Karst and Cave RSS news feed Like us on Facebook! follow us on Twitter!
Community news

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. ...

Did you know?

That rejuvenation is a process that interrupts an active erosional or development cycle and initiates a new cycle. rejuvenation is most commonly achieved in the karst and speleogenesis context by erosional baselevel changes caused by relative uplift (or sea-level fall) or by local water-table changes caused by downcutting of surface valleys intercepting deeper drainage lines [9].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

What is Karstbase?

Search KARSTBASE:

keyword
author

Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
Engineering challenges in Karst, Stevanović, Zoran; Milanović, Petar
See all featured articles
Featured articles from other Geoscience Journals
Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy), Dimuccio, L.A.; Rodrigues, N.; Larocca, F.; Pratas, J.; Amado, A.M.; Batista de Carvalho, L.A.
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
See all featured articles from other geoscience journals

Search in KarstBase

Your search for potassium (Keyword) returned 23 results for the whole karstbase:
Showing 1 to 15 of 23
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

Observations at the Blue Waterholes, March 1965 - April 1969, and Limestone Solution on Cooleman Plain, N.S.W., 1972, Jennings, J. N.

After brief descriptions of the geomorphology of the Cooleman Plain karst and in particular of the Blue Waterholes, the methods adopted to analyse the functioning of these major risings are detailed. The discharge regime of Cave Creek below them is oceanic pluvial in type perturbed by drought and snow. There is much annual variation both in seasonal incidence and total amount, with catchment efficiency correspondingly variable. Suspended sediment concentration is even more erratic and monthly determinations are inadequate for calculating corrasional denudation rates. Mean concentrations of suspended solids are about 1/18th of solute load. Total dissolved salts have a strong inverse relationship with discharge, and mean values are high compared with those for other catchments in eastern Australia but none of these determinations are from limestone catchments. Sodium, potassium, and chlorine contents are low compared with the same catchments but silica is relatively high. The ratio of alkaline earths to alkalis indicate that Cave Creek carries carbonate waters and there is an inverse regression of the ratio on discharge. There is inverse correlation of total hardness on discharge likewise due to concentration of surface waters by evaporation in dry periods, together with reduced underground solution rate at times of large, rapid flow. The spring waters remain aggressive. Close regressions of hardness on specific conductivity now permit the latter to be determined in the place of the former. Much evidence converges to indicate that all the springs at the Blue Waterholes are fed from the same conduit. The intermittent flow which comes down the North Branch on the surface to the Blue Waterholes differs significantly in many characters from the spring waters. Rates of Ca + M carbonate equivalent removal vary directly with discharge since hardness varies much less than does water volume. These gross rates have to be adjusted for (a) atmospheric salts entering the karst directly, (b) peripheral solute inputs from the non-karst two-thirds of the catchment and (c) subjacent karst solution before they can be taken as a measure of exposed karst denudation. The methods for achieving this are set out. The total corrections amount to about one third of the total hardness, though the correction for subjacent karst on its own lies within the experimental error of the investigation. The residual rate of limestone removal from the exposed karst also shows a winter/spring high rate and a summer/autumn low rate but the seasonal incidence and annual total varied very much from year to year. In comparison with results from karsts in broadly similar climate, the seasonal rhythm conforms and so does the high proportion (78%) of the solution taking place at or close to the surface. This reduces the importance of the impounded condition of this small karst but supports the use of karst denudation rate as a measure of surface lowering. Cave passage solution may however be more important in impounded karst than its absolute contribution might suggest, by promoting rapid development of underground circulation. The mean value of limestone removal is low for the climatic type and this is probably due to high evapotranspirational loss as well as to the process of eliminating atmospheric, peripheral non-karst and subjacent karst contributions. The difficulties of applying modern solution removal rate to the historical geomorphology of this karst are made evident; at the same time even crude extrapolations are shown to isolate problems valuably.


The use of Saturation Index and Potassium/Sodium ratios as indicators of Speleological potential with special reference to Derbyshire, 1975, Christopher N. S. J.

