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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. ...

Did you know?

That Spitzkarren is (german.) these are isolated projections that may be of a beehive form or may be sharply pointed and tend to lie between grikes and the strike ribs of bedding grikes [8]. see also grike; bedding grike; clint.?

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

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Chemistry and Karst, White, William B.
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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
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Your search for coating (Keyword) returned 30 results for the whole karstbase:
Showing 16 to 30 of 30
Palaeohydrogeological control of palaeokarst macro-porosity genesis during a major sea-level lowstand: Danian of the UrbasaAndia plateau, Navarra, North Spain, 2007, Baceta Juan Ignacio, Wright V. Paul, Beavingtonpenney Simon J. , Pujalte Victoriano

An extensive palaeokarst porosity system, developed during a pronounced mid-Paleocene third-order lowstand of sea level, is hosted in Danian limestones of the Urbasa–Andia plateau in north Spain. These limestones were deposited on a 40–50 km wide rimmed shelf with a margin characterised by coralgal buildups and coarse-grained bioclastic accumulations. The sea-level fall that caused karstification was of approximately 80–90 m magnitude and 2.5 Ma in duration. During the exposure, a 450 m wide belt of sub-vertical margin-parallel fractures developed a few hundred metres inboard of the shelf edge. Most fractures are 90–100 m deep, average 1 m in width, and are associated with large erosional features created by collapse of the reefal margin. Inland from the fracture belt, three superimposed laterally extensive cave systems were formed over a distance of 3.5 km perpendicular to shelf edge, at depths ranging from 8–31 m below the exposure surface. The palaeocaves range from 0.3 to 2 m in height, average 1.5 m high. They show no evidence of meteoric processes and are filled with Thanetian grainstones rich in reworked Microcodium, a lithology that also occurs infilling the fractures. The caves are interpreted as due to active corrosion at the saline water–fresh-water mixing zone. Caves are missing from the shelf edge zone probably because the fractures beheaded the meteoroic lens preventing mixing-zone cave development beyond the fracture zone. Towards the platform interior, each cave system passes into a prominent horizon, averaging 1 m in thickness, of spongy porosity with crystal silt infills and red Fe-oxide coatings. The spongy horizons can be traced for 5.5 km inboard from the cave zone and occur at 10.5 m, 25 m and 32 m below the exposure surface. In the inland zone, two additional horizons with the same spongy dissolution have been recognised at depths of 50 m and 95 m. All are analogous to Swiss-cheese mixing-zone corrosion in modern carbonate aquifers and probably owe their origins to microbiallymediated dissolution effects associated with a zone of reduced circulation in marine phreatic water. In the most landward sections a number of collapse breccia zones are identified, but their origin is unclear. The palaeokarst system as a whole formed during the pulsed rise that followed the initial sea-level drop, with the three main cave-spongy zones representing three successive sea-level stillstands, recorded by stacked parasequences infilling large erosional scallops along the shelf margin. The geometry of the palaeo-mixing zones indicates a low discharge system, and together with the lack of meteoric karstic features favours a semi-arid to arid climatic regime, which is further supported by extensive calcrete-bearing palaeosols occurring in coeval continental deposits.


Palaeohydrogeological control of palaeokarst macro-porosity genesis during a major sea-level lowstand: Danian of the UrbasaAndia plateau, Navarra, North Spain, 2007, Baceta J. I. , Wright V. P. , Beavingtonpenney S. J. , Pujalte V.

