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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 artesian well is a well deriving its water from a confined aquifer in which the water level stands above the ground surface [6]. synonym: flowing artesian well.?

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Chemistry and Karst, White, William B.
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Your search for dinantian (Keyword) returned 6 results for the whole karstbase:
DISLOCATION OF THE EVAPORITIC FORMATIONS UNDER TECTONIC AND DISSOLUTION CONTROLS - THE MODEL OF THE DINANTIAN EVAPORITES FROM VARISCAN AREA (NORTHERN FRANCE AND BELGIUM), 1993, Rouchy J. M. , Groessens E. , Laumondais A. ,
Within the Franco-Belgian segment of the Hercynian orogen, two thick Dinantian anhydritic formations are known, respectively in the Saint-Ghislain (765 m) and Epinoy 1 (904 m) wells. Nevertheless, occurrences of widespread extended breccias and of numerous pseudomorphs of gypsum/anhydrite in stratigraphically equivalent carbonate deposits (boreholes and outcrops), suggest a larger extent of the evaporitic conditions (fig. 1, 2). The present distribution of evaporites is controlled by palaeogeographical differentiation and post-depositional parameters such as tectonics and dissolution. These latter have dissected the deposits formerly present in all the structural units. By using depositional, diagenetic and deformational characters of these formations, the article provides a model for the reconstruction of a dislocated evaporitic basin. This segment of the Hercynian chain is schematically composed of two main units (fig. 1, 3) : (1) the autochthonous or parautochthonous deposits of the Namur synclinorium, (2) the Dinant nappe thrusted northward over the synclinorium of Namur. The major thrust surface is underlined by a complex fault bundle (faille du Midi) seismically recognized over more than 100 km. A complex system of thrust slices occurs at the Hercynian front. Except for local Cretaceous deposits, most of the studied area has been submitted to a long period of denudation since the Permian. Sedimentary, faunistic and geochemical data argue for a marine origin of the brines which have generated the evaporites interbedded with marine limestones. Sedimentary structures. - The thick evaporitic formations are composed of calcium-sulfates without any clear evidence of the former presence of more soluble salts (with the exception of a possible carbonate-sulfate breccia in the upper part of the Saint-Ghislain formation). As in all the deeply buried evaporitic formations, the anhydrite is the main sulfate component which displays all the usual facies : pseudomorphs after gypsum (fig. 4A, B), nodular and mosaic (fig. 4C), laminated. The gypsum was probably an important component during the depositional phase despite the predominant nodular pattern of the anhydrite. Early diagenetic nodular anhydrite may have grown during temporary emersion of the carbonates (sabkha environments), but this mechanism cannot explain the formation of the whole anhydrite. So, most of the anhydrite structures result from burial-controlled gypsum --> anhydrite conversion and from mechanical deformations. Moreover, a complex set of diagenetic processes leads to various authigenic minerals (celestite, fluorite, albite, native sulfur, quartz and fibrous silica) and to multistaged carbonate <> sulfate replacements (calcite and dolomite after sulfate, replacive anhydrite as idiomorphic poeciloblasts, veinlets, domino-like or stairstep monocrystals...). These mineral transformations observed ill boreholes and in outcrops have diversely been controlled during the complex evolution of the series as : depositional and diagenetic pore-fluid composition, pressure and temperature changes with burial, bacterial and thermochemical sulfate reduction, deep circulations favored by mechanical brecciation, mechanical stresses, role of groundwater during exhumation of the series. Deformational structures. - A great variety of deformational structures as rotational elongation, stretching, lamination, isoclinal microfolding, augen-like and mylonitic structures are generated by compressive tectonic stresses (fig. 4D to J). The similarities between tectonic-generated structures and sedimentary (lamination) or diagenetic (pseudo-nodules) features could lead lo misinterpretations. The calcareous interbeds have undergone brittle deformation the style and the importance of which depend of their relative thickness. Stretching, boudins, microfolds and augen structures F, H. I) affect the thin