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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 karst water is water discharged from karst springs which posses characteristics, primarily that of calcium content, indicating solution during the passage of that water across and through karst limestone. that part of karst spring water which is derived from watercourses sinking into the rock (and therefore originates mainly on impermeable rock) is said to be allogenic; that which derives from precipitation over the karst area alone is said to be autochthonous - the distinction between resurgence and exsurgence waters [19].?

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

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KarstBase a bibliography database in karst and cave science.

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;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for reefs (Keyword) returned 26 results for the whole karstbase:
Showing 16 to 26 of 26
The occurrence of sinkholes and subsidence depressions in the far west Rand and Gauteng Province, South Africa, and their engineering implications, 2001, De Bruyn Ia, Bell Fg,
Dewatering associated with mining in the gold-bearing reefs of the Far West Rand, which underlie dolomite and unconsolidated deposits, led to the formation of sinkholes and subsidence depressions. Hence, certain areas became unsafe for occupation and were evacuated. Although sinkholes were initially noticed in the 1950s, the seriousness of the situation was highlighted in December 1962 when a sinkhole engulfed a three-story crusher plant at West Driefontein Mine. Consequently, it became a matter of urgency that the areas at risk of subsidence and the occurrence of sinkholes were delineated. Sink-holes formed concurrently with the lowering of the water table in areas which formerly had been relatively free of sinkholes. In addition, subsidence occurred as a consequence of consolidation taking place in the unconsolidated deposits as the water table was lowered. In the latter case, the degree of subsidence which occurred reflected the thickness and original density of the unconsolidated deposits which were consolidated. These deposits vary laterally in thickness and thereby gave rise to differential subsidence. Subsidence also occurred due to the closure of dewatered voids at the rock-soil interface. The risk of sinkhole and subsidence occurrence is increased by urban development, since interrupted natural surface drainage, increased runoff, and leakage from water-bearing utilities can result in the concentrated ingress of water into the ground. Where the surficial deposits are less permeable, the risk of instability is reduced. In the area underlain by dolomite, which extends around Johannesburg and Pretoria, these problem have been more notable in recent years because of housing development, both low-cost and up-market, and the growth of informal settlements. Residential densities may be very high, especially for low-cost housing, the development of which frequently has proceeded without recognition of the risk posed by karst-related ground instability. The appearance of significant numbers of small sinkholes has been associated with dolomite at shallow depth, that is, occurring at less than 15 m beneath the ground surface. The vulnerability of an area overlying dolomite bedrock at shallow depth is largely dependent on the spacing, width and continuity of grikes. When dolomite is located at depths greater than 15 m, the sinkholes which appear at the surface usually are larger in diameter. The risk of sinkhole occurrence in areas of shallow dolomite in general, may be greater, although the hazard itself is less severe. A classification system for the evaluation of dolomitic land based on the risk of formation of certain sized sinkholes has enabled such land to be zoned for appropriate development. Ongoing monitoring and maintenance of water bearing services, and the implementation of precautionary measures relating to drainage and infiltration of surface water are regarded as essential in developed areas underlain by dolomite. Special types of foundation construction for structures are frequently necessary

Origin of atoll lagoons, 2001, Purdy Edward G. , Winterer Edward L. ,
A database of 301 atolls from the Pacific, Indian, and Atlantic Oceans has been analyzed with respect to factors governing maximum atoll lagoon depth. Statistically significant correlations between maximum atoll lagoon depth and both atoll area and present-day rainfall are viewed as the combined effect of paleorainfall precipitation and catchment area in contributing to overall atoll morphology. This interpretation is supported by the gross saucer-shaped morphology of several of the Lau group of the Fiji Islands, and the subsurface Cretaceous Golden Lane atoll of Mexico, where evidence of reef rim construction is lacking but evidence for significant solution relief is compelling. The contribution of reefs to atoll rim construction appears to be limited generally to [~]10 m, leaving more than 20 m of relief to be explained at most atolls. At a number of these, the last interglacial highstand surface is [~]15-20 m beneath Holocene rim sediments. Subsidence rates of even 5 cm/ k.y. do not suffice to explain the subsea depth of this unconformity, suggesting the dominating influence of solution on relief expression. Calculations of solution rates relative to the residence time of sea level below given depths during the past 700 k.y. suggest that the observed atoll relief is in part inherited from more than one Pleistocene, or perhaps earlier, glacial stage. Whatever the precise time of origin, the data available strongly suggest that atoll morphology is solution determined rather than growth predicated