An extensive palaeokarst porosity system, developed during a pronounced mid-Paleocene third-order lowstand of sea level, is hosted in Danian limestones of the Urbasa–Andia plateau in north Spain. These limestones were deposited on a 40–50 km wide rimmed shelf with a margin characterised by coralgal buildups and coarse-grained bioclastic accumulations. The sea-level fall that caused karstification was of approximately 80–90 m magnitude and 2.5 Ma in duration. During the exposure, a 450 m wide belt of sub-vertical margin-parallel fractures developed a few hundred metres inboard of the shelf edge. Most fractures are 90–100 m deep, average 1 m in width, and are associated with large erosional features created by collapse of the reefal margin. Inland from the fracture belt, three superimposed laterally extensive cave systems were formed over a distance of 3.5 km perpendicular to shelf edge, at depths ranging from 8–31 m below the exposure surface. The palaeocaves range from 0.3 to 2 m in height, average 1.5 m high. They show no evidence of meteoric processes and are filled with Thanetian grainstones rich in reworked Microcodium, a lithology that also occurs infilling the fractures. The caves are interpreted as due to active corrosion at the saline water–fresh-water mixing zone. Caves are missing from the shelf edge zone probably because the fractures beheaded the meteoroic lens preventing mixing-zone cave development beyond the fracture zone. Towards the platform interior, each cave system passes into a prominent horizon, averaging 1 m in thickness, of spongy porosity with crystal silt infills and red Fe-oxide coatings. The spongy horizons can be traced for 5.5 km inboard from the cave zone and occur at 10.5 m, 25 m and 32 m below the exposure surface. In the inland zone, two additional horizons with the same spongy dissolution have been recognised at depths of 50 m and 95 m. All are analogous to Swiss-cheese mixing-zone corrosion in modern carbonate aquifers and probably owe their origins to microbially mediated dissolution effects associated with a zone of reduced circulation in marine phreatic water. In the most landward sections a number of collapse breccia zones are identified, but their origin is unclear. The palaeokarst system as a whole formed during the pulsed rise that followed the initial sea-level drop, with the three main cave-spongy zones representing three successive sea-level stillstands, recorded by stacked parasequences infilling large erosional scallops along the shelf margin. The geometry of the palaeo mixing zones indicates a low discharge system, and together with the lack of meteoric karstic features favours a semi-arid to arid climatic regime, which is further supported by extensive calcrete-bearing palaeosols occurring in coeval continental deposits.


The mineralogy and trace element chemistry of black manganese oxide deposits from caves, 2009, White W. B. , Vito C. , And Scheetz B. E.

Free surface streams in caves and their surface infeeders often contain pebbles and cobbles coated with black manganese oxide minerals. Coating thicknesses vary from fractions of a millimeter to a few millimeters. In addition, a few caves contain loose masses of black oxide material. The results reported here are based on examination of 39 specimens and detailed chemical analyses of 18 of them. Most of the coatings are amorphous to x-rays, with at best, only a few broad diffraction lines. Infrared spectroscopy shows that most of the specimens are birnessite, with evidence for romanechite, ranceite, and pyrolusite in a few specimens. All specimens contain both iron and manganese, but the Mn/Fe ratio varies widely. Many specimens are enriched in Ba but depleted in Sr. The manganese and iron oxides contain the transition metals Co, Cu, Ni, V, and Zn in concentrations greater than 0.5 wt% in some specimens. Minor Cr and Mo also occur. Given the extremely low concentrations of these elements expected in freshwater streams in carbonate terrains, the manganese oxides exert a dramatic amplifying effect over the expected background. Manganese oxides appear to act as a dosimeter for heavy metals in karst waters.


Unique iron-manganese colonies of microorganisms in Zoloushka Cave (Ukraine-Moldova), 2009, Andreychouk V. N. , Klimchouk A. , Boston P. , Galuskin E.

During open-pit quarrying and related lowering of groundwater level in the gypsum karst aquifer (since 1950), large cave Zoloushka became accessible for direct exploration, in which considerable geochemical transformations of environment occurred, accompanied by the formation of specific deposits, as well as by burst of microbial activity. Among microorganisms, some of the most active were various iron bacteria. Microbial activity has resulted in precipitation of black and red biochemical formations – microbialites (coatings, crusts, films, stalactites, stalagmites, etc.), which cover walls and floors of cave passages. Most interesting among the microbialites are iron-rich colonial formations of various shapes (stalagmite-like, tube-like, coral-like, etc.) formed by yet unidentified fungi-like microorganisms which likely are new to science. In this paper, we characterize occurrence and morphology of the colonial aggregates, morphology and chemical composition of microorganisms  and develop working hypotheses of their identification.


Karst hydrology of Grand Canyon, Arizona, USA, 2010, Hill C. A. , Polyak V. J.

