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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 irrigation return flow is the part of artificially applied water that is not consumed by evapotranspiration and that migrates to an aquifer or surface water body [22].?

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Your search for parasequence (Keyword) returned 11 results for the whole karstbase:
STABLE ISOTOPIC COMPOSITION OF METEORIC CALCITES - EVIDENCE FOR EARLY MISSISSIPPIAN CLIMATE-CHANGE IN THE MISSION CANYON FORMATION, MONTANA, 1993, Smith T. M. , Dorobek S. L. ,
The Lower Mississippian Mission Canyon Formation of central to southwestern Montana was deposited under dominantly semiarid to arid climatic conditions during Osagean to early Meramecian times. Following deposition, a pronounced climatic shift to more humid conditions occurred during middle Meramecian times. This climatic change is indicated by extensive, post-depositional karst fabrics and in the stable isotopic composition of early, meteoric calcite cements and diagenetically altered sediments. Early meteoric calcite cement in Mission Canyon limestones is generally nonluminescent and fills intergranular and fenestral porosity. Petrographic data indicate that this cement formed during intermittent subaerial exposure of the Mission Canyon platform during Osagean times. This initial generation of meteoric calcite cement has deltaO-18 values from -8.1 to -2.6 parts per thousand PDB. These data, and the oxygen isotopic values from nonluminescent skeletal grains and micrite in host limestone indicate that Osagean meteoric water may have had deltaO-18 values as low as -6.0 parts per thousand SMOW. A second generation of petrographically similar, but isotopically distinct, calcite cement fills biomolds and porosity within solution-collapse breccias in the Mission Canyon Formation. This cement generation postdates earlier nonluminescent Osagean calcite cement and is volumetrically most abundant near the top of the Mission Canyon Formation. DeltaO-18 values from these cements and from nonluminescent lime mudstone clasts and matrix in solution collapse breccias range from -13.8 to -8.2 parts per thousand PDB. These data indicate that Meramecian meteoric water may have had deltaO-18 values as low as - 12.0 parts per thousand. However, a higher-temperature burial overprint on the deltaO-18 values of the calcite cement cannot be ruled out. The more positive deltaO-18 values of the Osagean calcite components probably indicate warm and arid conditions during short-term [10(4)(?) yr) subaerial exposure along intraformational sequence and parasequence boundaries. The more negative deltaO-18 values from Meramecian calcite components and the extensive karst associated with the post-Mission Canyon unconformity may have developed because of cooler and more humid climatic conditions and possible rain-out effects during middle Meramecian times. A dramatic shift towards cooler and more humid climatic conditions may be coincident with the onset of major continental glaciation in the Early Carboniferous. The post-Mission Canyon unconformity has been attributed to a major fall in sea level that may have glacio-eustatic origins. Growth of continental glaciers during a time of global cooling would have caused migration of polar fronts further toward the paleoequator. These polar fronts in turn, would have pushed moist, mid-latitude weather systems toward the paleoequator, resulting in cooler, more humid conditions in low-latitude settings during ''icehouse'' times

