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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 leader is in caving, the person directing the activities of a caving party, especially with regard to safety [25].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
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 burial (Keyword) returned 103 results for the whole karstbase:
Showing 76 to 90 of 103
Prhistorische Hhlenfundpltze im Changwat Kanchanaburi, Westthailand - Hhlengebiete Sdostasiens XVI, 2006, Kusch, H.
In second half of the last century some cave sites in the Changwat Kanchanaburi of West Thailand have already been excavated and analysed archeologically. Three new cave sites are reported here which contain hitherto unknown archaeological and palaeontological material. The results show that Tham Phi is a neolithic burial place, Tham Kaeng Lawa is a possible prehistoric settlement or burial place and Tham Dao Deung is a site of paleontological interest.

Late Quaternary environmental and human events at En Gedi, reflected by the geology and archaeology of the Moringa Cave (Dead Sea area, Israel), 2007, Lisker, S. , Porat, R. , Davidovich, U. , Eshel, H. , Steinerik Lauritzen, S. E. , Frumkin

The Moringa Cave within Pleistocene sediments in the En Gedi area of the Dead Sea Fault Escarpment contains a sequence of various Pleistocene lacustrine deposits associated with higher-than-today lake levels at the Dead Sea basin. In addition it contains Chalcolithic remains and 5th century BC burials attributed to the Persian period, cemented and covered by Late Holocene travertine flowstone. These deposits represent a chain of Late Pleistocene and Holocene interconnected environmental and human events, echoing broader scale regional and global climate events. A major shift between depositional environments is associated with the rapid fall of Lake Lisan level during the latest Pleistocene. This exposed the sediments, providing for cave formation processes sometime between the latest Pleistocene (ca. 15 ka) and the Middle Holocene (ca. 4500 BC), eventually leading to human use of the cave. The Chalcolithic use of the cave can be related to a relatively moist desert environment, probably related to a shift in the location of the northern boundary of the Saharo-Arabian desert belt. The travertine layer was U?Th dated 2.46± 0.10 to 2.10±0.04 ka, in agreement with the archaeological finds from the Persian period. Together with the inner consistency of the dating results, this strongly supports the reliability of the radiometric ages. The 2.46?2.10 ka travertine deposition within the presently dry cave suggests a higher recharge of the Judean Desert aquifer, correlative to a rising Dead Sea towards the end of the 1st millennium BC. This suggests a relatively moist local and regional climate facilitating human habitation of the desert.


Variation in rates of Karst processes, 2007, Palmer, A. N. ,

The development of karst is not a linear process but instead takes place at irregular rates that typically include episodes of stagnation and even retrograde processes in which the evolution toward maturity is reversed. The magnitude and nature of these irregularities differs with the length of time considered. Contemporary measurements in caves show fluctuations in dissolution rate with changes in season, discharge, and soil conditions. Dissolution is sometimes interrupted by intervals of mineral deposition. Observed dissolution rates can be extrapolated to obtain estimates of long-term growth of a solution feature. But this approach is flawed, because as the time scale increases, the rates are disrupted by climate changes, and by variations that are inherent within the evolutionary history of the karst feature (e.g., increased CO2 loss from caves as entrances develop). At time scales of 105-106 years, karst evolution can be interrupted or accelerated by widespread fluctuations in base level and surface river patterns. An example is the relation between karst and the development of the Ohio River valley in east-central U.S.A. At a scale of 106-108 years, tectonic and stratigraphic events cause long-term changes in the mechanism and style of karst development. For example, much of the karst in the Rocky Mountains of North America has experienced two phases of pre-burial Carboniferous karst, mineral accretion during deep burial from Permian to Cretaceous, extensive cave development during Paleocene-Eocene uplift, and stagnation and partial mineral deposition caused by late Tertiary aggradation. At such large time scales, it is difficult to determine rates of karst development precisely, if at all. Instead it is appropriate to divide the evolutionary history into discrete episodes that correlate with regional tectonic and stratigraphic events.


The worlds oldest caves: - how did they survive and what can they tell us?, 2007, Osborne, R. A. L.