Caves in Grand Canyon, Arizona, USA fall into two main categories: those formed under unconfined conditions and those formed under confined conditions. This study focuses on the hydrology and paleohydrology of the confined caves in the Redwall–Muav aquifer, where the aquifer is overlain by rocks of the Supai Group and underlain by the Bright Angel Shale. Unconfined caves are discussed only in their relation to confined caves. Discharge for confined groundwater was, as it is today, primarily from the Redwall Limestone where it has been incised by the main canyon or its tributaries and where it has converged along a structural low or fault. Descent of the potentiometric surface (or water table) over time is recorded by one ore episode and six cave episodes: (1) emplacement of Cu–U ore, (2) precipitation of iron oxide in cavities, (3) dissolution of cave passages, (4) precipitation of calcite-spar linings over cave passage walls, (5) precipitation of cave mammillary coatings, (6) minor replacement of cave wall and ceiling limestone by gypsum, and (7) deposition of subaerial speleothems. The mammillary episode records the approximate position of the water table when the incision of the canyon was at that level. Discharge toward spring points has reorganized and adjusted with respect to ongoing canyon and side-canyon incision. The dissolution of Grand Canyon confined caves was the result of the mixing of epigene waters with hypogene waters so that undersaturation with respect to calcite was achieved. The karst hydrology of Grand Canyon may be unique compared to other hypogene cave areas of the world.


Genesis and functioning of the Aix-les-Bains hydrothermal karst (Savoie, France): past research and recent advances, 2010, Hoblea F. , Gallinojosnin S. , Audra Ph.

Aix-les-Bains (Savoie, France) owes its name and reputation to the thermal springs that occur along the eastern shore of Lake Bourget, France largest natural lake. Although the city waters have been exploited since Antiquity, scientific investigations into the nature and characteristics of the hydrothermal karst from which they emerge did not begin until the early 19th century. The present article traces the history of these investigations and summarizes the results of more than two centuries of scientific research. Today, the only visible signs of karstification related to hydrothermal flows are to be found in the discharge zone in the Urgonian limestone anticline that rises above the city centre. These features are: – the Grotte des Serpents, which houses the Alun Spring, the system main natural discharge, – the Chevalley Aven, a blind chimney that was accidentally uncovered in 1996, – other hydrothermal springs that are too small to enter, including the Soufre Spring. Although scientific investigation of the thermal springs at Aix-les-Bains began in the early 19th century, it was not until the 1920s that scientists started examining the relationship between karstification and the state of the aquifer. E.A.Martel was the first researcher to describe the Aix-les-Bains site as an active hydrothermal karst, in a pioneering study published in 1935. Sixty years later, the discovery of the Chevalley Aven during building work on a new hydrotherapy center gave fresh impetus to research into the karstification of the Aix-les-Bains thermo-mineral aquifer. Recent studies have also investigated the deep aquifer below the karst, using data provided by boreholes. The Urgonian limestone karst at Aix-les-Bains is the site of mixing between thermal waters rising through the anticline and meteoric waters percolating from the surface. Meteoric infiltration is sufficiently high for the hydrological behavior of the thermal springs to be identical to that of exsurgences in gravity-fed, cold-water transmissive karsts. The Chevalley Aven is a shaft that descends 30 meters below the surface, thereby providing access to the ground-water at depth. Monitoring of the water quality in the aven has shown that the Legionella contamination of the springs was due to high concentrations of the bacteria in upstream passages in the karst. In 2006, dye-tracing tests confirmed the existence of a hydraulic connection between the Chevalley Aven and the Alun and Soufre Springs, the fact there is a single ascending hydrothermal conduit, which lies between the Chevalley Aven and the Alun Spring. In addition to providing a valuable source of information about the functioning of the thermo-mineral aquifer, the cavities at Aix-les-Bains are of great karstological interest, especially for the study of hypogene speleogenetic processes. The circulation of warm (40oC), sulfur-rich waters and vapours through the system has led to the development of conduits with specific morphologies and the precipitation of characteristic deposits. These features include: – “beaded” chimneys and galleries formed by the linking of spheres produced by condensation-corrosion. Diffuse karstification along bedding planes around the main conduit; – deposition of non-carbonate minerals (gypsum, native sulfur); – formation of biothems and biofilms on walls subject to condensation. The Grotte des Serpents is a horizontal cavity that formed at the upper limit of the water table. The Chevalley Aven is a hypogene chimney that was sculpted under vadose conditions by the release of sulfuric acid-rich vapours above the thermal water table. As well as a surface coating of microbial mats and the presence of bacterial flakes in the thermal water, the vadose parts of the Aix-les-Bains hydrothermal karst contain a characteristic microfauna and flora. These microorganisms are thought to play an active role in hypogene karstification processes.