CYCLOSTRATIGRAPHY OF MIDDLE DEVONIAN CARBONATES OF THE EASTERN GREAT-BASIN, 1995, Elrick M,
Middle Devonian carbonates (250-430 m thick) of the eastern Great Basin were deposited along a low energy, westward-thickening, distally steepened ramp. Four third-order sequences can be correlated across the ramp-to-basin transition and are composed of meter-scale, upward-shallowing carbonate cycles (or parasequences). Peritidal cycles (shallow subtidal facies capped by tidal-flat laminites) constitute 90% of all measured cycles and are present across the entire ramp. The peritidal cycles are regressive- and transgressive-prone (upward-deepening followed by upward-shallowing facies trends). Approximately 80% of the peritidal cycle caps show evidence of prolonged subaerial exposure including sediment-filled dissolution cavities, horizontal to vertical desiccation cracks, rubble and karst breccias, and pedogenic alteration; locally these features are present down to 2 m below the cycle caps. Subtidal cycles (capped by shallow subtidal facies) are present along the middle-outer ramp and ramp margin and indicate incomplete shallowing. submerged subtidal cycles (64% of all subtidal cycles) are composed of deeper subtidal facies overlain by shallow subtidal facies. Exposed subtidal cycles are composed of deeper subtidal facies overlain by shallow subtidal facies that are capped by features indicative of prolonged subaerial exposure (dissolution cavities and brecciation). Average peritidal and subtidal cycle durations are between approximately 50 and 130 k.y. (fourth- to fifth-order). The combined evidence of abundant exposure-capped peritidal and subtidal cycles, transgressive-prone cycles, and subtidal cycles correlative with updip peritidal cycles indicates that the cycles formed in response to fourth- to fifth-order, glacio-eustatic sea-level oscillations. Sea-level oscillations of relatively low magnitude (< 10 m) are suggested by the abundance of peritidal cycles, the lack of widely varying, water-depth-dependent facies within individual cycles, and the presence of noncyclic stratigraphic intervals within intrashelf-basin, slope, and basin facies. Noncyclic intervals represent missed subtidal beats when the seafloor lay too deep to record the effects of the short-term sea-level oscillations. Exposure surfaces at the tops of peritidal and subtidal cycles represent one, or more likely several, missed sea-level oscillations when the platform lay above fluctuating sea level, but the amplitude of fourth- to fifth-order sea-level oscillation(s) were not high enough to flood the ramp. The large number of missed beats (exposure-capped cycles), specifically in Sequences 2 and 4, results in Fischer plots that show poorly developed rising and falling limbs (subdued wave-like patterns); consequently the Fischer plots: are of limited use as a correlation tool for these particular depositional sequences. The abundance of missed beats also explains why Milankovitch-type cycle ratios (similar to 5:1 or similar to 4:1) are not observed and why such ratios would not be expected along many peritidal-cycle-dominated carbonate platforms

The Lower Triassic Montney Formation, west-central Alberta, 1997, Davies Gr, Moslow Tf, Sherwin Md,
The Lower Triassic Montney Formation was deposited in a west-facing, arcuate extensional basin, designated the Peace River Basin, on the northwestern margin of the Supercontinent Pangea, centred at about 30 degrees N paleolatitude. At least seasonally arid climatic conditions, dominance of northeast trade winds, minimum fluvial influx, offshore coastal upwelling, and north to south longshore sediment transport affected Montney sedimentation. Paleostructure, particularly highs over underlying Upper Devonian Leduc reefs and lows associated with graben trends in the Peace River area, strongly influenced Montney depositional and downslope mass-wasting processes. A wide range of depositional environments in the Montney is recorded by facies ranging from mid to upper shoreface sandstones, to middle and lower shoreface HCS sandstones and coarse siltstones, to finely laminated lower shoreface sand and offshore siltstones. and to turbidites. Dolomitized coquinal facies occur at seven stratigraphic horizons in the Montney. Some coquinas are capped by karst breccias and coarse-grained aeolian deflation lag sand residues indicating subaerial exposure. The Montney has been divided into three informal members that have been dated by palynology and compared with global Early Triassic sequences. The subdivisions are: the Lower member, of Griesbachian to Dienerian age, correlated with a third-order cycle; the Coquinal Dolomite Middle member, of mixed Dienerian and Smithian ages; and the Upper member, of Smithian to Spathian age, correlative with two, shorter-duration third-order cycles. A forced regressive wedge systems tract model is adopted for deposition of the Coquinal Dolomite Middle member and for turbidites in the Valhalla-La Glace area of west-central Alberta. With this model, coquinas and turbidites accumulated during falling base level to lowstand, with a basal surface of forced regression at the base of the coquina and a sequence boundary at the top of the coquinal member. This is supported by the evidence for subaerial exposure and maximum lowstand at the top of the coquina. Very limited grain size distribution in the Montney, dominantly siltstone to very fine-grained sandstone, but often very well sorted, is interpreted to reflect an aeolian influence on sediment source and transport, High detrital feldspar and detrital dolomite in the Montney are consistent with (but not proof of) aeolian source from an arid interior, as is high detrital mica content in finer size grades. Extensive and often pervasive dolomitization, and early anhydrite cementation within the Montney, are also consistent with an arid climatic imprint. As new exploratory drilling continues to reveal the wide range of facies in the Montney, it adds to both the complexity and potential of this relatively unique formation in western Canada