layers while thicker beds may be broken as large fractured blocks dragged within flown anhydrite leading to a mylonitic-like structure (fig, 4G). In such an inhomogeneous formation made of interlayered ductile (anhydrite) and brittle (carbonate) beds, the style and the intensity of the deformation vary with respect to the relative thickness of each of these components. Such deformational features of anhydrite may have an ubiquitous significance and can result either from compressive constraints or geostatic movements (halokinesis). Nevertheless, some data evidence a relation with regional tangential stresses: (1) increase of the deformation toward the bottom of the Saint-Ghislain Formation which is marked by a deep karst suggesting the presence of a mechanical discontinuity used as a drain for dissolving solutions (fig. 3, 4); (2) structural setting (reversed series, internal slidings) of the Epinoy 1 formation under the Midi thrust. However, tectonic stresses also induce flowing deformations which have contributed to cause their present discontinuity. It can be assumed that the evaporites played an active role for the buckling of the regional structure as detachment or gliding layers and more specifically for the genesis of duplex structures. Breccia genesis. - Great breccia horizons are widely distributed in outcrops as well as in the subsurface throughout the greater part of the Dinant and Namur units (fig. 2). The wide distribution of pseudomorphosed sulfates in outcrops and the stratigraphical correlation between breccia and Saint-Ghislain evaporitic masses (fig. 2) suggest that some breccia (although not all) have been originated from collapse after evaporites solution. Although some breccia may result from synsedimentary dissolution, studied occurrences show that most of dissolution processes started after the Hercynian deformation and, in some cases, were active until recently : elements made of lithified and fractured limestones (Llandelies quarries) (fig. 5A), preservation of pseudomorphs of late replacive anhydrite (Yves-Gomezee) (fig. 5B, C), deep karst associated with breccia (Douvrain, Saint Ghislain, Ghlin boreholes) (fig. 3, 4, 5D)). Locally, the final brecciation may have been favored by a mechanical fragmentation which controlled water circulations (fig. 5E). As postulated by De Magnee et al. [19861, the dissolution started mostly after the Permian denudation and continued until now in relation with deep circulations and surface weathering (fig. 6). So, the above-mentioned occurrences of the breccia are logically explained by collapse after dissolution of calcium-sulfates interbeds of significant thickness (the presence of salt is not yet demonstrated), but other Visean breccia may have a different origin (fig. 5F). So, these data prove the extension of thick evaporitic beds in all the structural units including the Dinant nappe, before dissolution and deformation. Implications. - Distribution of Visean evaporites in northern France and Belgium is inherited from a complicated paleogeographic, tectonic and post-tectonic history which has strongly modified their former facies, thicknesses and limits (fig. IA, 6). Diversified environments of deposition controlled by both a palaeogeographical differentiation and water level fluctuations led to the deposition of subaqueous (gypsum) or interstitial (gypsum, anhydrite) crystallization. Nevertheless, most of the anhydrite structures can be interpreted as resulting from burial conversion of gypsum to anhydrite rather than a generalized early diagenesis in sabkha-like conditions. Deformation of anhydrite caused by Hercynian tangential stresses and subsequent flow mechanisms, have completed the destruction of depositional and diagenetic features. The tectonic deformations allow us to consider the role of the evaporites in the Hercynian deformations. The evaporites supplied detachment and gliding planes as suggested for the base of the Saint-Ghislain Formation and demonstrated by the structural setting of Epinoy 1 evaporites in reverse position and in a multi-system of thrust-slices below the Midi overthrust (fig. 7). So, although the area in which evaporation and precipitation took place cannot be exactly delineated in geographic extent, all the data evidence that the isolated thick anhydritic deposits represent relics of more widespread evaporites extending more or less throughout the different structural units of this Hercynian segment (fig. 1B). Their present discontinuity results from the combination of a depositional differentiation, mechanical deformations and/or dissolution