Black Mn-Fe Crusts as Markers of Abrupt Palaeoenvironmental Changes in El Soplao Cave (Cantabria, Spain), 2011, Gzquez Fernando, Calaforra Jose Maria, Forti Paolo

Peculiar iron and manganese deposits coating walls, floors and ceilings of many galleries are one of the special features of the El Soplao Cave (Cantabria, Spain). These speleothems appear to have been deposited over wall clay deposits, as well as forming part of flowstones. Structure of crusts is essentially amorphous but several manganese and iron oxides were identified like goethite and birnessite, though all occur with a low degree of crystallinity. In the outer layer of the crusts, alteration iron minerals appear that derive from previous minerals in a process probably mediated by microorganisms. EDX microanalyses report fairly high values of Fe and Mn in the crusts, though the Mn/Fe ratio varies considerably as a function of distance from the substrate/bedrock. The present study proposes a genetic model for crust speleothems in El Soplao, based on oscillations of the phreatic level. The origin of these deposits is related to mobilization, under phreatic conditions, of polymetallic sulfides in the host rock. Metal ions (including Fe²⁺ and Mn²⁺) released into the cave under reducing conditions, are oxidized and fixed in a process mediated by bacteria, giving rise to oxides and hydroxides of low crystallinity. The presence of various black intercalated layers in aragonite flowstones indicate periods when cave conditions suddenly changed from vadose, when aragonite is precipitated, to phreatic and epiphreatic conditions, when the Mn-Fe deposits are precipitated. Subsequently, vadose conditions were re-established, leading to the final stages of precipitation of aragonite recorded in the flowstone and recent aragonite helictites on the surface of the Mn-Fe crusts.


Mineralogical and chemical characteristics of black coatings in Postojna cave system , 2011, Zupanč, Ič, Nina, ebela Stanka, Miler Milo

Mineralogical and chemical analyses of black coatings from two sites in Postojna cave system were studied. Scattered samples
were taken from the entrance parts of the cave and from Črna Jama. Thin sections, powder X-ray diffraction (XRD) technique and scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM/EDS) were used. Microscopic investigation of thin sections of black coloured material from both locations revealed that the main material is carbonate – calcite, with evenly dispersed prevailingly minute opaque black grains. The XRD analysis on samples from both locations confirmed just a presence of calcite with minor quartz and dolomite, excluding Mn and Fe oxides or apatite-group minerals as reason for black colouring. The SEM/EDS analysis
of samples from the entrance parts of Postojna cave system was consistent with XRD analysis, which did not show any Mn oxides. The high content of C measured in the black coatings from the cave entrance parts indicates organic C, which deposited
on the cave walls at time of the petrol explosion during WW2. We can attribute black coatings from Črna Jama to one form of organic C as well, but it is certainly different from the one in the entrance parts of Postojna cave system. As in Črna Jama no other evidence indicates for old human inhabitation of the place: torches of first tourists are a more probable origin of charcoal. On both locations black coatings can be at least partly described by microclimate conditions at cave entrances, which caused the deposition of organic material of allogenic origin (for example soot due to the forest fires).


Petrographic and isotopic evidence for late-stage processes in sulfuric acid caves of the Guadalupe Mountains, New Mexico, USA, 2012, Palmer Margaret, Palmer Arthur N.

