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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That round karren is see rundkarren.?

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

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Chemistry and Karst, White, William B.
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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
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Your search for succession (Keyword) returned 95 results for the whole karstbase:
Showing 16 to 30 of 95
Isolated carbonate platform of Caniego, Spain: A test of the latest Albian worldwide sea-level changes, 1997, Fernandezmendiola Pa, Garciamondejar J,
The upper Albian Caniego carbonate platform consists of a 20-m-thick unit of rudist- and coral-bearing limestones that crops out at the northern margin of the Mena diapir in northern Spain, The limestones were deposited on top of a slowly subsiding area, the Mena paleohigh, a diapiric-induced horst bounded by synsedimentary faults, The Caniego limestones originated in shallow warm tropical waters following a widespread marine transgression at the base of the foraminifera Rotalipora appenninica zone (ammonite Stoliczkaia dispar zone), Around the middle part of the appenninica zone the Caniego limestones underwent subaerial exposure and karst development, Fibrous calcite cements filled the bulk of the fissure-dike and dissolution cavities, Field, petrological, and geochemical data indicate that the fibrous calcites are meteoric flowstones, delta(18)O values in these cements range from -3 parts per thousand to -4.5 parts per thousand and delta(13)C values range from -7 parts per thousand to -14 parts per thousand (relative to the Peedee belemnite [PDB] standard), Thick wedges of nearshore shallow-marine siliciclastic sediments were deposited in paleotrough areas surrounding the Caniego paleohigh while the platform was subaerially exposed, The carbonate platform was drowned in early Cenomanian time and hardground-condensed facies developed during this period (Rotalipora brotzeni zone), Deeper water noncondensed marry sedimentation was reestablished in the mid-Cenomanian (Rotalipora reicheli zone), Comparison of the Iberian Caniego limestones with worldwide successions suggests a coincidence in the timing of platform formation emergence and drowning in several basins of different lithospheric plates, Nevertheless, an overall lack of coordination of sea-level histories from different basins may be related to tectonic movements of the lithospheric plates, Plate rearrangement is invoked as the primary control on relative sea-level changes and sequence development

Dispersion and tailing of tracer plumes in a karstic system (Milandre, JU, Switzerland), 1997, Jeannin Py. , Marechal Jc.
A large number of tracing experiments have been carried out in a karstic aquifer in the Swiss Jura. These allow to observe the evolution of a tracer plume along the length of a karst conduit. The method of Sauty was used to make possible the comparison between all the observed breakthrough curves. The flow velocities and the dispersivities obtained are extremely variable. The dispersivities measured at different points along the length of an underground stream in the course of the same tracing experiment increase with distance (scale effect). If the fit of theoretical Sauty curves on the experimental curves works well for rising limbs, this is not always the case for falling limbs: a tailing effect or lag of the experimental curves compared to the theoretical ones is often observed. Micro-tracings have shown that the lag effect is linked more to the karst conduit geometry than to the types of flows (turbulent or laminar). Measurable tailing effect is induced by the presence of a single conduit enlargement (also called pool). Further, the experiments have shown that a succession of enlargements along the length of the underground stream causes a clear increase in the dispersivity and a "homogenisation" of the recovery curve which shows up by the apparent disappearance of the lag effect. These observations show clearly the influence of the heterogeneity of the karst conduit geometry on the breakthrough curves. This effect might be considered when one interprets the shape of the breakthrough curves especially for dispersivity estimation.

