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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 stomatal transpiration is the transpiration by escape of water through pores (stomata) of leaves [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 diagenesis (Keyword) returned 93 results for the whole karstbase:
Showing 76 to 90 of 93
Interpretation of ancient epikarst features in carbonate successions A note of caution, 2011,
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Immenhauser Adrian, Rameil Niels

In shallowmarine carbonate successions of the Phanerozoic, evidence for shorter-lived subaerial exposure stages of ancient carbonate seafloors is commonly found in the presence of small-scale epi-karst solution pits in discontinuity surfaces. Under favorable conditions, these solution features are accompanied by soil features including calcretes or root traces, alveolar septal structures, petrographic evidence such as pendant cements, circumgranular cracks or pisoliths, bleaching and staining of carbonate rocks or circumstantial geochemical evidence. Perhaps more often, however, ancient carbonate successions lack undisputable evidence for meteoric karsting. Using a well exposed case example from the Aptian of Oman, we here document that the superficial visual field inspection of solution pits in discontinuity surfaces may lead to erroneous interpretations. Outcrops at
JabalMadar, a diapiric structure, allowfor an in-depth analysis of dissolution features in the regionally extensive top Shu'aiba discontinuity. The solution pits discussed here were investigated for their stratigraphic position, their orientation relative to bedding planes, diagenetic and petrographic features and their potential relation to extensional fractures related to the updoming of Jabal Madar. The mainmessage brought forward, is that under burial conditions, spatially localized, hypogenic carbonate leachingmay formfeatures that are easily mistaken for ancient meteoric epikarst. These features preferentially form in interstratal positions where fractured, massive carbonate rocks are capped by a major discontinuity surface overlain by non-fractured argillaceous sediments. Thus,while dissolution–reprecipitation processes in the burial phreatic realmare omni-directional in permeable carbonates, low-permeability, argillaceous fines are not, or to amuch lesser extent, prone to chemical corrosion.
As a consequence carbonate-aggressive burial fluids leach out pits at the carbonate–shale interface. These appear to protrude perpendicular as bowl-shaped depressions into the underlying limestones and are – in the case examples documented here – preferentially aligned along factures. These findings have significance for the interpretation of ancient epikarst features in shallow marine carbonate successions


Structural and host rock controls on the distribution, morphology and mineralogy of speleothems in the Castanar Cave (Spain), 2011,
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Alonsozarza A. M. , Martinperez A. , Martingarcia R. , Gilpena I. , Melendez A. , Martinezflores E. , Hellstrom J. , Munozbarco P.

The Castanar Cave (central western Spain) formed in mixed carbonate-siliciclastic rocks of Neoproterozoic age. The host rock is finely bedded and shows a complex network of folds and fractures, with a prevalent N150E strike. This structure controlled the development and the maze pattern of the cave, as well as its main water routes. The cave formed more than 350 ka ago as the result of both the dissolution of interbedded carbonates and weathering of siliciclastic beds, which also promoted collapse of the overlying host rock. At present it is a totally vadose hypergenic cave, but its initial development could have been phreatic. The cave's speleothems vary widely in their morphology and mineralogy. In general, massive speleothems (stalactites, stalagmites, flowstones, etc.) are associated with the main fractures of the cave and bedding planes. These discontinuities offer a fairly continuous water supply. Other branching, fibrous, mostly aragonite speleothems, commonly occur in the steeper cave walls and were produced by capillary seepage or drip water. Detailed petrographical and isotope analyses indicate that both aragonite and calcite precipitated as primary minerals in the cave waters. Primary calcite precipitated in waters of low magnesium content, whereas aragonite precipitated from magnesium-rich waters. Differences in isotope values for calcite (-5.2‰ for ?18O and -9.6‰ for ?13C) and aragonite (?18O of -4.5‰ and ?13C of -3.5‰ ) can be explained by the fact that the more unstable mineral (aragonite) tends to incorporate the heavier C isotope to stabilize its structure or that aragonite precipitates in heavier waters. Changes in the water supply and the chemistry and instability of aragonite caused: (1) inversion of aragonite to calcite, which led to the transformation of aragonite needles into coarse calcite mosaics, (2) micritization, which appears as films or crusts of powdery, opaque calcite, and (3) dissolution. Dolomite, huntite, magnesite and sepiolite were identified within moonmilk deposits and crusts. Moonmilk occurs as a soft, white powder deposit on different types of speleothems, but mostly on aragonite formations. Huntite and magnesite formed as primary minerals, whereas dolomite arose via the replacement of both huntite and aragonite. Owing to its variety of speleothems and location in an area of scarce karstic features, the Castanar Cave was declared a Natural Monument in 1997 and is presently the target of a protection and research programme. Although the main products formed in the cave and their processes are relatively well known, further radiometric data are needed to better constrain the timing of these processes. For example, it is difficult to understand why some aragonite speleothems around 350 ka old have not yet given way to calcite, which indicates that the environmental setting of the cave is still not fully understood. 