Caves of the Guadalupe Mountains have experienced many modifications since their final phase of sulfuric acid speleogenesis several million years ago. Petrographic and geochemical data reveal details of the change from H2SO4 to CO2-dominated reactions. The H2SO4 dissolution front acquired a coating of replacement gypsum with local pockets of anhydrite and by-products of altered clay, including Fe-Mn oxides. Alteration of bedrock beneath the gypsum produced a white micritized rind with small negative shifts in δ13C and δ18O. Solution basins contain records of the earliest post-speleogenetic processes: corroded bedrock, residual anhydrite, Fe-Mn oxides from fluctuating pH and Eh, mammillary calcite, and dolomitization. Later meteoric water removed or recrystallized much of the gypsum and early micrite, and replaced some gypsum with calcite. Mammillary crusts demonstrate fluctuating groundwater, with calcite layers interrupted by films of Fe-Mn oxides precipitated during periodic inflow of anoxic water. Condensation moisture (from local evaporation) absorbs CO2 from cave air, corroding earlier features and lowering their δ13C and δ18O. Drips of condensation water deposit minerals mainly by evaporation, which increases δ18O in the speleothems while δ13C remains nearly constant. By forcing calcite precipitation, evaporation raises the Mg content of remaining water and subsequent precipitates. Dolomite (both primary and replacive) is abundant. In areas of low air circulation, water on and within carbonate speleothems equilibrates with cave-air CO2, causing minerals to recrystallize with glassy textures. Fluorite on young evaporative speleothems suggests a recent release of deep-source HF gas and absorption by droplets of condensation water. 


Diagenesis of a drapery speleothem from Castaar Cave: from dissolution to dolomitization, 2012, Martnprez A. , Martngarca R. , Alonsozarza A. M.

A drapery speleothem (DRA-1) from Castañar Cave in Spain was subjected to a detailed petrographical study in order to identify its primary and diagenetic features. The drapery’s present day characteristics are the result of the combined effects of the primary and diagenetic processes that DRA-1 underwent. Its primary minerals are calcite, aragonite and huntite. Calcite is the main constituent of the speleothem, whereas aragonite forms as frostwork over the calcite. Huntite is the main mineral of moonmilk which covers the tips of aragonite. These primary minerals have undergone a set of diagenetic processes, which include: 1) partial dissolution or corrosion that produces the formation of powdery matt-white coatings on the surface of the speleothem. These are seen under the microscope as dark and highly porous microcrystalline aggregates; 2) total dissolution produces pores of few cm2 in size; 3) calcitization and dolomitization of aragonite result in the thickening and lost of shine of the aragonite fibres. Microscopically, calcitization is seen as rhombohedral crystals which cover and replace aragonite forming mosaics that preserve relics of aragonite precursor. Dolomitization results in the formation of microcrystalline rounded aggregates over aragonite fibres. These aggregates are formed by dolomite crystals of around 1 μm size. The sequence of diagenetic processes follows two main pathways. Pathway 1 is driven by the increase of saturation degree and Mg/Ca ratio of the karstic waters and is visible in the NW side of the drapery. This sequence of processes includes: 1) aragonite and huntite primary precipitation and 2) dolomitization. Pathway 2 is driven by a decrease in the degree of saturation of calcite and aragonite and Mg/Ca ratio of the cave waters, and it is observed in the SE side of the drapery. The diagenetic processes of the second pathway include: 1) calcitization of aragonite; 2) incomplete dissolution (micritization) of both aragonite and calcite; 3) total dissolution. This study highlights the importance of diagenetic processes on speleothems and their complexity. The correct interpretation of these processes is crucial for the understanding of possible changes in the chemistry of waters, temperature, or pCO2 and so is critical to the correct interpretation of the paleoenvironmental significance of speleothems.


