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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 ground water, phreatic water is 1. the part of the subsurface water that is in the phreatic zone [10]. its lower limits are the zone of rock flowage or the lowest fully confining bed; its upper limits are the uppermost fully confining bed or the water table [16]. 2. used loosely and incorrectly by some to refer to any water beneath the surface. see also phreas; phreatic water; phreatic zone.?

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

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Your search for cave sulfates (Keyword) returned 4 results for the whole karstbase:
EVIDENCE FROM CERNA VALLEY CAVES (SW ROMANIA) FOR SULFURIC ACID SPELEOGENESIS: A MINERALOGICAL AND STABLE ISOTOPE STUDY, 2009, Onac B. , Sumrall J. , Wynn J. , Tamas T. , Dormiceanu V. , Cizma? C.

Over 30 caves are known to develop in the Jurassic and Cretaceous limestone that outcrops along the lower part of the Cerna Valley and its tributaries in southwestern Romania. There are three features that strike observers when entering most of these caves: a variety of sulfate speleothems, large amounts of bat guano (both fossil and fresh), and unusually high cave temperatures. Such thermal anomalies are rather uncommon in the ordinary cave environment. Along Cerna Valley, however, one can measure temperatures (in some cavities) as high as 40ºC. This situation is due to (i) presence of thermal water pools, (ii) hot water flowing along cave passages, (iii) hot steam rising up fractures from depth.
Seventy-four mineral samples were collected from eight caves in the Cerna Valley. These were investigated by means of X-ray diffraction, scanning electron microscope, and electron microprobe analyses. The minerals identified so far in Sălitrari, Ion Barzoni, Sălitrari 2, Diana, Adam, Despicătura, and Grota cu Aburi caves, are: calcite [CaCO3], aragonite [CaCO3], gypsum [CaSO4•2H2O], anhydrite [CaSO4], pickeringite [MgAl2(SO4)4•22H2O], halotrichite [Fe2+Al2(SO4)4•22H2O], kalinite [KAl(SO4)2•11H2O], melanterite [FeSO4•7H2O], apatite- (Ca(OH) [Ca5(PO4)3(OH)], brushite [CaHPO4•2H2O], darapskite [Na3(SO4)(NO3)•H2O], and nitratine [NaNO3]. The phosphates and nitrates (except for darapskite) were precipitated in a typical vadose environment from reactions between phosphoric solutions supplied by bat guano and limestone bedrock. Most of the sulfates and darapskite are the result of sulfuric acid speleogenesis.
In addition, sulfur isotope measurements (δ34S) on sulfate speleothems and spring waters were undertaken to determine the origin of cave sulfates (i.e., vadose, hypogene, bacteriogenic, etc.). The isotope measurements in the springs show sulfide δ34S ranges from -21.9‰ to 24.0‰ with a mean value of 6.6‰ (n=9), whereas the sulfate δ34S ranges from 16.6‰ to 71.3‰ with a mean value of 30.1‰ (n=10).
Three populations of sulfur isotope values (negative, near zero, and positive) were found in the caves. Samples from Barzoni Cave (the most distant cave from any modern thermal spring) are extremely depleted (-23 to -28‰). Sulfide values of the nearest springs are approximately -20‰. In Sălitrari Cave, the range of values was from -19.8 to +6.5‰. It is more than likely a reflection of the increase in completeness of the reduction of sulfate. The δ34S value of gypsum in Grota cu Aburi (active H2S hot steam cave) was 6.5‰. This value is similar to the sulfur isotopic composition measured in darapskite from Sălitrari Cave; thus, probably documenting earlier sulfuric acid activity in the latter cave.
The final population of caves, especially Despicătura and Diana caves, has enriched sulfur isotope values, which correspond well to the sulfide values of nearby springs. Diana Cave from which Diana 3 spring originates has a sulfide isotopic composition of +19‰, which is approximately the value of the mean of the cave sulfates from Diana Cave. This shows that the cave sulfate isotopic value is controlled by the sulfide, which (after being oxidized) reacts with limestone/marls to produce gypsum or other sulfate minerals.


Tracing the sources of cave sulfates: a unique case from Cerna Valley, Romania, 2011, Onac Bogdan P. , Wynn Jonathan G. , Sumrall Jonathan B.

In order to reliably distinguish between different genetic processes of cave sulfate formation and to quantify the role of thermo-mineral waters on mineral deposition and cave morphology, it is critical to understand sulfur (S) sources and S transformations during hydrological and speleogenetic processes. Previous work has shown that sulfuric acid speleogenesis (SAS) often produces sulfate deposits with 34S-depleted isotopic signatures compared to those of the original source of S in sulfate rocks. However, 34S-depleted isotopic composition of S-bearing minerals alone does not provide enough information to clearly distinguish SAS from other speleogenetic processes driven by carbonic acid, geothermal heat, or other processes. The isotopic composition (δ18O and δ34S) of sulfate minerals (mainly gypsum) from seven caves of the Cerna Valley (Romania) defines three distinct populations, and demonstrates that the δ34S values of SAS-precipitated cave sulfates depend not only on the source of the S, but also on the H2S:SO4 2− ratio during aqueous S species reactions and mineral precipitation. Population 1 includes sulfates that are characterized by relatively low δ34S values (−19.4 to −27.9‰) with δ18O values between 0.2 and 4.3‰ that are consistent with oxidation of dissolved sulfide produced during methane-limited thermochemical sulfate reduction (TSR) that presently characterizes the chemistry of springs in the upper Cerna Valley. Population 2 of cave sulfates has 34S enriched δ34S values (14.3 to 19.4‰) and more 18O-depleted δ18O values (from −1.8 to −10.0‰). These values argue for oxidation of dissolved sulfide produced during sulfate-limited TSR that presently characterizes the chemistry of springs further downstream in the Cerna Valley. The δ18O values of cave sulfates from Population 1 are consistent with oxidation under more oxic aqueous conditions than those of Population 2. δ34S values of cave sulfates within Population 3 (δ34S: 5.8 to 6.5‰) may be consistent with several scenarios (i.e., pyrite oxidation, oxidation of dissolved sulfide produced during methane-limited TSR coupled with O2-limited oxidation during SAS). However, comparatively 18O-enriched δ18OSO4 values (11.9 to 13.9‰) suggest the majority of this sulfate O was derived from atmospheric O2 in gas-phase oxidation prior to hydration. Thus, the combined use of oxygen- and sulfur-isotope systematics of sulfate minerals precipitated in a variety of cave settings along Cerna Valley may serve as an example of how more complex cave systems can be deconvoluted to allow for more complete recognition of the range of processes and parameters that may be involved in SAS.