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

High-resolution sequence stratigraphic correlation in the Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) peritidal carbonate deposits (Western Taurides, Turkey), 1999, Altiner D, Yilmaz Io, Ozgul N, Akcar N, Bayazitoglu M, Gaziulusoy Ze,
Upper Jurassic (Kimmeridgian)- Upper Cretaceous (Cenomanian) inner platform carbonates in the Western Taurides are composed of metre-scale upward-shallowing cyclic deposits (parasequences) and important karstic surfaces capping some of the cycles. Peritidal cycles (shallow subtidal facies capped by tidal-Aat laminites or fenestrate limestones) are regressive- and transgressive-prone (upward-deepening followed by upward-shallowing facies trends). Subtidal cycles are of two types and indicate incomplete shallowing. Submerged subtidal cycles are composed of deeper subtidal facies overlain by shallow subtidal facies. Exposed subtidal cycles consist of deeper subtidal facies overlain by shallow subtidal facies that are capped by features indicative of prolonged subaerial exposure. Subtidal facies occur characteristically in the Jurassic, while peritidal cycles are typical for the Lower Cretaceous of the region. Within the foraminiferal and dasyclad algal biostratigraphic framework, four karst breccia levels are recognized as the boundaries of major second-order cycles, introduced for the first time in this study. These levels correspond to the Kimmeridgian-Portlandian boundary, mid-Early Valanginian, mid-Early Aptian and mid-Cenomanian and represent important sea level falls which affected the distribution of foraminiferal fauna and dasyclad flora of the Taurus carbonate platform. Within the Kimmeridgian-Cenomanian interval 26 third-order sequences (types and 2) are recognized. These sequences are the records of eustatic sea level fluctuations rather than the records of local tectonic events because the boundaries of the sequences representing 1-4 Ma intervals are correlative with global sea level falls. Third-order sequences and metre-scale cyclic deposits are the major units used for long-distance, high-resolution sequence stratigraphic correlation in the Western Taurides. Metre-scale cyclic deposits (parasequences) in the Cretaceous show genetical stacking patterns within third-order sequences and correspond to fourth-order sequences representing 100-200 ka. These cycles are possibly the E2 signal (126 ka) of the orbital eccentricity cycles of the Milankovitch band. The slight deviation of values, calculated for parasequences. from the mean value of eccentricity cycles can be explained by the currently imprecise geochronology established in the Cretaceous and missed sea level oscillations when the platform lay above fluctuating sea level. Copyright (C) 1999 John Wiley & Sons, Ltd

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

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

Seismic stratigraphy of Late Quaternary deposits from the southwestern Black Sea shelf: evidence for non-catastrophic variations in sea-level during the last ~10[punctuation space]000 yr, 2002, Aksu Ae, Hiscott Rn, Yasar D, Isler Fi, Marsh S,
Detailed interpretation of single channel seismic reflection and Huntec deep-tow boomer and sparker profiles demonstrates that the southwestern Black Sea shelf formed by a protracted shelf-edge progradation since the Miocene-Pliocene. Five seismic-stratigraphic units are recognized. Unit 1 represents the last phase of the progradational history, and was deposited during the last glacial lowstand and Holocene. It is divided into four subunits: Subunit 1A is interpreted as a lowstand systems tract, 1B and 1C are interpreted as a transgressive systems tract, and Subunit 1D is interpreted as a highstand systems tract. The lowstand systems tract deposits consist of overlapping and seaward-prograding shelf-edge wedges deposited during the lowstand and the subsequent initial rise of sea level. These shelf-edge wedges are best developed along the westernmost and easternmost segments of the study area, off the mouths of rivers. The transgressive systems tract deposits consist of a set of shingled, shore-parallel, back-stepping parasequences, deposited during a phase of relatively rapid sea-level rise, and include a number of prograded sediment bodies (including barrier islands, beach deposits) and thin veneers of seismically transparent muds showing onlap onto the flanks of older sedimentary features. A number of radiocarbon dates from gravity cores show that the sedimentary architecture of Unit 1 contain a detailed sedimentary record for the post-glacial sea-level rise along the southwestern Black Sea shelf. These data do not support the catastrophic refilling of the Black Sea by waters from the Mediterranean Sea at 7.1 ka postulated by [Ryan, Pitman, Major, Shimkus, Maskalenko, Jones, Dimitrov, Gorur, Sakinc, Yuce, Mar. Geol. 138 (1997) 119-126], [Ryan, Pitman, Touchstone Book (1999) 319 pp.], and [Ballard, Coleman, Rosenberg, Mar. Geol. 170 (2000) 253-261]