Le puits de Flenu : la plus grande structure endokarstique du monde (1200 m) et la problmatique des puits du Houiller (Belgique), 1994, Quinif, Y.
In the Hainaut province, in Belgium, great vertical and cylindrical structures pass through the productive Westphalian. They are several coal-miners. They contain rocks from the lower Cretaceous cover, for example die Wealdian formations (clays, lignites and sands). Those pits result from deep karst in the dinantian limestones under the Namuro--Westphalian.

The influence of climatic change on exposure surface development: a case study from the Late Dinantian of England and Wales, 1996, Vanstone Simon,
Exposure surfaces represent an integral part of Asbian-Brigantian cyclothemic platform carbonates in England and Wales. These are characterized by the association of clay palaeosols, calcrete and palaeokarst and in most instances would appear to have been polygenetic. Alternating calcrete-karst stratigraphies associated with individual exposure surfaces indicate that the climate changed from semi-arid to humid to semi-arid conditions during each sea-level fall/rise cycle. Lowstand intervals were humid and resulted in karstification of the cyclothem-top sediments and the formation of a mineral soil. In contrast, regressive/transgressive phases were semi-arid and resulted in calcretization of the emergent platform carbonates. The influence that climatic cyclicity had upon exposure surface development was modulated by variations in platform bathymetry, subsidence and spatial climatic variation, and platforms exhibit their own individual record of what was essentially an idealized sequence of events. As with the sea-level oscillations responsible for cyclothemic sedimentation, the climatic cyclicity is thought to be the product of orbital forcing and probably reflects either eccentricity-driven shifts in the locus of monsoonal precipitation, or precession-driven variations in monsoonal intensity. If precessional in origin, exposure surface development represents a single minimum to minimum excursion, some 20 ka in duration, whereas if eccentricity-driven this may have been appreciably longer. Nevertheless, the immature nature of the exposure surfaces suggests that emergence was probably only of the order of a few tens of thousands of years

Spheroidal dolomites in a Visean karst system - Bacterial induced origin?, 1997, Nielsen P. , Swennen R. , Dickson J. A. D. , Fallick A. E. , Keppens E. ,
Spheroidal dolomite crystals occur in the karstified top of a Dinantian dolomite sequence in eastern Belgium. The spheroidal dolomite crystals are best developed at the base of the karst system. The dolomite crystals are characterized by a spherulitic or dumb-bell inclusion pattern, and are overgrown by dolomite cements with a rhombohedral outline. They are considered to be bacterially related precipitates based on, (1) textural similarities with documented bacteriogenic precipitates, (2) the presence of 'bacterial' microspheres and framboidal pyrite embedded within the dolomite, and (3) their general geological setting. The geochemical characteristics of the dolomites and associated minerals support a bacterial origin. The ubiquity of framboidal pyrite, depleted in S-34 (delta(34)S = - 22.4 to - 25.5 parts per thousand CDT), testifies to a period of bacterial sulphate reduction. The isotopic composition of the spheroidal dolomites (delta(13)C = - 2.4 to - 3.2 parts per thousand PDB and delta(18)O = - 3.8 to - 3.4 parts per thousand PDB) suggest a contribution from oxidized organic carbon produced during bacterial sulphate reduction. Sulphate reduction may also result in a concomitant O-18 depletion if the system is nearly closed. It is however, evident from the sulphur isotopic composition of associated framboidal pyrite that the system was fairly open. The O-18 depletion of the spheroidal dolomite crystals (delta(18)O = - 3.8 to - 3.4 parts per thousand PDB) and their occurrence adjacent to, and within karst cavities suggests a mixing zone origin, with a significant proportion of freshwater in it. The rhombohedral cement-overgrowths have calculated delta(18)O values in the range of 0 to 5.3 parts per thousand PDB, which reflect precipitation from normal to slightly evaporated contemporaneous seawater