Research on the soils of karst areas in Hungary (example from Bükk Mountain), 1999, Zseni Anikó,

The author studied the characteristics of the soil nutrient system in a Hungarian karst area, that is on 8 km2 area of the Bükk plateau. The pH, total carbonate content, total soil-nitrogen content, plant available calcium, potassium, magnesium, and phosphorus contents of 63 soil samples were measured. She was able to compare the nutrient system of the soils which occurred in different ecological conditions. There are differences between the nutrient status of the soils of the beech and pine forest and the open fields. The knowledge of the pH plus the N, P, K, Ca, Mg content of the soils can be important regarding the protection of the environment, the maintenance of the forest and the management of the meadows.


Geological Controls on the Distribution and Origin of Selected Inorganic Ions in Ohio Groundwater, 2002, Levine Norman S. , Roberts Sheila J. , Aring Jennifer L. ,
Contour maps showing the concentration of selected inorganic ions across the state of Ohio illustrate that high concentrations of some ions visually correlate with the location of major geologic features, whereas other ions are randomly distributed. Strontium and sulfate have high concentrations over the Cincinnati, Findlay, and Kankakee arches, where carbonate aquifers containing gypsum and celestite are located. The highest concentrations of potassium and beryllium are located along the Cambridge fault zone, a major structural feature in eastern Ohio. High concentrations of iron and nitrate are found adjacent to single wells. Nitrate highs may be related to anthropogenic contamination, whereas some iron anomalies are located where sulfate is high. The maps produced in this study indicate that statewide contour maps of ion concentrations are useful for correlating aquifer chemistry with the regional geology of an area and determining the background level of ions on a state-wide scale

Carbonate-Hosted Zn-Pb Deposits in Upper Silesia, Poland: Origin and Evolution of Mineralizing Fluids and Constraints on Genetic Models, 2003, Heijlen Wouter, Muchez Philippe, Banks David A. , Schneider Jens, Kucha Henryk, Keppens Eddy,
Microthermometric and crush-leach analyses of fluid inclusions in ore and gangue minerals of the Upper Silesian Zn-Pb deposits, Poland, along with first results of Rb-Sr geochronology on sulfides, provide important constraints on the paleohydrogeologic and metallogenetic models for the origin of these ores. The analyzed samples comprise two generations of dolomite, two generations of sphalerite, galena, and late calcite. The two dolomite generations and the late calcite were also analyzed for their oxygen and carbon isotope compositions, allowing a characterization of the mineralizing fluids. The ore-forming fluids represent highly saline (20-23 wt % CaCl2 equiv) Na-Ca-Cl brines, episodically introduced into the Triassic host carbonates. They had an oxygen isotope composition of ~0 per mil V-SMOW. Their Na-Cl-Br content (molar Na/Br and Cl/Br ratios between 99 and 337 and between 248 and 560, respectively) suggests that they originated by evaporation of seawater, which most likely occurred in the Permian-Triassic. The relative concentrations of potassium (molar K/Cl between 0.0147 and 0.0746) and lithium (molar Li/Cl between 0.0004 and 0.0031) further indicate that the fluids significantly interacted with siliciclastic rocks. The ionic and calculated oxygen isotope compositions of the fluids indicate that they were more evolved than present-day brines in the Upper Silesian coal basin, and the present-day brines show more extensive mixing with low-salinity fluids. The first results of direct Rb-Sr dating of ore-stage sulfides yield an isochron model age of 135 {} 4 Ma for the mineralizing event. This is consistent with hydrothermal activity and ore formation in Upper Silesia occurring in response to Early Cretaceous crustal extension preceding the opening of the northern Atlantic Ocean. The data presented support a model in which bittern brines migrated down into the deep subsurface and evolved into mineralizing fluids owing to extensive water-rock interaction. They were episodically expelled along deeply penetrating faults during the Early Cretaceous to form Zn-Pb deposits in the overlying Mesozoic carbonate rocks

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

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

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


Halloysite clay minerals -- a review, 2005, Joussein E. , Petit S. , Churchman J. , Theng B. , Righi D. , Delvaux B. ,
Halloysite clay minerals are ubiquitous in soils and weathered rocks where they occur in a variety of particle shapes and hydration states. Diversity also characterizes their chemical composition, cation exchange capacity and potassium selectivity. This review summarizes the extensive but scattered literature on halloysite, from its natural occurrence, through its crystal structure, chemical and morphological diversity, to its reactivity toward organic compounds, ions and salts, involving the various methods of differentiating halloysite from kaolinite. No unique test seems to be ideal to distinguish these 1:1 clay minerals, especially in soils. The occurrence of 2:1 phyllosilicate contaminants appears, so far, to provide the best explanation for the high charge and potassium selectivity of halloysite. Yet, hydration properties of the mineral probably play a major role in ion sorption. Clear trends seem to relate particle morphology and structural Fe. However, future work is required to understand the possible mechanisms linking chemical, morphological, hydration and charge properties of halloysite