Mapping Chicxulub crater structure with gravity and seismic reflection data, 1998, Hildebrand A. R. , Pilkington M. , Ortizaleman C. , Chavez R. E. , Urrutiafucugauchi J. , Connors M. , Granielcastro E. , Camarazi A. , Halpenny J. F. , Niehaus D. ,
Aside from its significance in establishing the impact-mass extinction paradigm, the Chicxulub crater will probably come to exemplify the structure of large complex craters. Much of Chicxulub's structure may be mapped' by tying its gravity expression to seismic-reflection profiles revealing an [~]180 km diameter for the now-buried crater. The distribution of karst topography aids in outlining the peripheral crater structure as also revealed by the horizontal gradient of the gravity anomaly. The fracturing inferred to control groundwater flow is apparently related to subsidence of the crater fill. Modelling the crater's gravity expression based on a schematic structural model reveals that the crater fill is also responsible for the majority of the negative anomaly. The crater's melt sheet and central structural uplift are the other significant contributors to its gravity expression. The Chicxulub impact released [~]1.2 x 1031 ergs based on the observed collapsed disruption cavity of [~]86 km diameter reconstructed to an apparent disruption cavity (Dad) of [~]94 km diameter (equivalent to the excavation cavity) and an apparent transient cavity (Dat) of [~]80 km diameter. This impact energy, together with the observed [~]2 x 1011 g global Ir fluence in the Cretaceous-Tertiary (K-T) fireball layer indicates that the impactor was a comet estimated as massing [~]1.8 x 1018 g of [~]16.5 km diameter assuming a 0.6 gcm-3 density. Dust-induced darkness and cold, wind, giant waves, thermal pulses from the impact fireball and re-entering ejecta, acid rain, ozone-layer depletion, cooling from stratospheric aerosols, H2O greenhouse, CO2 greenhouse, poisons and mutagens, and oscillatory climate have been proposed as deleterious environmental effects of the Chicxulub impact with durations ranging from a few minutes to a million years. This succession of effects defines a temperature curve that is characteristic of large impacts. Although some patterns may be recognized in the K-T extinctions, and the survivorship rules changed across the boundary, relating specific environmental effects to species' extinctions is not yet possible. Geochemical records across the boundary support the occurrence a prompt thermal pulse, acid rain and a [~]5000 year-long greenhouse. The period of extinctions seems to extend into the earliest Tertiary

Growth and demise of an Archean carbonate platform, Steep Rock Lake, Ontario, Canada, 1999, Kusky T. P. , Hudleston P. J. ,
The Steep Rock Group of northwest Ontario's Wabigoon subprovince is one of the world's thickest Archean carbonate platform successions. It was deposited unconformably over a 3001-2928 Ma gneissic terrane, and contains a remarkable group of biogenic and oolitic limestones, dolostones, micrites, and karat breccias capped by a thick paleosol developed between and over karst towers. The presence of aragonite fans, herringbone calcite, and rare gypsum molds suggests that the carbonate platform experienced at least local anaerobic and hypersaline depositional conditions. This sequence shows that a combination of chemical and biological processes was able to build a carbonate platform 500 m thick by 3 billion years ago. The carbonate platform is structurally overlain by a mixture of complexly deformed rocks of the Dismal Ashrock forming a melange with blocks of ultramafic volcaniclastic rocks, mafic volcanics, carbonate, tonalite, lenses of Fe-ore rock, and metasedimentary rocks, in a shaly, serpentinitic, and fragmental ultramafic volcaniclastic matrix. The melange shows evidence of polyphase deformation, with early high-strain fabrics formed at amphibolite facies, and later superimposed brittle fabrics related to the final emplacement of the melange over the carbonate platform. An amphibolite- through greenschist-grade shear zone marks the upper contact of the melange with overlying mafic volcanic and tuffaceous rocks of the ca. 2932 Ma Witch Bay allochthon, interpreted as a primitive island are sequence. We suggest an evolutionary model for the area that begins with rifting of an are sequence (Marmion Complex of the Wabigoon are) that initiated subsidence and sedimentation on the Steep Rock platform and its correlatives that extend for a restored strike length exceeding 1000 km. Shallow water carbonate sedimentation continued until the platform was uplifted on the flanks of a flexural bulge related to the approach of the Witch Bay allochthon, representing collision of the rifted are margin of the Wabigoon subprovince with the Witch Bay are. Melange of the Dismal Ashrock was formed as off-axis volcanic rocks were accreted to the base of the Witch Bay allochthon prior to its collision with the Steep Rock platform