Giant pockmarks in a carbonate platform (Maldives, Indian Ocean), 2011,
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Betzler C. , Lindhorst S. , Hubscher C. , Ludmann T. , Furstenau J. , Reijmer J.

Circular structures and depressions in carbonate platforms are known to represent karst chimneys or sinkholes which form as a response to rock solution. This formation mechanism is plausible for shallow-water carbonates which lie in the reach of meteoric diagenesis or fresh-water lenses. Circular structures which occur in deeper waters, however, need an alternative interpretation. Such an example of sea-floor depressions in more than 300. m deep waters occurs in the Inner Sea of the Maldives carbonate platform in the Indian Ocean. The structures were mapped with multibeam and Parasound, multi-channel seismics were used to link the depressions with structures at depth. The circular depressions have diameters of up to 3000. m and depths of up to 180. m. The craters are interpreted as pockmarks formed through the venting of gas and fluids. Gas and fluid lenses below the pockmarks are reflected by bright spots in the seismic sections as well as a reduction of the instantaneous frequency. These areas at depth are linked to chimneys connected to faults and drowned Oligocene carbonate banks. A model is presented that relates the different forms and sizes of the structures to distinct development stages of sea floor deformation to one process. Early stages of gas and fluid migration into the shallow part of the sedimentary succession induce formation of dome-shaped bodies. Initial gas and fluid escape to the sea floor is reflected by the formation of sand volcanoes and aligned small pockmarks. Active pockmarks are the deepest, and have the shape of truncated cones in cross section. Mature pockmarks are characterized by erosion of the flanks of the structure by bottom currents. Late stage pockmarks are bowl-shaped in cross section, and are to different degrees filled by drift sediments. Packages of strata revealing high reflection amplitudes and high interval velocities interpreted as microbially-mediated carbonate precipitates underlie some of the pockmarks. The pockmarks in the Maldives show that circular structures other than solution-related features can be abundant in carbonate platform deposits and that such structures may be more abundant in the geological record of carbonate platforms as previously thought. Pockmarks in the Maldives indicate that the archipelago is an example of a hydrocarbon system which consists of an isolated oceanic carbonate platform overlying a volcanic basement and lacustrine source rocks.


Controls on paleokarst heterogeneity. Integrated study of the Upper Permian syngenetic karst in Rattlesnake Canyon, Guadalupe Mountains, USA, 2011,
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Labraa De Miguel, Gemma