Key Largo Limestone revisited: Pleistocene shelf-edge facies, Florida Keys, USA, 2002, Multer H. G. , Gischler E. , Lundberg J. , Simmons K. R. , Shinn E. A. ,
New dates and analysis of 12 deep and 57 shallow cores allow a more detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys. In this study a three-phase evolution of the Quaternary units (Q1-Q5) of the Key Largo is presented with new subdivision of the Q5. (1) In the first phase, the Q1 and Q2 (perhaps deposited during oxygen-isotope stage 11) deep-water quartz-rich environment evolved into a shallow carbonate phase. (2) Subsequently, a Q3 (presumably corresponding to oxygen-isotope stage 9) flourishing reef and productive high-platform sediment phase developed. (3) Finally, a Q4 and Q5 (corresponding to oxygen-isotope stages 7 and 5) stabilization phase occurred with reefs and leeward productive lagoons, followed by lower sea levels presenting a sequence of younger (isotope substages 5c, 5a) shelf-margin wedges, sediment veneers and outlier reefs. The Key Largo Limestone provides an accessible model of a carbonate shelf edge with fluctuating water depth, bordering a deep seaward basin for a period of at least 300 ka. During this time, at least four onlaps/offlaps, often separated by periods of karst development with associated diagenetic alterations, took place. The story presented by this limestone not only allows a better understanding of the history of south Florida but also aids in the interpretation of similar persistent shelf-edge sites bordering deep basins in other areas

The future of the dolomitic springs after mine closure on the Far West Rand, Gauteng, RSA, 2003, Swart C. J. U. , James A. R. , Kleywegt R. J. , Stoch E. J. ,
Approximately 1.2 km of dolomitic limestone overlies the Far West Rand gold reefs southwest of Johannesburg, South Africa. This karst aquifer is partitioned into several groundwater compartments by predominantly north-south trending syenite dykes. Prior to mining, the primary water flow was westwards, decanting over dyke boundaries as a succession of springs along the Lower Wonderfontein Spruit. Dewatering of the overlying dolomitic aquifer for safety and economic reasons by deep gold mining operations, caused the water levels of four compartments to drop and their respective springs to dry up. By perforating dykes, formerly separated aquifers were hydraulically interconnected by mining. Using historical and recent data of water flow-surface and groundwater-and pumping rates, a geohydrological model is presented. The results suggest that the water tables will rise to their pre-mining levels within 30 years after mining ceases and that the dry springs will flow again, despite the compartments being connected by the extensive mining operations

Regional Quaternary submarine geomorphology in the Florida Keys, 2003, Lidz Barbara H. , Reich Christopher D. , Shinn Eugene A. ,
High-quality seismic reflection profiles fill a major gap in geophysical data along the south Florida shelf, allowing updated interpretations of the history of the Quaternary coral reef system. Incorporation of the new and existing data sets provides the basis for detailed color maps of the Pleistocene surface and thickness of overlying Holocene accretions. The maps cover the Florida Keys to a margin-wide upper-slope terrace (30 to 40 m deep) and extend from The Elbow Reef (north Key Largo) to Rebecca Shoal (Gulf of Mexico). The data indicate that Pleistocene bedrock is several meters deeper to the southwest than to the north east, yet in general, Holocene sediments are [~]3 to 4 m thick shelf-wide. The Pleistocene map demonstrates the significance of a westward-dipping bedrock surface to Holocene flooding history and coral reef evolution. Seismic facies show evidence for two possible Holocene stillstands. Aerial photographs provide information on the seabed surface, much of which is below seismic resolution. The photographs define a prominent, regional nearshore rock ledge that extends [~]2.5 km seaward from the keys' shoreline. They show that bands of rock ridges exist along the outer shelf and on the upper-slope terrace. The photographs also reveal four tracts of outlier reefs on the terrace, one more than had been documented seismically. Seismic and photographic data indicate the tracts are >200 km long, nearly four times longer than previously thought. New interpretations provide insights into a youngest possible terrace age (ca. 175 ka?) and the likelihood that precise ages of oxygen isotope substage 5e ooid tidal-bar and coral reef components may differ. The tidal-bar/reef complex forms the Florida Keys

New studies of Pleistocene reefs on San Salvador Island, Bahamas: Implications for island geology., 2003, Egerton V. M. , Mylroie J. E.

Classic Upper Paleosoic reefs and bioherms of West Texas and New Mexico (A field guide to the Guadalupe and Sacramento mountains of West Texas and New Mexico), 2004, Sholle P. A. , Goldstein R. H. , Ulmerscholle D. S.