Facies differentiation and sequence stratigraphy in ancient evaporite basins - An example from the basal Zechstein (Upper Permian of Germany), 1999, Steinhoff I. , Strohmenger C. ,
Due to excellent preservation, the Werra Anhydrite (Al), the upper member of the Upper Permian Zechstein cycle I (Ist cycle, Z1), is readily studied in terms of the distribution of sulfate facies and sequence stratigraphy that can be interpreted from these facies. In this study cores taken from seven wells in the Southern Zechstein Basin were examined for their sedimentary structures and various petrographic features. Facies interpretation and depositional sequences are based on detailed examination of core material. Four main facies environments have been identified: (I) supratidal (II) intertidal (III) shallow subtidal, and (IV) deeper (hypersaline) subtidal. These are further subdivided into 10 subfacies types: (1) karst and (2) sabkha within the supratidal environment (I), (3) algal tidal-flat, (4) tidal flat and (5) beach deposit within the intertidal environment (II), (6) salina, and (7) sulfate arenites within the shallow subtidal enviromnent (III). The (8) slope subfacies type commonly associated with (9) turbidites and the (10) basin subfacies type subdivide the deeper subtidal environment (IV). Vertical stacking patterns of these facies and subfacies types reveal the sequence stratigraphic development of the sulfate cycles in response to sea-level and salinity fluctuations. The lower Werra Anhydrite (belonging to Zechstein Sequence ZS2) is characterized by a transgressive systems tract (IST) overlying the transgressive surface of Zechstein Sequence ZS2 within the Al-underlying upper Zechstein Limestone (Cal). The TST of the AT is several tens of meters thick in platform areas, where it is built up by sulfate arenites and swallow-tail anhydrite-after-gypsum, and thins out to a few meters of thickness toward the condensed basinal section, where laminites ('Linien-Anhydrit') are predominant. Most of the Al succession consists of three relatively thick parasequences belonging to the highstand systems tract (HST) that shows typical prograding sets. Enhanced platform Buildup, including sulfate arenites, salina deposits, intertidal sediments, and sabkha precipitation as well as turbidite shedding off the platforms produced marginal ''sulfate walls' up to 400 m thick as platform to slope portions of the Werra Anhydrite. Seaward, the Al thins to a few tens of meters of laminated sulfate basin muds. Increasingly pronounced Al topography during highstand narrowed the slope subfacies belt parallel to the platform margin This contrasts with the broad but considerably thinner slope deposits of transgressive times with much shallower slopes. The ensuing sea-level lowstand is reflected by a sequence boundary on top of the karstified Al-platform and a lowstand wedge (Zechstein Sequence ZS3) overlying portions of the slope and basinal subfacies of the Al highstand systems tract Beyond the lateral limits of the lowstand wedge, the sequence boundary merges with the transgressive surface of ZS3, shown by the lithologic change from the Al anhydrites to the overlying carbonates of the Stassfurt Carbonates ('Haupt Dolomit' Main Dolomite, Ca2). The Basal Anhydrite (A2), which overlies and seals the carbonate reservoir of the Ca2, can also be subdivided into systems tracts by means of facies analysis. It is, however, much less complex than the Al and is comprised almost exclusively of a transgressive systems tract of Zechstein Sequence ZS4

A succession of Miocene rodent assemblages from fissure fillings in southern France: palaeoenvironmental interpretation and comparison with Spain, 1999, Aguilar Jp, Escarguel G, Michaux J,
An Early to Late Miocene sequence of rodent assemblages from southern France has been quantitatively studied. The resulting pattern seems very similar to a contemporary sequence from central Spain (Calatayud-Teruel Basin). The fossil mammal-bearing localities are of different types: mainly karst infills in France and localities situated in sedimentary basins in Spain. In order to interpret the fossil record, a comparison has been made between southern France faunas of similar age but collected in karst infills and in basin deposits. There seems to be no difference between the two kinds of faunas and thus there is no indication that karst infills systematically give a picture of drier and more open environments. Both types of localities may give a similar relative abundance of taxa and when differences exist they can be attributed to local conditions. The comparison between southern France and the Calatayud-Teruel Basin (central Spain) shows that: (1) similar trends occurred in the two areas; (2) differences between spectra were more important during the late Early Miocene than during the Middle Miocene; (3) the shift between the late Early Miocene and the Middle Miocene environments in southern France does not seem to be correlated with. a general drop in temperatures as inferred from the analysis of central Spain faunas. (C) 1999 Elsevier Science B.V. All rights reserved