The present study contributes to a better understanding of early dissolution mechanisms for syngenetic karst development and provides constraints on the timing of formation of the Rattlesnake Canyon paleokarst system in the Guadalupe Mountains, New Mexico, U.S.A. Paleozoic paleokarsts commonly undergo burial and collapse, which reduces significantly the preservation of early fracture networks and geometries of dissolution. Rattlesnake Canyon constitutes a magnificent scenario for the study of global controls on Upper Permian karsting since early fracture networks and dissolution geometries are extremely well preserved and lack major tectonic deformation. This thesis sheds light on the scientific knowledge of paleokarsts and can be of interest to the oil industry since paleokarsts are common targets of exploration. As the evolution of the reservoir properties is often diagenetically controlled, the diagenetic study was particularly useful in determining the degree of sealing following hydrocarbon charge. 1) Aims This thesis seeks to improve our understanding of the relationship between early syndepositional fracture networks that are typically found in platform margins and syngenetic karst development. The thesis includes multidisciplinary carbonate studies aimed at understanding the multiscale paleokarst heterogeneity by means of (i) the development of a conceptual model for the karst evolution, (ii) the construction of a 3D paleokarst model, (iii) the determination of the diagenetic history of the paleokarst system and (iv) the paleokarst reservoir characterization. 2) Thesis Structure The thesis consists of 9 chapters and 2 appendices. Chapter 1 sets out the rationale for this thesis. Chapter 2 provides an introduction to the most basic aspects of karst science and to the hydrogeological model of Carbonate Island as well as an overview of the state-of-the-art paleokarst studies. The geological setting and the study area is detailed in Chapter 3. The results of the thesis are contained in Chapters 4 to 7. Because of the multidisciplinary nature of this thesis, each of these chapters is dedicated to one discipline. Chapter 4 focuses on the analysis of field data to obtain a conceptual model for the evolution of the paleokarst system. Chapter 5 discusses the methodology to implement the 3D paleokarst model and provides data to assess the dimensions of the system in subsurface. Chapter 6 focuses on the diagenetic stages that affected and controlled the karst development. Finally, Chapter 6 offers a paleokarst reservoir characterization. A comprehensive approach and discussion of the results obtained in each of these chapters are included in Chapter 8. General and specific conclusions are presented in Chapter 9. Appendix One contains a representative image compendium of the petrographic features observed in the paleokarst filling sequence of Fault N. Appendix Two sets out the raw data from the geochemical analysis. The paleokarst analysis using different disciplines provides a complete characterization of paleokarst heterogeneity and enables us to elucidate the controls of the system.


Fluid migration and porosity evolution in the Buda Hills, Hungary – selected examples from Triassic and Paleogene carbonate rocks/Dissertation submitted to the Ph.D. program for Geology and Geophysics at the Ph.D. School of Earth Sciences, Eötvös Lor, 2011,
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Poros, Zsófia

Porosity evolution of carbonates in the Buda Hills was the subject of this research. The aim was to provide an analogue for carbonate reservoirs that underwent multiphase diagenesis. Two major porosity types were recognized: 1) micro-porosity of powdered Triassic dolomites 2) cavernous and fracture porosity represented by the famous hypogenic cave system, hosted by Triassic and Paleogene carbonates. Powderization of dolomite is a general phenomenon in the Buda Hills, where its areal extent is exceptionally large compared to similar occurrences elsewhere in the world. Geochemistry and mineralogy of the dolomite remained constant throughout the disintegration. Powderization is absent at places where the Triassic dolomites are partially calcitized as a result of karst related dedolomitization. Since powderization was controlled by surface related processes and no geochemical changes were associated with it, disintegration of dolomite is interpreted as the result of sub-recent physical weathering, supposedly related to frost action.

Hypogenic caves are found along older calcite-barite-fluorite-sulphide veins, pointing to the fact that young cave-forming fluids migrated along the same fractures as the older mineralizing fluids did. Predominantly NNW–SSE strike of fractures concludes a latest Early Miocene maximum age for the fracture-filling minerals. Vein-calcite contains coeval primary, HC-bearing- and aqueous inclusions indicating that also HCs have migrated together with the mineralizing fluids. The coexistence of aqueous and HC inclusions permitted to establish the entrapment temperature (80°C) and pressure (85 bar) of the fluid and thus also the thickness of sediments, having been eroded since latest Early Miocene times, was calculated (800 m). Low salinity of the fluids (<1.7 NaCl eq. wt%) implies that HC-bearing fluids were diluted by regional karst water. Fluid inclusion studies also revealed that aggressive gases (e.g. CO2, H2S) were associated with HCs and that these gases may have played a role in dissolution of the carbonates. Based on the location of the paleo- and recent HC indications, identical migration pathways were reconstructed for both systems. It was proved that HC-bearing fluids have migrated northwestward from the basin east to the Buda Hills from the Miocene on. Due to the uplift related intensification of groundwater circulation, the proportion of hydrothermal fluids has diminished in favour of cold meteoric fluids. Establishment of the actual porosity of the Buda Karst initiated in Miocene times and earlier diagenetic history of the carbonates affected only the powderization of dolomite, and it had no direct effect on the localization of hypogenic caves.