Origin and transport of dissolved chemicals in a karst watershed, southwestern Illinois, 2005, Stueber A. M. , Criss R. E. ,
An extensive base of water quality information emphasizing the effects of land use and hydrology was obtained in the karstified Fountain Creek watershed of southwestern Illinois to help resolve local water quality issues. Agrichemicals dominate the loads of most water quality constituents in the streams and shallow karstic ground water. Only calcium (Ca), magnesium (Mg), Aluminum (AI), and sulfate (SO4) ions are predominantly derived from bedrock or soils, while agrichemicals contribute most of the sodium (Na), potassium (K), chlorine (Cl), nitrate (NO3), fluorine (F), phosphorus (P), and atrazine. Concentrations of individual ions correlate with discharge variations in karst springs and surface streams; highly soluble ions supplied by diffuse ground water are diluted by high flows, while less soluble ions increase with flow as they are mobilized from fields to karst conduits under storm conditions. Treated wastewater containing detergent residues dominates the boron load of streams and provides important subordinate loads of several other constituents, including atrazine derived from the Mississippi River via the public water supply. Average surface water concentrations at the watershed outlet closely approximate a 92:8 mixture of karst ground water and treated wastewater, demonstrating the dominance of ground water contributions to streams. Therefore the karst aquifer and watershed streams form a single water quality system that is also affected by wastewater effluent

The geochemistry of fluids from an active shallow submarine hydrothermal system: Milos island, Hellenic Volcanic Arc, 2005, Valsamijones E. , Baltatzis E. , Bailey E. H. , Boyce A. J. , Alexander J. L. , Magganas A. , Anderson L. , Waldron S. , Ragnarsdottir K. V. ,
Geothermal activity in the Aegean island of Milos (Greece), associated with island-arc volcanism, is abundant both on-and off-shore. Hydrothermal fluids venting from several sites, mainly shallow submarine (up to 10 m), but also just above seawater level in one locality, were sampled over four summer field seasons. Some of the discharging fluids are associated with the formation of hydrothermal edifices. Overall, the main characteristics of the hydrothermal fluids are low pH and variable chlorinity. The lowest recorded pH was 1.7, and chlorinity ranged from 0.1 to 2.5 times that of seawater. The highest fluid temperatures recorded on site were 115 degrees C. Two main types of fluids were identified: low-chlorinity fluids containing low concentrations of alkalis (potassium, lithium, sodium) and calcium, and high concentrations of silica and sulphate; and high-chlorinity fluids containing high concentrations of alkalis and calcium, and lower concentrations of silica and sulphate. The type locality of the high-chlorinity fluids is shallow submarine in Palaeochori, near the cast end of the south coast of the island, whereas the type locality of the low-chlorinity fluids is a cave to the west of Palaeochori. The two fluid types are therefore often referred to as 'submarine' and 'cave' fluids respectively. Both fluid types had low magnesium and high metal concentrations but were otherwise consistently different from each other. The low-chlorinity fluids had the highest cobalt, nickel, aluminium, iron and chromium (up to 1.6 mu M, 3.6 mu M, 1586 mu M, 936 mu M and 3.0 mu M, respectively) and the high-chlorinity fluids had the highest zinc, cadmium, manganese and lead (up to 4.1 mu M, 1.0 mu M, 230 mu M and 32 mu M, respectively). Geochemical modelling suggests that metals in the former are likely to have been transported as sulphate species or free ions and in the latter as chloride species or free ions. Isotopic values for both water types range between delta D -12 to 33 parts per thousand and delta(18)O 1.2 to 4.6 parts per thousand. The range of fluid compositions and isotopic contents indicates a complex history of evolution for the system. Both types of fluids appear to be derived from seawater and thus are likely to represent end members of a single fluid phase that underwent phase separation at depth. Crown Copyright (c) 2005 Published by Elsevier B.V. All rights reserved