Diagenetic History of Pipe Creek Jr. Reef, Silurian, North-Central Indiana, U.S.A, 2000, Simo J. A. , Lehmann Patrick J. ,
Calcite cements in the Silurian (Ludlovian) Pipe Creek Jr. Reef, north-central Indiana, are compositionally zoned with characteristic minor-element concentrations and stable-isotope signatures, and were precipitated in different diagenetic environments. Superposition and crosscutting relationships allow us to group cement zones and to relate them to the sequence stratigraphic evolution of the reef. Pipe Creek Jr. Reef grew in normal marine waters, with the reef top high (greater than 50 m) above the platform floor. Flank facies are volumetrically important and are preserved largely as limestone, in contrast to most dolomitized Silurian reefs in the midcontinent. Syndepositional marine cements fill primary porosity and synsedimentary fractures and are interlayered with marine internal sediment. Now low-magnesium calcite, their isotopic compositions are similar to those of depositional grains and cements estimated to have precipitated from Ludlovian sea waters. Depositional porosity was reduced by 75% by the precipitation of these syndepositional cements, which stabilized the steeply dipping flank slope. Postdepositional, clear calcite cements are interpreted as shallow-phreatic and burial cements on the basis of their relationship to periods of karstification and fracturing. Shallow-phreatic cements, with concentric cathodoluminescent (CL) zonation, precipitated in primary pores and are postdated by fractures and caves filled with Middle Devonian sandstone. CL zonal boundaries are sharp, and some, near a major stratigraphic unconformity, show evidence of dissolution. The volumetric abundance of the individual CL zones varies in the reef, indicating a complex superposition of waters of varying chemistry and rock-water interaction that are probably related to relative sea-level changes. This important aspect of the reef stratigraphy is recorded only by the diagenetic succession, because evidence of earlier sea-level changes is removed by a major later regional unconformity. Burial cements are the youngest diagenetic feature recognized, and they rest conformably or unconformably over older cements. They exhibit both concentric CL zonation and sectoral zoning, they are ferroan to nonferroan, and they contain thin sulfide zones along growth-band boundaries. Their isotopic compositions do not overlap with shallow-phreatic or marine cement values. Degraded oil postdates burial cements, and is composed of the same sterane class as the Devonian-age Antrim Shale, the probable source rock. This source contrasts with that of reef reservoirs in the Michigan Basin, where Silurian strata are commonly the hydrocarbon source

Forest recovery in abandoned agricultural lands in a karst region of the Dominican Republic, 2000, Rivera L. W. , Zimmerman J. K. , Aide T. M. ,
This study documents the status of forest vegetation in the karst region of Los Haitises National Park, Dominican Republic, following the abandonment of pastures (less than or equal to 5 years), young (less than or equal to 5 years) 'conucos' (mixed plantings), old (7-30 years) conucos, and cacao plantations (> 25 years). We compared these sites to vegetation characteristics of patches of forest in karst valleys ('old forest'-too old to know their exact land use) and on mogote tops with no recent history of human disturbance. The youngest sites date to when squatters were removed from Los Haitises National Park. Forest structure (density, basal area, and species richness of woody plants greater than or equal to 1 cm DBH) were all significantly affected by land use. Density was highest in intermediate-aged valley sites (old conucos) and mogote tops, while both basal area and species richness tended to increase with age of abandonment. Although cacao plantations had been abandoned for more than 25 years the species diversity was low, due to continued regeneration of this persistent crop. Abandoned pastures had the greatest nonwoody biomass and were dominated by the fern Nephrolepis multiflora which had completely replaced pasture grasses. An ordination of the woody plant communities separated the mogote tops from valleys, emphasizing the strong control that topography has on the forest community in moist and wet tropical forests on karst substrates. Valley sites were arranged in the ordination in order of their age, suggesting a successional sequence converging on the composition of the 'old forest' sites

