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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. ...

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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 turonian (Keyword) returned 6 results for the whole karstbase:
Karstification and tectonic evolution of the Jabal Madar (Adam Foothills, Arabian platform) during the Upper Cretaceous, 2000, Montenat C. , Soudet H. J. , Barrier P. , Chereau A. ,
A palaeokarst system of Turonian age, located on the Arabian platform, at the front of the ophiolitic nappes of Oman (Jabal Madar, Adam foothills), is described and placed in its geodynamic context. The development of the karst network in a vadose context was favoured by an episode of fracturing (N-S to NW-SE fractures) that affected the Cenomanian platform carbonates of the Natih Formation. The karstic filling comprises two main types of speleothems: - laminated bioclastic calcarenites with graded bedding essentially deposited by gravity currents in a vadose regime; - crystallisation of large masses of white calcite in a saturated regime. The calcite was deposited during several episodes, and often constitutes most of the filling. The episode of uplift and emergence, accompanied by fracturing which favoured the development of the Madar karstic system, was probably induced by the swelling of the Arabian platform, in response to the initiation of the ophiolitic nappe obduction. Karstic filling probably occurred during the rise of marine level, what is suggested by mixing of vadose and marine influences (production of bioclastic calcarenites and later dolomitisation of these ones; crystallisation of white calcite of various origins as evidenced by cathodoluminescence data and carbonate isotopes). At the beginning of the Senonian, the Jabal Madar area was again submerged and incorporated in a relatively deep foreland basin where pelagic marls and turbidites were deposited (Muti Formation). The Jabal Madar (and its karstic system) and the whole of the Adam foothills were affected by folding towards the end of the Cretaceous, during the final phase of thrusting of the Omani nappes. The folding was strongly reactivated by post-obduction compressional movement which occurred during Miocene times

The evolution of karst and caves in the Konûprusy region (Bohemian Karst, Czech Republic), Part III: Collapse structures, 2000, Bosak, Pavel

Vertical and subvertical pipes are circular to ovate in shape with diameters from 2-4 m up to tens of metres and with proven depth up to 82 m. Some of them terminate by horizontal cave levels at depth. Pipes are filled with complicated sedimentary sequences with clearly developed collapse structures. The fill is composed of pre-Cenomanian, Cenomanian-Turonian and Tertiary deposits. Internal structures of the fill indicate multi-phase collapses. Cretaceous and pre-Cretaceous deposits are often subvertical with chaotic internal texture. In the centre of some of pipes, there are traces of younger collapses, most probably induced by continuing karstification and suffosion at depth. Tertiary deposits overlay the Cretaceous ones unconformably; they show gentler centripetal inclination, but in places they fill the central parts of collapsed fill. The origin of solution pipes is connected with hydrothermal activity most probably during Paleogene to Miocene, when the surface of limestones was still covered by slightly eroded cover of Upper Cretaceous platform sediments. Hydrothermal karst forms developed up to the surface of limestones as the piezometric level was situated within the Cretaceous cover. After the lost of buoyancy support of water, sedimentary cover started to move (collapse) down.

Velika Jeršanova doline - a former collapse doline, 2000, Š, Ebela Stanka, Č, Ar Jož, E

The Velika Jeršanova doline (a.s.l.=535 m) is situated on the surface above the Postojnska Jama cave system. Its deepening undoubtedly interrupted the continuation of Pisani rov (a.s.l.=535,5 m) towards N. Through the Velika Jeršanova doline the Postojna anticline crest runs in the direction of NW-SE. The same direction has also the Jeršan fault. Strike and dip of thin bedded Turonian and Cenomanian limestones are disordered on the anticline's crest. The limestones dip 5-25°. The Velika Jeršanova doline today does not have the typical shape of a collapse doline. The main cause for the untypical collapse shape of Velika Jeršanova doline is its formation in the Postojna anticline crest, its shaping in thin bedded clay - rich limestones and intensive erosional lowering of the area. Regarding the actual shape of the slopes and outer edges, the Velika Jeršanova doline is a relic of a former well shaped collapse doline.

Vulnerability mapping of the Turonian limestone aquifer in the Phosphates Plateau (Morocco), 2004, Ettazarini S. , Mahmouhi El. N.

2D and 3D GPR imaging of sinkholes and dissolution features in Jandaíra karst of Fazenda Belém oil field, Potiguar Basin-CE, northeast of Brazil, PhD Thesis, 2005, Xavier Neto, Pedro

In Fazenda Belém oil field (Potiguar Basin, Ceará State, northeast Brazil) occur frequently sinkholes and sudden terrain collapses associated to an unconsolidated sedimentary cap covering the Jandaíra karst. This research was carried out in order to understand the mechanisms of generation of these collapses. The main tool used was Ground Penetrating Radar (GPR). This work is developed twofold: one aspect concerns methodology improvements in GPR data processing whilst another aspect concerns the geological study of the Jandaíra karst. This second aspect was strongly supported both by the analysis of outcropping karst structures (in another regions of Potiguar Basin) and by the interpretation of radargrams from the subsurface karst in Fazenda Belém.