Hypogene and supergene alteration of the Late Palaeozoic Ratburi Limestone during the Mesozoic and Cenozoic (Thailand, Surat Thani Province). Implications for the concentration of mineral commodities, 2005, Dill H. G. , Botz R. , Luppold F. W. , Henjeskunst F.
An interdisciplinary study of the Upper Carboniferous to Middle Permian Ratburi Group, Peninsular Thailand, is presented. The investigation involved sedimentary petrography, inorganic geochemistry, Sr, C, O isotope analyses, micropalaeontology as well as radio-carbon age dating. Emphasis was placed on the post-depositional evolution of the Ratburi Limestone in the Surat Thani Province. The Holocene chemical residues and the various calcite and dolomite minerals which have formed since the Late Palaeozoic in the Ratburi Limestone are the product of a complex, multistage alteration which is called supergene and hypogene karstifications, respectively. Sedimentation took place in a shelf environment with some reefs evolving during the late Murgabian at the shelf margin. There was no pre-concentration of elements, except for Ca and F during sedimentation. Diagenetic neomorphism and cementation under marine and freshwater conditions caused the Ratburi Limestone to convert into a marble-like rock. Fabric-selective dolomitization is of local scale and has impacted only on part of the Ratburi Limestone during the Lower to Upper Permian. A significant enhancement of pore space and better conduits were generated during the Late Cretaceous epithermal alteration. The most favorable conditions for the accumulation of metals were provided during the high-temperature stage of epithermal alteration when a low-metal concentration with As, Zn, Sb, U, Co and Pb existed. Unlike the other elements, Sb was subject to a multiphase concentration, giving rise to a considerable Sb deposit in the region. The most recent stage of karstification produced numerous caves, dripstones, tufa terraces and encrustations around brine pools in the study area. This alteration originated from per descensum and per ascensum processes which may be traced back to 15,000 years before present. The alteration of the Ratburi Limestone may be subdivided into two parts. The prograde post-depositional alteration, beginning with diagenesis, reached its temperature climax during epithermal subsurface alteration I. The retrograde branch of alteration lasted until the most recent times. The initial stages deposition and diagenesis took place under more or less closed-system conditions relative to the succeeding stages of the prograde alteration which saw the strongest influx of metal-bearing brine during the epithermal stage I. The retrograde branch of alteration is element-conservative.

Permo-Carboniferous Carbonate Platforms and Reefs: SEPM Special Publication No. 78, 2005, Kirkland Brenda L. ,

Contradicting barrier reef relationships for Darwin's evolution of reef types, 2006, Purdy E. G. , Winterer E. L. ,
The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the subsidence theory's implicit prediction that atolls should have significantly greater depths. In contrast, a great deal of evidence supports the influence of meteoric solution on barrier reef morphology. For example, the maximum lagoon depth of 56 modern barrier reefs is statistically correlated with the lagoon catchment area for modern annual rainfall. These modern rainfall patterns would seem to be a reasonable proxy for relative geographic differences in glacial lowstand rainfall, even though the absolute amounts of such rainfall are unknown. The correlation therefore suggests the importance of Pleistocene subaerial solution in contributing to barrier reef morphology. Further support for antecedent influence occurs in the form of barrier reef passes in which the depth of the reef pass is correlated with onshore drainage volumes. On a larger scale, the Cook Island of Mangaia provides evidence that solution can produce barrier reef morphology independent of reef development. In contrast, there are no examples of the subsidence-predicted lagoon transition of fringing reefs to barrier reefs to atolls. Moreover, the common occurrence of fringing reefs within barrier reefs negates subsidence as a causal factor in their 'presumed progressive evolutionary development. Consequently, the evidence to date suggests that a solution morphology template has been accentuated by reef construction to produce the diagnostic barrier reef morphology we see today. The importance of subsidence would seem to be in accounting for the overall thickness of the resulting carbonate caps of oceanic examples and in contributing to lagoon depth variation among the larger continental entities

Pervasive dolomitization with subsequent hydrothermal alteration in the Clarke Lake gas field, Middle Devonian Slave Point Formation, British Columbia, Canada , 2006, Lonnee J. , Machel H. G.

The Clarke Lake gas field in British Columbia, Canada, is hosted in pervasively dolomitized Middle Devonian carbonates of the Slave Point Formation. The Clarke Lake field consists mostly of pervasive matrix dolomite and some saddle dolomite, the latter varying in volume from about zero in limestones to normally 20–40% (locally up to 80%) in dolostones over any given 10-m (33-ft) core interval. Some of the saddle dolomite is replacive, some is cement, and both varieties are associated with dissolution porosity and recrystallized matrix dolomite. The major objective of this study is to identify the causes and timing of matrix and saddle dolomite formation, specifically, whether these dolomites are hydrothermal. A comprehensive petrographic and geochemical examination indicates that pervasive matrix dolomitization was accomplished by long-distance migration of halite-saturated brines during the Late Devonian toMississippian. Fluid-inclusion homogenization temperatures suggest about 150 (uncorrected) to 190jC (corrected) at the time of matrix dolomitization. These temperatures differ markedly from most published work on the dolomitized Devonian reefs in the Alberta Basin south of the Peace River arch, where pervasive matrix dolomitization was accomplished by advection of slightly modified seawater at temperatures of about 60–80jC, and where no hydrothermal influence was ever present. The saddle dolomites at Clarke Lake are not cogenetic with matrix dolomite and are not the product of hydrothermal dolomitization (sensu stricto). Instead, they formed through the hydrothermal alteration of matrix dolomite by way of invasion of a gypsum-saturated brine during periods of extremely high heat flow and regional plate-margin tectonics in the Late Devonian to Mississippian. Fluidinclusion homogenization temperatures suggest that hydrothermal alteration occurred between 230 (uncorrected) and 267jC (corrected), which is significantly higher than the maximumtemperature of about 190jC attained by the Slave Point Formation during burial. The sources of the halite- and gypsum-saturated brines are Middle Devonian evaporite depositional environments roughly 200 km (124 mi) south and/or east of Clarke Lake, near the Peace River arch

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