Boxwork and ferromanganese coatings in hypogenic caves: An example from Sima de la Higuera Cave (Murcia, SE Spain) , 2012, Gazquez Fernando, Calaforra Josemaria, Rull Fernando

This paper examines the greyish-blue deposits that were recently discovered in the lower levels of the Sima de la Higuera Cave (Murcia, SE Spain) which occur as patinas over the walls and ceilings, as well as coating boxwork formations. Their mineralogy was determined using XRD and micro-Raman spectroscopy, while EDX microanalysis was used to determine their elemental composition. The mineralogical analyses revealed the presence of Mn oxides (todorokite and pyrolusite) and Fe with a low degree of crystallinity, whereas EDX microprobe showed elevated concentrations of Mn (38.2 wt.%), Fe (15.2 wt.%) and Pb (8.1 wt.%). The ferromanganese oxyhydroxides occur as botryoidal aggregates overlying blades of calcite that have a visibly sugary texture. The speleogenetic model proposed describes (1) an initial phase of precipitation of hydrothermal calcite veins (of hypogenic origin) within the fissures of the host rock under phreatic conditions and (2) a subsequent vadose phase involving preferential corrosion of the carbonate host rock caused by lowering of the pH resulting from CO2 diffusion in condensed water and oxidation of Fe and Mn under aerobic conditions, probably mediated by microorganisms. It is this later phase that gave rise to the boxwork. The boxwork of the Sima de la Higuera Cave is a singular example of a formation that is generated by dissolution–corrosion of the rock due to acidification caused by oxidation of iron and manganese.


Boxwork and ferromanganese coatings in hypogenic caves: An example from Sima de la Higuera Cave (Murcia, SE Spain), 2012, Gazquez Fernando, Calaforra Josemaria, Rull Fernando

This paper examines the greyish-blue deposits that were recently discovered in the lower levels of the Sima de la Higuera Cave (Murcia, SE Spain) which occur as patinas over the walls and ceilings, as well as coating boxwork formations. Their mineralogy was determined using XRD and micro-Raman spectroscopy, while EDX microanalysis was used to determine their elemental composition. The mineralogical analyses revealed the presence of Mn oxides (todorokite and pyrolusite) and Fe with a low degree of crystallinity, whereas EDX microprobe showed elevated concentrations of Mn (38.2 wt.%), Fe (15.2 wt.%) and Pb (8.1 wt.%). The ferromanganese oxyhydroxides occur as botryoidal aggregates overlying blades of calcite that have a visibly sugary texture. The speleogenetic model proposed describes (1) an initial phase of precipitation of hydrothermal calcite veins (of hypogenic origin) within the fissures of the host rock under phreatic conditions and (2) a subsequent vadose phase involving preferential corrosion of the carbonate host rock caused by lowering of the pH resulting from CO2 diffusion in condensed water and oxidation of Fe and Mn under aerobic conditions, probably mediated by microorganisms. It is this later phase that gave rise to the boxwork. The boxwork of the Sima de la Higuera Cave is a singular example of a formation that is generated by dissolution–corrosion of the rock due to acidification caused by oxidation of iron and manganese.


Layer-bounding surfaces in stalagmites as keys to better paleoclimatological histories and chronologies, 2013, Railsback L. B. , Akers P. D. , Wang L. , Holdridge G. A. , Riavo Voarintsoa N.

Petrographic recognition of layer-bounding surfaces in stalagmites offers an important tool in constructing paleoclimate records. Previous petrographic efforts have examined thickness of layers (a possible proxy for annual rainfall) and alternation of layers in couplets (a possible indicator of seasonality). Layer-bounding surfaces, in contrast, delimit series of layers and represent periods of non-deposition, either because of exceptionally wet or exceptionally dry conditions.

Two types of layer-bounding surfaces can be recognized according to explicitly defined petrographic criteria. Type E layer-bounding surfaces are surfaces at which layers have been truncated or eroded at the crest of a stalagmite. Keys to their recognition include irregular termination of layers otherwise present on the stalagmite’s flank, dissolutional cavities, and coatings of non-carbonate detrital materials. Type E surfaces are interpreted to represent wet periods during which drip water became so undersaturated as to dissolve pre-existing stalagmite layers, and thus they necessarily represent hiatuses in the stalagmite record. Type L layer-bounding surfaces are surfaces below which layers become thinner upward and/or layers have lesser lateral extent upward, so that the stalagmite’s layer-specific width decreases. They are thus surfaces of lessened deposition and are interpreted to represent drier conditions in which drip rate slowed so much that little deposition occurred. A Type L surface may, but does not necessarily, represent a hiatus in deposition. However, radiometric age data show that Type L surfaces commonly represent significant hiatuses.