Sedimentology and geochemistry of fluvio-lacustrine tufa deposits controlled by evaporite solution subsidence in the central Ebro Depression, NE Spain, 2000, Arenas C, Gutierrez F, Osacar C, Sancho C,
The Urrea de Jalon tufa deposits constitute the 20- to 50-m-thick caprock (0.3 km(2)) of an isolated mesa. They disconformably overlie horizontal strata of the Tertiary Ebro Basin (NE Spain), which contains a thick succession of lacustrine gypsum and marls, followed by limestones, marls and, locally, fluvial sandstones and mudstones. The tufa deposits show a complex, large-scale framework of basin-like structures with centripetal dips that decrease progressively from the base to the top of the tufa succession, and beds that thicken towards the centre of the structure (cumulative wedge-out systems). These geometries reveal that the tufa deposits were affected by differential synsedimentary subsidence. Distinct onlapping depressions reflect time migration of the subsiding areas. The studied carbonates are composed mostly of low-Mg calcite, with minor quartz. Some samples have anomalously high contents of Fe, Mn and Ba that may exceed 1% (goethite, haematite and barite are present). Carbonate facies are: (a) macrophyte encrustation deposits; (b) bryophyte build-ups; (c) oncolite and coated grain rudstones; (d) non-concentric stromatolite-like structures; (e) massive or bioturbated biomicrites; and (f) green and grey marls. Facies a and c show a great variety of microbial-related forms. These facies can be arranged in dm- to 2-m-thick vertical associations representing: (i) fluvial-paludal sequences with bryophyte growths; (ii) pond-influenced fluvial sequences; and (iii) lacustrine-palustrine sequences. The Urrea de Jalon tufa deposits formed in a fluvio-lacustrine environment that received little alluvial sediment supply. Isotope compositions (delta(13)C and delta(18)O) reveal meteoric signatures and accord with such a hydrologically open system of fresh waters. The Fe, Mn and Ba contents suggest an additional supply of mineralized waters that could be related to springs. These would have been discharge points in the Ebro Depression of a regional aquifer of the Iberian Ranges. Rising groundwater caused the solution of the underlying evaporites and the synsedimentary subsidence of the tufa deposits

Role of stratigraphic elements in speleogenesis: the speleoinception concept, 2000, Lowe D. J.
Inception, the earliest phase of cave development, may begin during diagenesis. Within sedimentary rock sequences inception is generally related to specific favorable horizons or zones within the rock mass. These relatively thin inception horizons tend to display atypical chemical and/or physical properties, compared to the primary properties of the bulk of potentially cavernous rock successions. Commonly they correspond to depositional breaks or interruptions, particularly boundaries between major depositional cycles. Thus, according to the Inception Horizon Hypothesis, inception in sedimentary sequences (as typified by carbonate rocks) is inevitably related to, and guided by, thin relatively impure layers within thicker, otherwise pure beds, or at boundaries between impure and pure lithologies. Growth of incipient voids occurs potentially across the full lateral extent of inception horizons, generally very slowly during extended timescales. Growth may progress simultaneously at more than one stratigraphic level in a sequence, in deeply buried, confined or artesian conditions. Voids along individual inception horizons can be linked hydrologically by others that form concurrently or subsequently along tectonic or lithogenetic fissures. Later, interference between the imprinted inception framework and evolving surface landscapes leads to structurally advantageous elements of the potential three dimensional network being selected, linked and enlarged to form the skeletons of developing cave systems.

