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Enviroscan Ukrainian Institute of Speleology and Karstology


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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 leakage factor is the factor describing leakage flow into or out of a leaky aquifer [16].?

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


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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 backscatter (Keyword) returned 5 results for the whole karstbase:
LATE-STAGE DOLOMITIZATION OF THE LOWER ORDOVICIAN ELLENBURGER GROUP, WEST TEXAS, 1991,
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Kupecz J. A. , Land L. S. ,
Petrography of the Lower Ordovician Ellenburger Group, both in deeply-buried subsurface cores and in outcrops which have never been deeply buried, documents five generations of dolomite, three generations of microquartz chert, and one generation of megaquartz. Regional periods of karstification serve to subdivide the dolomite into 'early-stage', which predates pre-Middle Ordovician karstification, and 'late-stage', which postdates pre-Middle Ordovician karstification and predates pre-Permian karstification. Approximately 10% of the dolomite in the Ellenburger Group is 'late-stage'. The earliest generation of late-stage dolomite, Dolomite-L1, is interpreted as a precursor to regional Dolomite-L2. L1 has been replaced by L2 and has similar trace element, O, C, and Sr isotopic signatures, and similar cathodoluminescence and backscattered electron images. It is possible to differentiate L1 from L2 only where cross-cutting relationships with chert are observed. Replacement Dolomite-L2 is associated with the grainstone, subarkose, and mixed carbonate-siliciclastic facies, and with karst breccias. The distribution of L2 is related to porosity and permeability which focused the flow of reactive fluids within the Ellenburger. Fluid inclusion data from megaquartz, interpreted to be cogenetic with Dolomite-L2, yield a mean temperature of homogenization of 85 6-degrees-C. On the basis of temperature/delta-O-18-water plots, temperatures of dolomitization ranged from approximately 60 to 110-degrees-C. Given estimates of maximum burial of the Ellenburger Group, these temperatures cannot be due to burial alone and are interpreted to be the result of migration of hot fluids into the area. A contour map of delta-O-18 from replacement Dolomite-L2 suggests a regional trend consistent with derivation of fluids from the Ouachita Orogenic Belt. The timing and direction of fluid migration associated with the Ouachita Orogeny are consistent with the timing and distribution of late-stage dolomite. Post-dating Dolomite-L2 are two generations of dolomite cement (C1 and C2) that are most abundant in karst breccias and are also associated with fractures, subarkoses and grainstones. Sr-87/Sr-86 data from L2, C1, and C2 suggest rock-buffering relative to Sr within Dolomite-L2 (and a retention of a Lower Ordovician seawater signature), while cements C1 and C2 became increasingly radiogenic. It is hypothesized that reactive fluids were Pennsylvanian pore fluids derived from basinal siliciclastics. The precipitating fluid evolved relative to Sr-87/Sr-86 from an initial Pennsylvanian seawater signature to radiogenic values; this evolution is due to increasing temperature and a concomitant evolution in pore-water geochemistry in the dominantly siliciclastic Pennsylvanian section. A possible source of Mg for late-stage dolomite is interpreted to be from the dissolution of early-stage dolomite by reactive basinal fluids

Side-looking sonar backscatter response at dual frequencies, 1996,
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Ryan William B. F. , Flood Roger D. ,

Spaceborne imaging radar-C (SIR-C) observations of groundwater discharge and wetlands associated with the Chicxulub impact crater, northwestern Yucatan Peninsula, Mexico, 2001,
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Pope Kevin O. , Rejmankova Eliska, Paris Jack F. ,
Analyses of spaceborne imaging radar-C (SIR-C) data and field data from the northwestern Yucatan Peninsula, Mexico, demonstrate that spaceborne multifrequency polarimetric radars are excellent tools for characterizing patterns of wetland flooding. Seasonal flooding can be detected in most types of forest and marsh in the radar backscatter magnitude and phase data of both L and C band. Field observations made in the wet and dry seasons concurrent with the space missions and chemical analyses of floodwaters confirm that flooding is the product of discharge from the Yucatan aquifer, which consists of a fresh-water lens floating on seawater. This discharge controls the distribution of wetlands. Therefore, vegetation and flooding patterns, mapped with SIR-C imagery, provide valuable information on the hydrogeology of the region. Radar-image maps of wetlands and flooding indicate that there are three major zones of groundwater discharge that correlate with structures of the buried Chicxulub crater--zone 1 with the peak ring, zone 2 with the crater rim, and zone 3 with the exterior ring. Zone 1 has sulfate-poor discharge, unlike the sulfate-rich discharge in zones 2 and 3. The highest discharge is in zone 3, where the buried crater is closest to the surface. This groundwater-discharge pattern can be explained by tidal pumping of fresh water to the surface through high permeability zones developed in the Tertiary carbonates overlying crater faults and escarpments

Petrography of Finely Crystalline Cenozoic Dolostones as Revealed by Backscatter Electron Imaging: Case Study of the Cayman Formation (Miocene), Grand Cayman, British West Indies, 2003,
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Jones Brian, Luth Robert W. ,
Finely crystalline Cenozoic island dolostones, like those found in the Cayman Formation on Grand Cayman, are commonly assumed to be petrographically and compositionally homogeneous. Backscatter electron images (BSEI), however, show that the constituent dolomite crystals (< 100 {micro}m long and commonly < 20 {micro}m long) are commonly zoned with respect to their mol % CaCO3 content. Moreover, such images allow (1) depiction of growth patterns in the constituent crystals, irrespective of their origin, (2) recognition of replacive dolomite as opposed to dolomite cement, and (3) delineation of 'stratigraphic packages' in the dolomite cements that reflect different episodes of cementation. Integration of this information forms the basis for paragenetic interpretations of the dolostones. On Grand Cayman, the Miocene Cayman Formation can be divided into friable, high-porosity dolostones and hard, low-porosity dolostones. Backscatter electron images show that the hard dolostones are characterized by complex arrays of zoned dolomite cements that have occluded most of the pores. Caymanite, an internal sediment, has occluded many of the larger cavities. In contrast, the high-porosity dolostones contain little cement and no internal sediments. Precipitation of the cements and the deposition of internal sediments were related to the passage of large volumes of water through some of the dolostones. Thus, the hard, low-porosity dolostones are found in the 'cap rock' of the formation, in coastal locations, and in areas close to solution-widened fractures. Conversely, the friable, high-porosity dolostones form the lower 'porous unit' of the formation in the interior of the island, where the passage of water was more restricted

Wurmfrmige Excentriques mit ungewhnlichem Calcitgefge - Untersuchungen mit der Elektronen-Rckstreu-Beugungs-Methode, 2007,
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Richter D. K. , Neuser R. D.
Vermiform helictites (excentriques) from a former side branch of the Breitscheid-Erdbach cave are frequently polycrystalline and not composed of a single calcite crystal. The electron backscatter diffraction (EBSD)-technique reveals a lath-shaped calcite structure with c-axes oriented nearly parallel to the elongation of the helictites. The resulting structure of the helictites is a calcite fibre bundle diverging along the growth direction. Three equivalent symmetrical sectors can be distinguished. The maximum deviation from the elongation is 18 and occurs at the exterior in the centre of the segments of the excentriques. The complex internal structure and the conical shape of the tip of the excentriques suggest a special kind of calcite precipitation, whereby biofilms seem to have played a significant role.

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