Parts of an open cave system we can walk around in today are more than three hundred million years old. Common sense tells even enthusiasts like me that open caves this old should not still exist, but they do! Their survival can be partly explained by extremely slow rates of surface lowering, but this is not sufficient by itself. Isolation by burial and relative vertical displacement by faults are probably also required. Now one very old set of caves have been found, are there more of them? what can they tell us?


RESULTS OF PALEOSTOMATOLOGICAL ANALYSIS OF MATERIAL FROM THE CAVE NEAR GORNJI VAKUF (SOUTH-WEST BOSNIA), 2007, Zukanović, A. , Mulaomerović, J. , Marjanović, D.

Among explored speleological objects near the Krupa village, close to Gornji Vakuf, the most interesting cave from paleocultural aspect, is the cave named “Cave number 5”. In the internal part of that cave, besides ceramic fragments and one metal needle, rich anthropological material have been found, compounds of numerous humans bones and teeth. Anato-morphological analysis of the one part of material showed that this site is a prehistoric crypt with remains of at least 13 people. Radiocarbon 14C bone analysiss results showed that those people lived 2765 ± 75 before presence. The fact that anthropological material includes some remains which belonged to children shows some characteristics of burial culture of that period on area of Uskoplje. This cave crypt is the one of the biggest on this region. Paleostomatological analysis of teeth and jaw fragments gave us clear evidence about therapeutic interventions performed in this period. X-rays analysis showed presence of the metal body inside the bone in one mandibular fragment. It’s supposed that this metal is broken part of instrument used for tooth extraction.


THE POSSIBLY HYPOGENE KARSTIC IRON ORE DEPOSIT OF WARDA NEAR AJLOUN (NORTHERN JORDAN), ITS MINERALOGy, GEOCHEMISTRy AND HISTORIC MINE, 2008, Almalabeh Ahmad, Kempe Stephan, Henschel Horstvolker , Hofmann Heiko & Tobschall Heinz Jrgen

In this study the iron ore deposit of the historic Warda mine (District of Ajloun, Northern Jordan) and its speleological im­portance is discussed. The number of known dissolutional caves in Jordan is very low, in spite of the fact, that large sections of the country are underlain by Cretaceous limestone. The only large cave yet discovered is Al-Daher Cave, a hypogene maze cave (Kempe et al. 2006). The Warda Iron Deposit was mined during the time of the crusades by one of Saladin’s officers to build and stock the castle of Ajloun. The survey shows that the mine consists of two larger rooms, together about 1000 m2 in area. Much of the mine’s floor is now covered with recent flood sediments (680 m2), up to over 2 m deep. The mine cuts natural cavities, fissures with speleothems and a collapse hall in lime­stone, that may or may not have been created by a collapsed mine ceiling. Calculating the mine volume conservatively, a to­tal of about 1100 t of elemental iron may have been extracted. Mineralogical investigation (XRD) shows, that the iron ore is goethitic/limonitic with noticeable hematite contents. Geo­chemical (XRF) analysis shows that the goethite is very pure; impurities of main elements sum up to 1% only. Among the trace-elements W (248 ppm), As (168 ppm) and Co (124 ppm) show the highest concentrations, with all others < 37 (Ba) ppm. Former prospecting results show that the deposit has a spatial extent of 300 x 200 m with a maximal thickness of about 10 m. Textural, mineralogical and geochemical criteria suggest that the ore body could be of speleogene origin, i.e. deposited in a hypogene, deep phreathic setting, possibly before regional up­lift or even prior to the maximal burial depth. A possibly simi­lar ore-body is for example described from the gigantic Lower Cretaceous and sand-filled cave of Wlfrath (North Rhine-Westphalia, Germany) (Drozdzewski et al. 1998).


Young uplift in the non-glaciated parts of the Eastern Alps, 2010, Wagner T. , Fabel D. , Fiebig M. , Hä, Uselmann Ph. , Sahy D. , Xu S. , Stü, We K.