Diagenesis and porosity evolution of the Upper Silurian-lowermost Devonian West Point reef limestone, eastern Gaspe Belt, Quebec Appalachians, 2001, Bourque Pa, Savard Mm, Chi G, Dansereau P,
Diagenetic analysis based on cathodoluminescence petrography, cement stratigraphy, carbon and oxygen stable isotope geochemistry, and fluid inclusion microthermometry was used to reconstruct the porosity history and evaluate the reservoir potential of the Upper Silurian-Lower Devonian West Point limestone in the eastern part of the Gaspe Belt. The West Point limestone was investigated in two areas: 1) In the Chaleurs Bay Synclinorium, the limestone diagenesis of the lower and middle complexes of the Silurian West Point Formation was affected by repeated subaerial exposure related to late Ludlovian third-order eustatic low-stands, which coincided with the Salinic block tilting that produced the Salinic unconformity. The Anse McInnis Member (middle bank complex) underwent freshwater dissolution, and mixed marine and freshwater cementation during deposition. Concurrently, the underlying Anse a la Barbe and Gros Morbe members (lower mound and reef complex) experienced dissolution by fresh water percolating throughout the limestone succession. Despite this early development of karst porosity, subsequent meteoric-influenced cementation rapidly occluded all remaining pore space in the Gros Morbe, Anse a la Barbe, and Anse McInnis limestones. In contrast, the overlying Colline Daniel Member limestone (upper reef complex) does not show the influence of any freshwater diagenesis. Occlusion of its primary porosity occurred during progressive burial and was completed under a maximum burial depth of 1.2 kin. 2) In the Northern Outcrop Belt, the diagenesis of the Devonian pinnacle reefs of the West Point Formation followed a progressive burial trend. The primary pores of the reef limestone were not completely occluded before the reefs were buried at a significant depth (in some cases, to 6 km). Therefore, hydrocarbon migration in subsurface buildups before primary porosity occlusion might have created reservoirs. Moreover, the presence of gaseous hydrocarbons in Acadian-related veins attests to a hydrocarbon source in the area

The stratigraphical record and activity of evaporite dissolution subsidence in Spain, 2001, Gutierrez F. , Orti F. , Gutierrez M. , Perezgonzalez A. , Benito G. , Prieto J. G. , Valsero J. J. D. ,
The evaporite formations tin outcrop and at shallow depth) cover an extensive area of the Spanish territory. These soluble sediments are found in diverse geological domains and record a wide time span from the Triassic up to the present day. Broadly, the Mesozoic and Paleogene formations (Alpine cycle) are affected by compressional structures, whereas the Neogene (post-orogenic) sediments remain undeformed. The subsidence caused by subsurface dissolution of the evaporites (subjacent karst) takes place in three main types of stratigraphical settings: a) Subsidence affecting evaporite-bearing Mesozoic and Tertiary successions (interstratal karst); b) Subsidence in Quaternary alluvial deposits related to the exorheic evolution of the present-day fluvial systems (alluvial or mantled karst); c) Subsidence in exposed evaporites (uncovered karst). These types may be represented by paleosubsidence phenomena (synsedimentary and/or postsedimentary) recognizable in the stratigraphical record, or by equivalent currently active or modem examples with surface expression. The interstratal karstification of the Mesozoic marine evaporites and the consequent subsidence of the topstrata is revealed by stratiform collapse breccias and wedge-outs in the evaporites grading into unsoluble residues. In several Tertiary basins, the sediments overlying evaporites locally show synsedimentary and/or postsedimentary subsidence structures. The dissolution-induced subsidence coeval to sedimentation gives place to local thickenings in basin-like structures with convergent dips and cumulative wedge out systems. This sinking process controls the generation of depositional environments and lithofacies distribution. The postsedimentary subsidence produces a great variety of gravitational deformations in the Tertiary supra-evaporitic units including both ductile and brittle structures (flexures, synforms, fractures, collapse and brecciation). The Quaternary fluvial terrace deposits on evaporite sediments show anomalous thickenings (> 150 m) caused by a dissolution-induced subsidence process in the alluvial plain which is balanced by alluvial aggradation. The complex space and time evolution pattern of the paleosubsidence gives place to intricate and anarchical structures in the alluvium which may be erroneously interpreted as pure tectonic deformations. The current subsidence and generation of sinkholes due to suballuvial karstification constitutes a geohazard which affects to large densely populated areas endangering human safety and posing limitations to the development. An outstanding example corresponds to Calatayud historical city, where subsidence severely damages highly valuable monuments. The subsidence resulting from the underground karstification of evaporites has determined or influenced the generation of some important modem lacustrine basins like Gallocanta, Fuente de Piedra and Banyoles lakes. The sudden formation of sinkholes due to the collapse of cave roofs is relatively frequent in some evaporite outcrops. Very harmful and spectacular subsidence activity is currently occurring in the Cardona salt diapir where subsidence has been dramatically exacerbated by mining practices