Relative Sea-Level Changes Recorded on an Isolated Carbonate Platform: Tithonian to Cenomanian Succession, Southern Croatia, 2006, Husinec Antun, Jelaska Vladimir,
Superb sections of Tithonian to Cenomanian carbonates of the Adriatic (Dinaric) platform are exposed on the islands of southern Croatia. A succession approximately 1,800 m thick consists exclusively of shallow-water marine carbonates (limestone, dolomitized limestone, dolomite, and intraformational breccia), formed in a protected and tectonically stable part of the platform interior. Several phases of exposure and incipient drowning are recorded in the platform interior. Four are crucial for understanding the Late Jurassic to mid-Cretaceous evolution of the wider peri-Adriatic area: (1) latest Jurassic-earliest Cretaceous sea-level fall, (2) Aptian drowning, followed by (3) Late Aptian platform exposure, and (4) Late Albian-Early Cenomanian sea-level fall. Deciphering these complex events from the vertical and lateral facies distribution has led to an evaluation of facies dynamics and construction of a relative sea-level curve for the study area. This curve shows that long-term transgression during the Early Tithonian, Hauterivian, Early Aptian, and Early Albian, resulted in generally thicker beds deposited in subtidal environments of lagoons or shoals. Regression was characterized by shallowing-upward peritidal parasequences, with well-developed tidal-flat laminites commonly capped by emersion breccia and/or residual clay sheets (Early Berriasian, Barremian, Late Aptian, Late Albian). The southern part of the Dinarides was tectonically quiet during the Tithonian through Aptian; sea-level oscillations appear to have been the primary control on facies stacking. Some correlation exists between local sea-level fluctuations and the published global eustasy charts for the Tithonian through Aptian. A significant departure is recognized at the Albian-Cenomanian transition, suggesting that it was influenced by tectonics associated with the disintegration of the Adriatic (Dinaric) platform

Palaeohydrogeological control of palaeokarst macro-porosity genesis during a major sea-level lowstand: Danian of the UrbasaAndia plateau, Navarra, North Spain, 2007, Baceta Juan Ignacio, Wright V. Paul, Beavingtonpenney Simon J. , Pujalte Victoriano