Potential effects of recurrent low oxygen conditions on the Illinois cave amphipod, 2006, Panno, S. V. , Hackley, K. C. , Kelly, W. R. , Hwang, H. H. , Wilhelm, F. M. , Taylor, S. J. , Stiff B. J
The caves of Illinois sinkhole plain are the sole habitat of the Illinois Cave amphipod (Gammarus acherondytes), a federally endangered species. The sinkhole plain is a hydrologically-connected sequence of karstified limestone that constitutes an extensive karst aquifer which serves as an important source of potable water for area residents. During this investigation, we examined the ground-water quality in caves within two ground-water basins: 1) Illinois Caverns, where the amphipod is now present after previously reported to have been extirpated from the lower reaches, and 2) Stemler Cave, where the amphipod is reported to have been extirpated. The chemical composition of cave streams in Illinois Caverns and Stemler Cave were compared to determine which parameters, if any, could have contributed to the loss of G. acherondytes from Stemler Cave. Stream water in Stemler Cave contained higher concentrations of organic carbon, potassium, silica, chloride, fluoride, sulfate, iron and manganese than Illinois Caverns. Perhaps most importantly, dissolved oxygen (DO) concentrations in Stemler Cave were, during periods of low flow, substantially lower than in Illinois Caverns. Based on land use, there are probably at least eight times more private septic systems in the Stemler Cave ground-water basin than in the Illinois Caverns ground-water basin. Low DO concentrations were likely the result of microbial breakdown of soil organic matter and wastewater treatment system effluent, and the oxidation of pyrite in bedrock. The near-hypoxic DO in Stemler Cave that occurred during low-flow conditions, and, we speculate, a limited range of G. acherondytes within the Stemler Cave ground-water basin due to a metabolic advantage of the stygophilic aquatic invertebrates over the stygobitic G. acherodytes, resulted in the apparent loss of G. acherondytes from Stemler Cave.

Environmental Reconstruction of Karst using a Honeysuckle species widely used in Traditional Chinese Medicine, 2006, Xie Yunqiu, Zhang Cheng, L Yong, Deng Zhenping
As in the deserts of Northwestern China, there is a need to reconstruct the fragile karst of Southwestern China using sustainable techniques that protect the environment and develop the economy. One means of achieving this is to plant species used in traditional Chinese herbal medicine. The characteristics of Honeysuckle used in traditional Chinese medicine, when produced on the Donggangling Formation at Nongla Village in Mashan County, in Guangxi Province of Southwestern China, match those of Honeysuckle grown in traditional production areas of China, and comply with the specification set for the Honeysuckle by the P.R. China Codex. Added properties of the Honeysuckle are the accumulation of phosphorus and potassium, in addition to the accumulation of elements such as calcium, magnesium, copper, zinc and so on. Further discussion considers extending the areas in which this Honeysuckle is currently grown, and its limitations in the karst region of Southwestern China where 60% - 70% of calcareous soil may be suitable for its cultivation.

Environmental Reconstruction of Karst using a Honeysuckle species widely used in Traditional Chinese Medicine, 2006, Yunqiu Xie, Cheng Zhang, Yong L. , Zhenping Deng

As in the deserts of Northwestern China, there is a need to reconstruct the fragile karst of Southwestern China using sustainable techniques that protect the environment and develop the economy. One means of achieving this is to plant species used in traditional Chinese herbal medicine. The characteristics of Honeysuckle used in traditional Chinese medicine, when produced on the Donggangling Formation at Nongla Village in Mashan County, in Guangxi Province of Southwestern China, match those of Honeysuckle grown in traditional production areas of China, and comply with the specification set for the Honeysuckle by the P.R. China Codex. Added properties of the Honeysuckle are the accumulation of phosphorus and potassium, in addition to the accumulation of elements such as calcium, magnesium, copper, zinc and so on. Further discussion considers extending the areas in which this Honeysuckle is currently grown, and its limitations in the karst region of Southwestern China where 60% - 70% of calcareous soil may be suitable for its cultivation.


Evidence against the Dorag (mixing-zone) model for dolomitization along the Wisconsin arch - A case for hydrothermal diagenesis , 2006, Luczaj, J. A.