The Dachstein paleosurface and the Augenstein Formation in the Northern Calcareous Alps - a mosaic stone in the geomorphological evolution of the Eastern Alps, 2001, Frisch W, Kuhlemann J, Dunkl I, Szekely B,
The central and eastern areas of the Northern Calcareous Alps (NCA) are characterized by remnants of the Dachstein paleosurface, which formed in Late Eocene (?) to Early Oligocene time and is preserved with limited modification on elevated karst plateaus. In Oligocene time, the Dachstein paleosurface subsided and was sealed by the Augenstein Formation, a terrestrial succession of conglomerates and sandstones, which are only preserved in small remnants on the plateaus, some in an autochthonous position. Thermochronological data suggest a maximum thickness of the Augenstein Formation of >1.3 km, possibly >2 km. The age of the Augenstein Formation is constrained by the overall geological situation as Early Oligocene to earliest Miocene. Fission track age data support an Early Oligocene age of the basal parts of the formation. The source area of the Augenstein Formation consisted predominantly of weakly metamorphic Paleozoic terrains (Greywacke Zone and equivalents) as well as the Late Carboniferous to Scythian siliciclastic base of the NCA to the south of the depositional area. To the west, the Augenstein Formation interfingered with the Tertiary deposits of the Inntal. Sedimentation of the Augenstein Formation was terminated in Early Miocene time in the course of the orogenic collapse of the Eastern Alps. The Augenstein sediments were eroded and redeposited in the foreland Molasse zone. From Pannonian times (similar to 10 Ma) on, the NCA and the denuded Dachstein surface experienced uplift in several pulses. The Dachstein paleosurface has been preserved in areas, in which thick limestone sequences allowed subsurface erosion by cave formation and thus prevented major surface erosion