We report the first incision rates derived from burial ages of cave sediments from the Mur river catchment at the eastern margin of the Eastern Alps. At the transition zone between the Alpine orogen and the Pannonian basin, this river passes through the Paleozoic of Graz — a region of karstifiable rocks called the Central Styrian Karst. This river dissects the study area in a north–south direction and has left behind an abundance of caves. These caves can be grouped into several distinct levels according to their elevation above the present fluvial base level. Age estimates of abandoned cave levels are constrained by dating fluvial sediments washed into caves during the waning stages of speleogenesis with the terrestrial cosmogenic nuclide method. These ages and the elevations of the cave levels relative to the current valley floor are used to infer a very complex history of 4 million years of water table position, influenced by the entrenchment and aggradation of the Mur river. We observe rather low rates of bedrock incision over the last 4 Ma (in the order of 0.1 mm/y) with an e-folding decrease in this trend to lower rates at younger times. We relate this incision history to a tectonic setting where an increase of drainage area of the Mur river due to stream piracy in Late Miocene to Pliocene times is linked to surface uplift. The later decrease in valley lowering rates is attributed to the rise of the base level related to aggradation of sediments within the valley. Sediment transport through the valley from the upstream section of the Mur river limited the erosional potential of the river to a transport limited state at the later stages of the incision history.


Fluid flow reconstruction in karstified Panormide platform limestones (north-central Sicily): Implications for hydrocarbon prospectivity in the Sicilian fold and thrust belt, 2010, Dewever B. , Berwouts I. , Swennen R. , Breesch L. , Ellam R. M.

Diagenetic analysis based on field and petrographic observations, isotope and microthermometric data was used to reconstruct the fluid flow history of the Cretaceous shallow water limestones from the Panormide platform exposed in north-central Sicily. Analysis focused on diagenetic products in cavities and dissolution enlarged fractures of the karstified limestones that occur just below a regional unconformity. The fluid flow history could be broken down into five stages that were linked to the kinematic and burial history of the region. (1) Petrography (zoned cathodoluminescence and speleothem textures) and stable isotopes (6.5 PDB &/Tm_2 to _5 _C), but at increasingly higher temperatures (Th 60–120 _C). This has been interpreted as precipitation during Oligocene foredeep burial. (4) Hot (Th 130–180 _C), low saline (Tm he low salinity and relatively high d18OSMOW signatures of the fluids are interpreted to be the result of clay dewatering reactions. The presence of bitumen and associated fluorite with hydrocarbon inclusions at this stage in the paragenesis constrains the timing of oil migration in the region. (5) Finally, high saline fluids with elevated 87Sr/86Sr (0.7095–0.7105) signatures invaded the karst system. This last fluid flow event was possibly coeval with localized dolomitization and calcite cementation along high-angle faults of Pliocene age, as suggested by identical radiogenic signatures of these diagenetic products.


Correlations of cave levels, stream terraces and planation surfaces along the River MurTiming of landscape evolution along the eastern margin of the Alps, 2011, Wagner Thomas, Fritz Harald, Stü, We Kurt, Nestroy Othmar, Rodnight Helena, Hellstrom John, Benischke Ralf

The transition zone of the Eastern Alps to the Pannonian Basin provides one of the best sources of information on landscape evolution of the Eastern Alpine mountain range. The region was non-glaciated during the entire Pleistocene. Thus, direct influence of glacial carving as a landscape forming process can be excluded and relics of landforms are preserved that date back to at least the Late Neogene. In this study, we provide a correlation between various planation surfaces across the orogen-basin transition. In particular, we use stream terraces, planation surfaces and cave levels that cover a vertical spread of some 700 m. Our correlation is used to show that both sides of the transition zone uplifted together starting at least about 5 Ma ago. For our correlation we use recently published terrestrial cosmogenic nuclide (TCN) burial ages from cave sediments, new optically stimulated luminescence (OSL) ages of a stream terrace and U–Th ages from speleothems. Minimum age constraints of cave levels from burial ages of cave sediments covering the last ~ 4 Ma are used to place age constraints on surface features by parallelizing cave levels with planation surfaces. The OSL results for the top section of the type locality of the Helfbrunn terrace suggest an Early Würm development (80.5 ± 3.7 to 68.7 ± 4.0 ka). The terrace origin as a penultimate gravel deposit (in classical Alpine terminology Riss) is therefore questioned. U-series speleothem ages from caves nearby indicate formation during Marine Isotope Stages (MIS) 5c and 5a which are both interstadial warm periods. As OSL ages from the terrace also show a time of deposition during MIS 5a ending at the MIS 5/4 transition, this supports the idea of temperate climatic conditions at the time of deposition. In general, tectonic activity is interpreted to be the main driving force for the formation and evolution of these landforms, whilst climate change is suggested to be of minor importance. Obvious hiatuses in Miocene to Pleistocene sediments are related to ongoing erosion and re-excavation of an uplifting and rejuvenating landscape