It was designed and tested an adequate flux to process GPR data which was adapted from an usual flux to process seismic data. The changes were introduced to take into account important differences between GPR and Reflection Seismic methods, in particular: poor coupling between source and ground, mixed phase of the wavelet, low signal-to-noise ratio, monochannel acquisition, and high influence of wave propagation effects, notably dispersion. High frequency components of the GPR pulse suffer more pronounced effects of attenuation than low frequency components resulting in resolution losses in radargrams. In Fazenda Belém, there is a stronger need of an suitable flux to process GPR data because both the presence of a very high level of aerial events and the complexity of the imaged subsurface karst structures. The key point of the processing flux was an improvement in the correction of the attenuation effects on the GPR pulse based on their influence on the amplitude and phase spectra of GPR signals. In low and moderate losses dielectric media the propagated signal suffers significant changes only in its amplitude spectrum; that is, the phase spectrum of the propagated signal remains practically unaltered for the usual travel time ranges. Based on this fact, it is shown using real data that the judicious application of the well known tools of time gain and spectral balancing can efficiently correct the attenuation effects. The proposed approach can be applied in heterogeneous media and it does not require the precise knowledge of the attenuation parameters of the media. As an additional benefit, the judicious application of spectral balancing promotes a partial deconvolution of the data without changing its phase. In other words, the spectral balancing acts in a similar way to a zero phase deconvolution. In GPR data the resolution increase obtained with spectral balancing is greater than those obtained with spike and predictive deconvolutions.

The evolution of the Jandaíra karst in Potiguar Basin is associated to at least three events of subaerial exposition of the carbonatic plataform during the Turonian, Santonian, and Campanian. In Fazenda Belém region, during the mid Miocene, the Jandaíra karst was covered by continental siliciclastic sediments. These sediments partially filled the void space associated to the dissolution structures and fractures. Therefore, the development of the karst in this region was attenuated in comparison to other places in Potiguar Basin where this karst is exposed. In Fazenda Belém, the generation of sinkholes and terrain collapses are controlled mainly by: (i) the presence of an unconsolidated sedimentary cap which is thick enough to cover completely the karst but with sediment volume lower than the available space associated to the dissolution structures in the karst; (ii) the existence of important structural of SW-NE and NW-SE alignments which promote a localized increase in the hydraulic connectivity allowing the channeling of underground water, thus facilitating the carbonatic dissolution; and (iii) the existence of a hydraulic barrier to the groundwater flow, associated to the Açu-4 Unity.

The terrain collapse mechanisms in Fazenda Belém occur according to the following temporal evolution. The meteoric water infiltrates through the unconsolidated sedimentary cap and promotes its remobilization to the void space associated with the dissolution structures in Jandaíra Formation. This remobilization is initiated at the base of the sedimentary cap where the flow increases its abrasion due to a change from laminar to turbulent flow regime when the underground water flow reaches the open karst structures. The remobilized sediments progressively fill from bottom to top the void karst space. So, the void space is continuously migrated upwards ultimately reaching the surface and causing the sudden observed terrain collapses. This phenomenon is particularly active during the raining season, when the water table – that normally is located in the karst – may be temporarily located in the unconsolidated sedimentary cap.

Stable isotope analysis of the Cenomaniane Turonian (Late Cretaceous) oceanic anoxic event in the Crimea, 2005, Fisher J. K. , Price G. D. , Hart M. B. , Leng M. J.

Carbon and oxygen isotope data from Cenomaniane Turonian sediments from the southwest of the Crimea are presented. The sediments consist of limestones, marls and organic-rich claystones, the latter with total organic carbon values up to 2.6 wt. %, representing Oceanic Anoxic Event 2. A shift to more negatived 18 O values through the uppermost Cenomanian into the lowermost Turonian may be the result of warming; however, petrographic analysis shows that the samples have undergone a degree of diagenetic alteration. The carbon isotope data reveal a positive excursion fromw2.7&to a peak of 4.3&at the Cenomanian/Turonian boundary; values then decrease in the early Turonian. This excursion is comparable to those of other Cenomaniane Turonian sections, such as those seen in the Anglo-Paris Basin, and is thought to be due to global changes in the oceanic carbon reservoir. On this curve are a number of negatived 13 C excursions, just below the Cenomanian/Turonian boundary. It is suggested that these negative excursions are associated with the uptake of light carbon derived from the oxidation and deterioration of or-ganic material during localised exposure of the sediments to oxic or meteoric diagenetic conditions, possibly during sea-level fluctuations. 

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