MACROSCOPIC DIAGENETIC CHANGES IN LATE MIOCENE SPELEOTHEMS, WESTERN DESERT, EGYPT, 2012,
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Pickford, Martin

Understanding the diagenesis of speleothems is important on account of the fact that such deposits are often used for determining palaeoclimate parameters and for estimating the ages of speleothem growth. Impressive speleothem deposition of Vallesian age occurred in an immense palaeokarst network in the Western Desert, Egypt, the age of formation being determined on the basis of mammalian biochronology (fossils found in spelean clastic deposits intercalated between speleothems). Many of the Egyptian speleothems have been pervasively recrystallised internally, but their outer surfaces are usually well preserved except in the formations which were buried in clastic deposits, in which case the entire speleothem can be recrystallised. The recrystallisation results in large crystals (up to 20 cm diameter) growing radially outwards from the centre of stalagmites and stalactites, or at right angles to the outer surface of flowstone deposits. It is clear that crystal growth occurred without change of volume. Although the recrystallisation of speleothems in the Western Desert of Egypt resulted in the development of unusually large calcite crystals, it does indicate that diagenesis may be an important process that needs to be taken into account before speleothems in other karst systems can be used as raw material for unravelling palaeoclimatic and geochronological parameters. The gross morphology of the Egyptian speleothems is described in order to put on record the effects of diagenesis on them. The geochemistry of the speleothems remains to be studied.


Diagenesis of a drapery speleothem from Castaar Cave: from dissolution to dolomitization, 2012,
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Martnprez A. , Martngarca R. , Alonsozarza A. M.

A drapery speleothem (DRA-1) from Castañar Cave in Spain was subjected to a detailed petrographical study in order to identify its primary and diagenetic features. The drapery’s present day characteristics are the result of the combined effects of the primary and diagenetic processes that DRA-1 underwent. Its primary minerals are calcite, aragonite and huntite. Calcite is the main constituent of the speleothem, whereas aragonite forms as frostwork over the calcite. Huntite is the main mineral of moonmilk which covers the tips of aragonite. These primary minerals have undergone a set of diagenetic processes, which include: 1) partial dissolution or corrosion that produces the formation of powdery matt-white coatings on the surface of the speleothem. These are seen under the microscope as dark and highly porous microcrystalline aggregates; 2) total dissolution produces pores of few cm2 in size; 3) calcitization and dolomitization of aragonite result in the thickening and lost of shine of the aragonite fibres. Microscopically, calcitization is seen as rhombohedral crystals which cover and replace aragonite forming mosaics that preserve relics of aragonite precursor. Dolomitization results in the formation of microcrystalline rounded aggregates over aragonite fibres. These aggregates are formed by dolomite crystals of around 1 μm size. The sequence of diagenetic processes follows two main pathways. Pathway 1 is driven by the increase of saturation degree and Mg/Ca ratio of the karstic waters and is visible in the NW side of the drapery. This sequence of processes includes: 1) aragonite and huntite primary precipitation and 2) dolomitization. Pathway 2 is driven by a decrease in the degree of saturation of calcite and aragonite and Mg/Ca ratio of the cave waters, and it is observed in the SE side of the drapery. The diagenetic processes of the second pathway include: 1) calcitization of aragonite; 2) incomplete dissolution (micritization) of both aragonite and calcite; 3) total dissolution. This study highlights the importance of diagenetic processes on speleothems and their complexity. The correct interpretation of these processes is crucial for the understanding of possible changes in the chemistry of waters, temperature, or pCO2 and so is critical to the correct interpretation of the paleoenvironmental significance of speleothems.