Rapidcreekite in the sulfuric acid weathering environment of Diana Cave, Romania, 2013, Onac B. P. Effenberger H. S. Wynn J. G. Povară, I.

The Diana Cave in SW Romania develops along a fault line and hosts a spring of hot (Tavg = 51 °C), sulfate-rich, sodium-calcium-chloride bearing water of near-neutral pH. Abundant steam and H2S rises from the thermal water to condensate on the walls and ceiling of the cave. The sulfuric acid produced by H2S oxidation/hydrolysis causes a strong acid-sulfate weathering of the cave bedrock generating a sulfate-dominated mineral assemblage that includes rapidcreekite, Ca2(SO4)(CO3)•4H2O closely associated with gypsum and halotrichite group minerals. Rapidcreekite forms bundles of colorless tabular orthorhombic crystals elongated along [001] and reaching up to 1.5 mm in length. For verifying the hydrogen bond scheme and obtaining crystal-chemical details of the carbonate group a single-crystal structure refinement of rapidcreekite was performed. Its unit-cell parameters are: a = 15.524(2), b = 19.218(3), c = 6.161(1) Å; V = 1838.1(5) Å3, Z = 8, space group Pcnb. Chemi¬cal composition (wt%): CaO 35.65, SO3 24.97, CO2 13.7, H2O 23.9, Na2O 0.291, MgO 0.173, Al2O3 0.07, total 98.75%. The empirical formula, based on 7 non-water O atoms pfu, is: Ca1.98Na0.029Mg0.013 Al0.004(S0.971 O4)(C0.97O3)•4.13H2O. The d34S and d18O values of rapidcreekite and other cave sulfates range from 18 to 19.5‰ CDT and from –9.7 to 7.8‰ SMOW, respectively, indicating that the source of sulfur is a marine evaporite and that during hydration of the minerals it has been an abundant 18O exchange with percolating water but almost no oxygen is derived from O2(aq). This is the first descrip¬tion of rapidcreekite from a cave environment and one of the very few natural occurrences worldwide. We also report on the mineral stability and solubility, parameters considered critical to understand the co-precipitation of carbonates and sulfates, a process that has wide applications in cement industry and scaling prevention.


HYPOGENE VS EPIGENE CAVES: THE SULFUR AND OXYGEN ISOTOPE FINGERPRINT, 2014, Onac, B. P.

The classical epigene speleogenetic model in which CO2 is considered the main source of acidity has been challenged over the last three decades by observations that revealed cave passages unrelated to groundwater drainage routes and surface topography. Most of these passages show unusual morphologies, such are cupolas, floor feeders (i.e., inlets for deep-seated fluids), and huge irregular-shaped rooms that terminate abruptly, and often a rich and diverse mineral association. A hypogenetic speleogenetic pathway was proposed for this group of caves.
The presence of abundant gypsum deposits in caves with one or more of the passage morphologies listed above, have prompted scientists to suggest a new theory (i.e., sulfuric acid speleogenesis, SAS) of cave development. In the hypogenic SAS model, the source of acidity is the sulfuric acid produced by oxidation of H2S (originating from sulfate reduction or petroleum reservoirs) near or at the water table, where it dissolves the limestone bedrock and precipitates extensive gypsum deposits. SAS is now thoroughly documented from numerous caves around the world, with the best examples coming from the Guadalupe Mountains (NM), Frasassi caves (Italy), selected caves in France, Cueva de Villa Luz (Mexico), and Cerna Valley (SW Romania).
To date, discrimination between epigene and hypogene speleogenetic pathways is made using cave morphology criteria, exotic mineral assemblages, and the predominantly negative δ34S values for the cave sulfates. This presentation highlights the role sulfur and oxygen stable isotope analyses have in discriminating between epigene and hypogene caves.
Based on a number of case studies in caves of the Cerna Valley (Romania), we found that relatively S-depleted isotopic composition of cave minerals alone does not provide enough information to clearly distinguish SAS from other complex speleogenetic pathways. In fact, δ34S values of SAS by-products depend not only on the source of the S, but also on the completeness of S redox reactions. Therefore, similar studies to this are needed to precisely diagnose SAS and to provide information on the S cycle in a given karst system.
Integrating cave mineralogy, passage morphology, and geochemical studies may shed light on the interpretation of polygenetic caves, offering clues to processes, mechanisms, and parameters involved in their genesis (sulfate-dominated).


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