The Mammalian Fauna of Abismo Iguatemi, Southeastern Brazil, 2011, Castro Mariela C. , Langer Max C.

The Quaternary vertebrate fauna record of South America is characterized by the predominance of mammals, and the study of cave deposits can provide important information on their diversity and distribution. In Brazil, cave deposits have preserved remarkable fossil remains, including both large and small vertebrates, although the former have been the focus of most paleontological works. The fossils studied here came from Abismo Iguatemi, a karstic fissure located in the municipality of Apiaı´, upper Ribeira River valley, Sa˜o Paulo, Brazil. Blocks of sediment collected from its floor yielded a large sample of micro-remains, mainly composed of fragmentary small vertebrate specimens. Taphonomic parameters suggest that the fossil elements entered the cave either by entrapment or transported by rain runoff, as partially decayed carcasses or isolated elements. A total of 35 taxa were recorded in Abismo Iguatemi, four of which are extinct. The number of identified specimens per taxon (NISP index) is the best estimator of number of individuals at the burial site. The comparison of this fauna to that of other Quaternary deposits and to the present biodiversity of different areas reveals low similarity. The identification of fossil organisms with different ecological requirements (extinct savannah organisms and extant dense-forest organisms) suggests the existence of time averaging and may reflect environmental changes in the vicinity of the cave during the late Pleistocene and Holocene


Interpretation of ancient epikarst features in carbonate successions A note of caution, 2011, 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


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


Paleokarst of the USA: A Brief Review, 2011, Palmer A. N. , Palmer M. V.

Paleokarst consists of solutional features from a prior geomorphic phase that have been preserved by  burial or by a substantial change in local environment. The two major paleokarst horizons in North  America are of Early-Middle Ordovician (post-Sauk) age and Mississippian-Pennsylvanian (post-Kaskaskia) age. There are also several less extensive paleokarst zones. They all differ in detail but  typically include remnants of surface karst features, caves, breccias, hypogenic porosity, and related  mineral suites. In places they provide high-permeability zones significant to water supply, or serve as  hosts to petroleum, ores, and later karst development. Studies of paleokarst give significant evidence for  past geologic and hydrologic conditions, both surficial and deep seated.


Datierung fluviatiler Hhlensedimente mittels kosmogener Nuklide am Beispiel des Grazer Berglandes, 2011, Wagner, T.
The Central Styrian Karst north of Graz comprises a great number of caves of which many are of phreatic origin. Due to a clustering of caves at certain elevations above the current base level, the Mur River, these caves can be assigned to distinct levels. Caves cannot be older than the rock in which they formed, i.e. in the case of the region studied here not older than about 400 Ma (million years ago). Cave deposits on the other hand allow to infer a minimum age of cave formation, because they are deposited in the cave during or (mostly) after its development. Besides numerous autochthonous (i.e. in situ) sediments and speleothems, also a number of allochthonous (transported into the cave from the surface) sediments are encountered. Burial ages of several quartz-rich allochthonous cave sediments were determined using the radioactive cosmogenic nuclides 26Al and 10Be. The present article provides an insight into this rela tively new dating method (burial age dating) to constrain the age of cave deposits. The current state of knowledge about the timing of cave formation in the Grazer Bergland (Highland of Graz) will be discussed by summarizing the results of two recent papers (Wagner et al., 2010, 2011). Based on these results, conclusions are drawn about the age of the cave levels, relative incision rates of the River Mur and the landscape evolution of the eastern rim of the Alps in general. Sedimentation ages of 0 to about 5 Ma ago are in good agreement with increasingly higher cave levels above the present base level. This in turn reflects the stepwise relative incision of the River Mur. Based on the oldest samples, the onset of karstification and thus the exhumation of the Central Styrian Karst occurred at least 4-5 Ma ago. The oldest level, assigned to an age of at least 4 Ma, is situated some 500 m above the current valley bottom. Therefore, a relative incision rate of the River Mur in the order of only about 100 meters per million year (m/Myr) for the last 4-5 Ma is inferred. A more detailed examination of the levels reveals on average a decrease in the incision rate. Burial ages of ~2.5 Ma are determined only 100 m above the current base level. Moreover, the formation of planation surfaces and terraces in the Grazer Bergland is constrained by the correlation with cave levels and as such an important contribution to the understanding of landscape evolution of this region is made.