These surfaces are significant to paleoclimate research both for their implications regarding climate change (exceptionally wet or dry conditions) and in construction of chronologies in which other data, such as stable isotope ratios, are placed. With regard to climate change, recognition of these surfaces provides paleoclimatological information that can complement or even substitute for geochemical proxies. With regard to chronologies, recognition of layer- bounding surfaces allows correct placement of hiatuses in chronologies and thus correct placement of geochemical data in time series. Attention to changing thickness of annual layers and thus to accumulation rate can also refine a chronology. A chronology constructed with attention to layer-bounding surfaces and to changing layer thickness is much more accurate than a chronology in which hiatuses are not recognized at such surfaces.


HYPOGENE SPELEOGENESIS AND SPELEOTHEMS OF SIMA DE LA HIGUERA CAVE (MURCIA, SOUTH-EASTERN SPAIN), 2013, Gá, Zquez Fernando Calaforra José, Marí, A

 

Sima de la Higuera Cave (Pliego, south-eastern Spain) has been recently adapted for speleological use. Nevertheless, knowledge of the hypogenic origin of this cavity is still quite limited. The peculiar genetic mechanisms could provide added value if the cave is exploited for speleotourism. By studying geomorphological features and speleothem characteristics, it has been possible to deduce the predominant speleogenetic mechanism (whether hypogenic or epigenic) that controlled the evolution of this cave. The hypogenic mechanism that gave rise to this cavity was associated with upflow of CO2-rich hydrothermal fluid from depth, and was unconnected to meteoric water seepage. In this paper we describe some of the geomorphological evidence and unusual speleothems in Sima de la Higuera Cave. Large scallops are found on the upper level (-74 m); these are related to the mechanism of hypogenic speleogenesis and generally indicate the direction of ascending flow. There are also corrosion crusts made of micritic calcite. In addition, bubble trails related to bubbles of rising CO2 have been identified. Centimetric calcite spar speleothems frequently fill fractures in the host rock. Other typical hypogenic speleothems occur in this cave, including calcite raft cones, folia, cave clouds, tower coral and calcite raft deposits, all suggesting the influence of thermal water during the cave’s formation. Furthermore, the first reported occurrence of calcite raft double-tower cones has been described in this cave; their origin is linked to water table oscillations in Paradise Chamber (-82 m). At the deepest level (-110 m), Mn-Fe oxyhydroxides occur as a black coating totally covering the cave walls, usually over subaerial “boxwork” formations. The wide variety of speleothems unconnected to meteoric water seepage make Sima de la Higuera Cave one of the most unusual hypogenic caves in Spain.


Clay cortex in epikarst forms as an indicator of age and morphogenesis—case studies from Lublin–Volhynia chalkland (East Poland,West Ukraine), 2014,

Clay cortex from the contact zone between the host rock (chalk) and infilling deposits were examined in

paleokarst forms (pockets, pipes, and dolines of different age) from the Lublin–Volhynia chalk karst region. In light of the sedimentological and micromorphological analyses, it seems possible to work out a model as the basis for genetic and stratigraphic discussions. (1) Dolineswith the Paleogene orNeogene mineral infills are characterized by (a) homogeneous, residual type of massive clay gradually passing into the chalkmonolith, and at the sametime(b) relatively thickweathered zone. (2) Pipeswith glacigenic mineral infill fromthe Saalian Glacial are characterized by (a) sharp contact between host rock and clay, (b) narrow weathering zone of chalk, (c) diffuse nature of the contact zone between residual clay and mineral infill, and (d) contamination of clay by clastic material. (3) Pocketswith glacigenic mineral infill and traces of theWeichselian periglacial transformation are characterized by (a) strong contamination of chalk by quartz grains, (b) diffuse transition between clay and infill: fromclayey matrixwith single quartz grains (at the contactwith chalk) to clayey coatings and intergranular bridges (in the infill), (c) intensive weathering (cracking) of mineral grains in the infill.


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