Carbon and oxygen isotopic composition of the Middle Miocene Badenian gypsum-associated limestones of West Ukraine, 2012,
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Peryt T. M. , Durakiewicz T. , Peryt D. , Poberezhskyy A.

The middle Miocene Badenian basin of the Carpathian Foredeep is characterized by complex sedimentary and diagenetic carbonate-evaporite transitions. Six locations have been selected to evaluate the controls on the carbonand oxygen isotopic composition of the Badenian gypsum-associated limestones of the Tyras Formation in WestUkraine. At three locations marine limestones overlie the gypsum, at one location (Anadoly) the gypsum-associatedlimestones are polygenic, and at two localities (Pyshchatyntsi and Lozyna) gypsum deposits are lacking. Thestudied limestones have originated as primary, mostly peloidal carbonates as well as secondary carbonates formed by hypogene sulphate calcitisation. They show a wide range of δ13C (from from -0.9‰ to -39.8‰) and δ18O values(from 0.9‰ to -12.2‰). The Badenian limestones formed in marine environments (either as deposits accumulatedat the bottom of the sea or forming the infillings of solution cavities within gypsum) have less negative δ18O values compared to predominantly diagenetic formations. Wide ranges and usually very negative δ13C values andlow δ18O values of those limestones indicate that they suffered important meteoric diagenesis as supported bycommon sparitic fabrics. In addition, a large range of δ13C values even in the group of samples characterized byless-negative δ18O values shows that bacterial sulphate reduction and methane oxidation were active processes inthe pore fluids of the Tyras Formation. Very low carbon isotopic compositions (δ13C values from -22 to -40‰) of some sparitic limestones in the studied sections indicate the occurrence of oxidized methane within the diagenetic environment. Accordingly, the isotopic signatures of the studied limestones are a combination of both primary and secondary processes, the latter having a primordial importance. The common occurrence of similar negative δ13Cand δ18O values in evaporite-related carbonates in other Miocene evaporite basins suggest that extensive dissolution-reprecipitation in diagenetic or vadose-phreatic environments were common in evaporite-related carbonates.


Carbon and oxygen isotopic composition of the Middle Miocene Badenian gypsum-associated limestones of West Ukraine, 2012,
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Peryt T. M. , Durakiewicz T. , Peryt D. , Poberezhskyy A.

The middle Miocene Badenian basin of the Carpathian Foredeep is characterized by complex sedimentary and diagenetic carbonate-evaporite transitions. Six locations have been selected to evaluate the controls on the carbonand oxygen isotopic composition of the Badenian gypsum-associated limestones of the Tyras Formation in WestUkraine. At three locations marine limestones overlie the gypsum, at one location (Anadoly) the gypsum-associatedlimestones are polygenic, and at two localities (Pyshchatyntsi and Lozyna) gypsum deposits are lacking. Thestudied limestones have originated as primary, mostly peloidal carbonates as well as secondary carbonates formed by hypogene sulphate calcitisation. They show a wide range of δ13C (from from -0.9‰ to -39.8‰) and δ18O values(from 0.9‰ to -12.2‰). The Badenian limestones formed in marine environments (either as deposits accumulatedat the bottom of the sea or forming the infillings of solution cavities within gypsum) have less negative δ18O values compared to predominantly diagenetic formations. Wide ranges and usually very negative δ13C values andlow δ18O values of those limestones indicate that they suffered important meteoric diagenesis as supported bycommon sparitic fabrics. In addition, a large range of δ13C values even in the group of samples characterized byless-negative δ18O values shows that bacterial sulphate reduction and methane oxidation were active processes inthe pore fluids of the Tyras Formation. Very low carbon isotopic compositions (δ13C values from -22 to -40‰) of some sparitic limestones in the studied sections indicate the occurrence of oxidized methane within the diagenetic environment. Accordingly, the isotopic signatures of the studied limestones are a combination of both primary and secondary processes, the latter having a primordial importance. The common occurrence of similar negative δ13Cand δ18O values in 


Preservation and burial of ancient karst., 2013,
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Osborne, R. A. L.