Ordovician carbonates near the Wisconsin arch represent the type locality in ancient rocks for the Dorag, or mixing-zone, model for dolomitization. Field, petrographic, and geochemical evidence suggests a genetic link between the pervasive dolomite, trace Mississippi Valley–type (MVT) minerals, and potassium (K)-silicate minerals in these rocks, which preserve a regional hydrothermal signature. Constraints were placed on the conditions of water-rock interaction using fluid-inclusion methods, cathodoluminescence and plane-light petrography, stable isotopic analyses, and organic maturity data. Homogenization temperatures of two-phase aqueous fluid inclusions in dolomite, sphalerite, and quartz range between 65 and 120°C. Freezing data suggest a Na-Ca-Mg-Cl-H2O fluid with salinities between 13 and 28 wt.% NaCl equivalent. The pervasive dolomitization of Paleozoic rocks on and adjacent to the Wisconsin arch was the result of water-rock interaction with dense brines at elevated temperatures, and it was coeval with regional trace MVT mineralization and K-silicate diagenesis. A reevaluation of the Dorag (mixing-zone) model for dolomitization, in conjunction with convincing new petrographic and geochemical evidence, has ruled out the Dorag model as the process responsible for pervasive dolomitization along the Wisconsin arch and adds to the abundant body of literature that casts serious doubt about the viability of the Dorag model in general.

John Luczaj is an assistant professor of earth science in the Department of Natural and Applied Sciences at the University of Wisconsin–Green Bay. He earned his B. S. degree in geology from the University of Wisconsin–Oshkosh. This was followed by an M.S. degree in geology from the University of Kansas. He holds a Ph.D. in geology from Johns Hopkins University in Baltimore, Maryland. His recent interests include the investigation of water-rock interaction in Paleozoic sedimentary rocks in the Michigan Basin and eastern Wisconsin. Previous research activities involve mapping subsurface uranium distributions, reflux dolomitization, and U-Pb dating of Permian Chase Group carbonates in southwestern Kansas.


Ptrographie dune altrite rsiduelle de type fantme de roche , 2007, Havron Ccile, Baele Jeanmarc, Quinif Yves
PETROGRAPHY OF A RESIDUAL ALTERITE GHOST-ROCK . Classically, the karstogenesis begins with a phase of dissolution along fissures. Progressively, the fissure broadens and more water flows. Some fissures transform in more important void, sometimes galleries. The fondamental fact is that the removal of bed-rock is total, the greatest part by solution (carbonates, calcium and magnesium, sodium and potassium...), the rest one like solid phase (clay minerals, quartz...). We call this process total removal. But another karstification process exists: the ghost-rock formation. The first phase of the ghost-rock formation begins with an isovolumic alteration of the bed-rock. The insoluble parts remain while the soluble parts are evacuated with underground water. This insoluble part is constituted by clays minerals, silica phase, sparite like fossils, or big cristals and forms a residual alterite. That is the ghost-rock formation. This is the case for the present example which is a residual alterite in a very pure wackestone. This object presents like a volume of alterite confined in the intact bed-rock. We study this ghost-rock by a petrographic analysis. The macroscopic approach emphasizes the great porosity of the ghost-rock which is very crumbly. The border between the ghost-rock and the bed-rock is very irregular, emphazising the petrophysic differences. The microscopic approach shows in the ghost-rock a general collapse of the structure where subsist only the best cristallized grains. The alteration increases to the detriment of the little cristals, saving the bioclasts, or to the detriment of the fissures. One detects also another phase which is constituted by gypsum. The examination using the electron microscope shows that the bed-rock is formed by well soldered grains, crystals, primary pyrite. On the other hand, the ghost-rock is characterised by a great porosity, secondary pyrite, corrosion gulfs on crystals. This is the indication that the acid function comes from sulfuric acid by oxydation of the sulfide. This is the reason of the presence of gypsum. After the alteration, the organic matter present in the bed-rock (black limestone) can reduce the gypsum in secondary sulfide. The conclusion is that the formation of the ghost-rock can develop in a pure limestone, and non only in a limestone with silico-clay skeleton. This ghost-rock represents the first stage of the genesis: an isovolumic alteration, without macroscopic void, before a collapse of the weathering rock.

Results 1 to 15 of 23
You probably didn't submit anything to search for