An extensive palaeokarst porosity system, developed during a pronounced mid-Paleocene third-order lowstand of sea level, is hosted in Danian limestones of the Urbasa–Andia plateau in north Spain. These limestones were deposited on a 40–50 km wide rimmed shelf with a margin characterised by coralgal buildups and coarse-grained bioclastic accumulations. The sea-level fall that caused karstification was of approximately 80–90 m magnitude and 2.5 Ma in duration. During the exposure, a 450 m wide belt of sub-vertical margin-parallel fractures developed a few hundred metres inboard of the shelf edge. Most fractures are 90–100 m deep, average 1 m in width, and are associated with large erosional features created by collapse of the reefal margin. Inland from the fracture belt, three superimposed laterally extensive cave systems were formed over a distance of 3.5 km perpendicular to shelf edge, at depths ranging from 8–31 m below the exposure surface. The palaeocaves range from 0.3 to 2 m in height, average 1.5 m high. They show no evidence of meteoric processes and are filled with Thanetian grainstones rich in reworked Microcodium, a lithology that also occurs infilling the fractures. The caves are interpreted as due to active corrosion at the saline water–fresh-water mixing zone. Caves are missing from the shelf edge zone probably because the fractures beheaded the meteoroic lens preventing mixing-zone cave development beyond the fracture zone. Towards the platform interior, each cave system passes into a prominent horizon, averaging 1 m in thickness, of spongy porosity with crystal silt infills and red Fe-oxide coatings. The spongy horizons can be traced for 5.5 km inboard from the cave zone and occur at 10.5 m, 25 m and 32 m below the exposure surface. In the inland zone, two additional horizons with the same spongy dissolution have been recognised at depths of 50 m and 95 m. All are analogous to Swiss-cheese mixing-zone corrosion in modern carbonate aquifers and probably owe their origins to microbiallymediated dissolution effects associated with a zone of reduced circulation in marine phreatic water. In the most landward sections a number of collapse breccia zones are identified, but their origin is unclear. The palaeokarst system as a whole formed during the pulsed rise that followed the initial sea-level drop, with the three main cave-spongy zones representing three successive sea-level stillstands, recorded by stacked parasequences infilling large erosional scallops along the shelf margin. The geometry of the palaeo-mixing zones indicates a low discharge system, and together with the lack of meteoric karstic features favours a semi-arid to arid climatic regime, which is further supported by extensive calcrete-bearing palaeosols occurring in coeval continental deposits.


Palaeohydrogeological control of palaeokarst macro-porosity genesis during a major sea-level lowstand: Danian of the UrbasaAndia plateau, Navarra, North Spain, 2007, Baceta J. I. , Wright V. P. , Beavingtonpenney S. J. , Pujalte V.

An extensive palaeokarst porosity system, developed during a pronounced mid-Paleocene third-order lowstand of sea level, is hosted in Danian limestones of the Urbasa–Andia plateau in north Spain. These limestones were deposited on a 40–50 km wide rimmed shelf with a margin characterised by coralgal buildups and coarse-grained bioclastic accumulations. The sea-level fall that caused karstification was of approximately 80–90 m magnitude and 2.5 Ma in duration. During the exposure, a 450 m wide belt of sub-vertical margin-parallel fractures developed a few hundred metres inboard of the shelf edge. Most fractures are 90–100 m deep, average 1 m in width, and are associated with large erosional features created by collapse of the reefal margin. Inland from the fracture belt, three superimposed laterally extensive cave systems were formed over a distance of 3.5 km perpendicular to shelf edge, at depths ranging from 8–31 m below the exposure surface. The palaeocaves range from 0.3 to 2 m in height, average 1.5 m high. They show no evidence of meteoric processes and are filled with Thanetian grainstones rich in reworked Microcodium, a lithology that also occurs infilling the fractures. The caves are interpreted as due to active corrosion at the saline water–fresh-water mixing zone. Caves are missing from the shelf edge zone probably because the fractures beheaded the meteoroic lens preventing mixing-zone cave development beyond the fracture zone. Towards the platform interior, each cave system passes into a prominent horizon, averaging 1 m in thickness, of spongy porosity with crystal silt infills and red Fe-oxide coatings. The spongy horizons can be traced for 5.5 km inboard from the cave zone and occur at 10.5 m, 25 m and 32 m below the exposure surface. In the inland zone, two additional horizons with the same spongy dissolution have been recognised at depths of 50 m and 95 m. All are analogous to Swiss-cheese mixing-zone corrosion in modern carbonate aquifers and probably owe their origins to microbially mediated dissolution effects associated with a zone of reduced circulation in marine phreatic water. In the most landward sections a number of collapse breccia zones are identified, but their origin is unclear. The palaeokarst system as a whole formed during the pulsed rise that followed the initial sea-level drop, with the three main cave-spongy zones representing three successive sea-level stillstands, recorded by stacked parasequences infilling large erosional scallops along the shelf margin. The geometry of the palaeo mixing zones indicates a low discharge system, and together with the lack of meteoric karstic features favours a semi-arid to arid climatic regime, which is further supported by extensive calcrete-bearing palaeosols occurring in coeval continental deposits.


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