Ancient karst features can be preserved by burial, filling, or by occurring in areas with extremely slow denudation. Although the terms ‘paleokarst’, ‘relict karst’,‘buried karst’, and ‘fossil karst’ have caused much confusion, paleokarst, buried karst, and relict karst can be defined in terms useful to karst geomorphologists and cave scientists. The term ‘fossil karst’ is best abandoned. Burial and paleokarstification are not necessarily the end of karst. Ancient features may be exhumed and reactivated. Karst ends with denudation at the Earth’s surface. Unroofed caves are a particular feature of karst denudation. Most ancient karst features may be preserved by filling, burial, and exhumation. In unusual conditions, karst features have survived at the surface since the Mesozoic. Burial, exhumation, and slow denudation may not be sufficient for extreme survival; relative vertical movement may be required. As caves and many other karst landforms are negative features, they are prone to filling by a range of materials, making cave sediments and paleokarst deposits quite diverse. Whole karst landscapes can be buried and evidence of burial can be recorded in the diagenesis of sediments. Although filled and unfilled caves can survive shallow burial, deep burial can crush caves, forming crackle breccia. Exhumation can occur from the surface following uplift or from below following hypogene speleogenesis. Preservation, burial, and exhumation of ancient karst have two unexpected consequences. Caves can be older than the landscapes in which they occur and stalagmites can be the longest surviving karst features


Comment on Sandstone caves on Venezuelan tepuis: Return to pseudokarst? by R. Aubrecht, T. Lnczos, M. Gregor, J. Schlgl, B. Smda, P. Lisck, Ch. Brewer-Caras, L. Vlcek, Geomorphology 132 (2011), 351365, 2013,
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Sauro F. , Piccini L. , Mecchia M. , De Waele J.

In the recent work of Aubrecht et al. (2011) the presence of “unlithified or poorly-lithified beds” of sands in the quartz-sandstone stratigraphic succession is proposed as a key factor for speleogenesis in the Venezuelan tepuis.In this comment we observe that in the cited work the geologic history of the region, in terms of sedimentation environment, diagenesis and low grade burial metamorphism, has not been considered. Furthermore, the peculiar “pillar flow” columns that Aubrecht et al. describe as a proof of the unlithification are lacking in many other different cave systems in the same area.

Four critical points are discussed: the burial metamorphism of the Mataui Formation, the significance of the Schmidt Hammer measurements, the cave morphologies and the role of SiO2 dissolution. Finally we suggest that weathering, in its wider significance, is probably the triggering process in speleogenesis, and there is no need to invoke a differential diagenesis of the sandstone beds. ©


Unusual polygenetic void and cave development in dolomitized Miocene chalks on Barbados, West Indies, 2013,
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Sumrall J. B. , Mylroie J. E. , Machel H. G.

Barbados provides an unusual case of polygenetic cave development within dolomitized chalks and marls of the Miocene Oceanics Group. These diagenetic processes are driven by a succession and interplay of tectonic uplift, fracturing, hypogene fluid injection, overprinting by mixing zone diagenesis, and mechanical and biological erosion in the current littoral zone. The significance of the voids and caves within the chalks on Barbados are: 1) these appear to be the first dissolution caves documented in dolomitized chalk, and 2) these features show a polygenetic origin documenting the diagenetic changes in lithology that allowed the development and preservation of these cave types.


The Grosmont: the worlds largest unconventional oil reservoir hosted in polyphase-polygenetic karst, 2013,
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Machel Hans G. , Borrero Mary Luz, Dembicki Eugene, Huebscher Harald4