The sequence stratigraphy, sedimentology, and economic importance of evaporite-carbonate transitions: a review, 2001, Sarg J. F. ,
World-class hydrocarbon accumulations occur in many ancient evaporite-related basins. Seals and traps of such accumulations are, in many cases, controlled by the stratigraphic distribution of carbonate-evaporite facies transitions. Evaporites may occur in each of the systems tracts within depositional sequences. Thick evaporite successions are best developed during sea level lowstands due to evaporative drawdown. Type 1 lowstand evaporite systems are characterized by thick wedges that fill basin centers, and onlap basin margins. Very thick successions (i.e. saline giants) represent 2nd-order supersequence set (20-50 m.y.) lowstand systems that cap basin fills, and provide the ultimate top seals for the hydrocarbons contained within such basins.Where slope carbonate buildups occur, lowstand evaporites that onlap and overlap these buildups show a lateral facies mosaic directly related to the paleo-relief of the buildups. This facies mosaic, as exemplified in the Silurian of the Michigan basin, ranges from nodular mosaic anhydrite of supratidal sabkha origin deposited over the crests of the buildups, to downslope subaqueous facies of bedded massive/mosaic anhydrite and allochthonous dolomite-anhydrite breccias. Facies transitions near the updip onlap edges of evaporite wedges can provide lateral seals to hydrocarbons. Porous dolomites at the updip edges of lowstand evaporites will trap hydrocarbons where they onlap nonporous platform slope deposits. The Desert Creek Member of the Paradox Formation illustrates this transition. On the margins of the giant Aneth oil field in southeastern Utah, separate downdip oil pools have accumulated where dolomudstones and dolowackestones with microcrystalline porosity onlap the underlying highstand platform slope.Where lowstand carbonate units exist in arid basins, the updip facies change from carbonates to evaporite-rich facies can also provide traps for hydrocarbons. The change from porous dolomites composed of high-energy, shallow water grainstones and packstones to nonporous evaporitic lagoonal dolomite and sabkha anhydrite occurs in the Upper Permian San Andres/Grayburg sequences of the Permian basin. This facies change provides the trap for secondary oil pools on the basinward flanks of fields that are productive from highstand facies identical to the lowstand dolograinstones. Type 2 lowstand systems, like the Smackover Limestone of the Gulf of Mexico, show a similar relationship. Commonly, these evaporite systems are a facies mosaic of salina and sabkha evaporites admixed with wadi siliciclastics. They overlie and seal highstand carbonate platforms containing reservoir facies of shoalwater nonskeletal and skeletal grainstones. Further basinward these evaporites change facies into similar porous platform facies, and contain separate hydrocarbon traps.Transgressions in arid settings over underfilled platforms (e.g. Zechstein (Permian) of Europe; Ferry Lake Anhydrite (Cretaceous), Gulf of Mexico) can result in deposition of alternating cyclic carbonates and evaporites in broad, shallow subaqueous hypersaline environments. Evaporites include bedded and palmate gypsum layers. Mudstones and wackestones are deposited in mesosaline, shallow subtidal to low intertidal environments during periodic flooding of the platform interior.Highstand systems tracts are characterized by thick successions of m-scale, brining upward parasequences in platform interior settings. The Seven Rivers Formation (Guadalupian) of the Permian basin typifies this transition. An intertonguing of carbonate and sulfates is interpreted to occur in a broad, shallow subaqueous hypersaline shelf lagoon behind the main restricting shelf-edge carbonate complex. Underlying paleodepositional highs appear to control the position of the initial facies transition. Periodic flooding of the shelf interior results in widespread carbonate deposition comprised of mesosaline, skeletal-poor peloid dolowackestones/mudstones. Progressive restriction due to active carbonate deposition and/or an environment of net evaporation causes brining upward and deposition of lagoonal gypsum. Condensed sections of organic-rich black lime mudstones occur in basinal areas seaward of the transgressive and highstand carbonate platforms and have sourced significant quantities of hydrocarbons

The speleological objects in the area of the Rjecina nappe structure., 2001, Kuhta M.
According to the new geotectonic concept of the Dinarides (Herak 1986, 1991), the investigated carbonate region of the Rjecina nappe structure is locate along the margin of the mega-structural unit of the Adriatic carbonate platform, the Adriaticum. Folds and numerous reverse faults and thrusts of the Dinaric strike manifest the main structural and tectonical features. These structures are incised by younger diagonal faults. The whole structure is inclined towards the north-west, with a succession of younger deposits towards that direction and the structure terminates with flysch beds. The flysch forms a rim around the structure in contact with the Obruc nappe, which represents the boundary with the Dinaricum mega-structural unit. In a geomorphologic sense the studied area is a part of a karst plateau situate at an altitude of 580 m above sea level. The typical karst morphology on the surface extends to the underground were it is manifested by the existence of caves and pits formed by karstification. During the most recent speleological investigations 10 up to now unknown caves and pits were studied. For six objects located in the vicinity the data used was presented from previous studies (Bozicevic, 1969, Biondic and Dukaric, 1986). Together with four objects which were not investigated as jet in the studied region of the Rjecina nappe structure there are 20 registered speleological objects. The main data concerning these objects are given in the table and the morphological features are presented on topographic maps.

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