Sequence stratigraphy of the type Dinantian of Belgium and its correlation with northern France (Boulonnais, Avesnois), 2001, Hance L. , Poty E. , Devuyst F. X. ,
The relative influences of local tectonics and global eustasy in the architecture of the sedimentary units of the Namur-Dinant Basin (southern Belgium) are determined. Nine third-order sequences are recognised. During the Lower Tournaisian (Hastarian and lower Ivorian) a homoclinal ramp extended from southern Belgium through southern England (Mendips) and into southern Ireland. From the upper Ivorian to the lower Visean rapid facies changes occurred due to progradation and increasing prominence of Waulsortian mudmounds. Progradation gradually produced a situation in which inner shelf facies covered the Namur (NSA), Condroz (CSA) and southern Avesnes (ASA) sedimentation areas, whereas outer shelf facies were restricted to the Dinant sedimentation area (DSA). During the middle and late Viscan a broad shelf was established from western Germany to southern Ireland. Because the shelf built up mainly by aggradation, parasequences can be followed over a large area. An early phase of Variscan shortening is perceptible during the Livian. The stratigraphic gap between the first Namurian sediments (E2 Goniatite Zone) and the underlying Visean varies from place to place, but is more important in the north. Sequence 1 straddles the Devonian-Carboniferous boundary. It starts with a transgressive system tract (TST) corresponding to the Etroeungt Formation (Fm.) and its lateral equivalent (the upper part of the Comb lain-au-Pont Fin.), and to the lower member of the Hastiere Fin. The highstand system tract (HST) is represented by the middle member of the Hastiere Fin. which directly overlies Famennian silicielastics in the northern part of the NSA. Sequence 2 starts abruptly, in the DSA and CSA, with the upper member of the Hastiere Fin. as the TST. The maximum flooding surface (MFS) lies within the shales of the Pont d'Arcole Fin., whereas the thick-bedded crinoidal limestones of the Landelies Fm. form the HST. Sequence 3 can clearly be recognised in the DSA and CSA. Its TST is formed by the Maurenne Fm. and the Yvoir Fm. in the northern part of the DSA and by the Maurenne Fm. and the Bayard Fin. in the southern part of the DSA. The Ourthe Fin. represents the HST. Growth of the Waulsortian mudmounds started during the TST. Sequence 4 shows a significant change of architecture. The TST is represented by the Martinrive Fm. in the CSA and the lower part of the Leffe Fin. in the DSA. The HST is marked by the crinoidal rudstones of the Flemalle Member (Mbr.) and the overlying oolitic limestones of the Avins Mbr. (respectively lower and upper parts of the Longpre Fin.). These latter units prograded far southwards, producing a clinoform profile. Sequence 5 is only present in the DSA and in the Vise sedimentation area (VSA). The TST and the HST form most of the Sovet Fm. and its equivalents to the south, namely, the upper part of the Leffe Fm. and the overlying Molignee Fm. In the VSA, the HST is locally represented by massive grainstones. Sequence 6 filled the topographic irregularities inherited from previous sedimentation. In the CSA, NSA and ASA the TST is formed by the peritidal limestones of the Terwagne Fm. which rests abruptly on the underlying Avins Nibr. (sequence 4) with local karst development. In the DSA, the TST corresponds to the Salet Fin. and, further south, to the black limestones of the strongly diachronous Molignee Fin. Over the whole Namur-Dinant Basin, the sequence ends with the thick-bedded packstones and grainstones of the Neffe Frn. as the HST. Sequence 7 includes the Lives Fm. and the lower part of the Grands-Malades Fm. (Seilles Mbr. and its lateral equivalents), corresponding respectively to the TST and HST. Sequence 8 corresponds to the Bay-Bonnet Mbr. (TST), characterised by stromatolitic limestones. The HST corresponds to the Thon-Samson Mbr. Sequence 9 is the youngest sequence of the Belgian Dinantian in the CSA and DSA. It includes the Poilvache Nibr. (TST, Bonne Fm.) and the Anhee Fm. (HST). These units are composed of shallowing-upward parasequences. The uppermost Visean and basal Namurian are lacking in southern Belgium where sequence 9 is directly capped by Namurian E2 silicielastics. In the VSA, sequence 9 is well developed

A proposed conceptual model for the genesis of the Derbyshire thermal springs, 2007, Brassington Fc,
Ten thermal springs occur in seven centres in Derbyshire, England, with temperatures up to 27.5 {degrees}C compared with an ambient groundwater temperature of about 9 {degrees}C. The springs discharge from a karstic Dinantian limestone aquifer along the boundary with the overlying Namurian strata around the edge of a regional dome structure. The water is heated by deep circulation to as much as 1 km, with the hottest spring being at Buxton spring, where the water is 5000 years old. A comparison of flow data from the Buxton spring with groundwater hydrographs shows seasonality in the thermal flows, suggesting that the loading effects produced by recharge are transmitted through this deep aquifer system. From a review of the geological history and the hydrogeology and the use of measurements on the Buxton spring it is suggested that the thermal flow system may have its roots in ancient convection cells possibly established in the deeply buried aquifer in late Carboniferous-Early Permian times. Subaerial erosion during the Pliocene removed the impermeable cap rocks and allowed both the thermally heated water to form warm springs and this deep groundwater circulation to be recharged by meteoric waters. The location of the individual springs is likely to date from the downcutting during the Late Pleistocene that formed the modern river valley topography

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