The Upper Devonian Grosmont platform in Alberta, Canada, is the world’s largest heavy oil reservoir hosted in carbonates, with 400-500 billion barrels of IOIP at an average depth of about 250 – 400 m. Advanced thermal recovery technologies, such as SAGD and electrical in-situ retorting, much higher world market prices for oil and certain political pressures have led to a flurry of activity in the Grosmont since 2006.
The sedimentary stratigraphy of the Grosmont reservoir consists of six stacked car-bonate units interbedded with marls and some evaporites. The latter two originally acted as aquitards during diagenesis but are breached or missing in parts of the area today. Dolomitization by density-driven reflux was the first pervasive diagenetic pro-cess. A dense fracture network was created in three or four phases. Most fractures probably originated from collapse following subsurface salt dissolution and/or from Laramide tectonics far to the west, whereby pulsed crustal loading in the fold-and-thrust belt created a dynamic forebulge in the Grosmont region via multiple pulses of basin-wide crustal flexing, each followed by relaxation. The fracture network probably was reactivated and/or expanded by glacial loading and post-glacial isostatic rebound in the Pleistocene and Holocene, respectively.
The region experienced three or four prolonged periods of epigene karstification, alt-hough there is tangible evidence for only two of them in the Grosmont platform. The first of these episodes was a ‘warm epigene karstification’ during the Jurassic - Creta-ceous, and the second was/is a ‘cold epigene karstification’ that started sometime in the Cenozoic and is continuing to this day. In addition, there is circumstantial evidence for hypogene ‘karstification’ (= dissolution) throughout much of the geologic history of the Grosmont since the Late Devonian. Karstification was accompanied and/or by fol-lowed by extensive hydrocarbon biodegradation.


Comment on Sandstone caves on Venezuelan tepuis: Return to pseudokarst? by R. Aubrecht, T. Lnczos, M. Gregor, J. Schlgl, B. Smda, P. Lisck, Ch. Brewer-Caras, L. Vlcek, Geomorphology 132 (2011), 351365, 2013,
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Sauro Francesco, Piccini Leonardo, Mecchia Marco, De Waele Jo

In the recent work of Aubrecht et al. (2011) the presence of “unlithified or poorly-lithified beds” of sands in the   quartz-sandstone stratigraphic succession is proposed as a key factor for speleogenesis in the Venezuelan tepuis.   In this comment we observe that in the cited work the geologic history of the region, in terms of sedimentation   environment, diagenesis and low grade burial metamorphism, has not been considered. Furthermore, the   peculiar “pillar flow” columns that Aubrecht et al. describe as a proof of the unlithification are lacking in   many other different cave systems in the same area.   Four critical points are discussed: the burial metamorphism of the Mataui Formation, the significance of the   Schmidt Hammer measurements, the cave morphologies and the role of SiO2 dissolution. Finally we suggest   that weathering, in its wider significance, is probably the triggering process in speleogenesis, and there is no   need to invoke a differential diagenesis of the sandstone beds


EVAPORITE KARST AND HYDROGEOLOGY OF THE CASTILE FORMATION: CULBERSON COUNTY, TEXAS AND EDDY COUNTY, NEW MEXICO, 2013,
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Stafford, K. W.

Karst development in Permian Castile evaporites has resulted in complex speleogenetic evolution with multiple phases of diagenetic overprinting. More than 10,000 surficial features, primarily sinkholes, occur throughout Culberson County, Texas, and Eddy County, New Mexico, based on GIS-analyses where laminated Castile sulfates crop out. Cave development is largely the result of hypogene processes, where ascending fluids from the underlying Bell Canyon Formation migrate near vertically through the Castile Formation, creating caves up to 100 meters deep and over 500 meters long, which have been breached through a combination of collapse and surface denudation. Numerous small and laterally limited epigene features occur throughout the region, as well as the anomalously large Parks Ranch Cave System with more than 6.5 kilometers of cave development and multiple large, incised, sinkhole entrances. Hypogene caves exhibit varying degrees of epigenic overprinting as a result of surficial breaching.

Water resources in the Castile Formation are directly related to karst development with extremely heterogeneous flow networks. Most springs in the region discharge sulfate-rich waters, contain high levels of hydrogen sulfide, and support sulfate-reducing bacterial colonies. Isolated stream passages in northern Culberson County provide locally significant water resources that do not exhibit elevated hydrogen sulfide concentrations. Local water tables vary greatly over the region and few caves access base-level conditions. Upward migration of hydrocarbons complicates regional hydrology and diagenesis, resulting in extensive evaporite calcitization, which greatly modifies both fluid / rock interaction and permeability structures.


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