses and annual and intra-annual chemistry changes. Further in-situ studies should be performed to further differentiate influences, such as climate, soil/weathering and local hydrology in order to better constrain possible transfer functions between the surface and a speleothem.

Study of soil leachates in doline above the Beke Cave, Hungary, 2004, Tatar E. , Mihucz V. G. , Tompa K. , Poppl L. , Zaray G. , Zambo L. ,
Fulvic acid, Ca and Mg concentrations as well as dissolved inorganic carbon (DIC), pH and electric conductivity values of soil solutions which resulted from injecting bidistilled water onto glass columns filled with different soils (black rendzina, brown rendzina, red clayey rendzina, red clay) characteristic of the Aggtelek karst system (NE Hungary), were determined. Identification and determination of fulvic acid were achieved by size exclusion chromatography (SEC) and adsorption chromatography, respectively, with fluorescent spectrometric detection. The Ca and Mg concentration of the samples was determined by applying an inductively coupled plasma atomic emission spectrometric (ICP-AES) method. DIC-expressed in CO2 concentration values-was determined by using a CO2 selective electrode. According to the SEC analysis, the apparent molecular weight of the fulvic acids of the samples were between 500 and 1600 Da. The fulvic acid concentration values of the percolated water samples decreased in function of the soils investigated as follows: black rendzina>brown rendzina>red clayey rendzina>red clay, which is in concordance with the organic matter content of these types of soils. The results obtained for fulvic acid, Ca and Mg concentrations as well as for DIC, pH and electric conductivity of the water samples collected from the column filled with red clay were in good agreement with those of a seepage water sample collected from an observation station built in red clay above the Beke Cave (Aggtelek). Since the artificially prepared red clay column was exposed to the same temperature and humidity conditions like red clay of the sampling site, this method seems to be suitable for modelling infiltration of fulvic acid and metals from red clay into seepage water under laboratory conditions. (C) 2003 Elsevier B.V. All rights reserved

Concepts and models of dolomitization: a critical reappraisal, 2004, Machel Hans G. ,
Despite intensive research over more than 200 years, the origin of dolomite, the mineral and the rock, remains subject to considerable controversy. This is partly because some of the chemical and/or hydrological conditions of dolomite formation are poorly understood, and because petrographic and geochemical data commonly permit more than one genetic interpretation. This paper is a summary and critical appraisal of the state of the art in dolomite research, highlighting its major advances and controversies, especially over the last 20-25 years. The thermodynamic conditions of dolomite formation have been known quite well since the 1970s, and the latest experimental studies essentially confirm earlier results. The kinetics of dolomite formation are still relatively poorly understood, however. The role of sulphate as an inhibitor to dolomite formation has been overrated. Sulphate appears to be an inhibitor only in relatively low-sulphate aqueous solutions, and probably only indirectly. In sulphate-rich solutions it may actually promote dolomite formation. Mass-balance calculations show that large water/rock ratios are required for extensive dolomitization and the formation of massive dolostones. This constraint necessitates advection, which is why all models for the genesis of massive dolostones are essentially hydrological models. The exceptions are environments where carbonate muds or limestones can be dolomitized via diffusion of magnesium from seawater rather than by advection. Replacement of shallow-water limestones, the most common form of dolomitization, results in a series of distinctive textures that form in a sequential manner with progressive degrees of dolomitization, i.e. matrix-selective replacement, overdolomitization, formation of vugs and moulds, emplacement of up to 20 vol% calcium sulphate in the case of seawater dolomitization, formation of two dolomite populations, and -- in the case of advanced burial -- formation of saddle dolomite. In addition, dolomite dissolution, including karstification, is to be expected in cases of influx of formation waters that are dilute, acidic, or both. Many dolostones, especially at greater depths, have higher porosities than limestones, and this may be the result of several processes, i.e. mole-per-mole replacement, dissolution of unreplaced calcite as part of the dolomitization process, dissolution of dolomite due to acidification of the pore waters, fluid mixing (mischungskorrosion), and thermochemical sulphate reduction. There also are several processes that destroy porosity, most commonly dolomite and calcium sulphate cementation. These processes vary in importance from place to place. For this reason, generalizations about the porosity and permeability development of dolostones are difficult, and these parameters have to be investigated on a case-by-case basis. A wide range of geochemical methods may be used to characterize dolomites and dolostones, and to decipher their origin. The most widely used methods are the analysis and interpretation of stable isotopes (O, C), Sr isotopes, trace elements, and fluid inclusions. Under favourable circumstances some of these parameters can be used to determine the direction of fluid flow during dolomitization. The extent of recrystallization in dolomites and dolostones is much disputed, yet extremely important for geochemical interpretations. Dolomites that originally form very close to the surface and from evaporitic brines tend to recrystallize with time and during burial. Those dolomites that originally form at several hundred to a few thousand metres depth commonly show little or no evidence of recrystallization. Traditionally, dolomitization models in near-surface and shallow diagenetic settings are defined and/or based on water chemistry, but on hydrology in burial diagenetic settings. In this paper, however, the various dolomite models are placed into appropriate diagenetic settings. Penecontemporaneous dolomites form almost syndepositionally as a normal consequence of the geochemical conditions prevailing in the environment of deposition. There are many such settings, and most commonly they form only a few per cent of microcrystalline dolomite(s). Many, if not most, penecontemporaneous dolomites appear to have formed through the mediation of microbes. Virtually all volumetrically large, replacive dolostone bodies are post-depositional and formed during some degree of burial. The viability of the many models for dolomitization in such settings is variable. Massive dolomitization by freshwater-seawater mixing is a myth. Mixing zones tend to form caves without or, at best, with very small amounts of dolomite. The role of coastal mixing zones with respect to dolomitization may be that of a hydrological pump for seawater dolomitization. Reflux dolomitization, most commonly by mesohaline brines that originated from seawater evaporation, is capable of pervasively dolomitizing entire carbonate platforms. However, the extent of dolomitization varies strongly with the extent and duration of evaporation and flooding, and with the subsurface permeability distribution. Complete dolomitization of carbonate platforms appears possible only under favourable circumstances. Similarly, thermal convection in open half-cells (Kohout convection), most commonly by seawater or slightly modified seawater, can form massive dolostones under favourable circumstances, whereas thermal convection in closed cells cannot. Compaction flow cannot form massive dolostones, unless it is funnelled, which may be more common than generally recognized. Neither topography driven flow nor tectonically induced ( squeegee-type') flow is likely to form massive dolostones, except under unusual circumstances. Hydrothermal dolomitization may occur in a variety of subsurface diagenetic settings, but has been significantly overrated. It commonly forms massive dolostones that are localized around faults, but regional or basin-wide dolomitization is not hydrothermal. The regionally extensive dolostones of the Bahamas (Cenozoic), western Canada and Ireland (Palaeozoic), and Israel (Mesozoic) probably formed from seawater that was pumped' through these sequences by thermal convection, reflux, funnelled compaction, or a combination thereof. For such platform settings flushed with seawater, geochemical data and numerical modelling suggest that most dolomites form(ed) at temperatures around 50-80 {degrees}C commensurate with depths of 500 to a maximum of 2000 m. The resulting dolostones can be classified both as seawater dolomites and as burial dolomites. This ambiguity is a consequence of the historical evolution of dolomite research

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