Paleokarst Breccia-Pipe Reservoir Analogue, Carboniferous, Svalbard, 2011, Wheeler Walter, Tveranger Jan, Lauritzen Steinerik, Heincke Björn, Rossi Guiliana, Allroggen Niklas, Buckley Simon

Upwards-propagating collapse pipes typically form sinkholes where they meet the land surface. Renewed dissolution of breccia in ancient pipes can have a similar effect. For these cases, probability-based models of sinkhole hazard are closely related to the expected mature architecture of the collapse-pipe field. We present a case study of the architecture of a square-kilometre field of collapse-pipes from the Carboniferous-Permian in which the pipes are documented in outcrop and using shallow geophysical methods.

The study site is located on the Wordiekammen plateau in the Carboniferous Billefjorden half-graben basin on Spitsbergen. Cliffs bounding the plateau expose breccia pipes cutting a gently-dipping 200-m-thick series of platform carbonates, in turn underlain by stratiform breccias and residual pods of gypsum. Many of the breccia pipes are tall (>250 m) and postdate several shallow karstification episodes. Most pipes are inferred not to have reached the surface based on a lack of terrigenous material and fluvial structure, although several pipes show indications of such surface communication. Although the pipes are generally attributed to gypsum dissolution, a deep carbonate karstification event is inferred based on high temperature calcite cement, and burial dehydration of gypsum, may also have contributed to void formation.

On the plateau top the collapse pipes are obscured by thick scree, thus km-scale size and spacing data for the pipes and faults was collected by mapping the bedrock with 2D ground-penetrating radar (GPR). GPR profiles were acquired on a grid with 25-meter line spacing, using 50 MHz antennas and achieving 30-40 m penetration. Breccia bodies were identified by steep-sided zones of complex diffraction patterns interrupting bedding-related continuous reflections. Two pipes were further studied in 3D using high-resolution GPR, tomographic seismic and geo-electric. These geophysical data were merged into a comprehensive 3D framework including helicopter-borne lidar and photo scans of the plateau rim geology, thus allowing an integrated visualization and interpretation of the different datasets. The GPR data show the breccia pipes to be slightly oblate with diameters ranging from 20 to over 100 m; 60 meters is a typical value. Approximately 10 pipes are identified in cliff-side outcrops bordering the GPR area, whereas 30 more are identified within the plateau by the GPR data. The GPR volume lies about 200 m above the pipe base, hence the pipe-length frequency-distribution data are incomplete. The strata are cut by small-offset (<5m) faults related to collapse processes and larger-offset faults related to regional basin extension. The breccia pipe field appears to be delimited by these more regional faults, in turn inferred to control the thickness of syn-rift gypsum and/or the hydrology of its dissolution. Collapse breccia pipes form strong vertical heterogeneities in rock properties such as porosity and permeability, matrix density, cement, mechanical strength and lithology, affecting fluid-flow characteristics on a meter to hundred-meter scale. It is rare that pipe fields are well exposed at the kilometre scale. Although some scaling data can be obtained from 3D oil-industry seismic reflection data but the resolution insufficient to visualize critical details. The outcrop combination of seismic, electric and geologic techniques facilitates the interpretation of 3D facies architectures and by proxy porosity-permeability relationships. Studies at the km scale are fundamental for understanding basic karst and collapse processes, and yield petrophysical models that can be applied predictively to natural hazards and groundwater or hydrocarbon exploitation in paleokarst settings.


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